l337-docker

Docker via the CLI

Every operation here goes through the docker binary and its plugins. No SDK, no daemon library - docker, its subcommands, and (for registry queries that need no daemon) curl against the registry HTTP API.

This file is the router. It carries the rules that apply to every Docker operation plus a map into reference/ (how to do a thing) and workflows/ (multi-step procedures). Read the one reference file the task needs - not all of them.

Preflight

Run once at the start of a Docker session, before anything else:

docker version --format '{{.Server.Version}} (API {{.Server.APIVersion}})'   # daemon reachable?
docker context ls --format json                                              # which daemon, and what else is configured
docker system info --format '{{.Name}} {{.OperatingSystem}} {{.Swarm.LocalNodeState}}'

If the daemon is unreachable, say so and stop - do not fall back to guessing state from config files. The common causes are Docker Desktop not running (macOS/Windows), the user not being in the docker group (Linux), or DOCKER_HOST/DOCKER_CONTEXT pointing somewhere dead.

Check plugins only when the task needs one - compose, buildx and scout are separate binaries and are frequently absent on servers:

docker system info --format '{{range .ClientInfo.Plugins}}{{.Name}} {{end}}'

A missing plugin is a hard stop for that domain, not something to work around by hand-rolling the equivalent. Say which plugin is missing and what installs it.

Rules that always apply

1. Read before you write. Inspect current state before changing it, and show the user what you found. Most Docker mistakes are irreversible in the way that matters (a removed volume, a clobbered tag), and the read costs nothing.

2. Bound every output. The CLI streams without limit and will flood the context window. There is no server truncating for you.

• Logs: always --tail N (start at 100-200). Never bare docker logs.
• docker stats: always --no-stream. Without it, it never returns.
• docker events: never bare - it streams forever. Bound it with --until 0s for history, or a future epoch to wait (--until $(($(date +%s)+300))). --until now is invalid.
• Anything large (image save, container export, archives): write to a file, never into the context. Then report the path and size.
• Projecting fields with --format beats piping a full dump through head.