Workflow Exception - Retry handling - Adobe AEM/CQ - aem

Workflow Processes throw WorkflowException in case of failure, there is a setting in Web Console Apache Sling Job Default Queue. In this max retries is set to 10 on failure.
Now on failure, workflow is retried 10 more times on failure. So if a workflow if having step for example Version Creation, 10 more versions are created of resource.
I could think of following solutions
Set the max retries count on failure to 0 in Apache Sling Job Default Queue. Is it fine to do this?
Replace OOTB Version Creation process with custom process and add check for retries probably by saving flag in workflow metadata.
Version Creation process is taken as example here, it could be any other process which is doing some other functionality, that would also be tried 10 more times on failure. Has anyone faced similar situation?

It is not advisable to make it zero. Some workflow needs to be retried, for example activation workflow, when there were network issues or publish boxes were down etc. Your settings would totally bypass this safety mechanism.
I would prefer your second method as an alternative. org.apache.sling.event.jobs.Jobs has getRetryCount().

Related

Github Actions Concurrency Queue

Currently we are using Github Actions for CI for infrastructure.
Infrastructure is using terraform and a code change on a module triggers plan and deploy for changed module only (hence only updates related modules, e.g 1 pod container)
Since auto-update can be triggered by another github repository push they can come relatively on same time frame, e.g Pod A Image is updated and Pod B Image is updated.
Without any concurrency in place, since terraform holds lock, one of the actions will fail due to lock timeout.
After implementing concurreny it is ok for just 2 on same time pushes to deploy as second one can wait for first one to finish.
Yet if there are more coming, Githubs concurreny only takes into account last push for queue and cancels waiting ones (in progress one can still continue). This is logical from single app domain perspective but since our Infra code is using difference checks, by passing deployments on canceled job actually bypasses and deployment!.
Is there a mechanism where we can queue workflows (or even maybe give a queue wait timeout) on Github Actions ?
Eventually we wrote our own script in workflow to wait for previous runs
Get information on current run
Collect previous non completed runs
and wait until completed (in a loop)
If exited waiting loop continue
on workflow
Tutorial on checking status of workflow jobs
https://www.softwaretester.blog/detecting-github-workflow-job-run-status-changes

Is there a way to configure retries for Azure DevOps pipeline tasks or jobs?

Currently I have a OneBranch DevOps pipeline that fails every now and then while restoring packages. Usually it fails because of some transient error like a socket exception or timeout. Re-trying the job usually fixes the issue.
Is there a way to configure a job or task to retry?
Azure Devops now supports the retryCountOnTaskFailure setting on a task to do just this.
See this page for further information:
https://learn.microsoft.com/en-us/azure/devops/release-notes/2021/pipelines/sprint-195-update
Update:
Automatic retries for a task was added and when you read this it should be available for usage.
It can be used as follow:
- task: <name of task>
retryCountOnTaskFailure: <max number of retries>
...
Here are a few things to note when using retries:
The failing task is retried immediately.
There is no assumption about the idempotency of the task. If the task has side-effects (for instance, if it created an external resource partially), then it may fail the second time it is run.
There is no information about the retry count made available to the task.
A warning is added to the task logs indicating that it has failed before it is retried.
All of the attempts to retry a task are shown in the UI as part of the same task node.
Original answer:
There is no way of doing that with native tasks. However, if you can script then you can put such logic inside.
You could do this for instance in this way:
n=0
until [ "$n" -ge 5 ]
do
command && break # substitute your command here
n=$((n+1))
sleep 15
done
However there is no native way of doing this for regular tasks.
Automatically retry a task in on roadmap so it could change in near future.

Out of box distributed job queue solution

Are there any existing out of the box job queue framework? basic idea is
someone to enqueue a job with job status New
(multiple) workers get a job and work on it, mark the job as Taken. One job can only be running on at most one worker
something will monitor the worker status, if the running jobs exceed predefined timeout, will be re-queued with status New, could be worker health issue
Once a worker completes a task, it marks the task as Completed in the queue.
something keeps cleaning up completed tasks. Or at step #4 when worker completes a task, the worker simply dequeues the task.
From my investigation, things like Kafka (pub/sub) or MQ (push/pull & pub/sub) or cache (Redis, Memcached) are mostly sufficient for this work. However, they all require some sort of development around its core functionality to become a fully functional job queue.
Also looked into relational DB, the ones supports "SELECT * FOR UPDATE SKIP LOCKED" syntax is also a good candidate, this again requires a daemon between the DB and worker, which means extra effort.
Also looked into the cloud solutions, Azure Queue storage, etc. similar assessment.
So my question is, is there any out of the box solution for job queue, that are tailored and dedicated for one thing, job queuing, without much effort to set up?
Thanks
Take a look at Python Celery. https://docs.celeryproject.org/en/stable/getting-started/introduction.html
The default mode uses RabbitMQ as the message broker, but other options are available. Results can be stored in a DB if needed.

Batch account node restarted unexpectedly

I am using an Azure batch account to run sqlpackage.exe in order to move databases from a server to another. A task that has started 6 days ago has suddenly been restarted and started from the beginning after 4 days of running (extremely large databases). The task run uninterruptedly up until then and should have continued to run for about 1-2 days.
The PowerShell script that contains all the logic handles all the exceptions that could occur during the execution. Also, the retry count for the task was set to 0 in case it fails.
Unfortunately, I did not have diagnostics settings configured and I could only look at the metrics and there was a short period when there wasn't any node.
What can be the causes for this behavior? Restarting while the node is still running
Thanks
Unfortunately, there is no way to give a definitive answer to this question. You will need to dig into the compute node (interactively log in) and check system logs to give you details on why the node restarted. There is no guarantee that a compute node will have 100% uptime as there may be hardware faults or other service interruptions.
In general, it's best practice to have long running tasks checkpoint progress combined with a retry policy. Programs that can reload state can pick up at the time of the checkpoint when the Batch service automatically reschedules the task execution. Please see the Batch best practices guide for more information.

Spring batch jobOperator - how are multiple concurrent instances of a job from the same XML file controlled?

When we run multiple concurrent jobs with different parameters, how can we control (stop, restart) the appropriate jobs? Our internal code provides the jobExecution object, but under the covers The jobOperator uses the job name to get the job instance.
In our case all of the jobs are from "do-stuff.xml" (okay, it's sanitized and not very original). After looking at the spring-batch source code, our concern is that if there is more then one job running and we stop a job it will take the most recently submitted job and stop it.
The JobOperator will allow you to fetch all running executions of the job using getRunningExecutions(String jobName). You should be able to iterate over that list to find the one you want. Then, just call stop(long executionId) on the one you want.
Alternatively, we've also implemented listeners (both at step and chunk level) to check an outage status table. When we want to implement a system-wide outage, we add the outage there and have our listener throw an exception to bring our jobs down. once the outage is lifted, all "failed" executions may be restarted.