I'm working on a requirement that defines a job/execution unit as a list of ordered steps which are themselves defined as a list of ordered substeps/phases. This job can be started beginning at any of the first-level steps, potentially ignoring the N-th first steps (and their substeps/phases).
What would be the best strategy for implementing this with spring batch ?
Cheers
A way to programmatically branching job execution (eg. skip step) is to use a JobExecutionDecider.
Related
I'm just wondering whether its possible for a single Job_instance in spring Batch to have multiple Job_execution if so can anyone please explain the process? And also for step_execution please !
Yes, a job instance can have multiple job executions. The typical use case is when a job instance has a first execution that fails, and a second (or subsequent) execution that succeeds.
This is explained in details with concrete examples in the Domain language of Batch section of the reference documentation.
We would like to migrate the scheduling and sequence control of some Kettle import jobs from a proprietary implementation to a Spring Batch flavour, good practice implementation.
I intend to use Spring Cloud Data Flow (SCDF) server to implement and run a configurable sequence of the existing external import jobs.
The SCDF console Task editor UI seems promising to assemble a flow. So one Task wraps one Spring Batch, which in a single step only executes a Tasklet starting and polling the Carte REST API. Does this make sense so far?
Would you suggest a better implementation?
Constraints and Requirements:
The external Kettle jobs are triggered and polled using Carte REST API. Actually, it's one single Kettle job implementation, called with individual parameters for each entity to be imported.
There is a configurable, directed graph of import jobs for several entities, some of them being dependent on a correct import of the previous entity type. (e.g. Department, then Employee, then Role assignments...)
With the upcoming implementation, we would like to get
monitoring and controlling (start, abort, pause, resume)
restartability
easy reconfigurability of the sequence in production (possibly by GUI, or external editor)
possibly some reporting and statistics.
As my current understanding, this could be achieved by using Spring Cloud Data Flow (SCDF) server, and some Task / Batch implementation / combination.
Correct me if I'm wrong, but a single Spring Batch job with its hardwired flow seems not very suitable to me. Or is there an easy way to edit and redeploy a Spring Batch with changed flow in production? I couldn't find anything, not even an easy to use editor for the XML representation of a batch.
Yes, I believe you can achieve your design goals using Spring Cloud Data Flow along with the Spring Cloud Task/Spring Batch.
The flow of multiple Spring Batch Jobs (using the Composed Task) can be managed using Spring Cloud Data Flow as you pointed from the other SO thread.
The external Kettle jobs are triggered and polled using Carte REST API. Actually, it's one single Kettle job implementation, called with individual parameters for each entity to be imported.
There is a configurable, directed graph of import jobs for several entities, some of them being dependent on a correct import of the previous entity type. (e.g. Department, then Employee, then Role assignments...)
Again, both the above can be managed as a Composed Task (with the composed task consisting of a regular task as well as Spring Batch based applications).
You can manage the parameters passed to each task/batch upon invocation via batch job parameters or task/batch application properties or simply command-line arguments.
With the upcoming implementation, we would like to get
monitoring and controlling (start, abort, pause, resume)
restartability
easy reconfigurability of the sequence in production (possibly by GUI, or external editor)
possibly some reporting and statistics.
Spring Cloud Data Flow helps you achieve these goads. You can visit the Task Developer Guide and the Task Monitoring Guide for more info.
You can also check the Batch developer guide from the site as well.
I'm currently studiying Spring Batch and I don't get the difference between different steps types: chunk-oriented, item-oriented, stadalone...etc. I'm not even sure if these are actually steps types...
Thank you
There's really only two major "step types" in Spring Batch.
Chunk-Oriented Step
This step consists of a reader->processor->writer combination (where the processor is optional). This is the most common type of Batch step.
Tasklet Step
This step does not have a reader, processor, or writer but instead is simply a task to be executed. It is useful for running single command-like processes in your batch job (for example, to invoke a stored procedure on a database).
Technically speaking a chunk-oriented step is a sub-type of a Tasklet step. Also, there are different configurations of a chunk-oriented step that has different behavior. Like parallel step, partitioned step, mutli-threaded step, etc... but these are all more advanced concepts that build on top of the basics mentioned above. Understand chunk-oriented step first; then explore the more advanced configurations.
Hi
I am a novice in Spring Batch world and last days I've spent time watching Michael Minella's youtube video, read some documentation and successfully run some demo projects I found on the internet. I think Spring Batch is a hot candidate for our needs. But here is our story.
I am working in a company that developed their own scheduling and batch framework, for more than a decade ago, for their business department. The framework is capable of running DB stored procs, DB functions and dynamic SQLs. Needless to say it is very challenging to maintain it since too many people with various development skills did the coding and they don't work here anymore. Our framework may handle jobs and steps to run sequentially as well as async (as Spring Batch). We have also a Job Repository where we store whole job definitions (users create new jobs via GUI), job instances with its context (in case the server goes down, when server is up it will resume running a job).
My questions are following:
Can we create new Spring Batch jobs dynamically (either via XML og code) and via standard SB interfaces store them to the JobRepository DB?
Today, at certain time period, we have up to hundred of job executions simultaneously. They are also reusing a connection pool to the DB. Older Spring Batch ref documentation states JobFactory will create fresh ApplicationContext for each job execution. How can we achieve reusing connection pools if this is the case in Spring Batch.
I know there is a support for continuing failed steps but what if the server/app goes down, will I be able to restart my app and retrieve job instance with its context from JobRepository in order to continue from failed step?
Can a "step1.1" in "job1" be dependent on "step 2.1" from "job2" finishing within last hour? In such scenarios I may be using a step listener on "step1.1" to accomplish this?
Kind regards
Toto
You have a lot of material here to cover, so let me respond one point at a time:
Can we create new Spring Batch jobs dynamically (either via XML or code) and via standard SB interfaces store them to the JobRepository DB?
Can you generate a job definition dynamically? Yes. We do it in Spring XD with regards to the job orchestration piece (the composed job DSL is used to generate an XML file for example.
Does Spring Batch provide facilities to do this? No. You'd have to code it yourself.
Also note that you'd have to store the definition in your own table (the schema defined by Spring Batch doesn't have a table for this).
Today, at certain time period, we have up to hundred of job executions simultaneously. They are also reusing a connection pool to the DB. Older Spring Batch ref documentation states JobFactory will create fresh ApplicationContext for each job execution. How can we achieve reusing connection pools if this is the case in Spring Batch.
You can use parent/child context configurations to reuse beans including a DataSource. Define the DataSource in the parent and then the jobs that depend on it in child contexts.
I know there is a support for continuing failed steps but what if the server/app goes down, will I be able to restart my app and retrieve job instance with its context from JobRepository in order to continue from failed step?
This is really an orchestration concern. Spring Batch, by design, does not address the orchestration of jobs into consideration. This allows you to orchestrate them how you want.
The way I'd recommend handling this is via Spring XD or (depending on your timelines) Spring Cloud Data Flow. These tools provide orchestration capabilities including the redeployment of a job if it goes down. That being said, it won't restart a job that was running if it fails because that typically requires some form of human decision based on use case. However, Spring XD currently (and Spring Cloud Data Flow will) have the capabilities to implement something like this in a pretty straight forward way.
Can a "step1.1" in "job1" be dependent on "step 2.1" from "job2" finishing within last hour? In such scenarios I may be using a step listener on "step1.1" to accomplish this?
In cases like this, I'd start to question how your job is configured. You can use a JobExecutionDecider to decide if a step should be executed or not if it still makes sense.
All things considered, while you can accomplish most of what you're looking for with Spring Batch, using something like Spring XD or Spring Cloud Data Flow will make your life a lot easier.
Can we create new Spring Batch jobs dynamically (either via XML og code) and via standard SB interfaces store them the JobRepository DB?
It is easy to use StepBuilderFactory, FlowBuilder etc. to programatically build the Spring Batch artifacts. You'll probably want to back those artifacts with Spring Beans (to get nice facilities like the step/job spring scopes, injection and so on) and for that you can use prototype, execution scoped and job scoped beans, or even use facilities such as BeanDefinitionBuilder to dynamically create beans.
Older Spring Batch ref documentation states JobFactory will create fresh ApplicationContext for each job execution. How can we achieve reusing connection pools if this is the case in Spring Batch.
The GenericApplicationContextFactory creates a child application context. You can have the "global" beans in the parent application context.
I know there is a support for continuing failed steps but what if the server/app goes down, will I be able to restart my app and retrieve job instance with its context from JobRepository in order to continue from failed step?
Yes, but not that easily.
Can a "step1.1" in "job1" be dependent on "step 2.1" from "job2" finishing within last hour? In such scenarios I may be using a step listener on "step1.1" to accomplish this?
A JobExecutionDecider will likely be the best option there.
I need to execute a sequence of steps a specific number of times.. any pointers on what is the best way to do this in Spring Batch. I am able to implement executing a single step 'x' times. but my requirement is to execute a set of steps - based on a condition 'x' times.Any pointers will help.
Thanks
Lakshmi
You could put all steps in a job an start the whole job several times. There are different ways, how a job actually is launched in spring-batch. have a look at joboperator and launcher and then simply implement a loop around the launching of the job.
You can do this after the whole spring-context is initialized, so there will be no overhead concerning that. But you must by attention about the scope of your beans, especially the reader and writers.
Depending on your needs concerning failurehandling and restart, you also have pay attention how you manage the execution context of your job and steps.
You can simulate a loop with SB using a JobExecutionDecider:
Put it in front of all steps.
Store x in job execution context and check for x value into
decider: move to 'END' if x equals desidered value or increment it
and move to first step of set.
After last step move back to start (the decider).