gaborgsomogyi commented on code in PR #19372:
URL: https://github.com/apache/flink/pull/19372#discussion_r848157811
##########
flink-runtime/src/main/java/org/apache/flink/runtime/security/token/KerberosDelegationTokenManager.java:
##########
@@ -110,13 +126,84 @@ public void obtainDelegationTokens(Credentials
credentials) {
* task managers.
*/
@Override
- public void start() {
- LOG.info("Starting renewal task");
+ public void start() throws Exception {
+ checkState(renewalExecutor == null, "Manager is already started");
+
+ if (!isRenewalPossible()) {
+ LOG.info("Renewal is NOT possible, skipping to start renewal
task");
+ return;
+ }
+
+ ThreadFactory threadFactory =
+ new ThreadFactoryBuilder()
+ .setDaemon(true)
+ .setNameFormat("Credential Renewal Thread")
+ .build();
+ renewalExecutor = new ScheduledThreadPoolExecutor(1, threadFactory);
Review Comment:
After I've had a deep look I've found the following obstacles which blocks
us to use the mentioned executors:
* If you mean `ResourceManager.getMainThreadExecutor` to use in the first
bullet point then that's a `MainThreadExecutor` instance which doesn't support
`scheduleAtFixedRate`, please see
[here](https://github.com/apache/flink/blob/4034d3cd6d13e88e2e5ca101510bf333e94a53fa/flink-rpc/flink-rpc-core/src/main/java/org/apache/flink/runtime/rpc/RpcEndpoint.java#L537).
We can implement that from scratch but touching core threading can be super
dangerous, though I'm not against it to add such functionality.
* If we would rely on `ResourceManager.getMainThreadExecutor` then we must
modify the interface (`start` function) and we need to put implementation
details into the interface (the 2 executors) which would frustrate me a bit. I
think if we want to do dependency injection then the proper place would be the
constructor which is not touching the interface. Here if we decide to modify
the interface I can accept that but I would think the implementation would be
less clean.
* If we would add the new `scheduleAtFixedRate` functionality then
`ResourceManager` usage is covered but in
[MiniCluster](https://github.com/apache/flink/blob/f089a99ce73ad15531a4d1b72899d8367fab662a/flink-runtime/src/main/java/org/apache/flink/runtime/minicluster/MiniCluster.java#L431)
we must provide something too but there no such executor exists (at least I've
not found anything) so we need to come up w/ a new executor anyway.
All in all I've left the original code there for now until we make an
agreement.
I understand the direction not to pollute w/ threads but in this case the
return of investment is low because in some cases new executor is needed but
the code would be more complex.
Would like to hear your voice on this.
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: issues-unsubscr...@flink.apache.org
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
