Add support for logs of all lambda functions

[jamesls]

The chalice logs command was written when there was only a single lambda function used as your API handler. I've found it really useful, but I'd like to be able to use this command for all the lambda functions in my app.

I'd like a -f/--function-name arg added that lets me provide the logical resource name of the function whose logs I'd like.

Example

Given this app:

@app.lambda_function()
def foo(event, context): ...

@app.route('/')
def index(): ...

The chalice logs command will continue to give me lambda logs for my API handler, but I can now also say:

$ chalice logs -f foo

and it will give me logs for the foo function. Also I'd like to get #4 added as well so I might need to work out if we want -f to mean what tail -f means or if we just want to use --tail.

[kyleknap]

Yes! Both would be awesome.

[kadrach]

Perhaps slightly off-topic, but functionality to both enable (possible in SAM since 1.4.0) and get APIGateway logs would be awesome!

[aalvrz]

This sounds excellent. Never knew there was a chalice logs command. I am assuming these logs get pulled from CloudWatch?

[jamesls]

@BigChief45 yep they get pulled from cloudwatch logs. It also has some abstraction on top of the low level cloudwatch logs call to make the logs easier to read. I added a few examples over in #841 but our docs could probably use more examples.

@kadrach I'd like that as well, it's sometimes the only way to track down issues with bad responses from Lambda. I've created #849 to track this work.