How can I get the AWS Flow Framework to work using IntelliJ Idea and Gradle?
Adding the SWF build tools to the Gradle build is enough to generate the code required for basic use of your activities and workflows, but it doesn't perform the required AspectJ weaving to make the @Asynchronous and @ExponentialRetry annotations work in your workflow implementation. For the required weaving to be performed, you must tell AspectJ directly to perform the weaving.
Weaving is done at compile time, post-compile time or load time.
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Compile Time Weaving
This replaces the javac compiler with the ajc compiler. If you use Lombok, compile time weaving won't work because the Lombok annotations won't be handled.
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Load Time Weaving
Load time weaving weaves your code at runtime. It requires you to set your java agent as the aspectj weaver jar when starting your application (e.g. -javaagent:/aspectjweaver-1.8.9.jar). This is less than desirable if you're using SWF in a library/framework other applications will use as they would need to set the aspectj jar when their application starts.
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Post-compile Time Weaving
Post-compile time weaving weaves your bytecode after compilation is complete. No conflicts with Lombok and no special jvm args. Checkout the build.gradle file to see how it's done.
I was unable to make post-compile weaving for the Flow Framework work inside IntelliJ, it became a case of diminishing returns and I had to move on. Since it's only for development, I decided load time weaving would suffice. If you have gotten post-compile weaving to work,I'd love to hear how you did it. I ended up committing the aspectj weaver jar into my project and referencing it from the IntelliJ runner. Not the most desirable method, but it got me up and going.
- Checkin the aspectj weaver jar to a directory in your project
- Reference that jar in the vm options of your IntelliJ runner to load it as the java agent (e.g. -javaagent:./lib/aspectjweaver-1.8.9.jar)
It may be possible to teach Gradle to configure IntelliJ's annotation processing (e.g. http://mrhaki.blogspot.com/2016/03/gradle-goodness-enable-compiler.html), but for me it's a one-time project setup task since the configuration will be committed to VCS.
- Open IntelliJ settings to Build, Execution, Deployments > Compiler > Annotation Processors
- Check the box 'Enable annotation processing'
- Set 'Store generated sources relative to:' to 'Module content root'
- Set 'Production sources directory' to 'generated'
- Set 'Test sources directory' to 'generated_tests'
- Save the settings
