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ab-servers

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How to drive shaka-perf twin-servers (the control + experiment Docker pair) from an agent — which subcommand to use for build, start containers, start the app, stop, run a command inside a side, or sync code changes. Bare `shaka-perf servers` is for humans (interactive menu); agents must call subcommands directly. Use whenever you need to bring twin-servers up, restart them after a change, or run something inside a container. Triggers include "servers", "twin servers", "ab servers", "control/experiment server", "run X in container", "ab tests failing".

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Source SKILL.md: https://github.com/shakacode/react_on_rails/blob/HEAD/internal/analysis/rsc-fouc-shakaperf-artifacts/setup/generated-shakaperf-skills/ab-servers/SKILL.md

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Copying this prompt does not install or run the skill. Review third-party files before use. Codex skill guide

Driving twin-servers from an agent

shaka-perf servers (no subcommand) auto-rebuilds, starts containers, then drops into an interactive menu — that's the path for humans, not agents. As an agent, call the subcommands directly.

The dispatch table is the documentation

SubcommandWith shaka-perf servers running → proxiedWithout shaka-perf servers → local
build [--target control|experiment] [--no-cache]Rebuilds image(s) and restarts the servers (containers re-created — in-container state reset).Builds the Docker image(s) only; doesn't touch a running session.
start-containersRecreates containers and restarts the servers (state reset).Brings containers up idle and runs setupCommands on both sides.
stop-containersStops containers and ends the menu session.Stops containers and removes volumes.
start-serversRestarts overmind in the live session (containers untouched).Launches the app via Overmind in this terminal — blocks; run in background.
run-cmd <control|experiment> <cmd>Same as local — docker execs into the named side (queued behind any in-flight lifecycle work).Runs a one-off command inside the named side via docker exec.
run-cmd-parallel <cmd>Same as local — docker execs into both sides in parallel (queued behind lifecycle work).Runs the same command in both containers in parallel.
sync-changes <control|experiment>Fails — the menu's fs.watch already auto-syncs the build context on every save; re-running would race the watcher. Just edit your files.Syncs local git changes into the side's bind-mount volume.
get-config <key>Local — pure read; the value belongs on the caller's stdout.Reads a resolved config field (e.g. dockerfile, ports).
say <message>Local.Speaks the message via TTS (macOS/Linux).
notify-server-started <control|experiment>Local — Procfile helper.Waits for the side's URL to respond, announces it via TTS, then sleeps to keep Overmind happy.
run-overmind-command <control|experiment> <cmd>Local — Procfile helper.Runs a command inside a container with PID tracking (used inside Procfile lines).
copy-changes-to-ssh <port> <host> [control|experiment|all]Local.Copies local git changes to a CI SSH host for debugging.
forward-ports <port> <host> [controlPort] [experimentPort]Local.Forwards CI container ports to localhost via SSH.
customize-docker-composeLocal.Copies the bundled docker-compose.yml into the project for local editing.

Lifecycle from cold start (no menu): build → start-containers → start-servers. Inside a running menu, the proxied versions of build / start-containers already include the restart step.

Behaviour with shaka-perf servers running

The proxied work runs inside the menu's process, so its logs land in the user's interactive window and you just see the exit code on stderr after a → proxying to running shaka-perf servers (pid …) notice.

  • If another action is already in flight (menu item or earlier proxied command), your subcommand queues on the menu's session lock and the client just hangs until the slot opens — no fast-fail.
  • Exit code 75 (EX_TEMPFAIL) is reserved for terminal states only: the menu is shutting down, or hadn't finished booting yet — try again in a moment.
  • To change the running servers' environment (env vars, config file), ask the user to kill the interactive shaka-perf servers so your direct subcommands can take over.