Skip to content

Latest commit

 

History

History
34 lines (23 loc) · 3.44 KB

application-requirements.md

File metadata and controls

34 lines (23 loc) · 3.44 KB
Raw

Application Requirements

In order to use the template infrastructure, you need an application that meets the following requirements.

  • The application's source code lives in a folder that lives in the project root folder e.g. /app.
  • The application folder needs to have a Makefile that has a build target release-build that takes in a Makefile variable OPTS, and passes those OPTS as options to the docker build command. The top level Makefile in this repo will call the application's release-build make target passing in release tags to tag the docker image with.
  • The web application needs to listen on the port defined by the environment variable PORT, rather than hardcode the PORT. This allows the infrastructure to configure the application to listen on a container port specified by the infrastructure. See The Twelve-Factor App to learn more about designing applications to be portable to different infrastructure environments using environment variables.
  • The web application needs to have a health check endpoint at /health that returns an HTTP 200 OK response when the application is healthy and ready to accept requests.
  • The Docker image needs to have wget installed. This is used in the container task defintion's healthcheck configuration in order to ping the application's /health endpoint. If you want to use a different healthcheck command (e.g. curl) then you'll need to modify the healthCheck configuration in the aws_ecs_task_definition resource in modules/service/main.tf.

Database Requirements

If your application needs a database, it must also:

  • Have a db-migrate command available in the container's PATH for running migrations. If you use a migration framework like Alembic or Flyway you can create a db-migrate script that then calls your framework's binary.
  • Both the application service container and the container running the db-migrate script will receive the following environment variables that are needed to connect to the database using IAM authentication:
    • DB_HOST - the hostname to connect to
    • DB_PORT - the port that the database is listening on
    • DB_NAME - the PostgreSQL database to connect to
    • DB_USER - the username to log in as. For the application it will be app, and for the database migrations it will be migrator
    • DB_SCHEMA - the name of the PostgreSQL schema to be used by the application

Example Application

The infra template includes an example "hello, world" application that works with the template. The source code for this test application is at app.

A live demo of the test application is fully deployed by the https://github.com/navapbc/platform-test repo, which is used for testing the infra template. Please check that repo's README to locate a URL for seeing the live demo.

Template Applications

You can use the following template applications with the template infrastructure. Each of these includes a script to generate a working application that works with this infra template.