swo-summaraize-webhook-lambda

This is the SummarAIze lambda function which accepts GitHub webhook events for a pull request and adds a description to it.

Installation

To run SummarAIze, the following services are required:

• AWS Lambda
• AWS API Gateway

All the required AWS resources are created with a CloudFormation script.

In order to run the script, you will need:

• Python installed - you can download it from here.
• boto3 - The Python AWS SDK. Once you have installed Python, run pip install boto3.
• Node installed - you can download it from here.

After you have installed Python and Node, you should add the following environment variables to your machine:

• AWS_ACCESS_KEY_ID
• AWS_SECRET_ACCESS_KEY
• AWS_SESSION_TOKEN - needed only if assuming a different role than the default AWS one in your .aws/credentials folder
• AWS_DEFAULT_REGION - e.g. us-east-1.

To obtain the first three variables, you can use the assume-role command, e.g. aws sts assume-role --role-arn <AWS_PROFILE_ARN> --role-session-name <AWS_PROFILE_NAME>, where <AWS_PROFILE_ARN> is the arn of the profile you want to assume, and the <AWS_PROFILE_NAME> is the name you want to give to your assumed profile.

If you have troubles running this command, try deleting the existing values for the AWS_ACCESS_KEY_ID AWS_SECRET_ACCESS_KEY and AWS_SESSION_TOKEN or running the command with the --profile default parameter.

You can also use awsume command to directly change to your desired AWS profile - you can install it from here.

Prerequisites

A GitHub App is required for authorizing the Lambda function. When creating the app, add the following permissions to it:

• Commit statuses - read and write
• Contents - read and write
• Pull requests - read and write
• Webhooks - read only
• Metadata - read only

Running the script

Once everything is set up, navigate to the scripts folder and run the deploy-cloudformation.py script with python deploy-cloudformation.py

You will be prompted to input the following parameters:

• Github App secrets (required):
  • App Id
  • Client Id
  • Client Secret
  • Installation Id
  • Private Key - Make sure to paste the key as one line, with the \n character used for the new lines in the key. E.g. -----BEGIN RSA PRIVATE KEY-----\nABCDEFGHIKLMNOPQRSTVXYZABCDEFGHIKLMNOPQRSTVXYZABCDEFGHIKLMNOPQRS\nTUV
• API Key (required) - The API Key used for authentication. You can set this to an existing key if you want to. If you want to create a new key, you can do so by opening the AWS API Gateway console and navigating to API keys->Create API key. The key does not have to be attached to the created API for the webhook, you only need its value.
• GitHub Organization Name (required)
• Lambda function Name - The name of the Lambda function for handling webhook events (optional - default value: GitHubWebhookLambdaFunction)
• S3 Bucket name - The name of the S3 bucket where the lambda code will be stored. If the bucket does not exist it will be created. (optional - default value: summaraize-lambda-code)
• API Gateway name - The name of the API Gateway API (optional - default value: GitHubWebhookApi)
• API stage name - The name of the stage for the API (optional - default value: summaraize)
• CloudFormation stack name - The name of the AWS CloudFormation Stack (optional - default value: SummarAIzeStack)

Creating the webhook

After you have created the AWS CloudFormation Stack, navigate to AWS API Gateway and go to APIs->YOUR_API_NAME->Stages->YOUR_API_STAGE_NAME/api/webhook->POST. There you will find the Invoke URL for the API. Copy it.

Open GitHub and go to the repository where you want to add SummarAIze. Go to the Settings page and then the Webhooks tab. Click on Add Webhook. Input the required parameters:

• Payload URL - Your API Invoke URL.
• Content type - application/json
• Secret - Your API Key.
• Events - Click on Let me select individual events. and select only the Pull requests option.

Add the webhook.

Now everything should be set up and SummarAIze will add a description to your pull requests.