Profiles & Environments¶

Environment variable layers¶

Environment variables are resolved in layers. Later layers override earlier ones:

1. System environment
2. [env] section in Mustfile.toml
3. [env.<profile>] section
4. Recipe-level env field
5. MUST_ARGS environment variable

[env]
LOG_LEVEL = "info"
OPT_LEVEL = "2"
REGISTRY  = "ghcr.io/myorg"

[env]
OPT_LEVEL = "2"

[env.release]
OPT_LEVEL = "3"
LOG_LEVEL = "warn"

Select a profile:

must build --profile release

[recipe.build]
type    = "rust-bin"
package = "my-app"

[recipe.build.env]
RUSTFLAGS = "-C target-cpu=native"

Use ${VAR} syntax for runtime expansion:

[env]
TARGET_DIR = "target/${TARGET}"
IMAGE_TAG  = "${REGISTRY}/api:${VERSION}"

$VAR and ${VAR} are both supported. Undefined variables expand to empty strings.

Pass extra flags from CI or wrappers:

MUST_ARGS="--release --fail-fast" must build

Recipes inherit the full system environment plus all must-configured variables. This means: