Don't Slack Evil

Don't Slack Evil is the submission of the team "Les Gars" for the 2020 Slack App virtual hackathon

Getting started

1. Setup the serverless framework
2. Set up shared AWS credentials:

• Ask Cyril for the shared AWS credentials
• Add to your AWS credentials file (~/.aws/credentials) the following:

[dont-slack-evil-hackaton]
aws_access_key_id=SECRET_FROM_CYRIL
aws_secret_access_key=SECRET_FROM_CYRIL

• Add to your aws config file (~/.aws/config) the following:

[profile dont-slack-evil-hackaton]
region=us-east-1

3. Set up secret file: cp example.secrets.dev.yml secrets.dev.yml and fill the secrets
4. Deploy: make deploy
5. Configure your Slack app with your function URLs

• event subscriptions : use the /messages endpoint
• interactive components : use the /interactive endpoint

Requirements

• golang >= 1.13
• direnv (if you are not using VSCode)

Updating env variables

Currently if you need to update environment variables you need to

• update example.secrets.dev.yml
• update secrets.dev.yml, the actual env file
• update serverless.yml to inject the env variable where it is needed
• update the "Create secrets file" section of continuous_production.yml to create the env file in CI

Setting up your Go environment

If you are using VSCode

• Install the Go extension. When prompted, install the necessary Go Tools (golint, goreturns, gopls)
• Add these properties to your settings.json file:

{
    "go.useLanguageServer": true,
    "go.toolsEnvVars": {
            "GO111MODULES": "on",
            "GOFLAGS": "-mod=vendor"
    }
}

The first property, go.useLanguageServer, will activate the Language Server for Go, which will improve features such as autocompletion, when using modules.

The second property, go.toolsEnvVars, will export 2 env vars when code analysis is performed by VSCode:

1. GO111MODULES=on: this will activate the use of Golang modules
2. GOFLAGS=-mod=vendor: references to external packages will be looked up in the /vendor gitignored folder

You can make use of the following extra properties:

• go.testOnSave: true for triggering go test on each save (if autosave is disabled) or CTRL+S (if autosave is enabled)
• go.testOnSave: false for deactivating build on each save

Setup tests

Under Debug > open configurations, add the following ENV variables

"env": {
  "DYNAMODB_TABLE_PREFIX": "dont-slack-evil-test-",
  "AWS_REGION": "us-east-1"
},

Under Code > Preferences > Settings, search for "testEnvVars" and add your vars again under settings

"settings": {
  "go.testEnvVars": {
    "DYNAMODB_TABLE_PREFIX": "dont-slack-evil-test-",
    "AWS_REGION": "us-east-1"
  },
}

If you are using a regular text editor

• direnv will execute the .envrc file and leverage the 2 env variables
• Install golint (the linter) and goreturns (the formatter)

go get -u golang.org/x/lint/golint
go get -u github.com/sqs/goreturns

• Before committing your code, run the formatter, and then, run the linter and correct any error it raises

go fmt ./..
$HOME/go/bin/golint ./..

WARNING: The linter will also show errors from the /vendor directory

Adding/removing a dependency

• If you are using VSCode, the added dependency will be downloaded in the background. Otherwise, you will have to run

go get -u <Dependency_Path>

• Delete the vendor/ folder, cd into the project's root dir and run these 2 commands:

# Recreate the vendor/ folder
go mod vendor

# Update go.mod and go.sum
go mod tidy

Running tests

Project-level tests can be run with this single command:

go test ./...

You can append the -v flag for verbose input

Useful links

Serverless AWS Lambda in Golang

https://github.com/serverless/examples

DynamoDB

https://github.com/awsdocs/aws-doc-sdk-examples/tree/456068072ee2ee696b2aac4724c925171c2bb2ff/go/example_code/dynamodb

Useful commands

# Deploy
serverless deploy function -f webhook
# OR
serverless deploy

# Logs the activity of a lambda
serverless logs -t -f hello

# Encrypt / Decrypt secrets
serverless encrypt --stage dev --password 'your-password'
serverless decrypt --stage dev --password 'your-password'

# Remove all serverless services
serverless remove

If make deploy fails:

go get -u github.com/aws/aws-lambda-go/lambda