Erlang web server with Pulumi

This demo erlang web server is using Pulumi to be deployed to AWS and available through an ALB over a set of containers in Fargate ECS. It includes:

1. A dedicated VPC and subnets with relevant security group for the ALB
2. ALB and Fargate ECS task for the containers
3. A dockerized erlang application that shows the relevant request information (host,port,method,scheme,version,query_params, headers excluding Cookie,query_params (for a GET request) and body (for a POST or PUT request)).

Prerequisites

1. You should have the following executables installed on your system in order for the automated processes to run: pulumi,AWS CLI,docker engine,node.js and npm. If you don't have them (or not sure), just run make init from the root and the script will figure it out and install what's missing.
2. You should have an AWS IAM user that is capable of creating the required resources for the Pulumi stack. If you don't have one, you can create a user with the relevant permissions using make init-user. Note that you will still need a user that has permissions to create users, groups and policies in IAM configured (either with AWS_PROFILE or aws configure or with the AWS_ACCESS_KEY_ID/AWS_SECRET_ACCESS_KEY env variables). For security purposes the access key and secret key are not created through pulumi and have to be created and retrieved manually from the AWS console and configured before running the actual stack init.
3. Docker engine needs to be running. The init script will not attempt to mess with a running docker daemon so this either needs to be up before the init script is running or before the deployment is run.

Note that if the credStore for docker on your machine is ecr-login the stack creation for pulumi will not work (not supported yet) - it needs to be osxkeychain for a mac based docker engine.

Initialization

1. Run make init if you need to install any of the required executables: pulumi, awcli, docker.io,nodejs or npm.
2. Run make init-user to create a user with relevant permissions on AWS if one is not already configured
3. Get the AWS_ACCES_KEY_ID and AWS_SECRET_ACCESS_KEY for the user from the AWS console (these are not exported for security reasons) and either store them in ~/.aws/credentials and alter to the relevant user profile by setting AWS_PROFILE, or set the env variables.

Deployment

1. In order to run the application, run make deploy.
2. If everything is set correctly, you will receive the URL to access the application as an output.
3. Use that URL on a browser or with curl to see the results of the application.

Testing

Currently available maually through a Postman collection (examples/erlang_web_server_examples.postman_collection.json)

Destroying

In order to destroy the pulumi stacks, use either make destroy (for the application stack) or make destroy-user (for the user resources that were created with init-user). Note that these are deliberately not using the auto approval (-y flag) so that you have a chance to regret it after initiating the rule.

Future improvements

1. Automated integration and E2E tests
2. Fighting some more with the jsone module for erlang so that it can be used for JSON formatting of the response from cowboy.
3. Prettifying (?) of the response JSON