GitHub user aljoscha opened a pull request:

https://github.com/apache/flink/pull/4232

FLINK-7041 Deserialize StateBackend from JobCheckpointingSettings with user classloader

R: @tzulitai

CC: @StephanEwen I noticed that the state backend that is in the configuration is never used anywhere. I'm guessing this is for future work or is something missing in the code?

You can merge this pull request into a Git repository by running:

$ git pull https://github.com/aljoscha/flink jira-7041-fix-state-backend-classloader

Alternatively you can review and apply these changes as the patch at:

https://github.com/apache/flink/pull/4232.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 #4232

commit 5ed5300b510f1439ceb516b44592e433dbc46931
Author: Aljoscha Krettek <aljoscha.krettek@gmail.com>
Date: 2017-06-30T09:19:30Z

FLINK-7041 Deserialize StateBackend from JobCheckpointingSettings with user classloader

This also adds a test for serializability with a class that's not in the
default classloader.

Github user tzulitai commented on the issue:

https://github.com/apache/flink/pull/4232

Thanks for the quick fix @aljoscha!

Regarding tests:
Can we also have another test that verifies `JobGraphs` containing custom `StateBackend`s or `StateBackends` with custom classes can be submitted without exceptions?
Looks like `org.apache.flink.runtime.jobmanager.JobSubmitTest` is a good place for that.

Github user tzulitai commented on the issue:

https://github.com/apache/flink/pull/4232

Ah scratch that, perhaps the `CheckpointSettingsSerializableTest` is sufficient.

Github user tzulitai commented on a diff in the pull request:

https://github.com/apache/flink/pull/4232#discussion_r125004426

— Diff: flink-runtime/src/main/java/org/apache/flink/runtime/executiongraph/ExecutionGraphBuilder.java —
@@ -223,19 +223,21 @@ public static ExecutionGraph buildGraph(
// if specified in the application, use from there, otherwise load from configuration
final StateBackend metadataBackend;

• final StateBackend applicationConfiguredBackend = snapshotSettings.getDefaultStateBackend();
  + final SerializedValue<StateBackend> applicationConfiguredBackend = snapshotSettings.getDefaultStateBackend();
  if (applicationConfiguredBackend != null) {
• metadataBackend = applicationConfiguredBackend;
  + try { + metadataBackend = applicationConfiguredBackend.deserializeValue(classLoader); + }

  catch (IOException | ClassNotFoundException e)

  { + throw new JobExecutionException(jobId, "Could not instantiate configured state backend.", e); + }

log.info("Using application-defined state backend for checkpoint/savepoint metadata: {}.",
applicationConfiguredBackend);
— End diff –

Need to change the argument for this log to `metadataBackend`

Github user aljoscha commented on a diff in the pull request:

https://github.com/apache/flink/pull/4232#discussion_r125034182

— Diff: flink-runtime/src/main/java/org/apache/flink/runtime/executiongraph/ExecutionGraphBuilder.java —
@@ -223,19 +223,21 @@ public static ExecutionGraph buildGraph(
// if specified in the application, use from there, otherwise load from configuration
final StateBackend metadataBackend;

• final StateBackend applicationConfiguredBackend = snapshotSettings.getDefaultStateBackend();
  + final SerializedValue<StateBackend> applicationConfiguredBackend = snapshotSettings.getDefaultStateBackend();
  if (applicationConfiguredBackend != null) {
• metadataBackend = applicationConfiguredBackend;
  + try { + metadataBackend = applicationConfiguredBackend.deserializeValue(classLoader); + }

  catch (IOException | ClassNotFoundException e)

  { + throw new JobExecutionException(jobId, "Could not instantiate configured state backend.", e); + }

log.info("Using application-defined state backend for checkpoint/savepoint metadata: {}.",
applicationConfiguredBackend);
— End diff –

Good catch!

Github user tzulitai commented on the issue:

https://github.com/apache/flink/pull/4232

Thanks for the fixups @aljoscha :-D
The last Travis run was successful, the test name rename should not affect anything.
Merging this ..

Github user aljoscha commented on the issue:

https://github.com/apache/flink/pull/4232

Thanks! 😃

Github user asfgit closed the pull request at:

https://github.com/apache/flink/pull/4232

Fixed for master via 64c6fa70f53425d09717e1560db88d5733601c24.
Fixed for 1.3 via 78bbb844a0b33d4297e9fa1044401a51e219fcfa.