feat(cli): rewrite CLI in Python with Typer and Rich

[jcardozo-eth]

Summary

Python CLI for DAP built on Typer and Rich, with ETH Zurich branded terminal output, grouped help, tool version caching, and a full test suite. Replaces the previous Go implementation; simplifies the Nix flake and CI accordingly.

CLI features

Command surface

Four command groups, accessible via dap <command> or dap k8s <subcommand>:

Group	Commands	Purpose
Development	test, lint, typecheck, check	Run quality checks (--scope core/cli/all)
Environment	welcome, tools, env, clean, reset	Manage the local dev environment
Hints	uv, dagster, direnv	Quick-reference cards for shell tools
Infrastructure	k8s up/down/restart/status/logs/shell	Kubernetes lifecycle via Helm

• dap --help uses a custom GroupedCommands class that organizes commands under section headers instead of a flat list
• dap welcome displays the DAP-O logo, project info, and detected tool versions
• dap dev check --scope cli runs only CLI checks (ruff + pytest); --scope core runs only pipeline checks; default runs both

Themed output (theme.py)

All output goes through a centralized Rich Console (writing to stderr) with:

• ETH Zurich brand palette — Blue, Petrol, Green, Bronze, Red, Grey — each with light-background and dark-background variants selected automatically (via COLORFGBG detection or DAP_THEME=light|dark override)
• Semantic styles — success (green), error (red), warning (bronze), info (petrol), title (bold blue), hint (grey), command (bold blue)
• Standard symbols — OK (checkmark), FAIL (cross), WARN (exclamation), ARROW (right arrow), DASH (em dash)
• 2-space indent on all output lines for visual consistency
• NO_COLOR and CI support — color disabled automatically in CI or when NO_COLOR is set

Tool version cache (utils/cache.py)

dap welcome and dap tools detect versions of Python, uv, kubectl, Helm, etc. Results are cached to a JSON file with a configurable TTL (default 1 hour), so repeated runs skip the subprocess calls. Cache auto-invalidates on TTL expiry and handles file corruption gracefully.

Developer experience

The dap CLI gives every operator of this repository — human developers, coding agents, and CI pipelines — a single, predictable interface for common tasks.

• Onboarding. dap welcome shows installed tools, active versions, and environment health at a glance. Hint commands (dap uv, dap dagster, dap direnv) provide cheat sheets without leaving the terminal.

• Common tasks. dap check runs lint, typecheck, and test in sequence with live progress and clear pass/fail output. dap k8s up encodes a multi-step workflow so the right flags and ordering are always applied.

• Agents and automation. NO_COLOR and CI detection ensure clean output in non-interactive contexts. CI calls the same commands developers run locally, so there is one definition of "passing" everywhere.

Build and infrastructure changes

• UV workspace. The CLI lives at cli/ as a workspace member. uv sync installs both the pipeline and CLI in one step — no separate build artifact.
• Nix flake. Reduced from 4 devshells + a sub-flake to 2 devshells (default, minimal). Go toolchain removed.
• CI. New setup-nix-env reusable composite action shared by ci.yml and cli.yml. GoReleaser release workflow removed.
• Helm. values-local.yaml gains readiness and startup probes for the webserver.

Testing

dap check --scope cli runs the full CLI quality pipeline: ruff (linting and format checking), mypy (static type checking), and pytest (unit and behavioral tests). This is the same command used in CI.

The test suite (~430 lines, 3 files) uses typer.testing.CliRunner and unittest.mock:

• test_commands.py — structural tests (all commands registered, help text present) and behavioral tests for dev/env/hints commands
• test_k8s.py — unit tests for helper functions, behavioral tests for down, status, and wait logic
• test_cache.py — roundtrip serialization, TTL invalidation, corruption recovery, integration with welcome

---

Terminal output

dap welcome

  ██████╗  █████╗ ██████╗          ██████╗
  ██╔══██╗██╔══██╗██╔══██╗        ██╔═══██╗
  ██║  ██║███████║██████╔╝ █████╗ ██║   ██║
  ██║  ██║██╔══██║██╔═══╝  ╚════╝ ██║   ██║
  ██████╔╝██║  ██║██║             ╚██████╔╝
  ╚═════╝ ╚═╝  ╚═╝╚═╝              ╚═════╝
  Data Archive Pipeline (DAP) — Orchestrator
  ETH Library Zurich

  Tools
  python         3.12.12
  uv             0.9.29
  dap            0.1.0
  dagster        1.12.14
  ruff           0.15.1
  mypy           1.19.1
  pytest         9.0.2

  Environment
  nix flake      /home/runner/work/data-assets-pipeline
  python venv    /home/runner/work/data-assets-pipeline/.venv
  DAGSTER_HOME   /home/runner/work/data-assets-pipeline/.dagster

  Quick Start
  dap test       Run tests (pytest)
  dap check      Run all quality checks (lint, typecheck, test)
  dap tools      Show installed tool versions

  Run 'dap --help' for all commands

dap --help

Usage: dap [OPTIONS] COMMAND [ARGS]...

  Developer tools for the Data Archive Pipeline (DAP) Orchestrator.

Options:
  -V, --version  Show version and exit.
  --help         Show this message and exit.

Development:
  test       Run tests with pytest.
  lint       Check code style and formatting with ruff.
  typecheck  Run type checking with mypy.
  check      Run all quality checks (ruff, mypy, pytest).

Environment:
  welcome  Show welcome banner and environment info.
  tools    Show installed tool versions and paths.
  env      Show environment paths and status.
  clean    Remove .venv and caches.
  reset    Clean and reinstall dependencies.

Hints:
  uv       Show how to use uv directly.
  dagster  Show how to use dagster and dg directly.
  direnv   Show how to use direnv directly.

Infrastructure:
  k8s  Kubernetes operations.

dap check --scope cli

  → Lint (CLI) — checking code style
    ruff check cli/dap_cli
  ✓ Lint (CLI) — checking code style — passed

  → Lint (CLI) — checking formatting
    ruff format --check cli/dap_cli
  ✓ Lint (CLI) — checking formatting — passed

  → Typecheck (CLI) — running mypy
    mypy cli/dap_cli
  ✓ Typecheck (CLI) — running mypy — passed

  → Test (CLI) — running pytest
    pytest cli/tests
  ✓ Test (CLI) — running pytest — passed

  ✓ All checks passed (CLI)