What does depends_on actually guarantee?

By default depends_on only controls start order — Compose starts the dependency container first, but does not wait for the service inside it to be ready. For true readiness, add a healthcheck to the dependency and use depends_on with condition: service_healthy.

When is a volume a named volume versus a bind mount?

If the source side of a mount is a plain name like db-data it is a named volume, managed by Docker and listed under the top-level volumes block. If it starts with ./ or / it is a bind mount of a host path, which is not declared at the top level.

Why put every service on a shared network?

Compose creates a default network automatically, but declaring an explicit bridge network makes intent clear and lets services reach each other by name. Inside the network, your api can connect to the database using the hostname db rather than an IP.

Should I commit secrets in the environment block?

No. The environment block is convenient for local development, but for anything sensitive use an env_file, Docker secrets, or values injected from your shell. The generated file is a starting point, not a place to store production passwords.

Why is restart: unless-stopped added to every service?

It tells Docker to restart a container automatically if it crashes or the daemon restarts, but to respect a manual stop. It is a sensible default for long-running services so a transient failure does not leave part of your stack down.

docker-compose.yml Builder

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A docker-compose.yml builder that turns a list of services — each with an image, ports, environment variables, volumes, and dependencies — into a valid Compose file complete with a top-level volumes block and a shared bridge network. It is built for developers spinning up a multi-container stack without hand-writing YAML and worrying about indentation.

How it works

Each service you add becomes one entry under the top-level services: key. The builder emits the image, a sensible restart: unless-stopped, a quoted list of ports, an environment map, a volumes list, and a depends_on list. Every service is attached to a single declared appnet bridge network so containers can resolve one another by service name.

Volume mounts are inspected: a source like db-data:/var/lib/postgresql/data is recognised as a named volume and collected into the top-level volumes: block, while a source like ./src:/app is treated as a bind mount and left inline. This keeps the generated file valid — named volumes must be declared, bind mounts must not.

Tips and notes

depends_on only orders startup. For databases, add a healthcheck to the db service and depend on it with condition: service_healthy so your app does not connect before Postgres is accepting queries.
Inside the network, use the service name as the hostname. An api connecting to a db service should use db:5432, not localhost.
Keep secrets out of the committed file — point sensitive services at an env_file or use shell-substituted variables like POSTGRES_PASSWORD=${DB_PASSWORD}.
Run docker compose config after pasting the file to have Docker validate and normalise it before you bring the stack up.