Backend

This is the Metrist.io backend app.

Prerequisites

• Current versions of Elixir and Erlang, and NodeJs.
  • There is an asdf-vm .tool-versions file which is the simple and recommended way to install all three.
• Assuming you're using a Debian-variant OS, there are some other packages you'll want to install:

sudo apt-get install erlang-dev
sudo apt-get install erlang-xmerl
sudo apt-get install npm

Development

Run docker-compose up -d to start PostgreSQL. Initialize everything with make dev, then make run to start the local server.

The docker-compose includes pgAdmin. The username is test@metrist.io and the password is 123qwe.

All you need to do is add a database connection (host, user, pass are all "postgres"). You'll want to ensure that you're connecting to the correct host IP, which should simply be postgres:5432 if you're using the Docker setup.

TimescaleDB is also started with docker-compose and it can be connected to by using

tsdb:5432 - from inside pgadmin
localhost:5532 from outside the container
postgres
postgres

Mix tests:

• run with mix test
• watch with mix test.watch
• watch specific test files with mix test.watch path/to/file.exs, example: mix test.watch test/domain/alert_manager_test.exs

A bunch of helpful stuff lives in the How-to directory.

RDS databases

We use the standard "prod" MIX_ENV for deployed environments, but that really means "AWS managed deployments". There are RDS databases configured per Stackery environment tag with secrets in Secrets Manager. The config.releases.exs module is a run-time configuration that fetches these secrets and uses them to configure users.

For now, we do manual migrations. Set the AWS environment variables, then point ENVIRONMENT_TAG and SECRETS_NAMESPACE to dev1 or prod, and run make migrate.

Auth, secrets, and so on

In development, the code can run without secrets but functionality will be limited (logging in will not be possible, for starters). Therefore, please set the following environment variables before starting mix phx.server:

  AWS_ACCESS_KEY_ID=<secret>
  AWS_SECRET_ACCESS_KEY=<secret>
  SECRETS_NAMESPACE=/dev1/
  AWS_REGION=us-east-1

This will run the backend with access to the dev1 environment's Secrets Manager values for accessing Auth0 and so on. See Backend.Application for details on the secrets pulled.

Other docs

• An explanation of our clustering setup
• Debugging deployed instances