Post-mortem Timeline Generator

Mark messages in a public slack channel with a reaction emoji such as :small_blue_diamond: and export them to a file sent via DM.

Trigger with: /timeline :small_blue_diamond:

Here's what it looks like when used:

and here's the backend:

To deploy:

Set up pre-requisites

• Python3
• pip install --user awscli aws-sam-cli pipenv
• Valid AWS credentials
• Slack permission to create a Slack application.

Create a Slack App

• Start here: https://api.slack.com/apps and create an App.

• add a Bot user, and hit Install App. Customise the name and preference :)

• Note down the App and Bot OAuth tokens, and the Signing Secret to set as variables later.

• In OAuth and Permissions, add these:

  • channels:history (to parse the channel’s messages for reactions)
  • chat:write:bot (to message the user as the bot)
  • chat:write:user (to write ephemeral user-only messages to the user)
  • im:read (to handle the slash command and fail gracefully in dm’s)
  • files:write:user (to send the file)
  • users:read (to read the user directory and work out username to user id to make the output legible).

• You'll need your API Gateway URL to enable the slash command: we'll come back to this.

Set AWS parameters

Create S3 bucket if required:

aws s3 mb s3://deploy-timeline-<uniquename>

Set:

BUCKET='deploy-timeline' # Bucket to hold .yml in AWS for SAM
STACK_NAME='timeline-tool' # CF stack name
BOT_TOKEN=<slack bot token> # From slack app
SLACK_TOKEN=<slack app token> # From slack app
SIGNING_SECRET=<slack signing secret> # From slack app
LOGGING_DESTINATION=<arn of logging resource>
LOGGING_FORMAT=<desired logging format>

Deploy

From this repo's directory, deploy deploy.yml using SAM CLI (a Cloudformation transform) to create the AWS resources required. The below will upload requirements to S3, create a new .yml, push to AWS then clean up after itself.

Run:

./package.sh
sam package --template-file deploy.yml \
 --s3-bucket $BUCKET --output-template-file packaged.yml --region eu-west-1
sam deploy --template-file packaged.yml \
 --stack-name $STACK_NAME --capabilities CAPABILITY_NAMED_IAM \
 --region eu-west-1 --parameter-overrides SigningSecret=$SIGNING_SECRET \
 SlackBotToken=$BOT_TOKEN SlackAppToken=$SLACK_TOKEN \
 LoggingDestinationArn=$LOGGING_DESTINATION LoggingFormat=$LOGGING_FORMAT \
 --confirm-changeset
./package_cleanup.sh

You can now create your Slack App's slash command (I went with /timeline) and add the created API Gateway's URL to it! 🎉