AWS Lambda triggered by pushes/commits, constructs simple message and then triggers a SNS topic

README.md

Follow the steps in: http://docs.aws.amazon.com/codecommit/latest/userguide/how-to-notify-lambda.html

Below is my summary of what you need to do.

create SNS Topic

• Visit AWS SNS control panel > Topics > Create topic, name = "commits" or something
• Create Subscription to topic > email

create an IAM Role

• Visit IAM control panel > Roles > Create Role
• Service role: Lambda
• Add AWSCodeCommitFullAccess policy
• Add AmazonSNSFullAccess policy

create Lambda Function

• Visit AWS Lambda control panel > Dashboard

• Create Function > blueprint = Author from scratch

• Configure triggers dialogue: click on dashed box, choose CodeCommit, make up a trigger name

• Configure function dialogue: name something like CodeCommitLambdaFunction, Runtime = Python 2.7

• Existing role: service-role/CodeCommitLambdaRole

• paste code from this gist, CodeCommitLambdaFunction_allEvents.py

• uncomment print of "Received event"

• Save

• Commit and push to repo. The Lambda function should get triggered.

• Go to the Lambda function you created, Monitoring tab, View Logs in CloudWatch, choose event, view in plain text.

• Grab the text of the incoming event in order to create a test input for your function.

• Back to Code tab

• Actions > Configure Test Event

• paste in '{ "Records" : [ ... ] }' you copied from logs. Save and Test.

CodeCommitLambdaFunction_allEvents.py

# ARN - arn:aws:lambda:us-east-2:750303481583:function:DoverCodeCommitLambdaFunction_allEvents

import json
import boto3
from datetime import datetime as dt
from string import split

codecommit = boto3.client('codecommit')
sns = boto3.client('sns')

doverCommits_topicARN = 'arn:aws:sns:us-east-2:750303481583:DoverCommits'

def lambda_handler(event, context):
    #Log the updated references from the event
    references = event['Records'][0]['codecommit']['references']
    print("References: " + str(references))

    repo = event['Records'][0]['eventSourceARN'].split(':')[5]
    msg = ""
    response = ""
    primary_author = ""
    
    for record in references:
        commit = record['commit']
        ref = record['ref']
        # get commit info
        try:
            response = codecommit.get_commit(commitId=commit, repositoryName=repo)
        except Exception as e:
            print(e)
            print("Error getting commit {}.".format(commit))
            raise e

        print("get_commit response for commit {} and repo {}:\n\t{}".format(
            commit, repo, str(response)))

        c = response['commit']
        author = c['author']['name']
        primary_author = author
        authorDate = dt.fromtimestamp(int(split(c['author']['date'])[0]))
        committer = c['committer']['name']
        committerDate = dt.fromtimestamp(int(split(c['committer']['date'])[0]))
        msg += "Commit {}: \n".format(commit)
        msg += "Author: {} <{}>. Date: {}\n".format(
            c['author']['name'],
            c['author']['email'], 
            dt.isoformat(authorDate))
        if author != committer:
            msg += "\tCommitter: {} <{}>. Date: {}\n".format(
                c['committer']['name'],
                c['committer']['email'], 
                dt.isoformat(committerDate))
        msg += "Ref: {}\n".format(ref)
        msg += "\n{}\n".format(c['message'])
            
        # get files info
        firstParent = c['parents'][0]
        try:
            response = codecommit.get_differences(
                repositoryName=repo,
                beforeCommitSpecifier = firstParent,
                afterCommitSpecifier = commit)
            print("get_differences response = {}".format(json.dumps(response)))
        except Exception as e:
            print(e)
            print("Error doing get_differences")
            raise e

        msg += "Files:\n"
        for diff in response['differences']:
            if 'beforeBlob' in diff:
                msg += "\t {}".format(
                    diff['beforeBlob']['path'])
            elif 'afterBlob' in diff:
                msg += "\t {}".format(
                    diff['afterBlob']['path'])
            msg += " ({})\n".format(
                diff['changeType'])

        # end of for commit in commits loop

    print("publishing message: {}\n".format(msg))

    subj = "{} :: {}".format(repo, author)
    try:
        response = sns.publish(Message=msg,
                               TopicArn=doverCommits_topicARN,
                               Subject=subj)
    except Exception as e:
        print(e)
        print("Error doing sns.publish")
        raise e

    print("publish response: {}".format(json.dumps(response)))
    return response