lambda-cloudwatch-slack

An AWS Lambda function for better Slack notifications. Check out the blog post.

Overview

This function was originally derived from the AWS blueprint named cloudwatch-alarm-to-slack. The function in this repo improves on the default blueprint in several ways:

Better default formatting for CloudWatch notifications:

Support for notifications from Elastic Beanstalk:

Support for notifications from Code Deploy:

Basic support for notifications from ElastiCache:

Support for encrypted and unencrypted Slack webhook url:

Configuration

1. Clone this repository

2. Configure environment variables

cp .env.example .env

Fill in the variables in the .env.

3. Setup Slack hook

Follow these steps to configure the webhook in Slack:

1. Navigate to https://slack.com/services/new and search for and select "Incoming WebHooks".

2. Choose the default channel where messages will be sent and click "Add Incoming WebHooks Integration".

3. Copy the webhook URL from the setup instructions and use it in the next section.

4. Click 'Save Settings' at the bottom of the Slack integration page.

Encrypted the Slack webhook URL

If you don't want or need to encrypt your hook URL, you can use the UNENCRYPTED_HOOK_URL. If this variable is specified, the KMS_ENCRYPTED_HOOK_URL is ignored.

If you do want to encrypt your hook URL, follow these steps to encrypt your Slack hook URL for use in this function:

1. Create a KMS key - http://docs.aws.amazon.com/kms/latest/developerguide/create-keys.html.

2. Encrypt the event collector token using the AWS CLI. $ aws kms encrypt --key-id alias/ --plaintext "<SLACK_HOOK_URL>"

   Note: You must exclude the protocol from the URL (e.g. "hooks.slack.com/services/abc123").

3. Copy the base-64 encoded, encrypted key (CiphertextBlob) to the ENCRYPTED_HOOK_URL variable.

4. Give your function's role permission for the kms:Decrypt action. Example:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "Stmt1443036478000",
            "Effect": "Allow",
            "Action": [
                "kms:Decrypt"
            ],
            "Resource": [
                "<your KMS key ARN>"
            ]
        }
    ]
}

4. Deploy to AWS Lambda

The final step is to deploy the integration to AWS Lambda:

npm install
npm run deploy

Tests

With the variables filled in, you can test the function:

npm install
npm test

License

MIT License