How do I kickoff a batch job when input file arrives? - spring

We have Spring4 and Spring Batch 3 and our app consumes CSV files as input file. Currently we kick off the jobs manually from the command line, using CommandLineJobRunner with parms, including the name of the file to process.
I want to kick off a job to process asynchronously just as soon as the input file arrives in a monitored directory. How can we do that?

You may use java.nio.file.WatchService to monitor directory for a file.
Once file appears you may start (or kick off a job to process asynchronously) actual processing.
You may also use FileReadingMessageSource.WatchServiceDirectoryScanner from Spring Integration (https://docs.spring.io/spring-integration/reference/html/files.html#watch-service-directory-scanner)
Comparing release notes Spring Batch https://github.com/spring-projects/spring-batch/releases
to Spring Integration https://github.com/spring-projects/spring-integration/releases it looks that Spring Integration is released more often. It also has more features and Integration points.
In this case it looks like a overkill to bring Spring Integration if you just need to watch a directory for a file.

I would recommend using the powerful combination of Spring Batch with Spring Integration. For example, you can use a FileInboundChannelAdapter from Spring Integration to monitor a directory and start a Spring Batch Job as soon as the input file arrives.
There is a code example for this typical use case in the reference documentation of Spring Batch here: https://docs.spring.io/spring-batch/4.0.x/reference/html/spring-batch-integration.html#launching-batch-jobs-through-messages
I hope this helps.

Related

Spring batch or Spring core libraries for building file operation process

I'm dipping my toes into the microservices, is spring boot batch applicable to the following requirements?
Files of one or multiple are read from a specific directory in Linux.
Several operations like regex, build new files, write the file and ftp to a location
Send email during a process fail
Using spring boot is confirmed, now the question is
Should I use spring batch or just core spring framework?
I need to integrate with Control-M to trigger the job. Can the Control-M be completely removed by using Spring batch library? As we don't know when to expect the files in the directory.
I've not seen a POC with these requirements. Would someone provide an example POC or an affirmation this could be achieved with Spring batch?
I would use Spring Batch for that use case. Not only does it provide out of the box components for reading, processing, and writing files, it adds a lot more for error handling, scalability, etc. All of those things you'd probably end up wiring up by yourself if you go without Spring Batch.
As for being launched via Control-M, yes MANY large customers use Control-M to launch their jobs. Unfortunately, I've never done it myself so I cannot provide any details on the mechanics, but if Control-M can either launch a script or call a REST API, you can launch a job with it.
I would suggest you, go for spring batch as it has much-inbuilt functionality which will be provided to you for file reading and writing to your required location. Even you will be able to handle record skipping requirement. Your mail triggering requirement will be handled by Control M. You just need to decide one exit code for your handled exception and on the basis of that exit code you can trigger the mail to respective members. And there are many other features which will be helpful if you go for spring batch.

Java Spring Boot Batch - Need some advise in design

I am a newbie in Java and trying to implement a Spring Boot batch application.
My requirement is like to check some data in database (one part) and delete if found (another part).
I am planning to implement Spring Boot batch for this.
I will have one job which will have 2 steps. If Step 1 find some data then only execute step 2? Can I achieve in Spring Boot Batch? Or what is the best way to achieve this keeping in mind I have to schedule this to run weekly.
With just the scheduled job for find and delete records from DB, I don't suggest using Spring Batch. Spring has nice good way of doing it without Batch using scheduling-tasks. You can see example here. Use Spring Batch only if you need to run jobs in batch that can't be handled with normal operation.
If you need complex scheduler, you can use Spring Quartz scheduler.

Spring Integration Invoking Spring Batch

Just looking for some information if others have solved this pattern. I want to use Spring Integration and Spring Batch together. Both of these are SpringBoot applications and ideally I'd like to keep them and their respective configuration separated, so they are both their own executable jar. I'm having problems executing them in their own process space and I believe I want, unless someone can convince me otherwise, each to run like they are their own Spring Boot app and initialize themselves with their own profiles and properties. What I'm having trouble with though is the invocation of the job in my SpringBatch project from my SpringIntegration project. At first I couldn't get the properties loaded from the batch project, so I realized I need to pass the spring.active.profiles as a Job Parameter and that seemed to solve that. But there are other things in the Spring Boot Batch application that aren't loading correctly like the schema-platform.sql file and the database isn't getting initialized, etc.
On this initial launch of the job I might want the response to go back to Spring Integration for some messaging on Job Status. There might be times when I want to run a job without Spring Integration kicking off the job, but still take advantage of sending statuses back to the Spring Integration project providing its listening on a channel or something.
I've reviewed quite a few Spring samples and have yet to find my exact scenario, most are with the two dependencies in the same project, so maybe I'm doing something that's not possible, but I'm sure I'm just missing a little something in the Spring configuration.
My questions/issues are:
I don't want the Spring Integration project to know anything about the SpringBatch configuration other than the job its kicking off. I have found a good way to do that reference to the Job Bean without getting my entire batch configuration loading.
Should I keep these two projects separated or would it be better to combine them since I have two-way communication between both.
How should the Job be launch from the integration project. We're using the spring-batch-integration project with JobLaunchRequest and JobLauncher. This seems to run it in the same process as the Spring Integration project and I'm missing a lot of my SpringBootBatch projects initialization
Should I be using a CommandLineRunner instead to force it to another process.
Is SpringApplication.run(BatchConfiguration.class) the answer?
Looking for some general project configuration setup to meet these requirements.
Spring Cloud Data Flow in combination with Spring Cloud Task does exactly what you're asking. It launches Spring Cloud Task applications (which can contain batch jobs) as new processes on the platform you choose. I'd encourage you to check out that project here: http://cloud.spring.io/spring-cloud-dataflow/

Can I use Spring Integration as a daemon in order to poll a directory?

I am new to Spring Integration and I am considering using it in order to poll a directory for new files in order to process those files.
My question is: is Spring Integration some sort of daemon one can launch and that one can use in order to poll a directory?
Is this is possible can someone please direct me to relevant section of the official documentation on how to launch Spring Integration?
All you need is to have a main method (or a WAR file if you want to deploy to Tomcat or another servlet container) that creates a Spring ApplicationContext (e.g. new ClassPathXmlApplicationContext("file-poller.xml"))
It can run with a cron trigger, fixed-rate or fixed-delay trigger.
JMX operations can be exposed on Spring Integration's File adapter (or any adapter) by simply adding a single config element (e.g. <mbean-export>).
Bottom line: you REALLY do not need an ESB if you simply want a File poller to run continuously. You can have a single small config file and one line of code in a main method.
Visit the samples for more info: https://github.com/springsource/spring-integration-samples (look under basic/file specifically)
Hope that helps,
Mark
Spring Integration is a part of framework, its not a programm or daemon.
What you cant do — is to configure Spring Integration to poll a directory, lunch JVM with Spring onboard and poller will do what you want.
You can start with this blog post.
More samples
Relevant section of documentation

Spring Batch for File Processing

Is Spring Batch a good fit for processing a a large number of individual files?
Spring Batch seems to be geared towards data-centric jobs. I've got a requirement to pull down several million files from an S3 bucket, unzip them, perform some logic based on the contents, then call a web service.
Implementing this by hand is trivial, but I don't much fancy re-inventing the wheel when it comes to tracking job executions, and how far a job got along before it failed. Spring Batch seems to be an ideal fit for this job-monitoring, but I'm not sure whether subverting it to do file processing is a step too far.
Short answer is Yes, you can use spring batch for this. I had done a small POC where we had to migrate millions of images from source system to target system in a batch process and it works well IMHO.
Adding on to comment by #Prasanna Talakanti, I would suggest to use a combination of Spring Integration and Spring Batch. While Spring batch will provide you infrastructure for batch processing (Commit at intervals, restart job if failed etc), Spring integration will provide you things around web service gateways.
In Spring batch, you can define reader for reading data from S3 and writer for writing to your destination with processor in between if needed. You could also fine tune the commit interval so if the job fails in between, you have a point of rollback.

Resources