GitHub user zsxwing opened a pull request:
https://github.com/apache/spark/pull/15367
[SPARK-17346][SQL] Add Kafka source for Structured Streaming (branch 2.0)
## What changes were proposed in this pull request?
Backport
https://github.com/apache/spark/commit/9293734d35eb3d6e4fd4ebb86f54dd5d3a35e6db
into branch 2.0.
The only difference is the Spark version in pom file.
## How was this patch tested?
Jenkins.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/zsxwing/spark kafka-source-branch-2.0
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/15367.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #15367
----
commit 17e6b5c3fb702e66748634260670f4f843aa38fe
Author: Shixiong Zhu <shixi...@databricks.com>
Date: 2016-10-05T23:45:45Z
[SPARK-17346][SQL] Add Kafka source for Structured Streaming
## What changes were proposed in this pull request?
This PR adds a new project ` external/kafka-0-10-sql` for Structured
Streaming Kafka source.
It's based on the design doc:
https://docs.google.com/document/d/19t2rWe51x7tq2e5AOfrsM9qb8_m7BRuv9fel9i0PqR8/edit?usp=sharing
tdas did most of work and part of them was inspired by koeninger's work.
### Introduction
The Kafka source is a structured streaming data source to poll data from
Kafka. The schema of reading data is as follows:
Column | Type
---- | ----
key | binary
value | binary
topic | string
partition | int
offset | long
timestamp | long
timestampType | int
The source can deal with deleting topics. However, the user should make
sure there is no Spark job processing the data when deleting a topic.
### Configuration
The user can use `DataStreamReader.option` to set the following
configurations.
Kafka Source's options | value | default | meaning
------ | ------- | ------ | -----
startingOffset | ["earliest", "latest"] | "latest" | The start point when a
query is started, either "earliest" which is from the earliest offset, or
"latest" which is just from the latest offset. Note: This only applies when a
new Streaming query is started, and that resuming will always pick up from
where the query left off.
failOnDataLost | [true, false] | true | Whether to fail the query when it's
possible that data is lost (e.g., topics are deleted, or offsets are out of
range). This may be a false alarm. You can disable it when it doesn't work as
you expected.
subscribe | A comma-separated list of topics | (none) | The topic list to
subscribe. Only one of "subscribe" and "subscribeParttern" options can be
specified for Kafka source.
subscribePattern | Java regex string | (none) | The pattern used to
subscribe the topic. Only one of "subscribe" and "subscribeParttern" options
can be specified for Kafka source.
kafka.consumer.poll.timeoutMs | long | 512 | The timeout in milliseconds to
poll data from Kafka in executors
fetchOffset.numRetries | int | 3 | Number of times to retry before giving
up fatch Kafka latest offsets.
fetchOffset.retryIntervalMs | long | 10 | milliseconds to wait before
retrying to fetch Kafka offsets
Kafka's own configurations can be set via `DataStreamReader.option` with
`kafka.` prefix, e.g, `stream.option("kafka.bootstrap.servers", "host:port")`
### Usage
* Subscribe to 1 topic
```Scala
spark
.readStream
.format("kafka")
.option("kafka.bootstrap.servers", "host:port")
.option("subscribe", "topic1")
.load()
```
* Subscribe to multiple topics
```Scala
spark
.readStream
.format("kafka")
.option("kafka.bootstrap.servers", "host:port")
.option("subscribe", "topic1,topic2")
.load()
```
* Subscribe to a pattern
```Scala
spark
.readStream
.format("kafka")
.option("kafka.bootstrap.servers", "host:port")
.option("subscribePattern", "topic.*")
.load()
```
## How was this patch tested?
The new unit tests.
Author: Shixiong Zhu <shixi...@databricks.com>
Author: Tathagata Das <tathagata.das1...@gmail.com>
Author: Shixiong Zhu <zsxw...@gmail.com>
Author: cody koeninger <c...@koeninger.org>
Closes #15102 from zsxwing/kafka-source.
commit a560190dba618698ae2d9728e8b35c5954772467
Author: Shixiong Zhu <shixi...@databricks.com>
Date: 2016-10-06T00:02:12Z
Fix version
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