Services

Coherence supports any application that can be containerized and which serves HTTP traffic. Here are some common examples. Be sure to review the documentation on database seeding and loading data from database snopshots, which apply to all Coherence applications.

Redwood.js

See a full example repo here. The Dockerfiles are optional - we will build your app with nixpacks if you do not provide them.

api:
  type: backend
  url_path: "/api"
  prod:
    dockerfile: Dockerfile.api
    command: ["yarn", "rw", "serve", "api"]
  dev:
    command: ["yarn", "rw", "dev", "api"]
  local_packages: ["node_modules"]

  system:
    cpu: 2
    memory: 2G
    health_check: "/graphql/health"

  resources:
  - name: db1
    engine: postgres
    version: 13
    type: database

web:
  type: frontend
  assets_path: "web/dist"
  prod:
    dockerfile: Dockerfile.web
    command: ["yarn", "rw", "serve", "web"]
  dev:
    command: ["yarn", "rw", "dev", "web", "--fwd=\"--allowed-hosts all\""]
  build: ["yarn", "rw", "build", "web"]
  local_packages: ["node_modules"]

  system:
    cpu: 2
    memory: 2G

React Exmaple

See a full example repo here.

frontend:
  type: frontend
  assets_path: dist
  local_packages: ["node_modules"]
  install: ["yarn", "install"]
  build: ["yarn", "build"]
  dev: ["yarn", "dev"]

Django Example

See a full example repo (this repo includes a react frontend and a django backend) here. A few other things you'd want to do:

• Install dj-database-url package to easily get the right database configuration. You can add this to your requirements.txt file.
• Make sure to use COHERENCE_DEV environment variable to set the DEBUG value in your settings.
• Add the COHERENCE_ENVIRONMENT_DOMAIN and COHERENCE_CUSTOM_DOMAIN to the ALLOWED_HOSTS settings to prevent CORS issues.
• You can configure the prod command to use another python WSGI server like gunicorn as well by changing the command in the yaml configuration below.

See the Environment Variables docs for more info on the variables mentioned above.

server:
  type: backend
  repo_path: backend
  migration: ["python", "manage.py", "migrate"]
  dev: ["python", "manage.py", "runserver", "0.0.0.0:$PORT"]
  prod: ["python", "manage.py", "collectstatic", "&&", "python", "manage.py", "runserver", "0.0.0.0:$PORT"]

  resources:
  - name: db1
    engine: postgres
    version: 13
    type: database
  - name: redis
    engine: redis
    version: 4
    type: cache

Rails Example

You need to make sure to either collect static assets in your docker build, or include in the prod command below...

server:
  type: backend
  repo_path: backend
  migration: ["rails", "server:migrate"]
  dev: ["rails", "server", "-p", "$PORT"]
  prod: ["rails", "server", "-e",  "production", "-p", "$PORT"]

  system:
    memory: 2G
    cpu: 1

  resources:
  - name: db1
    engine: mysql
    version: 8.0
    type: database
  - name: redis
    engine: redis
    version: 4
    type: cache

flask example

flask is a popular python web framework. This is a simple example, assuming your app does not need a database and that your app.py file runs the flask server on the PORT environment variable provided by Coherence when it is run via python. You can configure the dev or prod commands to use flask run or another python WSGI server like gunicorn as well by changing the commands in the yaml configuration below.

You can also add a database and cache easily, see the other examples on this page including the redwood and Rails examples above for syntax, nothing special needs to be done for flask itself, aside from listening to the appropriate variables to configure your database connections, e.g. DATABASE_URL.

backend:
  type: "backend"
  dev: ["python", "app.py"]
  prod: ["python", "app.py"]

Next.js Example

There are 2 common configurations used for Next.js. One is static export where your site ends up as single page app served from a CDN. The other (more common) configuration is where you run a server process and this configuration supports functionality such as server-side rendering, API routes, and database-backed services. See more in the Next docs.

For running a server process, use the backend service type on Coherence. See a full example repo here.

backend:
  type: backend
  local_packages: ["node_modules"]
  dev: ["npm", "run", "dev"]
  prod: ["npm", "run", "start"]

For deploying a single page app, use a frontend service type.

frontend:
  type: frontend
  local_packages: ["node_modules"]
  dev: ["npm", "run", "dev"]
  build: ["npm", "run", "export"]