Weekly Review

I love getting things done and sometimes you need to reflect back on the things you've done. This AWS Lambda function does exactly that. Based on scheduled AWS CloudWatch events, it'll get all items from a specific list in Trello and send them to Slack (because that is where the work happens 😄)

Prerequisites

Environment Variables

The app relies on AWS Systems Manager Parameter Store (SSM) to store variables on how to connect to Jenkins. Some of the variables are encrypted using KMS. The variables the app relies on are:

• /prod/trello/key: The application key to authenticate to Trello (encrypted)
• /prod/trello/token The application token to authenticate to Trello (encrypted)
• /prod/trello/user The username to get details from Trello (encrypted)
• /prod/trello/board The name of the board to get details from
• /prod/trello/list The name of the list to get details from
• /prod/slack/url The webhook URL to connect to Slack (encrypted)
• /prod/slack/channel The name of the Slack channel to post to
• /prod/slack/user The name of the user a Slack message should be sent as
• /prod/slack/emoji The emoji for the Slack user

These parameters are encrypted using Amazon KMS and retrieved from the Parameter Store on deployment. This way the encrypted variables are given to the Lambda function and the function needs to take care of decrypting them at runtime.

To create the encrypted variables, run the below command for all of the variables

aws ssm put-parameter                       \
   --type String                            \
   --name "<token-name>"                    \
   --value $(aws kms encrypt                \
              --output text                 \
              --query CiphertextBlob        \
              --key-id <YOUR_KMS_KEY_ID>    \
              --plaintext "PLAIN TEXT HERE")

To create non-encrypted variables in SSM, run

aws ssm put-parameter                       \
   --type String                            \
   --name "<token-name>"                    \
   --value  "PLAIN TEXT HERE"

To test the function locally, using SAM, you'll have to uncomment lines 66-69 in the template.yaml file and update these with base64 encoded values from the Parameter Store. Only during deployment to AWS Lambda will these variables get their actual values from the Parameter Store.

Build and Deploy

There are several Make targets available to help build and deploy the function

Target	Description
build	Build the executable for Lambda
clean	Remove all generated files
deploy	Deploy the app to AWS Lambda
deps	Get the Go modules from the GOPROXY
help	Displays the help for each target (this message).
local	Run SAM to test the Lambda function using Docker
test	Run all unit tests and print coverage

License

See the LICENSE file for details