Fix: Non node functions are attempted to be packaged

[roni-frantchi]

What did you implement:

Closes --

#579 helped in making webpack not compile any non-node functions, BUT the plugin still attempts to package what it think would be webpack's output and fails miserably.

This PR will make it so that non node runtime packages are also not attempted to be packaged.

How did you implement it:

packageModules.js will now only package functions set as entryFunctions so that any functions that were not not listed as entry points will not attempted to be packaged.

How can we verify it:

There's a unit test added, plus you could:

provider:
  name: aws
  runtime: nodejs12.x 

functions:
  node:
    handler: lambda.echo

  py:
    handler: backend.lambda.LambdaFunction
    runtime: python 

Todos:

• Write tests
• Write documentation
• Fix linting errors
• Make sure code coverage hasn't dropped
• Provide verification config / commands / resources
• Enable "Allow edits from maintainers" for this PR (can't check this as this is an organization PR)
• Update the messages below

Is this ready for review?: YES
Is it a breaking change?: NO

[j0k3r]

Can you create a separate function to re-use this code from line 217?
For example, you can create that function just below the getHandlerFile function:

    const isNodeRuntime = funcName => {
      const func = this.serverless.service.getFunction(funcName);
      const runtime = func.runtime || this.serverless.service.provider.runtime || 'nodejs';

      return runtime.match(/node/);
    };

And then, re-use it here (and when we build the allEntryFunctions const):

Suggested change

	const func = this.serverless.service.getFunction(funcName);
	const runtime = func.runtime || this.serverless.service.provider.runtime || 'nodejs';
	return runtime.match(/node/);
	return isNodeRuntime(funcName);

[timbodeit]

Another option might be to add something like a getAllNodeFunctions() at a higher to replace this.serverless.service.getAllFunctions() calls with a filtered version. This could then also be used to provide similar logic in files like validate.js.

[timbodeit]

The same nodeFunctionNames would also need to be used below in lines 149 (previously 154) and 165 (previously 160) to avoid serverless-webpack still overriding the artifact path of the given function.

[murilolobato]

There is any workaround for webpack avoid packaging a python function while this solution is not merged into master?

[j0k3r]

Done by #876