Re: Consumer and offset management support in 0.8.2 and 0.9
Catching up on email - yes the wire protocol change was a big mistake and +1 on this approach. I'm reviewing KAFKA-1841 right now. On Thu, Jan 08, 2015 at 10:07:44PM -0800, Dana Powers wrote: This approach makes sense to me -- thanks, Jun. -Dana On Thu, Jan 8, 2015 at 3:57 PM, Jun Rao j...@confluent.io wrote: I took a stab at fixing this issue in KAFKA-1841. This is actually a bit tricky to fix. In addition to the incompatible wire protocol change of version 0 of OffsetCommitRequest, there is also a functionality change. Specifically, in 0.8.1, version 0 of OffsetCommitRequest writes to ZK and version 0 of OffsetFetchRequest reads from ZK. In 0.8.2/trunk, this is changed to version 0 and version 1 of OffsetCommitRequest writes to Kafka and version 0 of OffsetFetchRequest reads from Kafka. To make this really backward compatible with 0.8.1, we have to (1) revert the wire protocol change of version 0 of OffsetCommitRequest. (2) change the behavior of version 0 of OffsetCommitRequest and OffsetFetchRequest to read from ZK (3) create version 1 of OffsetFetchRequest that reads from Kafka (so that it behaves consistently with version 1 of OffsetCommitRequest) That's what the patch in KAFKA-1841 does. This works as long as people are only using released final version. However, since this introduces an incompatible (functional) change of OffsetFetchRequest in 0.8.2-beta and trunk, this will create problems for people (assuming that they are using this api) who have a deployment of 0.8.2-beta and want to upgrade to 0.8.2 final, or a deployment from trunk and want to upgrade to a later version of trunk in the future. In either case, the upgrade of the broker will cause the old client to behave differently and incorrectly. The only choice there is to stop the client and the broker and upgrade them together. Most people will probably only deploy final released version in production. However, I want to bring this up to see if anyone has concerns on this. Thanks, Jun On Wed, Jan 7, 2015 at 10:32 AM, Jay Kreps jay.kr...@gmail.com wrote: Yes, I think we are saying the same thing. Basically I am saying version 0 should be considered frozen as of the format and behavior in the 0.8.1 release and we can do whatever we want as a version 1+. -Jay On Wed, Jan 7, 2015 at 10:10 AM, Joe Stein joe.st...@stealth.ly wrote: We need to take the versioning of the protocol seriously amen People are definitely using the offset commit functionality in 0.8.1 agreed I really think we should treat this as a bug and revert the change to version 0. What do you mean exactly by revert? Why can't we use version as a feature flag and support 0 and 1 at the same time? in the handleOffsetFetch and handleOffsetCommit functions that process the request messages just do if version == 0 old functionality else if version == 1 new functionality. This way everyone works and nothing breaks =8^) /*** Joe Stein Founder, Principal Consultant Big Data Open Source Security LLC http://www.stealth.ly Twitter: @allthingshadoop http://www.twitter.com/allthingshadoop / On Wed, Jan 7, 2015 at 1:04 PM, Jay Kreps j...@confluent.io wrote: Hey guys, We need to take the versioning of the protocol seriously. People are definitely using the offset commit functionality in 0.8.1 and I really think we should treat this as a bug and revert the change to version 0. -Jay On Wed, Jan 7, 2015 at 9:24 AM, Jun Rao j...@confluent.io wrote: Yes, we did make an incompatible change in OffsetCommitRequest in 0.8.2, which is a mistake. The incompatible change was introduced in KAFKA-1012 in Mar, 2014 when we added the kafka-based offset management support. However, we didn't realize that this breaks the wire protocol until much later. Now, the wire protocol has evolved again and it's a bit hard to fix the format in version 0. I can see a couple of options. Option 1: Just accept the incompatible change as it is. The argument is that even though we introduced OffsetCommitRequest in 0.8.1, it's not used in the high level consumer. It's possible that some users of SimpleConsumer started using it. However, that number is likely small. Also, the functionality of OffsetCommitRequest has changed since it's writing the offset to a Kafka log, instead of ZK (for good reasons). So, we can document this as a wire protocol and functionality incompatible change. For users who don't mind the functionality change, they will need to upgrade the client to the new protocol before they can use the new
Re: Consumer and offset management support in 0.8.2 and 0.9
Hey guys,
We need to take the versioning of the protocol seriously. People are
definitely using the offset commit functionality in 0.8.1 and I really
think we should treat this as a bug and revert the change to version 0.
-Jay
On Wed, Jan 7, 2015 at 9:24 AM, Jun Rao j...@confluent.io wrote:
Yes, we did make an incompatible change in OffsetCommitRequest in 0.8.2,
which is a mistake. The incompatible change was introduced in KAFKA-1012 in
Mar, 2014 when we added the kafka-based offset management support. However,
we didn't realize that this breaks the wire protocol until much later. Now,
the wire protocol has evolved again and it's a bit hard to fix the format
in version 0. I can see a couple of options.
Option 1: Just accept the incompatible change as it is.
The argument is that even though we introduced OffsetCommitRequest in
0.8.1, it's not used in the high level consumer. It's possible that some
users of SimpleConsumer started using it. However, that number is likely
small. Also, the functionality of OffsetCommitRequest has changed since
it's writing the offset to a Kafka log, instead of ZK (for good reasons).
So, we can document this as a wire protocol and functionality incompatible
change. For users who don't mind the functionality change, they will need
to upgrade the client to the new protocol before they can use the new
broker. For users who want to preserve the old functionality, they will
have to write the offsets directly to ZK. In either case, hopefully the
number of people being affected is small.
Option 2: Revert version 0 format to what's in 0.8.1.
There will be a few issues here. First, it's not clear how this affects
other people who have been deploying from trunk. Second, I am not sure that
we want to continue supporting writing the offset to ZK in
OffsetCommitRequest
since that can cause ZK to be overloaded.
Joel Koshy,
Any thoughts on this?
Thanks,
Jun
On Mon, Jan 5, 2015 at 11:39 PM, Joe Stein joe.st...@stealth.ly wrote:
In addition to the issue you bring up, the functionality as a whole has
changed.. when you call OffsetFetchRequest the version = 0 needs to
preserve the old functionality
https://github.com/apache/kafka/blob/0.8.1/core/src/main/scala/kafka/server/KafkaApis.scala#L678-L700
and version = 1 the new
https://github.com/apache/kafka/blob/0.8.2/core/src/main/scala/kafka/server/KafkaApis.scala#L153-L223
.
Also the OffsetFetchRequest functionality even though the wire protocol
is
the same after the 0.8.2 upgrade for OffsetFetchRequest if you were using
0.8.1.1 OffsetFetchRequest
https://github.com/apache/kafka/blob/0.8.1/core/src/main/scala/kafka/server/KafkaApis.scala#L705-L728
will stop going to zookeeper and start going to Kafka storage
https://github.com/apache/kafka/blob/0.8.2/core/src/main/scala/kafka/server/KafkaApis.scala#L504-L519
so more errors will happen and things break too.
I think we should treat the version field not just to stop from breaking
the wire protocol calls but also as a feature flag preserving upgrades
and multiple pathways.
I updated the JIRA for the feature flag needs for OffsetFetch and
OffsetCommit too.
/***
Joe Stein
Founder, Principal Consultant
Big Data Open Source Security LLC
http://www.stealth.ly
Twitter: @allthingshadoop http://www.twitter.com/allthingshadoop
/
On Mon, Jan 5, 2015 at 3:21 PM, Dana Powers dana.pow...@rd.io wrote:
ok, opened KAFKA-1841 . KAFKA-1634 also related.
-Dana
On Mon, Jan 5, 2015 at 10:55 AM, Gwen Shapira gshap...@cloudera.com
wrote:
Ooh, I see what you mean - the OffsetAndMetadata (or PartitionData)
part of the Map changed, which will modify the wire protocol.
This is actually not handled in the Java client either. It will send
the timestamp no matter which version is used.
This looks like a bug and I'd even mark it as blocker for 0.8.2 since
it may prevent rolling upgrades.
Are you opening the JIRA?
Gwen
On Mon, Jan 5, 2015 at 10:28 AM, Dana Powers dana.pow...@rd.io
wrote:
specifically comparing 0.8.1 --
https://github.com/apache/kafka/blob/0.8.1/core/src/main/scala/kafka/api/OffsetCommitRequest.scala#L37-L50
```
(1 to partitionCount).map(_ = {
val partitionId = buffer.getInt
val offset = buffer.getLong
val metadata = readShortString(buffer)
(TopicAndPartition(topic, partitionId),
OffsetMetadataAndError(offset,
metadata))
})
```
totrunk --
https://github.com/apache/kafka/blob/trunk/core/src/main/scala/kafka/api/OffsetCommitRequest.scala#L44-L69
```
(1 to partitionCount).map(_ = {
val partitionId = buffer.getInt
val offset = buffer.getLong
val timestamp = {
val given = buffer.getLong
Re: Consumer and offset management support in 0.8.2 and 0.9
We need to take the versioning of the protocol seriously amen People are definitely using the offset commit functionality in 0.8.1 agreed I really think we should treat this as a bug and revert the change to version 0. What do you mean exactly by revert? Why can't we use version as a feature flag and support 0 and 1 at the same time? in the handleOffsetFetch and handleOffsetCommit functions that process the request messages just do if version == 0 old functionality else if version == 1 new functionality. This way everyone works and nothing breaks =8^) /*** Joe Stein Founder, Principal Consultant Big Data Open Source Security LLC http://www.stealth.ly Twitter: @allthingshadoop http://www.twitter.com/allthingshadoop / On Wed, Jan 7, 2015 at 1:04 PM, Jay Kreps j...@confluent.io wrote: Hey guys, We need to take the versioning of the protocol seriously. People are definitely using the offset commit functionality in 0.8.1 and I really think we should treat this as a bug and revert the change to version 0. -Jay On Wed, Jan 7, 2015 at 9:24 AM, Jun Rao j...@confluent.io wrote: Yes, we did make an incompatible change in OffsetCommitRequest in 0.8.2, which is a mistake. The incompatible change was introduced in KAFKA-1012 in Mar, 2014 when we added the kafka-based offset management support. However, we didn't realize that this breaks the wire protocol until much later. Now, the wire protocol has evolved again and it's a bit hard to fix the format in version 0. I can see a couple of options. Option 1: Just accept the incompatible change as it is. The argument is that even though we introduced OffsetCommitRequest in 0.8.1, it's not used in the high level consumer. It's possible that some users of SimpleConsumer started using it. However, that number is likely small. Also, the functionality of OffsetCommitRequest has changed since it's writing the offset to a Kafka log, instead of ZK (for good reasons). So, we can document this as a wire protocol and functionality incompatible change. For users who don't mind the functionality change, they will need to upgrade the client to the new protocol before they can use the new broker. For users who want to preserve the old functionality, they will have to write the offsets directly to ZK. In either case, hopefully the number of people being affected is small. Option 2: Revert version 0 format to what's in 0.8.1. There will be a few issues here. First, it's not clear how this affects other people who have been deploying from trunk. Second, I am not sure that we want to continue supporting writing the offset to ZK in OffsetCommitRequest since that can cause ZK to be overloaded. Joel Koshy, Any thoughts on this? Thanks, Jun On Mon, Jan 5, 2015 at 11:39 PM, Joe Stein joe.st...@stealth.ly wrote: In addition to the issue you bring up, the functionality as a whole has changed.. when you call OffsetFetchRequest the version = 0 needs to preserve the old functionality https://github.com/apache/kafka/blob/0.8.1/core/src/main/scala/kafka/server/KafkaApis.scala#L678-L700 and version = 1 the new https://github.com/apache/kafka/blob/0.8.2/core/src/main/scala/kafka/server/KafkaApis.scala#L153-L223 . Also the OffsetFetchRequest functionality even though the wire protocol is the same after the 0.8.2 upgrade for OffsetFetchRequest if you were using 0.8.1.1 OffsetFetchRequest https://github.com/apache/kafka/blob/0.8.1/core/src/main/scala/kafka/server/KafkaApis.scala#L705-L728 will stop going to zookeeper and start going to Kafka storage https://github.com/apache/kafka/blob/0.8.2/core/src/main/scala/kafka/server/KafkaApis.scala#L504-L519 so more errors will happen and things break too. I think we should treat the version field not just to stop from breaking the wire protocol calls but also as a feature flag preserving upgrades and multiple pathways. I updated the JIRA for the feature flag needs for OffsetFetch and OffsetCommit too. /*** Joe Stein Founder, Principal Consultant Big Data Open Source Security LLC http://www.stealth.ly Twitter: @allthingshadoop http://www.twitter.com/allthingshadoop / On Mon, Jan 5, 2015 at 3:21 PM, Dana Powers dana.pow...@rd.io wrote: ok, opened KAFKA-1841 . KAFKA-1634 also related. -Dana On Mon, Jan 5, 2015 at 10:55 AM, Gwen Shapira gshap...@cloudera.com wrote: Ooh, I see what you mean - the OffsetAndMetadata (or PartitionData) part of the Map changed, which will modify the wire protocol. This is actually not handled in the Java client either. It will send the timestamp no matter which version is used.
Re: Consumer and offset management support in 0.8.2 and 0.9
Yes, I think we are saying the same thing. Basically I am saying version 0 should be considered frozen as of the format and behavior in the 0.8.1 release and we can do whatever we want as a version 1+. -Jay On Wed, Jan 7, 2015 at 10:10 AM, Joe Stein joe.st...@stealth.ly wrote: We need to take the versioning of the protocol seriously amen People are definitely using the offset commit functionality in 0.8.1 agreed I really think we should treat this as a bug and revert the change to version 0. What do you mean exactly by revert? Why can't we use version as a feature flag and support 0 and 1 at the same time? in the handleOffsetFetch and handleOffsetCommit functions that process the request messages just do if version == 0 old functionality else if version == 1 new functionality. This way everyone works and nothing breaks =8^) /*** Joe Stein Founder, Principal Consultant Big Data Open Source Security LLC http://www.stealth.ly Twitter: @allthingshadoop http://www.twitter.com/allthingshadoop / On Wed, Jan 7, 2015 at 1:04 PM, Jay Kreps j...@confluent.io wrote: Hey guys, We need to take the versioning of the protocol seriously. People are definitely using the offset commit functionality in 0.8.1 and I really think we should treat this as a bug and revert the change to version 0. -Jay On Wed, Jan 7, 2015 at 9:24 AM, Jun Rao j...@confluent.io wrote: Yes, we did make an incompatible change in OffsetCommitRequest in 0.8.2, which is a mistake. The incompatible change was introduced in KAFKA-1012 in Mar, 2014 when we added the kafka-based offset management support. However, we didn't realize that this breaks the wire protocol until much later. Now, the wire protocol has evolved again and it's a bit hard to fix the format in version 0. I can see a couple of options. Option 1: Just accept the incompatible change as it is. The argument is that even though we introduced OffsetCommitRequest in 0.8.1, it's not used in the high level consumer. It's possible that some users of SimpleConsumer started using it. However, that number is likely small. Also, the functionality of OffsetCommitRequest has changed since it's writing the offset to a Kafka log, instead of ZK (for good reasons). So, we can document this as a wire protocol and functionality incompatible change. For users who don't mind the functionality change, they will need to upgrade the client to the new protocol before they can use the new broker. For users who want to preserve the old functionality, they will have to write the offsets directly to ZK. In either case, hopefully the number of people being affected is small. Option 2: Revert version 0 format to what's in 0.8.1. There will be a few issues here. First, it's not clear how this affects other people who have been deploying from trunk. Second, I am not sure that we want to continue supporting writing the offset to ZK in OffsetCommitRequest since that can cause ZK to be overloaded. Joel Koshy, Any thoughts on this? Thanks, Jun On Mon, Jan 5, 2015 at 11:39 PM, Joe Stein joe.st...@stealth.ly wrote: In addition to the issue you bring up, the functionality as a whole has changed.. when you call OffsetFetchRequest the version = 0 needs to preserve the old functionality https://github.com/apache/kafka/blob/0.8.1/core/src/main/scala/kafka/server/KafkaApis.scala#L678-L700 and version = 1 the new https://github.com/apache/kafka/blob/0.8.2/core/src/main/scala/kafka/server/KafkaApis.scala#L153-L223 . Also the OffsetFetchRequest functionality even though the wire protocol is the same after the 0.8.2 upgrade for OffsetFetchRequest if you were using 0.8.1.1 OffsetFetchRequest https://github.com/apache/kafka/blob/0.8.1/core/src/main/scala/kafka/server/KafkaApis.scala#L705-L728 will stop going to zookeeper and start going to Kafka storage https://github.com/apache/kafka/blob/0.8.2/core/src/main/scala/kafka/server/KafkaApis.scala#L504-L519 so more errors will happen and things break too. I think we should treat the version field not just to stop from breaking the wire protocol calls but also as a feature flag preserving upgrades and multiple pathways. I updated the JIRA for the feature flag needs for OffsetFetch and OffsetCommit too. /*** Joe Stein Founder, Principal Consultant Big Data Open Source Security LLC http://www.stealth.ly Twitter: @allthingshadoop http://www.twitter.com/allthingshadoop / On Mon, Jan 5, 2015 at 3:21 PM, Dana Powers dana.pow...@rd.io wrote: ok, opened KAFKA-1841 .
Re: Consumer and offset management support in 0.8.2 and 0.9
Yes, we did make an incompatible change in OffsetCommitRequest in 0.8.2,
which is a mistake. The incompatible change was introduced in KAFKA-1012 in
Mar, 2014 when we added the kafka-based offset management support. However,
we didn't realize that this breaks the wire protocol until much later. Now,
the wire protocol has evolved again and it's a bit hard to fix the format
in version 0. I can see a couple of options.
Option 1: Just accept the incompatible change as it is.
The argument is that even though we introduced OffsetCommitRequest in
0.8.1, it's not used in the high level consumer. It's possible that some
users of SimpleConsumer started using it. However, that number is likely
small. Also, the functionality of OffsetCommitRequest has changed since
it's writing the offset to a Kafka log, instead of ZK (for good reasons).
So, we can document this as a wire protocol and functionality incompatible
change. For users who don't mind the functionality change, they will need
to upgrade the client to the new protocol before they can use the new
broker. For users who want to preserve the old functionality, they will
have to write the offsets directly to ZK. In either case, hopefully the
number of people being affected is small.
Option 2: Revert version 0 format to what's in 0.8.1.
There will be a few issues here. First, it's not clear how this affects
other people who have been deploying from trunk. Second, I am not sure that
we want to continue supporting writing the offset to ZK in OffsetCommitRequest
since that can cause ZK to be overloaded.
Joel Koshy,
Any thoughts on this?
Thanks,
Jun
On Mon, Jan 5, 2015 at 11:39 PM, Joe Stein joe.st...@stealth.ly wrote:
In addition to the issue you bring up, the functionality as a whole has
changed.. when you call OffsetFetchRequest the version = 0 needs to
preserve the old functionality
https://github.com/apache/kafka/blob/0.8.1/core/src/main/scala/kafka/server/KafkaApis.scala#L678-L700
and version = 1 the new
https://github.com/apache/kafka/blob/0.8.2/core/src/main/scala/kafka/server/KafkaApis.scala#L153-L223
.
Also the OffsetFetchRequest functionality even though the wire protocol is
the same after the 0.8.2 upgrade for OffsetFetchRequest if you were using
0.8.1.1 OffsetFetchRequest
https://github.com/apache/kafka/blob/0.8.1/core/src/main/scala/kafka/server/KafkaApis.scala#L705-L728
will stop going to zookeeper and start going to Kafka storage
https://github.com/apache/kafka/blob/0.8.2/core/src/main/scala/kafka/server/KafkaApis.scala#L504-L519
so more errors will happen and things break too.
I think we should treat the version field not just to stop from breaking
the wire protocol calls but also as a feature flag preserving upgrades
and multiple pathways.
I updated the JIRA for the feature flag needs for OffsetFetch and
OffsetCommit too.
/***
Joe Stein
Founder, Principal Consultant
Big Data Open Source Security LLC
http://www.stealth.ly
Twitter: @allthingshadoop http://www.twitter.com/allthingshadoop
/
On Mon, Jan 5, 2015 at 3:21 PM, Dana Powers dana.pow...@rd.io wrote:
ok, opened KAFKA-1841 . KAFKA-1634 also related.
-Dana
On Mon, Jan 5, 2015 at 10:55 AM, Gwen Shapira gshap...@cloudera.com
wrote:
Ooh, I see what you mean - the OffsetAndMetadata (or PartitionData)
part of the Map changed, which will modify the wire protocol.
This is actually not handled in the Java client either. It will send
the timestamp no matter which version is used.
This looks like a bug and I'd even mark it as blocker for 0.8.2 since
it may prevent rolling upgrades.
Are you opening the JIRA?
Gwen
On Mon, Jan 5, 2015 at 10:28 AM, Dana Powers dana.pow...@rd.io
wrote:
specifically comparing 0.8.1 --
https://github.com/apache/kafka/blob/0.8.1/core/src/main/scala/kafka/api/OffsetCommitRequest.scala#L37-L50
```
(1 to partitionCount).map(_ = {
val partitionId = buffer.getInt
val offset = buffer.getLong
val metadata = readShortString(buffer)
(TopicAndPartition(topic, partitionId),
OffsetMetadataAndError(offset,
metadata))
})
```
totrunk --
https://github.com/apache/kafka/blob/trunk/core/src/main/scala/kafka/api/OffsetCommitRequest.scala#L44-L69
```
(1 to partitionCount).map(_ = {
val partitionId = buffer.getInt
val offset = buffer.getLong
val timestamp = {
val given = buffer.getLong
if (given == -1L) now else given
}
val metadata = readShortString(buffer)
(TopicAndPartition(topic, partitionId), OffsetAndMetadata(offset,
metadata, timestamp))
})
```
should the `timestamp` buffer read be wrapped in an api version
check?
Dana Powers
Rdio, Inc.
dana.pow...@rd.io
rdio.com/people/dpkp/
On Mon, Jan 5, 2015 at 9:49 AM, Gwen
Re: Consumer and offset management support in 0.8.2 and 0.9
OffsetCommitRequest has two constructors now: For version 0: OffsetCommitRequest(String groupId, MapTopicPartition, PartitionData offsetData) And version 1: OffsetCommitRequest(String groupId, int generationId, String consumerId, MapTopicPartition, PartitionData offsetData) None of them seem to require timestamps... so I'm not sure where you see that this is required. Can you share an example? Gwen On Sun, Jan 4, 2015 at 11:15 PM, Dana Powers dana.pow...@rd.io wrote: Hi Joel, I'm looking more closely at the OffsetCommitRequest wire protocol change you mentioned below, and I cannot figure out how to explicitly construct a request with the earlier version. Should the api version be different for requests that do not include it and/or servers that do not support the timestamp field? It looks like 0.8.1.1 did not include the timestamp field and used api version 0. But 0.8.2-beta seems to now require timestamps even when I explicitly encode OffsetCommitRequest api version 0 (server logs a BufferUnderflowException). Is this the expected server behavior? Can you provide any tips on how third-party clients should manage the wire-protocol change for this api method (I'm working on kafka-python)? Thanks, -Dana On Tue, Nov 18, 2014 at 1:27 PM, Joel Koshy jjkosh...@gmail.com wrote: Yes it should be backwards compatible. So for e.g., you should be able to use an 0.8.1 client with an 0.8.2 broker. In general, you should not upgrade your clients until after the brokers have been upgraded. However, you can point an 0.8.2 client at an 0.8.1 broker. One wire protocol change I'm aware of is the OffsetCommitRequest. There is a change in the OffsetCommitRequest format (KAFKA-1634) although you can explicitly construct an OffsetCommitRequest with the earlier version. Thanks, Joel On Tue, Nov 18, 2014 at 03:39:41PM -0500, Marius Bogoevici wrote: Hi Joel, Thanks for all the clarifications! Just another question on this: will 0.8.2 be backwards compatible with 0.8.1, just as 0.8.1 was with 0.8? Generally speaking, would there be any concerns with using the 0.8.2 consumer with a 0.8.1 broker, for instance? Marius On Tue, Nov 18, 2014 at 2:55 PM, Joel Koshy jjkosh...@gmail.com wrote: Inline.. On Tue, Nov 18, 2014 at 04:26:04AM -0500, Marius Bogoevici wrote: Hello everyone, I have a few questions about the current status and future of the Kafka consumers. We have been working to adding Kafka support in Spring XD [1], currently using the high level consumer via Spring Integration Kafka [2]. We are working on adding features such as: - the ability to control offsets/replay topics; - the ability to control partition allocation across multiple consumers; We are currently at version 0.8.1.1, so using the simple consumer is a pretty straightforward choice right now. However, in the light of the upcoming consumer changes for 0.8.2 and 0.9, I have a few questions: 1) With respect to the consumer redesign for 0.9, what is the future of the Simple Consumer and High Level Consumer? To my best understanding, the existing high level consumer API will be deprecated in favour of the new consumer API. What is the future of the Simple Consumer, in this case? it will continue to exist as a low-level API implementing the Kafka protocol [3] and providing the building blocks for the new consumer, or will it be deprecated as well? The new consumer will subsume both use-cases (simple and high-level). You can still use the old SimpleConsumer if you wish - i.e., the wire protocol for fetch and other requests will still be supported. 2) Regarding the new consumer: the v0.8.2 codebase contains an early implementation of it, but since this a feature scheduled only for 0.9, what is its status as well? Is it included only as a future reference and for stabilizing the API? It is a WIP so you cannot really use it. 3) Obviously, offset management is a concern if using the simple consumer, so - wondering about the Offset Management API as well. The Kafka protocol document specifically indicates that it will be fully functional in 0.8.2 [4] - however, a functional implementation is already available in 0.8.1.1 (accessible via the SimpleConsumer API but not documented in [5]). Again, trying to understand the extent of what 0.8.1.1 already supports (ostensibly, the offset manager support seems to have been added only in 0.8.2 - please correct me if I am wrong), and whether if it is recommended for use in production in any form (with the caveats that accompany the use of ZooKeeper). In 0.8.2 the OffsetCommitRequest and OffsetFetchRequest will use Kafka as the offsets storage mechanism (not zookeeper). High-level Java consumers can choose to store offsets in ZooKeeper instead
Re: Consumer and offset management support in 0.8.2 and 0.9
Hi Gwen, I am using/writing kafka-python to construct api requests and have not dug too deeply into the server source code. But I believe it is kafka/api/OffsetCommitRequest.scala and specifically the readFrom method used to decode the wire protocol. -Dana OffsetCommitRequest has two constructors now: For version 0: OffsetCommitRequest(String groupId, MapTopicPartition, PartitionData offsetData) And version 1: OffsetCommitRequest(String groupId, int generationId, String consumerId, MapTopicPartition, PartitionData offsetData) None of them seem to require timestamps... so I'm not sure where you see that this is required. Can you share an example? Gwen On Sun, Jan 4, 2015 at 11:15 PM, Dana Powers dana.pow...@rd.io wrote: Hi Joel, I'm looking more closely at the OffsetCommitRequest wire protocol change you mentioned below, and I cannot figure out how to explicitly construct a request with the earlier version. Should the api version be different for requests that do not include it and/or servers that do not support the timestamp field? It looks like 0.8.1.1 did not include the timestamp field and used api version 0. But 0.8.2-beta seems to now require timestamps even when I explicitly encode OffsetCommitRequest api version 0 (server logs a BufferUnderflowException). Is this the expected server behavior? Can you provide any tips on how third-party clients should manage the wire-protocol change for this api method (I'm working on kafka-python)? Thanks, -Dana On Tue, Nov 18, 2014 at 1:27 PM, Joel Koshy jjkosh...@gmail.com wrote: Yes it should be backwards compatible. So for e.g., you should be able to use an 0.8.1 client with an 0.8.2 broker. In general, you should not upgrade your clients until after the brokers have been upgraded. However, you can point an 0.8.2 client at an 0.8.1 broker. One wire protocol change I'm aware of is the OffsetCommitRequest. There is a change in the OffsetCommitRequest format (KAFKA-1634) although you can explicitly construct an OffsetCommitRequest with the earlier version. Thanks, Joel On Tue, Nov 18, 2014 at 03:39:41PM -0500, Marius Bogoevici wrote: Hi Joel, Thanks for all the clarifications! Just another question on this: will 0.8.2 be backwards compatible with 0.8.1, just as 0.8.1 was with 0.8? Generally speaking, would there be any concerns with using the 0.8.2 consumer with a 0.8.1 broker, for instance? Marius On Tue, Nov 18, 2014 at 2:55 PM, Joel Koshy jjkosh...@gmail.com wrote: Inline.. On Tue, Nov 18, 2014 at 04:26:04AM -0500, Marius Bogoevici wrote: Hello everyone, I have a few questions about the current status and future of the Kafka consumers. We have been working to adding Kafka support in Spring XD [1], currently using the high level consumer via Spring Integration Kafka [2]. We are working on adding features such as: - the ability to control offsets/replay topics; - the ability to control partition allocation across multiple consumers; We are currently at version 0.8.1.1, so using the simple consumer is a pretty straightforward choice right now. However, in the light of the upcoming consumer changes for 0.8.2 and 0.9, I have a few questions: 1) With respect to the consumer redesign for 0.9, what is the future of the Simple Consumer and High Level Consumer? To my best understanding, the existing high level consumer API will be deprecated in favour of the new consumer API. What is the future of the Simple Consumer, in this case? it will continue to exist as a low-level API implementing the Kafka protocol [3] and providing the building blocks for the new consumer, or will it be deprecated as well? The new consumer will subsume both use-cases (simple and high-level). You can still use the old SimpleConsumer if you wish - i.e., the wire protocol for fetch and other requests will still be supported. 2) Regarding the new consumer: the v0.8.2 codebase contains an early implementation of it, but since this a feature scheduled only for 0.9, what is its status as well? Is it included only as a future reference and for stabilizing the API? It is a WIP so you cannot really use it. 3) Obviously, offset management is a concern if using the simple consumer, so - wondering about the Offset Management API as well. The Kafka protocol document specifically indicates that it will be fully functional in 0.8.2 [4] - however, a functional implementation is already available in 0.8.1.1 (accessible via the SimpleConsumer API but not documented in [5]). Again, trying to understand the extent of what 0.8.1.1 already supports (ostensibly, the offset manager support seems to have been added only in 0.8.2 - please correct me if I am wrong), and whether if it is recommended for use in production in any form (with the
Re: Consumer and offset management support in 0.8.2 and 0.9
Ah, I see :)
The readFrom function basically tries to read two extra fields if you
are on version 1:
if (versionId == 1) {
groupGenerationId = buffer.getInt
consumerId = readShortString(buffer)
}
The rest looks identical in version 0 and 1, and still no timestamp in sight...
Gwen
On Mon, Jan 5, 2015 at 9:33 AM, Dana Powers dana.pow...@rd.io wrote:
Hi Gwen, I am using/writing kafka-python to construct api requests and have
not dug too deeply into the server source code. But I believe it is
kafka/api/OffsetCommitRequest.scala and specifically the readFrom method
used to decode the wire protocol.
-Dana
OffsetCommitRequest has two constructors now:
For version 0:
OffsetCommitRequest(String groupId, MapTopicPartition,
PartitionData offsetData)
And version 1:
OffsetCommitRequest(String groupId, int generationId, String
consumerId, MapTopicPartition, PartitionData offsetData)
None of them seem to require timestamps... so I'm not sure where you
see that this is required. Can you share an example?
Gwen
On Sun, Jan 4, 2015 at 11:15 PM, Dana Powers dana.pow...@rd.io wrote:
Hi Joel,
I'm looking more closely at the OffsetCommitRequest wire protocol change
you mentioned below, and I cannot figure out how to explicitly construct a
request with the earlier version. Should the api version be different for
requests that do not include it and/or servers that do not support the
timestamp field? It looks like 0.8.1.1 did not include the timestamp
field
and used api version 0. But 0.8.2-beta seems to now require timestamps
even when I explicitly encode OffsetCommitRequest api version 0 (server
logs a BufferUnderflowException).
Is this the expected server behavior? Can you provide any tips on how
third-party clients should manage the wire-protocol change for this api
method (I'm working on kafka-python)?
Thanks,
-Dana
On Tue, Nov 18, 2014 at 1:27 PM, Joel Koshy jjkosh...@gmail.com wrote:
Yes it should be backwards compatible. So for e.g., you should be able
to use an 0.8.1 client with an 0.8.2 broker. In general, you should
not upgrade your clients until after the brokers have been upgraded.
However, you can point an 0.8.2 client at an 0.8.1 broker. One wire
protocol change I'm aware of is the OffsetCommitRequest. There is a
change in the OffsetCommitRequest format (KAFKA-1634) although you can
explicitly construct an OffsetCommitRequest with the earlier version.
Thanks,
Joel
On Tue, Nov 18, 2014 at 03:39:41PM -0500, Marius Bogoevici wrote:
Hi Joel,
Thanks for all the clarifications! Just another question on this: will
0.8.2 be backwards compatible with 0.8.1, just as 0.8.1 was with 0.8?
Generally speaking, would there be any concerns with using the 0.8.2
consumer with a 0.8.1 broker, for instance?
Marius
On Tue, Nov 18, 2014 at 2:55 PM, Joel Koshy jjkosh...@gmail.com
wrote:
Inline..
On Tue, Nov 18, 2014 at 04:26:04AM -0500, Marius Bogoevici wrote:
Hello everyone,
I have a few questions about the current status and future of the
Kafka
consumers.
We have been working to adding Kafka support in Spring XD [1],
currently
using the high level consumer via Spring Integration Kafka [2]. We
are
working on adding features such as:
- the ability to control offsets/replay topics;
- the ability to control partition allocation across multiple
consumers;
We are currently at version 0.8.1.1, so using the simple consumer
is
a
pretty straightforward choice right now. However, in the light of
the
upcoming consumer changes for 0.8.2 and 0.9, I have a few
questions:
1) With respect to the consumer redesign for 0.9, what is the
future
of
the
Simple Consumer and High Level Consumer? To my best understanding,
the
existing high level consumer API will be deprecated in favour of
the
new
consumer API. What is the future of the Simple Consumer, in this
case? it
will continue to exist as a low-level API implementing the Kafka
protocol
[3] and providing the building blocks for the new consumer, or will
it be
deprecated as well?
The new consumer will subsume both use-cases (simple and high-level).
You can still use the old SimpleConsumer if you wish - i.e., the wire
protocol for fetch and other requests will still be supported.
2) Regarding the new consumer: the v0.8.2 codebase contains an
early
implementation of it, but since this a feature scheduled only for
0.9,
what
is its status as well? Is it included only as a future reference
and
for
stabilizing the API?
It is a WIP so you cannot really use it.
3) Obviously, offset management is a concern if using the simple
consumer,
so - wondering about the Offset Management API as well. The Kafka
protocol
document specifically indicates that it will be fully functional in
0.8.2
[4] - however, a functional implementation
Re: Consumer and offset management support in 0.8.2 and 0.9
ok, opened KAFKA-1841 . KAFKA-1634 also related.
-Dana
On Mon, Jan 5, 2015 at 10:55 AM, Gwen Shapira gshap...@cloudera.com wrote:
Ooh, I see what you mean - the OffsetAndMetadata (or PartitionData)
part of the Map changed, which will modify the wire protocol.
This is actually not handled in the Java client either. It will send
the timestamp no matter which version is used.
This looks like a bug and I'd even mark it as blocker for 0.8.2 since
it may prevent rolling upgrades.
Are you opening the JIRA?
Gwen
On Mon, Jan 5, 2015 at 10:28 AM, Dana Powers dana.pow...@rd.io wrote:
specifically comparing 0.8.1 --
https://github.com/apache/kafka/blob/0.8.1/core/src/main/scala/kafka/api/OffsetCommitRequest.scala#L37-L50
```
(1 to partitionCount).map(_ = {
val partitionId = buffer.getInt
val offset = buffer.getLong
val metadata = readShortString(buffer)
(TopicAndPartition(topic, partitionId), OffsetMetadataAndError(offset,
metadata))
})
```
totrunk --
https://github.com/apache/kafka/blob/trunk/core/src/main/scala/kafka/api/OffsetCommitRequest.scala#L44-L69
```
(1 to partitionCount).map(_ = {
val partitionId = buffer.getInt
val offset = buffer.getLong
val timestamp = {
val given = buffer.getLong
if (given == -1L) now else given
}
val metadata = readShortString(buffer)
(TopicAndPartition(topic, partitionId), OffsetAndMetadata(offset,
metadata, timestamp))
})
```
should the `timestamp` buffer read be wrapped in an api version check?
Dana Powers
Rdio, Inc.
dana.pow...@rd.io
rdio.com/people/dpkp/
On Mon, Jan 5, 2015 at 9:49 AM, Gwen Shapira gshap...@cloudera.com
wrote:
Ah, I see :)
The readFrom function basically tries to read two extra fields if you
are on version 1:
if (versionId == 1) {
groupGenerationId = buffer.getInt
consumerId = readShortString(buffer)
}
The rest looks identical in version 0 and 1, and still no timestamp in
sight...
Gwen
On Mon, Jan 5, 2015 at 9:33 AM, Dana Powers dana.pow...@rd.io wrote:
Hi Gwen, I am using/writing kafka-python to construct api requests and
have
not dug too deeply into the server source code. But I believe it is
kafka/api/OffsetCommitRequest.scala and specifically the readFrom
method
used to decode the wire protocol.
-Dana
OffsetCommitRequest has two constructors now:
For version 0:
OffsetCommitRequest(String groupId, MapTopicPartition,
PartitionData offsetData)
And version 1:
OffsetCommitRequest(String groupId, int generationId, String
consumerId, MapTopicPartition, PartitionData offsetData)
None of them seem to require timestamps... so I'm not sure where you
see that this is required. Can you share an example?
Gwen
On Sun, Jan 4, 2015 at 11:15 PM, Dana Powers dana.pow...@rd.io
wrote:
Hi Joel,
I'm looking more closely at the OffsetCommitRequest wire protocol
change
you mentioned below, and I cannot figure out how to explicitly
construct a
request with the earlier version. Should the api version be
different
for
requests that do not include it and/or servers that do not support
the
timestamp field? It looks like 0.8.1.1 did not include the timestamp
field
and used api version 0. But 0.8.2-beta seems to now require
timestamps
even when I explicitly encode OffsetCommitRequest api version 0
(server
logs a BufferUnderflowException).
Is this the expected server behavior? Can you provide any tips on
how
third-party clients should manage the wire-protocol change for this
api
method (I'm working on kafka-python)?
Thanks,
-Dana
On Tue, Nov 18, 2014 at 1:27 PM, Joel Koshy jjkosh...@gmail.com
wrote:
Yes it should be backwards compatible. So for e.g., you should be
able
to use an 0.8.1 client with an 0.8.2 broker. In general, you should
not upgrade your clients until after the brokers have been upgraded.
However, you can point an 0.8.2 client at an 0.8.1 broker. One wire
protocol change I'm aware of is the OffsetCommitRequest. There is a
change in the OffsetCommitRequest format (KAFKA-1634) although you
can
explicitly construct an OffsetCommitRequest with the earlier
version.
Thanks,
Joel
On Tue, Nov 18, 2014 at 03:39:41PM -0500, Marius Bogoevici wrote:
Hi Joel,
Thanks for all the clarifications! Just another question on this:
will
0.8.2 be backwards compatible with 0.8.1, just as 0.8.1 was with
0.8?
Generally speaking, would there be any concerns with using the
0.8.2
consumer with a 0.8.1 broker, for instance?
Marius
On Tue, Nov 18, 2014 at 2:55 PM, Joel Koshy jjkosh...@gmail.com
wrote:
Inline..
On Tue, Nov 18, 2014 at 04:26:04AM -0500, Marius Bogoevici
wrote:
Hello everyone,
I have a few questions about the current status and future of
Re: Consumer and offset management support in 0.8.2 and 0.9
specifically comparing 0.8.1 --
https://github.com/apache/kafka/blob/0.8.1/core/src/main/scala/kafka/api/OffsetCommitRequest.scala#L37-L50
```
(1 to partitionCount).map(_ = {
val partitionId = buffer.getInt
val offset = buffer.getLong
val metadata = readShortString(buffer)
(TopicAndPartition(topic, partitionId), OffsetMetadataAndError(offset,
metadata))
})
```
totrunk --
https://github.com/apache/kafka/blob/trunk/core/src/main/scala/kafka/api/OffsetCommitRequest.scala#L44-L69
```
(1 to partitionCount).map(_ = {
val partitionId = buffer.getInt
val offset = buffer.getLong
val timestamp = {
val given = buffer.getLong
if (given == -1L) now else given
}
val metadata = readShortString(buffer)
(TopicAndPartition(topic, partitionId), OffsetAndMetadata(offset,
metadata, timestamp))
})
```
should the `timestamp` buffer read be wrapped in an api version check?
Dana Powers
Rdio, Inc.
dana.pow...@rd.io
rdio.com/people/dpkp/
On Mon, Jan 5, 2015 at 9:49 AM, Gwen Shapira gshap...@cloudera.com wrote:
Ah, I see :)
The readFrom function basically tries to read two extra fields if you
are on version 1:
if (versionId == 1) {
groupGenerationId = buffer.getInt
consumerId = readShortString(buffer)
}
The rest looks identical in version 0 and 1, and still no timestamp in
sight...
Gwen
On Mon, Jan 5, 2015 at 9:33 AM, Dana Powers dana.pow...@rd.io wrote:
Hi Gwen, I am using/writing kafka-python to construct api requests and
have
not dug too deeply into the server source code. But I believe it is
kafka/api/OffsetCommitRequest.scala and specifically the readFrom method
used to decode the wire protocol.
-Dana
OffsetCommitRequest has two constructors now:
For version 0:
OffsetCommitRequest(String groupId, MapTopicPartition,
PartitionData offsetData)
And version 1:
OffsetCommitRequest(String groupId, int generationId, String
consumerId, MapTopicPartition, PartitionData offsetData)
None of them seem to require timestamps... so I'm not sure where you
see that this is required. Can you share an example?
Gwen
On Sun, Jan 4, 2015 at 11:15 PM, Dana Powers dana.pow...@rd.io wrote:
Hi Joel,
I'm looking more closely at the OffsetCommitRequest wire protocol change
you mentioned below, and I cannot figure out how to explicitly
construct a
request with the earlier version. Should the api version be different
for
requests that do not include it and/or servers that do not support the
timestamp field? It looks like 0.8.1.1 did not include the timestamp
field
and used api version 0. But 0.8.2-beta seems to now require timestamps
even when I explicitly encode OffsetCommitRequest api version 0 (server
logs a BufferUnderflowException).
Is this the expected server behavior? Can you provide any tips on how
third-party clients should manage the wire-protocol change for this api
method (I'm working on kafka-python)?
Thanks,
-Dana
On Tue, Nov 18, 2014 at 1:27 PM, Joel Koshy jjkosh...@gmail.com
wrote:
Yes it should be backwards compatible. So for e.g., you should be able
to use an 0.8.1 client with an 0.8.2 broker. In general, you should
not upgrade your clients until after the brokers have been upgraded.
However, you can point an 0.8.2 client at an 0.8.1 broker. One wire
protocol change I'm aware of is the OffsetCommitRequest. There is a
change in the OffsetCommitRequest format (KAFKA-1634) although you can
explicitly construct an OffsetCommitRequest with the earlier version.
Thanks,
Joel
On Tue, Nov 18, 2014 at 03:39:41PM -0500, Marius Bogoevici wrote:
Hi Joel,
Thanks for all the clarifications! Just another question on this:
will
0.8.2 be backwards compatible with 0.8.1, just as 0.8.1 was with 0.8?
Generally speaking, would there be any concerns with using the 0.8.2
consumer with a 0.8.1 broker, for instance?
Marius
On Tue, Nov 18, 2014 at 2:55 PM, Joel Koshy jjkosh...@gmail.com
wrote:
Inline..
On Tue, Nov 18, 2014 at 04:26:04AM -0500, Marius Bogoevici wrote:
Hello everyone,
I have a few questions about the current status and future of the
Kafka
consumers.
We have been working to adding Kafka support in Spring XD [1],
currently
using the high level consumer via Spring Integration Kafka [2].
We
are
working on adding features such as:
- the ability to control offsets/replay topics;
- the ability to control partition allocation across multiple
consumers;
We are currently at version 0.8.1.1, so using the simple consumer
is
a
pretty straightforward choice right now. However, in the light of
the
upcoming consumer changes for 0.8.2 and 0.9, I have a few
questions:
1) With respect to the consumer redesign for 0.9, what is the
future
of
the
Simple Consumer and High Level Consumer? To my best
understanding,
the
Re: Consumer and offset management support in 0.8.2 and 0.9
Ooh, I see what you mean - the OffsetAndMetadata (or PartitionData)
part of the Map changed, which will modify the wire protocol.
This is actually not handled in the Java client either. It will send
the timestamp no matter which version is used.
This looks like a bug and I'd even mark it as blocker for 0.8.2 since
it may prevent rolling upgrades.
Are you opening the JIRA?
Gwen
On Mon, Jan 5, 2015 at 10:28 AM, Dana Powers dana.pow...@rd.io wrote:
specifically comparing 0.8.1 --
https://github.com/apache/kafka/blob/0.8.1/core/src/main/scala/kafka/api/OffsetCommitRequest.scala#L37-L50
```
(1 to partitionCount).map(_ = {
val partitionId = buffer.getInt
val offset = buffer.getLong
val metadata = readShortString(buffer)
(TopicAndPartition(topic, partitionId), OffsetMetadataAndError(offset,
metadata))
})
```
totrunk --
https://github.com/apache/kafka/blob/trunk/core/src/main/scala/kafka/api/OffsetCommitRequest.scala#L44-L69
```
(1 to partitionCount).map(_ = {
val partitionId = buffer.getInt
val offset = buffer.getLong
val timestamp = {
val given = buffer.getLong
if (given == -1L) now else given
}
val metadata = readShortString(buffer)
(TopicAndPartition(topic, partitionId), OffsetAndMetadata(offset,
metadata, timestamp))
})
```
should the `timestamp` buffer read be wrapped in an api version check?
Dana Powers
Rdio, Inc.
dana.pow...@rd.io
rdio.com/people/dpkp/
On Mon, Jan 5, 2015 at 9:49 AM, Gwen Shapira gshap...@cloudera.com wrote:
Ah, I see :)
The readFrom function basically tries to read two extra fields if you
are on version 1:
if (versionId == 1) {
groupGenerationId = buffer.getInt
consumerId = readShortString(buffer)
}
The rest looks identical in version 0 and 1, and still no timestamp in
sight...
Gwen
On Mon, Jan 5, 2015 at 9:33 AM, Dana Powers dana.pow...@rd.io wrote:
Hi Gwen, I am using/writing kafka-python to construct api requests and
have
not dug too deeply into the server source code. But I believe it is
kafka/api/OffsetCommitRequest.scala and specifically the readFrom method
used to decode the wire protocol.
-Dana
OffsetCommitRequest has two constructors now:
For version 0:
OffsetCommitRequest(String groupId, MapTopicPartition,
PartitionData offsetData)
And version 1:
OffsetCommitRequest(String groupId, int generationId, String
consumerId, MapTopicPartition, PartitionData offsetData)
None of them seem to require timestamps... so I'm not sure where you
see that this is required. Can you share an example?
Gwen
On Sun, Jan 4, 2015 at 11:15 PM, Dana Powers dana.pow...@rd.io wrote:
Hi Joel,
I'm looking more closely at the OffsetCommitRequest wire protocol change
you mentioned below, and I cannot figure out how to explicitly
construct a
request with the earlier version. Should the api version be different
for
requests that do not include it and/or servers that do not support the
timestamp field? It looks like 0.8.1.1 did not include the timestamp
field
and used api version 0. But 0.8.2-beta seems to now require timestamps
even when I explicitly encode OffsetCommitRequest api version 0 (server
logs a BufferUnderflowException).
Is this the expected server behavior? Can you provide any tips on how
third-party clients should manage the wire-protocol change for this api
method (I'm working on kafka-python)?
Thanks,
-Dana
On Tue, Nov 18, 2014 at 1:27 PM, Joel Koshy jjkosh...@gmail.com
wrote:
Yes it should be backwards compatible. So for e.g., you should be able
to use an 0.8.1 client with an 0.8.2 broker. In general, you should
not upgrade your clients until after the brokers have been upgraded.
However, you can point an 0.8.2 client at an 0.8.1 broker. One wire
protocol change I'm aware of is the OffsetCommitRequest. There is a
change in the OffsetCommitRequest format (KAFKA-1634) although you can
explicitly construct an OffsetCommitRequest with the earlier version.
Thanks,
Joel
On Tue, Nov 18, 2014 at 03:39:41PM -0500, Marius Bogoevici wrote:
Hi Joel,
Thanks for all the clarifications! Just another question on this:
will
0.8.2 be backwards compatible with 0.8.1, just as 0.8.1 was with 0.8?
Generally speaking, would there be any concerns with using the 0.8.2
consumer with a 0.8.1 broker, for instance?
Marius
On Tue, Nov 18, 2014 at 2:55 PM, Joel Koshy jjkosh...@gmail.com
wrote:
Inline..
On Tue, Nov 18, 2014 at 04:26:04AM -0500, Marius Bogoevici wrote:
Hello everyone,
I have a few questions about the current status and future of the
Kafka
consumers.
We have been working to adding Kafka support in Spring XD [1],
currently
using the high level consumer via Spring Integration Kafka [2].
We
are
working on adding features such as:
- the ability to control offsets/replay topics;
- the
Re: Consumer and offset management support in 0.8.2 and 0.9
Hi Joel, I'm looking more closely at the OffsetCommitRequest wire protocol change you mentioned below, and I cannot figure out how to explicitly construct a request with the earlier version. Should the api version be different for requests that do not include it and/or servers that do not support the timestamp field? It looks like 0.8.1.1 did not include the timestamp field and used api version 0. But 0.8.2-beta seems to now require timestamps even when I explicitly encode OffsetCommitRequest api version 0 (server logs a BufferUnderflowException). Is this the expected server behavior? Can you provide any tips on how third-party clients should manage the wire-protocol change for this api method (I'm working on kafka-python)? Thanks, -Dana On Tue, Nov 18, 2014 at 1:27 PM, Joel Koshy jjkosh...@gmail.com wrote: Yes it should be backwards compatible. So for e.g., you should be able to use an 0.8.1 client with an 0.8.2 broker. In general, you should not upgrade your clients until after the brokers have been upgraded. However, you can point an 0.8.2 client at an 0.8.1 broker. One wire protocol change I'm aware of is the OffsetCommitRequest. There is a change in the OffsetCommitRequest format (KAFKA-1634) although you can explicitly construct an OffsetCommitRequest with the earlier version. Thanks, Joel On Tue, Nov 18, 2014 at 03:39:41PM -0500, Marius Bogoevici wrote: Hi Joel, Thanks for all the clarifications! Just another question on this: will 0.8.2 be backwards compatible with 0.8.1, just as 0.8.1 was with 0.8? Generally speaking, would there be any concerns with using the 0.8.2 consumer with a 0.8.1 broker, for instance? Marius On Tue, Nov 18, 2014 at 2:55 PM, Joel Koshy jjkosh...@gmail.com wrote: Inline.. On Tue, Nov 18, 2014 at 04:26:04AM -0500, Marius Bogoevici wrote: Hello everyone, I have a few questions about the current status and future of the Kafka consumers. We have been working to adding Kafka support in Spring XD [1], currently using the high level consumer via Spring Integration Kafka [2]. We are working on adding features such as: - the ability to control offsets/replay topics; - the ability to control partition allocation across multiple consumers; We are currently at version 0.8.1.1, so using the simple consumer is a pretty straightforward choice right now. However, in the light of the upcoming consumer changes for 0.8.2 and 0.9, I have a few questions: 1) With respect to the consumer redesign for 0.9, what is the future of the Simple Consumer and High Level Consumer? To my best understanding, the existing high level consumer API will be deprecated in favour of the new consumer API. What is the future of the Simple Consumer, in this case? it will continue to exist as a low-level API implementing the Kafka protocol [3] and providing the building blocks for the new consumer, or will it be deprecated as well? The new consumer will subsume both use-cases (simple and high-level). You can still use the old SimpleConsumer if you wish - i.e., the wire protocol for fetch and other requests will still be supported. 2) Regarding the new consumer: the v0.8.2 codebase contains an early implementation of it, but since this a feature scheduled only for 0.9, what is its status as well? Is it included only as a future reference and for stabilizing the API? It is a WIP so you cannot really use it. 3) Obviously, offset management is a concern if using the simple consumer, so - wondering about the Offset Management API as well. The Kafka protocol document specifically indicates that it will be fully functional in 0.8.2 [4] - however, a functional implementation is already available in 0.8.1.1 (accessible via the SimpleConsumer API but not documented in [5]). Again, trying to understand the extent of what 0.8.1.1 already supports (ostensibly, the offset manager support seems to have been added only in 0.8.2 - please correct me if I am wrong), and whether if it is recommended for use in production in any form (with the caveats that accompany the use of ZooKeeper). In 0.8.2 the OffsetCommitRequest and OffsetFetchRequest will use Kafka as the offsets storage mechanism (not zookeeper). High-level Java consumers can choose to store offsets in ZooKeeper instead by setting offsets.storage=zookeeper However, if you are using the simple consumer and wish to store offsets in ZooKeeper you will need to commit to ZooKeeper directly. You can use ZkUtils in the kafka.utils package for this. If you wish to move to Kafka-based offsets we will be adding a new OffsetsClient that can be used to commit/fetch offsets to/from Kafka. This is currently not listed as a blocker for 0.8.2 but I think we should include it. I will update
Re: Consumer and offset management support in 0.8.2 and 0.9
Inline.. On Tue, Nov 18, 2014 at 04:26:04AM -0500, Marius Bogoevici wrote: Hello everyone, I have a few questions about the current status and future of the Kafka consumers. We have been working to adding Kafka support in Spring XD [1], currently using the high level consumer via Spring Integration Kafka [2]. We are working on adding features such as: - the ability to control offsets/replay topics; - the ability to control partition allocation across multiple consumers; We are currently at version 0.8.1.1, so using the simple consumer is a pretty straightforward choice right now. However, in the light of the upcoming consumer changes for 0.8.2 and 0.9, I have a few questions: 1) With respect to the consumer redesign for 0.9, what is the future of the Simple Consumer and High Level Consumer? To my best understanding, the existing high level consumer API will be deprecated in favour of the new consumer API. What is the future of the Simple Consumer, in this case? it will continue to exist as a low-level API implementing the Kafka protocol [3] and providing the building blocks for the new consumer, or will it be deprecated as well? The new consumer will subsume both use-cases (simple and high-level). You can still use the old SimpleConsumer if you wish - i.e., the wire protocol for fetch and other requests will still be supported. 2) Regarding the new consumer: the v0.8.2 codebase contains an early implementation of it, but since this a feature scheduled only for 0.9, what is its status as well? Is it included only as a future reference and for stabilizing the API? It is a WIP so you cannot really use it. 3) Obviously, offset management is a concern if using the simple consumer, so - wondering about the Offset Management API as well. The Kafka protocol document specifically indicates that it will be fully functional in 0.8.2 [4] - however, a functional implementation is already available in 0.8.1.1 (accessible via the SimpleConsumer API but not documented in [5]). Again, trying to understand the extent of what 0.8.1.1 already supports (ostensibly, the offset manager support seems to have been added only in 0.8.2 - please correct me if I am wrong), and whether if it is recommended for use in production in any form (with the caveats that accompany the use of ZooKeeper). In 0.8.2 the OffsetCommitRequest and OffsetFetchRequest will use Kafka as the offsets storage mechanism (not zookeeper). High-level Java consumers can choose to store offsets in ZooKeeper instead by setting offsets.storage=zookeeper However, if you are using the simple consumer and wish to store offsets in ZooKeeper you will need to commit to ZooKeeper directly. You can use ZkUtils in the kafka.utils package for this. If you wish to move to Kafka-based offsets we will be adding a new OffsetsClient that can be used to commit/fetch offsets to/from Kafka. This is currently not listed as a blocker for 0.8.2 but I think we should include it. I will update that ticket. 4) Trying to interpret the existing examples in [6] and the comments on [7] - the version of the Offset Management API that exists in 0.8.1.1 is using ZooKeeper - whereas ZooKeeper will be optional in 0.8.2 - to be replaced by Kafka, and phased out if possible. To my understanding, the switch between the two will be controlled by the broker configuration (along with other parameters that control the performance of offset queues. Is that correct? The switch is a client-side configuration. That wiki is not up-to-date. The most current documentation is available as a patch in https://issues.apache.org/jira/browse/KAFKA-1729 5) Also, wondering about the timeline of 0.8.2 - according to the roadmaps it should be released relatively shortly. Is that correct? Yes - once the blockers are ironed out. Thanks, Marius [1] http://projects.spring.io/spring-xd/ [2] https://github.com/spring-projects/spring-integration-kafka [3] https://cwiki.apache.org/confluence/display/KAFKA/A+Guide+To+The+Kafka+Protocol [4] https://cwiki.apache.org/confluence/display/KAFKA/A+Guide+To+The+Kafka+Protocol#AGuideToTheKafkaProtocol-OffsetCommit/FetchAPI [5] http://kafka.apache.org/082/documentation.html#simpleconsumerapi [6] https://cwiki.apache.org/confluence/display/KAFKA/Committing+and+fetching+consumer+offsets+in+Kafka [7] https://issues.apache.org/jira/browse/KAFKA-1729
Re: Consumer and offset management support in 0.8.2 and 0.9
Hi Joel, Thanks for all the clarifications! Just another question on this: will 0.8.2 be backwards compatible with 0.8.1, just as 0.8.1 was with 0.8? Generally speaking, would there be any concerns with using the 0.8.2 consumer with a 0.8.1 broker, for instance? Marius On Tue, Nov 18, 2014 at 2:55 PM, Joel Koshy jjkosh...@gmail.com wrote: Inline.. On Tue, Nov 18, 2014 at 04:26:04AM -0500, Marius Bogoevici wrote: Hello everyone, I have a few questions about the current status and future of the Kafka consumers. We have been working to adding Kafka support in Spring XD [1], currently using the high level consumer via Spring Integration Kafka [2]. We are working on adding features such as: - the ability to control offsets/replay topics; - the ability to control partition allocation across multiple consumers; We are currently at version 0.8.1.1, so using the simple consumer is a pretty straightforward choice right now. However, in the light of the upcoming consumer changes for 0.8.2 and 0.9, I have a few questions: 1) With respect to the consumer redesign for 0.9, what is the future of the Simple Consumer and High Level Consumer? To my best understanding, the existing high level consumer API will be deprecated in favour of the new consumer API. What is the future of the Simple Consumer, in this case? it will continue to exist as a low-level API implementing the Kafka protocol [3] and providing the building blocks for the new consumer, or will it be deprecated as well? The new consumer will subsume both use-cases (simple and high-level). You can still use the old SimpleConsumer if you wish - i.e., the wire protocol for fetch and other requests will still be supported. 2) Regarding the new consumer: the v0.8.2 codebase contains an early implementation of it, but since this a feature scheduled only for 0.9, what is its status as well? Is it included only as a future reference and for stabilizing the API? It is a WIP so you cannot really use it. 3) Obviously, offset management is a concern if using the simple consumer, so - wondering about the Offset Management API as well. The Kafka protocol document specifically indicates that it will be fully functional in 0.8.2 [4] - however, a functional implementation is already available in 0.8.1.1 (accessible via the SimpleConsumer API but not documented in [5]). Again, trying to understand the extent of what 0.8.1.1 already supports (ostensibly, the offset manager support seems to have been added only in 0.8.2 - please correct me if I am wrong), and whether if it is recommended for use in production in any form (with the caveats that accompany the use of ZooKeeper). In 0.8.2 the OffsetCommitRequest and OffsetFetchRequest will use Kafka as the offsets storage mechanism (not zookeeper). High-level Java consumers can choose to store offsets in ZooKeeper instead by setting offsets.storage=zookeeper However, if you are using the simple consumer and wish to store offsets in ZooKeeper you will need to commit to ZooKeeper directly. You can use ZkUtils in the kafka.utils package for this. If you wish to move to Kafka-based offsets we will be adding a new OffsetsClient that can be used to commit/fetch offsets to/from Kafka. This is currently not listed as a blocker for 0.8.2 but I think we should include it. I will update that ticket. 4) Trying to interpret the existing examples in [6] and the comments on [7] - the version of the Offset Management API that exists in 0.8.1.1 is using ZooKeeper - whereas ZooKeeper will be optional in 0.8.2 - to be replaced by Kafka, and phased out if possible. To my understanding, the switch between the two will be controlled by the broker configuration (along with other parameters that control the performance of offset queues. Is that correct? The switch is a client-side configuration. That wiki is not up-to-date. The most current documentation is available as a patch in https://issues.apache.org/jira/browse/KAFKA-1729 5) Also, wondering about the timeline of 0.8.2 - according to the roadmaps it should be released relatively shortly. Is that correct? Yes - once the blockers are ironed out. Thanks, Marius [1] http://projects.spring.io/spring-xd/ [2] https://github.com/spring-projects/spring-integration-kafka [3] https://cwiki.apache.org/confluence/display/KAFKA/A+Guide+To+The+Kafka+Protocol [4] https://cwiki.apache.org/confluence/display/KAFKA/A+Guide+To+The+Kafka+Protocol#AGuideToTheKafkaProtocol-OffsetCommit/FetchAPI [5] http://kafka.apache.org/082/documentation.html#simpleconsumerapi [6] https://cwiki.apache.org/confluence/display/KAFKA/Committing+and+fetching+consumer+offsets+in+Kafka [7] https://issues.apache.org/jira/browse/KAFKA-1729
Re: Consumer and offset management support in 0.8.2 and 0.9
Yes it should be backwards compatible. So for e.g., you should be able to use an 0.8.1 client with an 0.8.2 broker. In general, you should not upgrade your clients until after the brokers have been upgraded. However, you can point an 0.8.2 client at an 0.8.1 broker. One wire protocol change I'm aware of is the OffsetCommitRequest. There is a change in the OffsetCommitRequest format (KAFKA-1634) although you can explicitly construct an OffsetCommitRequest with the earlier version. Thanks, Joel On Tue, Nov 18, 2014 at 03:39:41PM -0500, Marius Bogoevici wrote: Hi Joel, Thanks for all the clarifications! Just another question on this: will 0.8.2 be backwards compatible with 0.8.1, just as 0.8.1 was with 0.8? Generally speaking, would there be any concerns with using the 0.8.2 consumer with a 0.8.1 broker, for instance? Marius On Tue, Nov 18, 2014 at 2:55 PM, Joel Koshy jjkosh...@gmail.com wrote: Inline.. On Tue, Nov 18, 2014 at 04:26:04AM -0500, Marius Bogoevici wrote: Hello everyone, I have a few questions about the current status and future of the Kafka consumers. We have been working to adding Kafka support in Spring XD [1], currently using the high level consumer via Spring Integration Kafka [2]. We are working on adding features such as: - the ability to control offsets/replay topics; - the ability to control partition allocation across multiple consumers; We are currently at version 0.8.1.1, so using the simple consumer is a pretty straightforward choice right now. However, in the light of the upcoming consumer changes for 0.8.2 and 0.9, I have a few questions: 1) With respect to the consumer redesign for 0.9, what is the future of the Simple Consumer and High Level Consumer? To my best understanding, the existing high level consumer API will be deprecated in favour of the new consumer API. What is the future of the Simple Consumer, in this case? it will continue to exist as a low-level API implementing the Kafka protocol [3] and providing the building blocks for the new consumer, or will it be deprecated as well? The new consumer will subsume both use-cases (simple and high-level). You can still use the old SimpleConsumer if you wish - i.e., the wire protocol for fetch and other requests will still be supported. 2) Regarding the new consumer: the v0.8.2 codebase contains an early implementation of it, but since this a feature scheduled only for 0.9, what is its status as well? Is it included only as a future reference and for stabilizing the API? It is a WIP so you cannot really use it. 3) Obviously, offset management is a concern if using the simple consumer, so - wondering about the Offset Management API as well. The Kafka protocol document specifically indicates that it will be fully functional in 0.8.2 [4] - however, a functional implementation is already available in 0.8.1.1 (accessible via the SimpleConsumer API but not documented in [5]). Again, trying to understand the extent of what 0.8.1.1 already supports (ostensibly, the offset manager support seems to have been added only in 0.8.2 - please correct me if I am wrong), and whether if it is recommended for use in production in any form (with the caveats that accompany the use of ZooKeeper). In 0.8.2 the OffsetCommitRequest and OffsetFetchRequest will use Kafka as the offsets storage mechanism (not zookeeper). High-level Java consumers can choose to store offsets in ZooKeeper instead by setting offsets.storage=zookeeper However, if you are using the simple consumer and wish to store offsets in ZooKeeper you will need to commit to ZooKeeper directly. You can use ZkUtils in the kafka.utils package for this. If you wish to move to Kafka-based offsets we will be adding a new OffsetsClient that can be used to commit/fetch offsets to/from Kafka. This is currently not listed as a blocker for 0.8.2 but I think we should include it. I will update that ticket. 4) Trying to interpret the existing examples in [6] and the comments on [7] - the version of the Offset Management API that exists in 0.8.1.1 is using ZooKeeper - whereas ZooKeeper will be optional in 0.8.2 - to be replaced by Kafka, and phased out if possible. To my understanding, the switch between the two will be controlled by the broker configuration (along with other parameters that control the performance of offset queues. Is that correct? The switch is a client-side configuration. That wiki is not up-to-date. The most current documentation is available as a patch in https://issues.apache.org/jira/browse/KAFKA-1729 5) Also, wondering about the timeline of 0.8.2 - according to the roadmaps it should be released relatively shortly. Is that correct? Yes - once the blockers are ironed out. Thanks, Marius [1]
