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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 any public interfaces and the subsequent KIP process, we can
* Create a class which inherits or wraps AbstractConfig that contains a new
method which will return a ConfiguredInstanceResult class. This
ConfiguredInstanceResult class will contain an optional list of successfully
created interceptors and/or exception which occurred while calling each
Interceptor::configure. Additionally, it will contain a helper method to
rethrow an exception as well as a method which returns the underlying
exception. The caller is expected to handle the exception and perform clean up
e.g. call Interceptor::close on each interceptor in the list provided by the
ConfiguredInstanceResult class.
* Automatically invoke {{close}} on any {{Closeable}} or {{AutoCloseable}}
instances if/when a failure occurs
* Add a new overloaded {{getConfiguredInstance}} / {{getConfiguredInstances}}
variant that allows users to specify whether already-instantiated classes
should be closed or not when a failure occurs
* Add a new exception type to the public API that includes a list of all of
the successfully-instantiated (and/or successfully-configured) instances before
the error was encountered so that callers can choose how to handle the failure
however they want (and possibly so that instantiation/configuration can be
attempted on every class before throwing the exception)
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
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 any public interfaces and the subsequent KIP process, we can
create a class which inherits or wraps AbstractConfig that contains a new
method which will return a ConfiguredInstanceResult class. This
ConfiguredInstanceResult class will contain an optional list of successfully
created interceptors and/or exception which occurred while calling each
Interceptor::configure. Additionally, it will contain a helper method to
rethrow an exception as well as a method which returns the underlying
exception. The caller is expected to handle the exception and perform clean up
e.g. call Interceptor::close on each interceptor in the list provided by the
ConfiguredInstanceResult class.
> 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
> 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 any public interfaces and the subsequent KIP process, we can
> * Create a class which inherits or wraps AbstractConfig that contains a new
> method which will return a ConfiguredInstanceResult class. This
> ConfiguredInstanceResult class will contain an optional list of successfully
> created interceptors and/or exception which occurred while calling each
> Interceptor::configure. Additionally, it will contain a helper method to
> rethrow an exception as well as a method which returns the underlying
> exception. The caller is expected to handle the exception and perform clean
> up e.g. call Interceptor::close on each interceptor in the list provided by
> the ConfiguredInstanceResult class.
> * Automatically invoke {{close}} on any {{Closeable}} or {{AutoCloseable}}
> instances if/when a failure occurs
> * Add a new overloaded {{getConfiguredInstance}} /
> {{getConfiguredInstances}} variant that allows users to specify whether
> already-instantiated classes should be closed or not when a failure occurs
> * Add a new exception type to the public API that includes a list of all of
> the successfully-instantiated (and/or successfully-configured) instances
> before the error was encountered so that callers can choose how to handle the
> failure however they want (and possibly so that instantiation/configuration
> can be attempted on every class before throwing the exception)
>
>
>
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