０．はじめに

AWS CodeCommit を利用していたんですが、

Git Push した時の変更情報の通知が欲しかったので、試してみました。

大枠の流れは、以下。

１．SNS のトピックを作成し、所定のメールアドレスを登録する。

基本的に、以下のページの手順に従って設定します。

[基本操作]Amazon SNSでメールを送信する｜ DevelopersIO

SNS のトピックを作成します。設定は、以下。
- トピック名 : ※任意
- アクセスポリシー : ※以下参考。

{
"Version": "2008-10-17",
"Id": "__default_policy_ID",
"Statement": [
{
"Sid": "__default_statement_ID",
"Effect": "Allow",
"Principal": {
"AWS": "*"
},
"Action": [
"SNS:GetTopicAttributes",
"SNS:SetTopicAttributes",
"SNS:AddPermission",
"SNS:RemovePermission",
"SNS:DeleteTopic",
"SNS:Subscribe",
"SNS:ListSubscriptionsByTopic",
"SNS:Publish",
"SNS:Receive"
],
"Resource": "arn:aws:sns:ap-northeast-1:XXXXXXXXXXXX:SysOps-Lambda-Mnt",
"Condition": {
"StringEquals": {
"AWS:SourceOwner": "XXXXXXXXXXXX"
}
}
}
]
}
```
*

作成した SNS のトピックへ、所定のメールアドレスをサブスクリプションとして登録する。
- 　
登録後、作成した SNS のトピックへ、パブリッシュして SNS トピックが正常に設定されているか、確認する。

２．Lambda ファンクションを作成する。

IAM ロールを作成します。設定は、以下。
- ロール名 : ※任意
- ポリシー名 : ※任意
- ポリシー : ※以下参考。

{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "VisualEditor0",
"Effect": "Allow",
"Action": "sns:Publish",
"Resource": [
"arn:aws:sns::XXXXXXXXXXXX:SysOps-Lambda-DLQ",
"arn:aws:sns:ap-northeast-1:XXXXXXXXXXXX:DevOps-Team-XXXX",
"arn:aws:sns:ap-northeast-1:XXXXXXXXXXXX:SysOps-Lambda-Mnt"
]
},
{
"Sid": "VisualEditor1",
"Effect": "Allow",
"Action": [
"codecommit:GetCommit",
"logs:CreateLogStream",
"codecommit:GetDifferences",
"codecommit:GetBlob",
"logs:CreateLogGroup",
"logs:PutLogEvents"
],
"Resource": ""
}
]
}
```
*
*

Lambda ファンクションを作成します。設定は、以下。
- ファンクション名 : ※任意
- 実行ロール : ※作成した IAM ロール
- コード : ※以下参考。

#!/usr/bin/env python
# -*- coding: utf-8-unix; -*-
"""AWS Lambda Function - Maintenance DevOps CodeCommit Push to SNS
"""
from __future__ import print_function

import logging
import boto3
import os
import difflib

# 「python - aws lambda Unable to import module 'lambda_function': No module named 'requests' - Stack Overflow」
# https://stackoverflow.com/questions/48912253/aws-lambda-unable-to-import-module-lambda-function-no-module-named-requests
from botocore.vendored import requests

# 「Python 3 で少しだけ便利になった datetime の新機能 - Qiita」
# <https://qiita.com/methane/items/d7ac3c9af5a2c659bc51>
from datetime import datetime, timezone, timedelta
TimeZone = timezone(timedelta(hours=+9), 'JST')

# ISO 8601の日付フォーマットをPythonでparseするには
# http://blog.kzfmix.com/entry/1311336119
import dateutil.parser

# 「Lambdaの本番業務利用を考える① - ログ出力とエラーハンドリング | ナレコムAWSレシピ」
# <https://recipe.kc-cloud.jp/archives/9968>
logger = logging.getLogger()
logLevelTable={'DEBUG':logging.DEBUG,'INFO':logging.INFO,'WARNING':logging.WARNING,'ERROR':logging.ERROR,'CRITICAL':logging.CRITICAL}
if os.environ.get('logging_level') in logLevelTable :
    logger.setLevel(logLevelTable[os.environ['logging_level']])
else:
    logger.setLevel(logging.WARNING)

#
StartDateTime = datetime.now(TimeZone)

# Aws

# Mail
MailSubjectTemplate = "AWS CodeCommit Push ({0}/{1}) By {2} At {3:%Y/%m/%dT%H:%M:%S.%f%z}"

MailMessageTemplate00 = "\
\n\
{0}\n\
\n\
　■処理時間 : {1:%Y/%m/%d %H:%M:%S} ～ {2:%Y/%m/%d %H:%M:%S}\n\
\n\
　■コミット\n\
　　・ID　　　　　:　{3}\n\
　　・Last ID 　　:　{4}\n\
　　・Comment 　　:\n\
----\n\
{5}\
----\n\
　　・Author　　　:　{6}\n\
　　・Committer 　:　{7}\n\
　　・AddData 　　:\n\
----\n\
{8}\
----\n\
\n\
　■差分\n\
"

MailMessageTemplate01 = "{0}\n\
[{1}] {2}\n\
{3}\
"

MailMessageTemplate02 = "{0}\n\
\n\
----\n\
"

# ------------------------------------------------------------------------------
# CodeCommit Info Get
# ------------------------------------------------------------------------------
def CodeCommitInfoGet(prmRepositoryName, prmBranchName, prmCommitID, prmInfo):
    logging.info("prmRepositoryName:[%s]", prmRepositoryName)
    logging.info("prmBranchName:[%s]", prmBranchName)
    logging.info("prmCommitID:[%s]", prmCommitID)
    result = 0
    try:
        # CodeCommit — Boto 3 Docs 1.9.95 documentation
        # https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/codecommit.html
        # Amazon CodeCommit にPushしたファイルを S3 に自動保存してみた - 挫折から何かしら学んでいきたい
        # https://rioner2525.hatenablog.com/entry/2018/11/10/161030
        # Automatically publish to S3 using AWS CodeCommit and Lambda – nlytn
        # https://nlytn.me/archives/2018/09/06/204
        codecommit = boto3.client('codecommit')
        commit = codecommit.get_commit(repositoryName=prmRepositoryName,commitId=prmCommitID)
        logging.info("commit:[%s]", commit)
        prmInfo['commit'] = commit['commit']
        prmInfo['differences'] = {}
        if 'commit' in commit:
            if 'parents' in commit['commit'] and len(commit['commit']['parents']) > 0:
                differences = []
                response = codecommit.get_differences(
                    repositoryName=prmRepositoryName,
                    beforeCommitSpecifier=commit['commit']['parents'][0],
                    afterCommitSpecifier=prmCommitID)
                while 'nextToken' in response:
                    differences += response['differences']
                    response = codecommit.get_differences(
                        repositoryName=prmRepositoryName,
                        beforeCommitSpecifier=commit['commit']['parents'][0],
                        afterCommitSpecifier=prmCommitID,
                        nextToken=response['nextToken'])
                else:
                    differences += response['differences']
                logging.info("differences:[%s]", differences)
                for difference in differences:
                    logging.info("difference:[%s]", difference)
                    changeType = difference.get('changeType', '')
                    beforeBlobPath = ''
                    beforeBlobContent = ''
                    if 'beforeBlob' in difference:
                        beforeBlobPath = difference['beforeBlob'].get('path', '')
                        blobID = difference['beforeBlob'].get('blobId', '')
                        if blobID:
                            try:
                                beforeBlobContent = codecommit.get_blob(repositoryName=prmRepositoryName, blobId=blobID)['content'].decode('utf-8')
                            except UnicodeDecodeError:
                                beforeBlobContent = "??? beforeBlobContent UnicodeDecodeError ???\n"
                    logging.info("beforeBlobPath:[%s]", beforeBlobPath)
                    logging.info("beforeBlobContent:[%s]", beforeBlobContent)
                    afterBlobPath = ''
                    afterBlobContent = ''
                    if 'afterBlob' in difference:
                        afterBlobPath = difference['afterBlob'].get('path', '')
                        blobID = difference['afterBlob'].get('blobId', '')
                        if blobID:
                            try:
                                afterBlobContent = codecommit.get_blob(repositoryName=prmRepositoryName, blobId=blobID)['content'].decode('utf-8')
                            except UnicodeDecodeError:
                                afterBlobContent = "??? afterBlobContent UnicodeDecodeError ???\n"
                    logging.info("afterBlobPath:[%s]", afterBlobPath)
                    logging.info("afterBlobContent:[%s]", afterBlobContent)
                    path = ''
                    blobid = ''
                    if changeType:
                        if beforeBlobPath:
                            path = beforeBlobPath
                        elif afterBlobPath:
                            path = afterBlobPath
                    if path:
                        key = changeType + '_' + path
                        prmInfo['differences'][key] = {
                            'changeType': changeType,
                            'path': path,
                            'difference': difference,
                            'beforeBlobContent': beforeBlobContent,
                            'afterBlobContent': afterBlobContent,
                        }
    except Exception as e:
        logger.exception("Error dosomething: %s", e)
        result = 1
        raise
    else:
        pass
    finally:
        pass
    return result
    
# 「【Python】Lambdaからメールを送信 | ハックノート」
# https://hacknote.jp/archives/35679/
def MailSend(prmTopic, prmSubject, prmMessage):
    result = -1
    try:
        sns = boto3.client('sns')
        response = sns.publish(
            TopicArn = 'arn:aws:sns:ap-northeast-1:XXXXXXXXXXXX:' + prmTopic,
            Message = prmMessage,
            Subject = prmSubject
        )
    except Exception as e:
        logger.exception("Error dosomething: %s", e)
        result = -1
        raise
    else:
        pass
    finally:
        pass
    return result

def lambda_handler(event, context):
    try:
        global StartDateTime
        StartDateTime = datetime.now(TimeZone)
        logger.info("StartDateTime:[%s]", StartDateTime)
        #
        logger.info("event:[%s]", event)
        commitID = ""
        commitRef = ""
        eventTime = ""
        eventSourceARN = ""
        userIdentityARN = ""
        customData = ""
        if 'Records' in event and len(event['Records']) > 0:
            eventTime = event['Records'][0].get('eventTime', '')
            eventTime = dateutil.parser.parse(eventTime).astimezone(TimeZone)
            eventSourceARN = event['Records'][0].get('eventSourceARN', '')
            userIdentityARN = event['Records'][0].get('userIdentityARN', '')
            customData = event['Records'][0].get('customData', '')
            if 'codecommit' in event['Records'][0] and 'references' in event['Records'][0]['codecommit'] and len(event['Records'][0]['codecommit']['references']) > 0:
                commitID = event['Records'][0]['codecommit']['references'][0]['commit']
                commitRef = event['Records'][0]['codecommit']['references'][0]['ref']
        logger.info("commitID:[%s]", commitID)
        logger.info("commitRef:[%s]", commitRef)
        logger.info("eventTime:[%s]", eventTime.isoformat())
        logger.info("eventSourceARN:[%s]", eventSourceARN)
        logger.info("userIdentityARN:[%s]", userIdentityARN)
        logger.info("customData:[%s]", customData)
        logger.info("context:[%s]", context)
        #
        branchName = os.path.basename(commitRef)
        userName = os.path.basename(userIdentityARN)
        repositoryName = eventSourceARN.split(":")[-1]
        logger.info("branchName:[%s]", branchName)
        logger.info("userName:[%s]", userName)
        logger.info("repositoryName:[%s]", repositoryName)
        # ----------------------------------
        # CodeCommit Info Get
        # ----------------------------------
        dicInfo = {}
        CodeCommitInfoGet(repositoryName, branchName, commitID, dicInfo)
        logging.info("dicInfo:[%s]", dicInfo)
        # ----------------------------------
        # Mail Create Message
        # ----------------------------------
        # Subject
        tmpSubject = MailSubjectTemplate.format(repositoryName, branchName, userName, eventTime)
        # Message
        tmpMessage = MailMessageTemplate00.format(
            tmpSubject,
            StartDateTime,
            datetime.now(TimeZone),
            dicInfo['commit']['commitId'],
            dicInfo['commit']['parents'],
            dicInfo['commit']['message'],
            dicInfo['commit']['author'],
            dicInfo['commit']['committer'],
            dicInfo['commit']['additionalData'])
        #
        for key in sorted(dicInfo['differences']):
            logging.info("key:[%s]", key)
            logging.info("difference:[%s]", dicInfo['differences'][key])
            # 6.3. difflib — 差分の計算を助ける — Python 3.6.5 ドキュメント
            # https://docs.python.jp/3/library/difflib.html
            # text 文字列 差分 - ファイルを比較するpython difflib - CODE Q&A 問題解決
            # https://code.i-harness.com/ja-jp/q/f21341
            # Pythonのdifflibモジュールを用いて複数行テキストどうしの差分を取得する - 試験運用中なLinux備忘録
            # http://d.hatena.ne.jp/kakurasan/20100308/p1
            diff = difflib.unified_diff(
                dicInfo['differences'][key].get('beforeBlobContent', '').splitlines (True),
                dicInfo['differences'][key].get('afterBlobContent', '').splitlines (True),
                fromfile=dicInfo['differences'][key].get('path', ''),
                tofile=dicInfo['differences'][key].get('path', ''),
                lineterm='\n')
            changes = ""
            for l in diff:
                changes += l
            #changes = [l for l in diff if l.startswith('+ ') or l.startswith('- ')]
            logging.info("changes:[%s]", changes)
            tmpMessage = MailMessageTemplate01.format(
                tmpMessage,
                dicInfo['differences'][key].get('changeType'),
                dicInfo['differences'][key].get('path'),
                changes)
        #
        tmpMessage = MailMessageTemplate02.format(tmpMessage)
        
        # Mail Send
        tmpTopic = 'SysOps-Lambda-Mnt'
        if customData:
            tmpTopic = customData
        logging.info("tmpTopic:[%s]", tmpTopic)
        logging.info("tmpSubject:[%s]", tmpSubject)
        logging.info("tmpMessage:[%s]", tmpMessage)
        MailSend(tmpTopic, tmpSubject, tmpMessage)
        
    except Exception as e:
        logger.exception("Error dosomething: %s", e)
    else:
        pass
    finally:
        pass
    #
    return "normal end"

３．AWS CodeCommit のトリガーを追加する。

Lambda のコンソールから、「トリガーを追加」ボタンを押下し、「CodeCommit」を選択する。
Lambda のコンソールから、「トリガーを追加」ボタンを押下し、「CodeCommit」を選択する。
- リポジトリ名 : ※所定のリポジトリ
- トリガー名 : ※任意
- イベント : ※任意
- ブランチ名 : ※任意

９９．ハマりポイント

Python スクリプトで、Diff 情報を作成するのが結構面倒でしたね…。

ＸＸ．まとめ

ご参考になれば♪