Slack signup serverless

Serverless signup to Slack and more. Lambda with Python, StepFunctions, and Web front end. Python boilerplate included.

Community Signup Serverless Service with Lambda, Python, StepFunction and DynamoDB

Build Status Python 2.7

Blog post: Exploring Serverless with Python, StepFunctions, and Web Front-end Serverless

This time, with Serverless framework

This is a 'take two' on Slack Signup with AWS Lambda. It was simple and functional, but working with AWS raw is such a pain in the butt...

Here, I use 1) to make working with lambda enjoyable and 2) AWS step-functions for multi-step sign-up workflow that touches multiple services. In this particular example, the workflow does what StackStorm signtup needs:

It is easy to modify to add your custom steps, have fun!

Serverless application diagram

Install, configure, deploy, test

  1. Clone this repository.

  2. Install serverless framework, and the required plugins:

    npm install -g serverless
    npm install

    I use serverless-stepfunction plugin to write stepfunction as YAML in serverless.yaml and expose it as an API endpoint, and serverless-apig-s3 for convenient front-end deployment to the same URI (no CORS messing).

  3. Configure credentials

    1. For AWS credentials, follow setup docs. I prefer using [AWS CLI with named profiles]( cli-multiple-profiles.html). To use an AWS profile, export AWS_DEFAULT_PROFILE="profileName". Test AWS CLI settings: aws lambda list-functions.

      To use an AWS profile in Serverless, export AWS_PROFILE=$AWS_DEFAULT_PROFILE, to match aws CLI profile and avoid confusion. You MUST also specify the AWS region in AWS_REGION for serverless, as it won't take it from AWS profile. So, three env vars in total:

      export AWS_DEFAULT_PROFILE="profileName"
      export AWS_REGION=us-west-2

      NOTE: Till the bug #3947 fixed,the way to set a region is by --region in sls CLI.

      Or use --aws-profile profileName when invoking sls CLI. Unfortunately there's no way to test it before you try to deploy.

      Create ./private.yml file and set up the accountID and region there, see private.yml.example. Note that region must match

    2. Slack and ActiveCampaign: place your credentials and config in ./env.yml, use env.yml.example. To find your Slack credentials for production or testing, use this hint from Stackstorm-Exchange.

  4. Deploy

    1. Install Python dependencies:

    2. Deploy serverless stack

      sls deploy -v
    3. Deploy web client

      sls client deploy
  5. Run, with curl:

    curl -X POST -H "Content-Type: application/json" -d '{"email":"", "first_name":"Donald", "last_name":"Trump"}'

    Or, with serverless, for convenience:

    sls invoke stepf --name signup --data '{"email":"", "first_name":"Donald", "last_name":"Trump"}' 

Unit testing and local development

  1. Run tox (dah, tox and all your Python stack needs to be installed)

    virtualenv .venv
    source .venv/bin/activate
    pip install -r tests/test_requirements.txt
  2. To run unit tests for local testing/development:

    # Activate virtualenv from tox
    source ./tox/py27/bin/activate
    # Run all tests
    python -m pytest
    # Run a single test and print the output ( -s flag ) 
    python -m pytest -s tests/ 

Tips and tricks

  • Call individual lambda functions with serverless

    sls invoke -f RecordAC --data '{"email":"", "first_name":"Donald", "last_name":"Trump"}' 
  • Watch the logs:

    sls logs -f RecordAC
  • On subsequent web client updates, just run sls client deploy. However when changes touch API Gateway settings, the full deploy is needed.

  • Web updates doesn't [always, ever] deploy the API Gateway changes. Need to deploy manually (Console->Resources->Actions-Deploy API).

  • Due to apig-s3 bug, remove the web s3 bucket manually when removing a stack. aws s3 rb s3://bucketname --force

  • Removing the stack does not remove the DynamoDB table. If you really want to start from scratch, delete it manually (export the data first): aws dynamodb delete-table --table-name slack-signup-dev