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https://issues.apache.org/jira/browse/KAFKA-14565?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Terry Beard updated KAFKA-14565:
--------------------------------
Description:
The Consumer and Producer interceptor interfaces and their corresponding Kafka
Consumer and Producer constructors do not adequately support cleanup of
underlying interceptor resources.
Currently within the Kafka Consumer and Kafka Producer constructors, the
*AbstractConfig.getConfiguredInstances()* is delegated responsibility for both
creating and configuring each interceptor listed in the interceptor.classes
property and returns a configured *List<ConsumerInterceptor<K,V>>*
interceptors.
This dual responsibility for both creation and configuration is problematic
when it involves multiple interceptors where at least one interceptor's
configure method implementation creates and/or depends on objects which creates
threads, connections or other resources which requires clean up and the
subsequent interceptor's configure method raises a runtime exception. This
raising of the runtime exception produces a resource leakage in the first
interceptor as the interceptor container i.e.
ConsumerInterceptors/ProducerInterceptors is never created and therefore the
first interceptor's and really any interceptor's close method are never called.
To help ensure the respective container interceptors are able to invoke their
respective interceptor close methods for proper resource clean up, I propose
two approaches:
+*PROPOSAL 1*+
Define a default *open* or *configureWithResources()* or *acquireResources()*
method with no implementation and check exception on the respective
Consumer/Producer interceptor interfaces. This method as a part the
interceptor life cycle management will be responsible for creating threads
and/or objects which utilizes threads, connections or other resource which
requires clean up. Additionally, this default method enables implementation
optionality as it's empty default behavior means it will do nothing when
unimplemented mitigating backwards compatibility impact to exiting
interceptors. Finally, the Kafka Consumer/Producer Interceptor containers will
implement a corresponding *maybeOpen* or *maybeConfigureWithResources* or
*maybeAcquireResources* method which also throws a checked exception.
See below code excerpt for the Consumer/Producer constructor:
{code:java}
List<ConsumerInterceptor<K, V>> interceptorList = (List)
config.getConfiguredInstances(
ConsumerConfig.INTERCEPTOR_CLASSES_CONFIG,
ConsumerInterceptor.class,
Collections.singletonMap(ConsumerConfig.CLIENT_ID_CONFIG, clientId));
this.interceptors = new ConsumerInterceptors<>(interceptorList);
this.interceptors.maybeConfigureWithResources();
{code}
+*PROPOSAL 2*+
To avoid changing a public interface and the subsequent KIP process we can
replace the *AbstractConfig.getConfiguredInstances()* with a new factory class
which wraps the *AbstractConfig* while introducing a replacement method for
*getConfiguredInstances* e.g.
{*}interceptorLoader.loadConfiguredInstances(){*}. This approach enables reuse
of the existing *AbstractConfig* methods along side the new and improved
factory method. It also enables reuse of the existing try/catch interceptor
*close()* method clean up behavior within the respective clients in the event
of a configuration failure. See below example code.
{color:#de350b}Loader interceptorLoader = new Loader(config);
LoadConfiguredInstanceResult loadConfiguredInstanceResult =
interceptorLoader.loadConfiguredInstances(
ConsumerConfig.INTERCEPTOR_CLASSES_CONFIG,
ConsumerInterceptor.class,
Collections.singletonMap(ConsumerConfig.CLIENT_ID_CONFIG,
clientId));
List<ConsumerInterceptor<K, V>> interceptorList =
loadConfiguredInstanceResult.getInstances();
loadConfiguredInstanceResult.throwWhenAnyConfigurationFailed();{color}
In terms of impact to the developers, one could argue coding may be required in
both approaches to get the full benefit of either. However, I'm open to either
approach or another approach outside of these.
was:
The Consumer and Producer interceptor interfaces and their corresponding Kafka
Consumer and Producer constructors do not adequately support cleanup of
underlying interceptor resources.
Currently within the Kafka Consumer and Kafka Producer constructors, the
AbstractConfig.getConfiguredInstances() is delegated responsibility for both
creating and configuring each interceptor listed in the interceptor.classes
property and returns a configured List<ConsumerInterceptor<K,V>> interceptors.
This dual responsibility for both creation and configuration is problematic
when it involves multiple interceptors where at least one interceptor's
configure method implementation creates and/or depends on objects which creates
threads, connections or other resources which requires clean up and the
subsequent interceptor's configure method raises a runtime exception. This
raising of the runtime exception produces a resource leakage in the first
interceptor as the interceptor container i.e.
ConsumerInterceptors/ProducerInterceptors is never created and therefore the
first interceptor's and really any interceptor's close method are never called.
To help ensure the respective container interceptors are able to invoke their
respective interceptor close methods for proper resource clean up, I propose
defining a default open or configureWithResources() or acquireResources()
method with no implementation and check exception on the respective
Consumer/Producer interceptor interfaces. This method will be responsible for
creating threads and/or objects which utilizes threads, connections or other
resource which requires clean up. Additionally, the default method enables
implementation optionality as it's empty default behavior means it will do
nothing when unimplemented mitigating backwards compatibility impact to exiting
interceptors.
Additionally, the Kafka Consumer/Producer Interceptor containers will implement
a corresponding maybeOpen or maybeConfigureWithResources or
maybeAcquireResources method which also throws a checked exception.
Alternatively, to avoid changing a public interfaces and the subsequent KIP
process, the AbstractConfig.getConfiguredInstances() can be replaced with a
new factory which wraps the AbstractConfig while introducing a new factory
method which addresses the problem.
> Improve Interceptor Resource Leakage Prevention
> -----------------------------------------------
>
> Key: KAFKA-14565
> URL: https://issues.apache.org/jira/browse/KAFKA-14565
> Project: Kafka
> Issue Type: Improvement
> Components: clients
> Reporter: Terry Beard
> Assignee: Terry Beard
> Priority: Major
> Labels: needs-kip
> Fix For: 3.5.0
>
>
> The Consumer and Producer interceptor interfaces and their corresponding
> Kafka Consumer and Producer constructors do not adequately support cleanup of
> underlying interceptor resources.
> Currently within the Kafka Consumer and Kafka Producer constructors, the
> *AbstractConfig.getConfiguredInstances()* is delegated responsibility for
> both creating and configuring each interceptor listed in the
> interceptor.classes property and returns a configured
> *List<ConsumerInterceptor<K,V>>* interceptors.
> This dual responsibility for both creation and configuration is problematic
> when it involves multiple interceptors where at least one interceptor's
> configure method implementation creates and/or depends on objects which
> creates threads, connections or other resources which requires clean up and
> the subsequent interceptor's configure method raises a runtime exception.
> This raising of the runtime exception produces a resource leakage in the
> first interceptor as the interceptor container i.e.
> ConsumerInterceptors/ProducerInterceptors is never created and therefore the
> first interceptor's and really any interceptor's close method are never
> called.
> To help ensure the respective container interceptors are able to invoke their
> respective interceptor close methods for proper resource clean up, I propose
> two approaches:
> +*PROPOSAL 1*+
> Define a default *open* or *configureWithResources()* or *acquireResources()*
> method with no implementation and check exception on the respective
> Consumer/Producer interceptor interfaces. This method as a part the
> interceptor life cycle management will be responsible for creating threads
> and/or objects which utilizes threads, connections or other resource which
> requires clean up. Additionally, this default method enables implementation
> optionality as it's empty default behavior means it will do nothing when
> unimplemented mitigating backwards compatibility impact to exiting
> interceptors. Finally, the Kafka Consumer/Producer Interceptor containers
> will implement a corresponding *maybeOpen* or *maybeConfigureWithResources*
> or *maybeAcquireResources* method which also throws a checked exception.
> See below code excerpt for the Consumer/Producer constructor:
> {code:java}
> List<ConsumerInterceptor<K, V>> interceptorList = (List)
> config.getConfiguredInstances(
> ConsumerConfig.INTERCEPTOR_CLASSES_CONFIG,
> ConsumerInterceptor.class,
> Collections.singletonMap(ConsumerConfig.CLIENT_ID_CONFIG, clientId));
> this.interceptors = new ConsumerInterceptors<>(interceptorList);
> this.interceptors.maybeConfigureWithResources();
> {code}
> +*PROPOSAL 2*+
> To avoid changing a public interface and the subsequent KIP process we can
> replace the *AbstractConfig.getConfiguredInstances()* with a new factory
> class which wraps the *AbstractConfig* while introducing a replacement method
> for *getConfiguredInstances* e.g.
> {*}interceptorLoader.loadConfiguredInstances(){*}. This approach enables
> reuse of the existing *AbstractConfig* methods along side the new and
> improved factory method. It also enables reuse of the existing try/catch
> interceptor *close()* method clean up behavior within the respective clients
> in the event of a configuration failure. See below example code.
>
> {color:#de350b}Loader interceptorLoader = new Loader(config);
> LoadConfiguredInstanceResult loadConfiguredInstanceResult =
> interceptorLoader.loadConfiguredInstances(
> ConsumerConfig.INTERCEPTOR_CLASSES_CONFIG,
> ConsumerInterceptor.class,
> Collections.singletonMap(ConsumerConfig.CLIENT_ID_CONFIG,
> clientId));
> List<ConsumerInterceptor<K, V>> interceptorList =
> loadConfiguredInstanceResult.getInstances();
> loadConfiguredInstanceResult.throwWhenAnyConfigurationFailed();{color}
>
> In terms of impact to the developers, one could argue coding may be required
> in both approaches to get the full benefit of either. However, I'm open to
> either approach or another approach outside of these.
>
>
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