[AIRFLOW-1571] Add AWS Lambda Hook

[sid88in]

Dear Airflow maintainers,

Please accept this PR. I understand that it will not be reviewed until I have checked off all the steps below!

JIRA

• My PR addresses the following Airflow JIRA issues and references them in the PR title. For example, "[AIRFLOW-XXX] My Airflow PR"
  • https://issues.apache.org/jira/browse/AIRFLOW-1571

Description

• Here are some details about my PR, no UI changes

Details of this PR are in the Jira above.

Tests

• My PR adds the following unit tests

1. test_aws_lambda_hook
   This unit test uses moto to mock aws lambda. Firstly, we create a lambda function (assuming this function is already created by aws cloudformation template in production). Secondly, we trigger lambda function using invoke function in the hook. Lastly, we parse the response and assert statements.

Commits

• My commits all reference JIRA issues in their subject lines, and I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"

[codecov-io]

Codecov Report

Merging #2570 into master will increase coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2570      +/-   ##
==========================================
+ Coverage   71.13%   71.14%   +<.01%     
==========================================
  Files         150      150              
  Lines       11741    11741              
==========================================
+ Hits         8352     8353       +1     
+ Misses       3389     3388       -1

Impacted Files	Coverage Δ
airflow/models.py	87.15% <0%> (+0.04%)	⬆️

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[saguziel]

can we textwrap.dedent here instead

[sid88in]

thanks @saguziel for reviewing my PR :) Pushed the change.

[sid88in]

@artwr @criccomini (+ @saguziel @bolkedebruin) seems like you guys reviewed similar AWS related PR - #1630

Would be great if you could help review my PR. Any inputs are welcome (this is my first contribution to airflow) :)

[bolkedebruin]

Please make sure your commits are merged into one.

[sid88in]

@bolkedebruin resolved commits. thanks

[ghost]

You need some :paramname: and :type: documentation for the Class docstring, for the constructor properties
e.g.
:param function_name: The name of the AWS Lambda function to call
:type function_name: string

etc

[sid88in]

Good catch Thanks. ! I'll add docstrings today to both #2570 and #2586

[ghost]

Looking through the contrib codebase I see a lot of missing docstrings and param info, which is a shame because it's then missing when generating the docs, so maybe I will contribute to improving that.
But generally I can't see any other issues with the code, so it's a great effort! At some point soon I will be using your dynamodb stuff heavily, so if it's not in a release by then I will borrow it for my plugins folder 😀

[sid88in]

thanks @davoscollective for all the positive energy :)

[sid88in]

Closing this PR - its a duplicate of #2718