Replaced nerdctl CLI shell-out with direct gRPC communication via
wfe-containerd-protos (tonic 0.14). Connects to containerd daemon
over Unix socket.
Implementation:
- connect() with tonic Unix socket connector
- ensure_image() via ImagesClient (full pull is TODO)
- build_oci_spec() constructing OCI runtime spec with process args,
env, user, cwd, mounts, and linux namespaces
- Container lifecycle: create → snapshot → task create → start →
wait → read FIFOs → cleanup
- containerd-namespace header injection on every request
FIFO-based stdout/stderr capture using named pipes.
40 tests, 88% line coverage (cargo-llvm-cov).