Is it possible to access JobParameters knowing the job (execution) ID outside?

Question

Suppose I want to build an API for (1) submitting jobs to be executed and (2) later get their result/status.

Now, the submit endpoint receives a payload and some headers. The payload is persisted through a custom JpaRepository and the headers are pushed into an instance of JobParameters (which is then fed to the JobLauncher). From what I know so far, there is a JobRepository that will end up persisting my JobParameters.

A. My first question on this design would be: should the JobRepository be used to persist the job payload instead of doing it in a custom JpaRepository?

B. I want access the JobParameters of a certain job (by job ID, which is given back when a job is submitted to the JobLauncher, through the JobExecution; this is standard Spring Batch stuff).

Is this possible from a normal bean (a @Service class)?

• The JobRepository does not expose anything that access a job id and returns the job parameters associated with that.

• There is a JobExecutionDao that, given an execution ID, could give me access to the JobParameters, but I cannot inject that into my beans.

Parameter <#> of constructor in required a bean of type 'org.springframework.batch.core.repository.dao.JobExecutionDao' that could not be found.

Answer 1

I will answer your questions and then give you an idea about how I would do it.

A. My first question on this design would be: should the JobRepository be used to persist the job payload instead of doing it in a custom JpaRepository?

It depends on the request payload. The job repository should be enough to store job meta-data.

B. I want access the JobParameters of a certain job (by job ID, which is given back when a job is submitted to the JobLauncher, through the JobExecution; this is standard Spring Batch stuff).

Given a job execution id, you can get the parameters using JobOperator#getParameters(Long executionId)

Now the following is how I would implement your requirement:

Suppose I want to build an API for (1) submitting jobs to be executed and (2) later get their result/status.

• The API controller receives the name of the job to launch + job parameters and launches the job in a background thread using an asynchronous job launcher. This launcher immediately returns the job execution, so the API can return its ID to the caller (without waiting for the job to finish.
• JobExplorer#getJobExecution(Long executionId) can be used later on to inspect the job execution status/result
• JobOperator#getParameters(Long executionId) can be used to retrieve the parameters used to launch the job