Advent of Code Slack Notifier

What?

This project is aimed at those participating in https://adventofcode.com/ and who are member of one ore more private leaderboards.

This application will poll the AOC API, store the data in a DynamoDB and notify a Slack channel of your choice if there has been a change in the leaderboard.

How it works

This projects runs on AWS and uses the following component:

• A Lambda to poll adventofcode.com API
• DynamoDB to store historical data
• A Lambda to compare the latest two polling events
• An SQS queue to pass data between the two lambdas

This project also uses the following frameworks:

• Serverless to deploy and manage the AWS resources
• Spring Boot to bootstrap the Java code
• Spring Cloud Function to integrate between Serverless and Spring
• jslack to talk to the slack API

Prerequisites

To run this project you need to do the following:

• (JDK 11 [or above] and Maven) OR (Docker)
• Create an AWS account and and IAM user configured in your ~/.aws/credentials file. See AWS tutorial for help
• Install Serverless via npm as explained here
• Create a Slack Incoming Webhook in your Slack environment and make sure you know the token. If your slack webhook is https://hooks.slack.com/services/abc/123 then your token is abc/123
• You are member of a AOC leaderboard and you know the id, typically https://adventofcode.com/2019/leaderboard/private/view/<id>
• You are logged in adventofcode.com and you know your sessionId (to get it just inspect the network and look at the cookie header: e.g. session=123...)

How to run

Step 1 - Configure your leaderboard(s)

You need to configure one or more leaderboard to poll. To do so update src/resource/application.yml:

polling:
  leaderboards:
    - leaderboardId: '<leaderboard ID>'
      year: '<year e.g. 2019>'
      slackToken: '<the slack token mentioned above>'

You can poll multiple leaderboards by adding more elements to the leaderboards list:

polling:
  leaderboards:
    - leaderboardId: '123'
      year: '2019'
      slackToken: 'abc/def'
    - leaderboardId: '345'
      year: '2019'
      slackToken: 'xxx/yyy'

Step 2: Build the project.

In the folder where you have checked out this project run the following command:

If you have Java 11 and Maven install locally just run:

mvn package -DskipTests

Alternatively if you have Docker installed locally you can simply run:

./buildWithDocker.sh

Step 3: Deploy to AWS

serverless deploy --sessionid <aocSessionId>

To remove all AWS resources simply run

serverless remove --sessionid <aocSessionId>

The polling uses the cron expression 0 */1 * * ? * by default (i.e. every hour). If you want to change this just add a -schedule 'cron(<write cron here>)' argument to the deploy command.

However please see this message from https://adventofcode.com:

Please don't make frequent automated requests to this service - avoid sending requests more often than once every 15 minutes (900 seconds).

Troubleshooting

• If your session cookie expires, just get another by refreshing your browser session and just rerun the deploy command above.

TODO

• write more tests
• compute hash of AOC response and don't save new dynamo DB event if there was no change
• Ability to customise Slack message with env variable
• Use block kit to write slack message
• Could add more complex logic in Slack by getting info from the
• Process dynamoDB data to draw interesting graph of ranks/stars in time