ext-container-agent-dev

avocado-ext-container-agent-dev - the device side of Container Dev Mode.

The agent holds a control WebSocket open to the host CLI, proxies image pulls from the host's registry over a bootstrap-delivered pinned CA, and hot-reloads the target container when a sync lands. It is what makes avocado container dev transfer only the changed layer instead of a whole image.

Development only. This extension exists so it can be composed into a dev runtime and left out of production. The -dev suffix is the gate. Do not ship it on a production device.

Layout

Path	What it is
agent/	the Rust crate, cross-compiled at package time
cad-compile.sh	resolves the target triple and builds the crate
cad-install.sh	stages the built binary into the extension sysroot
cad-clean.sh	clears the build directory
overlay/	the container-agent-dev path and service units
avocado.yaml	extension manifest

Requires a container engine

The agent execs the engine CLI as its own child on every sync, so a runtime without the docker extension gives it nothing to do. That dependency is stated rather than declared: avocado-cli parses an inter-extension dependency and logs it without installing anything, so declaring it would read as a guarantee and deliver none. Compose both into the runtime yourself. The agent's startup preflight is what makes a missing engine fail loudly rather than silently.

Building locally

The SDK image tag is release-scoped and comes from the environment, so export it before building:

AVOCADO_DISTRO_RELEASE=2024 avocado ext install -t qemux86-64 avocado-ext-container-agent-dev
AVOCADO_DISTRO_RELEASE=2024 avocado ext build   -t qemux86-64 avocado-ext-container-agent-dev

Two things that will otherwise cost you time:

• avocado runs its SDK container with a TTY, so a build launched without one fails with cannot attach stdin to a TTY-enabled container. Wrap it in script -qefc '<cmd>' /dev/null when running from CI or a background shell.
• dnf prompts for confirmation and blocks; --no-tui does not suppress it. Pass --dnf-arg -y.

Supported targets

avocado.yaml lists them explicitly rather than using '*'. A target belongs there once it has produced an installable package and the produced binary has been seen to exec on that architecture. The release matrix in .github/workflows/release.yml should carry one row per declared target.

Releasing

Tag the version in avocado.yaml. The release workflow guards that the tag and the manifest version match, packages one leg per matrix row, and publishes each to the feed derived from that row's distro release and channel.

Bump release: whenever the packaged payload changes without a version change. An unchanged version-release identity means the package manager never delivers the new payload to a device that already has the extension installed, and both the build and the install report success anyway.