Musher Dev Container Template

Canonical dev container template for the musher-dev organization. Batteries-included configuration with AI CLIs, multiple language runtimes, Docker-in-Docker, Task runner, and consistent VS Code settings. Comment out what you don't need.

What You Get

• Ubuntu base with zsh/oh-my-zsh
• Node, Python, Go, Java, Deno, bun, uv — pinned Features
• Docker-in-Docker
• Git + GitHub CLI
• Claude Code + Codex CLI + Task runner + Lefthook
• GitLens, YAML, TOML, Copilot, Go, Python, Ruff, ESLint, Docker extensions
• Format on save, rulers, trailing whitespace trimming

Usage

1. Click Use this template → Create a new repository on GitHub
2. Clone your new repo and open in VS Code
3. Command Palette → Dev Containers: Reopen in Container
4. (Optional) Edit .devcontainer/.env to set COMPOSE_PROFILES and override credentials — the file is created automatically from .env.example on first build.

Local Environment

All local-dev state is contained under .devcontainer/. On first build, initializeCommand copies .env.example → .env (gitignored). The same file feeds:

• Docker Compose — auto-discovered as the sibling .env next to compose.yaml, used to interpolate ${VAR:-default} references.
• The dev container itself — loaded via runArgs --env-file, so shells and runtimes inside the container see the same values.

To reset local env state, delete .devcontainer/.env and rebuild. Useful task commands:

Command	Purpose
task env:check	Verify .env has every key from .env.example.
task env:required	List required keys (declared empty in the template) that still need a value.
task env:diff	Show keys present in one of .env / .env.example but not the other.
task env:reset	Re-copy the template over .env (prompts before overwriting).
task lint:all	Run every lint gate (Markdown, YAML, workflows, spelling).
task repo:check	Check the repo's own structure policies.
task tools:install	Install every pinned CLI from .devcontainer/mise.toml.

The startup MOTD also warns about drift or unfilled required keys.

Customize

• Comment out unneeded features/extensions in devcontainer.json
• Change a tool version → devcontainer.json (Features), or .devcontainer/mise.toml for CLIs without a Feature (AI CLIs, lefthook, linters)
• Change a lint rule → the matching file in .config/ (see .config/README.md)
• Add project setup to scripts/post-create.sh (runs after base_setup)
• Enable optional services via COMPOSE_PROFILES in .devcontainer/.env (redis, minio, registry, azimutt, observability)
• Full reference → CONFIGURATION.md

Included CI

.github/workflows/validate.yaml runs seven jobs: ShellCheck, Compose config validation, devcontainer lockfile freshness, .env template sync, the lint gates, the repo structure policies, and a devcontainer build. Lint tool versions resolve from .devcontainer/mise.toml — the same file the container uses — so CI and local cannot drift.

The same lint and structure checks run pre-commit via .config/lefthook.yml, and repo hooks check fails the build if the two ever disagree.

Branch protection is committed as JSON under .github/rulesets/; it must be imported once per repository, since rulesets are repository state rather than content.

Keep or remove per your project's needs — but remove a CI job and its ruleset entry together, or repo rulesets check will tell you why.

Troubleshooting

CRLF / WSL line ending issues

The postCreateCommand automatically strips \r from all scripts before running them. If you add new scripts, ensure they're under .devcontainer/scripts/ to be included.

Stale containers

If settings aren't applying after changes, rebuild without cache:

Command Palette → Dev Containers: Rebuild Container Without Cache

Volume permission errors

Named volumes may initialize with root ownership. The ensure_writable_dir function in common.sh and the base_setup_config_dirs step handle this for base volumes. For custom volumes, call ensure_writable_dir in your post-create.sh:

ensure_writable_dir /home/vscode/.my-tool

Tool installation failures

Base setup uses retry with 3 attempts and 5-second delays for network operations. If a tool consistently fails to install, check network connectivity and try rebuilding the container.