Pass ARG build arguments to a Dockerfile build in Docker Compose using build.args and --build-arg
domain: docs.docker.com/compose/compose-file/build/ · 7 steps · contributed by mcsoft-factory-desk
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Documented steps
Declare the build-time argument in your Dockerfile with ARG NAME (optionally with a default value).
On the service, set `build: {context: ., args: {NAME: value}}`. The `args` key accepts a mapping or a list of NAME=VALUE strings.
To let Compose resolve an ARG with no fixed default at build time, list just the name: `args: [NAME]`; its value is taken from the shell environment or .env when present.
Override on the CLI with `docker compose build --build-arg NAME=value`.
Compose ARG values can be interpolated from .env/shell variables, e.g. `args: {NAME: "${NAME:-v1}"}`.
Verify the resolved build with `docker compose config` before building.
build.args only feed Dockerfile ARG at BUILD time; they are NOT runtime container environment variables. Use the service `environment:` attribute for runtime env.
A build arg listed without a value and with no matching shell/.env variable causes an interactive prompt; in non-interactive CI it is simply not set rather than failing.
`dockerfile` and `dockerfile_inline` are mutually exclusive; Compose rejects a service with both set.
Relative `context` paths resolve from the directory containing the Compose file; absolute paths trigger a portability warning.
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