# Rack Elevation (Phase 1) Implementation Plan

> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.

**Goal:** Document the 48U rack as host frontmatter and generate, via CI, an SVG rack elevation plus an occupancy table — mirroring the existing `gen_overview.py` → generated-index pattern.

**Architecture:** A new self-contained script `scripts/gen_rack.py` reads `docs/hardware/*.md`, selects files carrying a `rack:` field, validates placement (U range, no overlaps), and writes two generated artifacts per rack into `docs/infrastructure/racks/`: a `<rack>-elevation.svg` picture and a `<rack>.md` page embedding it. CI regenerates and fails on drift, exactly like the existing indices.

**Tech Stack:** Python 3 (stdlib + PyYAML only), pytest (new dev dependency), MkDocs Material, Forgejo Actions CI.

**Spec:** `notes/dev/specs/2026-06-24-rack-documentation-design.md` (Phase 1 only — power and network are later phases).

## Global Constraints

- Scripts use **stdlib + PyYAML only**; deterministic and offline (copy `gen_overview.py`'s style). No `Date.now`/randomness in generated output.
- Rack has **48 U**; the physical rack is labeled **U1 at the top**, descending to U48 — the SVG must render U1 at the top.
- Generated files carry the banner: `_Auto-generated … do not edit by hand. Run `make docs-index` after changing a source file._`
- Filenames: ASCII lowercase kebab-case; generated rack files are named after the rack id (e.g. `rack01.md`, `rack01-elevation.svg`).
- Language: English for code, docs, commits. Trunk-based; simple commit messages.
- `mkdocs build --strict` must pass; the drift guard must cover the new generated artifacts.

---

### Task 1: Extend the hardware `kind` enum for rack items

**Files:**
- Modify: `scripts/overview_config.yml`

**Interfaces:**
- Produces: new valid `kind` values (`pdu`, `patch-panel`, `shelf`, `blank`, `ups`, `kvm`) that later tasks' rack item files may use. Phase 1 only uses existing kinds (`server`), but the enum must accept the rest so Phase 2/3 files validate.

- [ ] **Step 1: Extend the `kind` enum and `group_titles` under the `hardware` block**

In `scripts/overview_config.yml`, the `hardware` block currently has:

```yaml
  enums:
    kind: [server, laptop, sbc, switch, ap, desktop]
    status: [in-use, staging, spare, broken, donated]
    storage_type: [nvme, ssd, hdd, mixed]
```

Replace the `kind:` line with:

```yaml
    kind: [server, laptop, sbc, switch, ap, desktop, pdu, patch-panel, shelf, blank, ups, kvm]
```

And in the same block's `group_titles:` map, add these entries below the existing ones:

```yaml
    pdu: PDUs
    patch-panel: Patch panels
    shelf: Shelves
    blank: Blank panels
    ups: UPS
    kvm: KVM
```

- [ ] **Step 2: Confirm the existing hardware index still regenerates cleanly**

Run: `python3 scripts/gen_overview.py --category hardware`
Expected: `Wrote docs/hardware/index.md (N item(s))` and `git diff --exit-code docs/hardware/index.md` is clean (no new kinds are used yet, so the table is unchanged).

- [ ] **Step 3: Commit**

```bash
git add scripts/overview_config.yml
git commit -m "feat(hardware): allow rack item kinds (pdu, patch-panel, shelf, blank, ups, kvm)"
```

---

### Task 2: `gen_rack.py` core — parse, load, validate placement (TDD)

This task introduces the test harness and the first slice of the generator: frontmatter parsing, selecting rack items, and per-item placement validation.

**Files:**
- Create: `scripts/gen_rack.py`
- Create: `tests/test_gen_rack.py`
- Create: `tests/conftest.py`
- Create: `requirements-dev.txt`

**Interfaces:**
- Produces:
  - `SchemaError` (exception)
  - `RACK_UNITS = 48`, `FACES`, `ZERO_U_FACES` (constants)
  - `parse_frontmatter(path: Path) -> dict | None`
  - `load_rack_items(hardware_dir: Path) -> list[dict]` — returns frontmatter dicts (each with an added `_path` key) for files declaring a `rack`
  - `validate_item(fm: dict) -> None` — raises `SchemaError` on bad placement

- [ ] **Step 1: Create `requirements-dev.txt`**

```
-r requirements.txt
pytest==8.*
```

- [ ] **Step 2: Install dev dependencies**

Run: `pip install -r requirements-dev.txt`
Expected: pytest installs successfully.

- [ ] **Step 3: Create `tests/conftest.py` so tests can import the script**

```python
import sys
from pathlib import Path

# Make scripts/ importable as top-level modules in tests.
sys.path.insert(0, str(Path(__file__).resolve().parent.parent / "scripts"))
```

- [ ] **Step 4: Write the failing tests for `validate_item`**

Create `tests/test_gen_rack.py`:

```python
import pytest

import gen_rack


def item(**kw):
    base = {"hostname": "x", "kind": "server", "status": "in-use", "rack": "rack01"}
    base.update(kw)
    return base


def test_validate_accepts_valid_placement():
    gen_rack.validate_item(item(rack_u=12, u_height=2, rack_face="front"))


def test_validate_rejects_u_overflow():
    with pytest.raises(gen_rack.SchemaError):
        gen_rack.validate_item(item(rack_u=47, u_height=3, rack_face="front"))


def test_validate_rejects_u_below_one():
    with pytest.raises(gen_rack.SchemaError):
        gen_rack.validate_item(item(rack_u=0, u_height=1, rack_face="front"))


def test_validate_rejects_bad_face():
    with pytest.raises(gen_rack.SchemaError):
        gen_rack.validate_item(item(rack_u=1, u_height=1, rack_face="sideways"))


def test_validate_rejects_zero_u_with_units():
    with pytest.raises(gen_rack.SchemaError):
        gen_rack.validate_item(item(rack_face="left", rack_u=1, u_height=1))


def test_validate_accepts_zero_u_rail():
    gen_rack.validate_item(item(rack_face="left"))


def test_validate_rejects_missing_units_on_faced_item():
    with pytest.raises(gen_rack.SchemaError):
        gen_rack.validate_item(item(rack_face="front"))
```

- [ ] **Step 5: Run the tests to verify they fail**

Run: `pytest tests/test_gen_rack.py -q`
Expected: FAIL — `ModuleNotFoundError: No module named 'gen_rack'`.

- [ ] **Step 6: Create `scripts/gen_rack.py` with constants, parsing, loading, and `validate_item`**

```python
#!/usr/bin/env python3
"""Generate per-rack elevation SVG + page from hardware frontmatter.

Reads `docs/hardware/*.md`, selects files that declare a `rack` field,
validates rack placement, and writes for each rack:
  docs/infrastructure/racks/<rack>-elevation.svg
  docs/infrastructure/racks/<rack>.md

Deterministic, offline, stdlib + PyYAML. Non-zero exit on schema violation.
The physical rack is labeled U1 at the top; the SVG renders U1 at the top.
"""

from __future__ import annotations

import re
import sys
from pathlib import Path

import yaml

REPO_ROOT = Path(__file__).resolve().parent.parent
HARDWARE_DIR = REPO_ROOT / "docs" / "hardware"
OUTPUT_DIR = REPO_ROOT / "docs" / "infrastructure" / "racks"
RACK_UNITS = 48

FRONTMATTER_RE = re.compile(r"^---\s*\n(.*?)\n---\s*\n", re.DOTALL)

FACES = {"front", "rear", "both", "left", "right"}
ZERO_U_FACES = {"left", "right"}

KIND_COLORS = {
    "server": "#4c78a8",
    "switch": "#59a14f",
    "patch-panel": "#9c755f",
    "pdu": "#e15759",
    "ups": "#edc948",
    "shelf": "#bab0ac",
    "kvm": "#b07aa1",
    "blank": "#d4d4d4",
}
DEFAULT_COLOR = "#888888"


class SchemaError(Exception):
    pass


def parse_frontmatter(path: Path) -> dict | None:
    text = path.read_text(encoding="utf-8")
    m = FRONTMATTER_RE.match(text)
    if not m:
        return None
    data = yaml.safe_load(m.group(1))
    if not isinstance(data, dict):
        raise SchemaError(f"{path}: frontmatter is not a mapping")
    return data


def load_rack_items(hardware_dir: Path) -> list[dict]:
    """Return frontmatter dicts for hardware files that declare a rack."""
    items: list[dict] = []
    for path in sorted(hardware_dir.glob("*.md")):
        if path.name == "index.md":
            continue
        fm = parse_frontmatter(path)
        if fm is None or "rack" not in fm:
            continue
        fm = dict(fm)
        fm["_path"] = str(path)
        items.append(fm)
    return items


def validate_item(fm: dict) -> None:
    name = fm.get("hostname") or fm.get("_path", "?")
    face = fm.get("rack_face")
    if face not in FACES:
        raise SchemaError(f"{name}: rack_face={face!r} not in {sorted(FACES)}")
    if face in ZERO_U_FACES:
        if "rack_u" in fm or "u_height" in fm:
            raise SchemaError(
                f"{name}: 0U item (face={face}) must omit rack_u/u_height"
            )
        return
    u = fm.get("rack_u")
    h = fm.get("u_height")
    if not isinstance(u, int) or not isinstance(h, int):
        raise SchemaError(f"{name}: rack_u and u_height must be integers")
    if u < 1 or u > RACK_UNITS:
        raise SchemaError(f"{name}: rack_u={u} out of range 1..{RACK_UNITS}")
    if h < 1:
        raise SchemaError(f"{name}: u_height={h} must be >= 1")
    if u + h - 1 > RACK_UNITS:
        raise SchemaError(
            f"{name}: occupies U{u}..U{u + h - 1}, exceeds {RACK_UNITS}U"
        )
```

- [ ] **Step 7: Run the tests to verify they pass**

Run: `pytest tests/test_gen_rack.py -q`
Expected: PASS (7 passed).

- [ ] **Step 8: Commit**

```bash
git add scripts/gen_rack.py tests/test_gen_rack.py tests/conftest.py requirements-dev.txt
git commit -m "feat(rack): gen_rack placement parsing and validation"
```

---

### Task 3: Overlap detection (TDD)

**Files:**
- Modify: `scripts/gen_rack.py`
- Modify: `tests/test_gen_rack.py`

**Interfaces:**
- Consumes: `validate_item` semantics (items already individually valid).
- Produces: `check_overlaps(items: list[dict]) -> None` — raises `SchemaError` if any two items share a U on the same face. `both` expands to both `front` and `rear`; 0U rail items are exempt.

- [ ] **Step 1: Add failing overlap tests to `tests/test_gen_rack.py`**

Append:

```python
def test_overlaps_detects_same_face_overlap():
    items = [
        item(hostname="a", rack_u=1, u_height=2, rack_face="front"),
        item(hostname="b", rack_u=2, u_height=1, rack_face="front"),
    ]
    with pytest.raises(gen_rack.SchemaError):
        gen_rack.check_overlaps(items)


def test_overlaps_allows_same_u_different_face():
    items = [
        item(hostname="a", rack_u=5, u_height=1, rack_face="front"),
        item(hostname="b", rack_u=5, u_height=1, rack_face="rear"),
    ]
    gen_rack.check_overlaps(items)  # no raise


def test_overlaps_both_face_conflicts_with_front():
    items = [
        item(hostname="a", rack_u=5, u_height=1, rack_face="both"),
        item(hostname="b", rack_u=5, u_height=1, rack_face="front"),
    ]
    with pytest.raises(gen_rack.SchemaError):
        gen_rack.check_overlaps(items)


def test_overlaps_ignores_zero_u_rails():
    items = [
        item(hostname="p1", rack_face="left"),
        item(hostname="p2", rack_face="left"),
    ]
    gen_rack.check_overlaps(items)  # no raise
```

- [ ] **Step 2: Run to verify failure**

Run: `pytest tests/test_gen_rack.py -q`
Expected: FAIL — `AttributeError: module 'gen_rack' has no attribute 'check_overlaps'`.

- [ ] **Step 3: Implement `check_overlaps` in `scripts/gen_rack.py`**

Add after `validate_item`:

```python
def check_overlaps(items: list[dict]) -> None:
    """Raise if two items share a U on the same face within one rack."""
    occupied: dict[tuple[str, int], str] = {}
    for fm in items:
        face = fm.get("rack_face")
        if face in ZERO_U_FACES:
            continue
        faces = ("front", "rear") if face == "both" else (face,)
        u = fm["rack_u"]
        h = fm["u_height"]
        name = fm.get("hostname", "?")
        for f in faces:
            for uu in range(u, u + h):
                key = (f, uu)
                if key in occupied:
                    raise SchemaError(
                        f"U{uu} {f}: {name} overlaps {occupied[key]}"
                    )
                occupied[key] = name
```

- [ ] **Step 4: Run to verify pass**

Run: `pytest tests/test_gen_rack.py -q`
Expected: PASS (11 passed).

- [ ] **Step 5: Commit**

```bash
git add scripts/gen_rack.py tests/test_gen_rack.py
git commit -m "feat(rack): detect U overlaps within a rack face"
```

---

### Task 4: SVG elevation rendering (TDD)

**Files:**
- Modify: `scripts/gen_rack.py`
- Modify: `tests/test_gen_rack.py`

**Interfaces:**
- Consumes: validated items (non-0U items have integer `rack_u`/`u_height`).
- Produces: `render_svg(rack: str, items: list[dict]) -> str` — a complete deterministic `<svg>…</svg>` string ending in a newline; front and rear columns of 48 U slots with U1 at the top, device boxes colored by kind, 0U items as side rails.

- [ ] **Step 1: Add failing SVG tests**

Append to `tests/test_gen_rack.py`:

```python
def test_render_svg_has_two_columns_of_48_slots():
    svg = gen_rack.render_svg("rack01", [])
    # one faint slot rect per U per column (front + rear)
    assert svg.count('fill="#f5f5f5"') == 2 * gen_rack.RACK_UNITS
    assert svg.startswith("<svg")
    assert svg.rstrip().endswith("</svg>")


def test_render_svg_includes_device_label():
    items = [item(hostname="mf00", rack_u=1, u_height=2, rack_face="front")]
    svg = gen_rack.render_svg("rack01", items)
    assert "mf00" in svg
    assert "U1" in svg


def test_render_svg_is_deterministic():
    items = [
        item(hostname="b", rack_u=3, u_height=1, rack_face="front"),
        item(hostname="a", rack_u=1, u_height=1, rack_face="rear"),
    ]
    assert gen_rack.render_svg("rack01", items) == gen_rack.render_svg(
        "rack01", list(reversed(items))
    )
```

- [ ] **Step 2: Run to verify failure**

Run: `pytest tests/test_gen_rack.py -q`
Expected: FAIL — `AttributeError: module 'gen_rack' has no attribute 'render_svg'`.

- [ ] **Step 3: Implement `_esc`, `_sorted_items`, and `render_svg`**

Add to `scripts/gen_rack.py`:

```python
def _esc(s: object) -> str:
    return str(s).replace("&", "&amp;").replace("<", "&lt;").replace(">", "&gt;")


def _sorted_items(items: list[dict]) -> list[dict]:
    """Deterministic order: faced items by U then hostname, 0U items last."""
    return sorted(
        items,
        key=lambda i: (
            0 if i.get("rack_face") not in ZERO_U_FACES else 1,
            i.get("rack_u", 0) if isinstance(i.get("rack_u"), int) else 0,
            i.get("hostname", ""),
        ),
    )


def render_svg(rack: str, items: list[dict]) -> str:
    U_H = 20
    COL_W = 240
    LABEL_W = 30
    RAIL_W = 16
    PAD = 12
    GAP = 50
    TITLE_H = 28

    items = _sorted_items(items)
    left_items = [i for i in items if i.get("rack_face") == "left"]
    right_items = [i for i in items if i.get("rack_face") == "right"]

    body_h = RACK_UNITS * U_H
    height = PAD + TITLE_H + body_h + PAD
    front_x = PAD + len(left_items) * RAIL_W + LABEL_W
    rear_x = front_x + COL_W + GAP
    width = rear_x + COL_W + len(right_items) * RAIL_W + PAD
    top = PAD + TITLE_H

    def u_y(u: int) -> int:
        # U1 at the top; U numbers increase downward.
        return top + (u - 1) * U_H

    p: list[str] = []
    p.append(
        f'<svg xmlns="http://www.w3.org/2000/svg" width="{width}" '
        f'height="{height}" viewBox="0 0 {width} {height}" '
        f'font-family="sans-serif" font-size="11">'
    )
    p.append(f'<rect width="{width}" height="{height}" fill="#ffffff"/>')
    p.append(
        f'<text x="{PAD}" y="{PAD + 16}" font-size="16" '
        f'font-weight="bold">Rack {_esc(rack)}</text>'
    )

    for col_x, col_label in ((front_x, "front"), (rear_x, "rear")):
        p.append(
            f'<text x="{col_x + COL_W // 2}" y="{top - 6}" '
            f'text-anchor="middle" font-weight="bold">{col_label}</text>'
        )
        for u in range(1, RACK_UNITS + 1):
            y = u_y(u)
            p.append(
                f'<rect x="{col_x}" y="{y}" width="{COL_W}" height="{U_H}" '
                f'fill="#f5f5f5" stroke="#e0e0e0"/>'
            )

    # U numbers in the gutter left of the front column.
    for u in range(1, RACK_UNITS + 1):
        y = u_y(u)
        p.append(
            f'<text x="{front_x - 4}" y="{y + 14}" text-anchor="end" '
            f'fill="#999">{u}</text>'
        )

    def draw_device(fm: dict, col_x: int) -> None:
        u = fm["rack_u"]
        h = fm["u_height"]
        y = u_y(u)
        box_h = h * U_H
        color = KIND_COLORS.get(fm.get("kind", ""), DEFAULT_COLOR)
        name = fm.get("hostname", "?")
        urange = f"U{u}" if h == 1 else f"U{u}–U{u + h - 1}"
        p.append(
            f'<rect x="{col_x + 1}" y="{y + 1}" width="{COL_W - 2}" '
            f'height="{box_h - 2}" rx="3" fill="{color}" stroke="#333"/>'
        )
        p.append(
            f'<text x="{col_x + COL_W // 2}" y="{y + box_h // 2 + 4}" '
            f'text-anchor="middle" fill="#ffffff">'
            f'{_esc(name)} ({urange})</text>'
        )

    for fm in items:
        face = fm.get("rack_face")
        if face in ("front", "both"):
            draw_device(fm, front_x)
        if face in ("rear", "both"):
            draw_device(fm, rear_x)

    def draw_rail(fm: dict, x: int) -> None:
        color = KIND_COLORS.get(fm.get("kind", ""), DEFAULT_COLOR)
        name = fm.get("hostname", "?")
        cx = x + RAIL_W // 2
        cy = top + body_h // 2
        p.append(
            f'<rect x="{x}" y="{top}" width="{RAIL_W}" height="{body_h}" '
            f'fill="{color}" stroke="#333"/>'
        )
        p.append(
            f'<text x="{cx}" y="{cy}" text-anchor="middle" fill="#ffffff" '
            f'transform="rotate(-90 {cx} {cy})">{_esc(name)}</text>'
        )

    for idx, fm in enumerate(left_items):
        draw_rail(fm, PAD + idx * RAIL_W)
    for idx, fm in enumerate(right_items):
        draw_rail(fm, rear_x + COL_W + idx * RAIL_W)

    p.append("</svg>")
    return "\n".join(p) + "\n"
```

- [ ] **Step 4: Run to verify pass**

Run: `pytest tests/test_gen_rack.py -q`
Expected: PASS (14 passed).

- [ ] **Step 5: Commit**

```bash
git add scripts/gen_rack.py tests/test_gen_rack.py
git commit -m "feat(rack): render SVG elevation (U1 at top, front/rear columns)"
```

---

### Task 5: Page rendering + orchestration (TDD)

**Files:**
- Modify: `scripts/gen_rack.py`
- Modify: `tests/test_gen_rack.py`

**Interfaces:**
- Consumes: `render_svg`, `validate_item`, `check_overlaps`, `load_rack_items`.
- Produces:
  - `render_page(rack: str, items: list[dict]) -> str` — the generated Markdown page (banner, embedded SVG image, occupancy table linking to host pages).
  - `generate(hardware_dir: Path, output_dir: Path) -> int` — orchestrates load/validate/group/write; returns `0` on success, `1` on any schema error (printing errors to stderr, writing nothing on failure).
  - `main() -> int` — calls `generate(HARDWARE_DIR, OUTPUT_DIR)`.

- [ ] **Step 1: Add failing tests for `render_page` and `generate`**

Append to `tests/test_gen_rack.py`:

```python
def test_render_page_has_banner_image_and_table():
    items = [item(hostname="mf00", rack_u=1, u_height=2, rack_face="front")]
    page = gen_rack.render_page("rack01", items)
    assert "do not edit by hand" in page
    assert "![Rack rack01 elevation](rack01-elevation.svg)" in page
    assert "../../hardware/mf00.md" in page
    assert "U1–U2" in page


def _write_item(d, name, body):
    (d / f"{name}.md").write_text(body, encoding="utf-8")


def test_generate_writes_artifacts(tmp_path):
    hw = tmp_path / "hardware"
    out = tmp_path / "out"
    hw.mkdir()
    _write_item(
        hw,
        "mf00",
        "---\nhostname: mf00\nkind: server\nstatus: in-use\n"
        "rack: rack01\nrack_u: 1\nu_height: 1\nrack_face: front\n---\n",
    )
    # a non-rack file must be ignored
    _write_item(hw, "cloud", "---\nhostname: cloud\nkind: server\nstatus: in-use\n---\n")

    rc = gen_rack.generate(hw, out)

    assert rc == 0
    assert (out / "rack01.md").exists()
    assert (out / "rack01-elevation.svg").exists()
    assert "mf00" in (out / "rack01-elevation.svg").read_text()


def test_generate_returns_1_on_overlap(tmp_path):
    hw = tmp_path / "hardware"
    out = tmp_path / "out"
    hw.mkdir()
    for n, u in (("a", 1), ("b", 1)):
        _write_item(
            hw,
            n,
            f"---\nhostname: {n}\nkind: server\nstatus: in-use\n"
            f"rack: rack01\nrack_u: {u}\nu_height: 1\nrack_face: front\n---\n",
        )

    rc = gen_rack.generate(hw, out)

    assert rc == 1
    assert not (out / "rack01.md").exists()
```

- [ ] **Step 2: Run to verify failure**

Run: `pytest tests/test_gen_rack.py -q`
Expected: FAIL — `AttributeError: module 'gen_rack' has no attribute 'render_page'`.

- [ ] **Step 3: Implement `render_page`, `generate`, and `main`**

Add to `scripts/gen_rack.py`:

```python
def render_page(rack: str, items: list[dict]) -> str:
    items = _sorted_items(items)
    lines: list[str] = []
    lines.append(f"# Rack {rack}")
    lines.append("")
    lines.append(
        f"_Auto-generated from `docs/hardware/*.md` (items with `rack: {rack}`) "
        f"— do not edit by hand. Run `make docs-index` after changing a "
        f"source file._"
    )
    lines.append("")
    lines.append("## Elevation")
    lines.append("")
    lines.append(f"![Rack {rack} elevation]({rack}-elevation.svg)")
    lines.append("")
    lines.append("## Occupancy")
    lines.append("")
    lines.append("| U | Device | Kind | Face | Status |")
    lines.append("|---|---|---|---|---|")
    for fm in items:
        name = fm.get("hostname", "?")
        link = f"[{name}](../../hardware/{name}.md)"
        face = fm.get("rack_face", "")
        if face in ZERO_U_FACES:
            urange = "0U"
        else:
            u = fm["rack_u"]
            h = fm["u_height"]
            urange = f"U{u}" if h == 1 else f"U{u}–U{u + h - 1}"
        lines.append(
            f"| {urange} | {link} | {fm.get('kind', '')} | {face} "
            f"| {fm.get('status', '')} |"
        )
    lines.append("")
    return "\n".join(lines).rstrip() + "\n"


def generate(hardware_dir: Path, output_dir: Path) -> int:
    items = load_rack_items(hardware_dir)

    errors: list[str] = []
    for fm in items:
        try:
            validate_item(fm)
        except SchemaError as e:
            errors.append(str(e))

    racks: dict[str, list[dict]] = {}
    for fm in items:
        racks.setdefault(fm["rack"], []).append(fm)

    if not errors:  # only check overlaps once placements are individually valid
        for rack, ritems in racks.items():
            try:
                check_overlaps(ritems)
            except SchemaError as e:
                errors.append(f"{rack}: {e}")

    if errors:
        for err in errors:
            print(f"ERROR: {err}", file=sys.stderr)
        return 1

    output_dir.mkdir(parents=True, exist_ok=True)
    for rack in sorted(racks):
        ritems = racks[rack]
        (output_dir / f"{rack}-elevation.svg").write_text(
            render_svg(rack, ritems), encoding="utf-8"
        )
        (output_dir / f"{rack}.md").write_text(
            render_page(rack, ritems), encoding="utf-8"
        )
        print(f"Wrote {rack}.md + {rack}-elevation.svg ({len(ritems)} item(s))")
    return 0


def main() -> int:
    return generate(HARDWARE_DIR, OUTPUT_DIR)


if __name__ == "__main__":
    sys.exit(main())
```

- [ ] **Step 4: Run to verify pass**

Run: `pytest tests/test_gen_rack.py -q`
Expected: PASS (18 passed).

- [ ] **Step 5: Commit**

```bash
git add scripts/gen_rack.py tests/test_gen_rack.py
git commit -m "feat(rack): render page and orchestrate generation"
```

---

### Task 6: Wire build tooling and populate rack01

**Files:**
- Modify: `Makefile`
- Modify: `docs/hardware/mf00.md` (and other host files actually in the rack — see note)
- Create (generated): `docs/infrastructure/racks/rack01.md`, `docs/infrastructure/racks/rack01-elevation.svg`

**Interfaces:**
- Consumes: `gen_rack.main` via `python3 scripts/gen_rack.py`.

> **Operator note — real data required.** I do not know the true U positions of the devices in the physical rack, and the `mfNN` machines are tower/desktop units that may sit on a shelf rather than occupy U slots. The edit below is a **worked example** for `mf00`. Apply the same shape to **each device actually mounted in the rack**, using its real `rack_u`, `u_height`, and `rack_face` (front/rear/both). Remove rack fields from any host not in the rack. The overlap validator (`check_overlaps`) will reject conflicting positions, so wrong guesses fail loudly rather than silently. `makerfloss.eu` is cloud-hosted and must NOT get a `rack` field.

- [ ] **Step 1: Add rack placement to each in-rack host file (example: `mf00`)**

In `docs/hardware/mf00.md`, add these four lines to the frontmatter (between the existing keys and the closing `---`):

```yaml
rack: rack01
rack_u: 1
u_height: 1
rack_face: front
```

Repeat for every other device physically in the rack, choosing real, non-overlapping U positions.

- [ ] **Step 2: Add the `gen_rack` step to the Makefile**

In `Makefile`, change the `docs-index` target to:

```makefile
docs-index:
	python3 scripts/gen_overview.py --category hardware
	python3 scripts/gen_overview.py --category services
	python3 scripts/gen_rack.py
```

Change the `docs-check` target to:

```makefile
docs-check:
	python3 scripts/gen_overview.py --category hardware
	python3 scripts/gen_overview.py --category services
	python3 scripts/gen_rack.py
	git diff --exit-code docs/hardware/index.md docs/services/index.md docs/infrastructure/racks/
```

Add a `test` target at the end of the file:

```makefile
test:
	pytest -q
```

And add `test` to the `.PHONY` line and a help line:

```makefile
.PHONY: help docs-index docs-build docs-serve docs-check slides test
```

```makefile
	@echo "  test         Run the Python unit tests (pytest)"
```

- [ ] **Step 3: Generate the rack artifacts**

Run: `make docs-index`
Expected: prints `Wrote rack01.md + rack01-elevation.svg (N item(s))`; the two files now exist under `docs/infrastructure/racks/`.

- [ ] **Step 4: Eyeball the SVG**

Open `docs/infrastructure/racks/rack01-elevation.svg` in a browser. Expected: a "Rack rack01" title, front and rear columns, U numbers running **1 at the top → 48 at the bottom**, and each placed device as a colored box at its U position.

- [ ] **Step 5: Commit**

```bash
git add Makefile docs/hardware/*.md docs/infrastructure/racks/
git commit -m "feat(rack): populate rack01 and wire gen_rack into make targets"
```

---

### Task 7: CI integration, nav, and end-to-end verification

**Files:**
- Modify: `.forgejo/workflows/docs.yml`
- Modify: `mkdocs.yml`

**Interfaces:**
- Consumes: `python3 scripts/gen_rack.py`, `pytest`, the generated artifacts under `docs/infrastructure/racks/`.

- [ ] **Step 1: Add a test step and the rack generator to CI**

In `.forgejo/workflows/docs.yml`, after the `Install Python dependencies` step, add a new step:

```yaml
      - name: Install dev dependencies and run tests
        run: |
          pip install --quiet -r requirements-dev.txt
          pytest -q
```

In the `Regenerate hardware and services indices` step, append the rack generator so the `run:` block reads:

```yaml
        run: |
          python3 scripts/gen_overview.py --category hardware
          python3 scripts/gen_overview.py --category services
          python3 scripts/gen_rack.py
```

In the `Fail on drift in generated indices` step, extend the diff to cover the rack artifacts:

```yaml
        run: |
          if ! git diff --exit-code docs/hardware/index.md docs/services/index.md docs/infrastructure/racks/; then
            echo
            echo "::error::A generated index is stale."
            echo "Regenerate locally via 'make docs-index' and commit the result."
            exit 1
          fi
```

- [ ] **Step 2: Add an Infrastructure section to the MkDocs nav**

In `mkdocs.yml`, replace the `nav:` block with:

```yaml
nav:
  - Home: index.md
  - Hardware:
      - hardware/index.md
  - Services:
      - services/index.md
  - Infrastructure:
      - Lab design: infrastructure/labdesign.md
      - VPS & DNS: infrastructure/vps-and-dns.md
      - Rack rack01: infrastructure/racks/rack01.md
  - House rules: house-rules.md
```

- [ ] **Step 3: Build the site strictly and confirm it passes**

Run: `mkdocs build --strict`
Expected: build succeeds with no warnings-as-errors. The rack page and its SVG appear under `site/infrastructure/racks/`.

- [ ] **Step 4: Confirm the drift guard is satisfied**

Run: `make docs-check`
Expected: exit 0 (no diff) — the committed artifacts match a fresh regeneration.

- [ ] **Step 5: Preview the page**

Run: `mkdocs serve`
Open `http://127.0.0.1:8000/infrastructure/racks/rack01/`. Expected: the elevation SVG renders inline, U1 at the top; the occupancy table lists devices and links to their host pages.

- [ ] **Step 6: Commit**

```bash
git add .forgejo/workflows/docs.yml mkdocs.yml
git commit -m "ci(rack): generate rack artifacts, run tests, add nav entry"
```

- [ ] **Step 7: Push and confirm CI is green**

```bash
git push origin main
```

Open the Forgejo Actions run for this push. Expected: the tests step passes, the drift guard passes, the site builds, and `docs.makerfloss.eu/infrastructure/racks/rack01/` shows the elevation.

---

## Self-Review

**Spec coverage (Phase 1 scope):**
- Placement schema (`rack`, `rack_u`, `u_height`, `rack_face`) — Task 2 (validation), Task 6 (population). ✔
- New `kind` values — Task 1. ✔
- `gen_rack.py` producing SVG elevation + occupancy table — Tasks 4, 5. ✔
- U1-at-top rendering — Task 4 (`u_y`), verified Task 6 Step 4 / Task 7 Step 5. ✔
- Validation rules 1, 2, 5 (U range, overlap, 0U-omits-units) — Tasks 2, 3. (Rules 3, 4 are power/network — Phases 2/3, out of scope.) ✔
- Do-not-edit banner — Task 5 (`render_page`). ✔
- CI drift check + nav + strict build — Task 7. ✔
- Generated artifacts under `docs/infrastructure/racks/` — Tasks 5, 6. ✔

**Placeholder scan:** No "TBD"/"handle edge cases"/"similar to" placeholders. The only deferred-to-operator item is real U-position data in Task 6, which is unavoidable physical-world input and is explicitly bounded with a worked example and the overlap validator as a safety net.

**Type consistency:** `SchemaError`, `RACK_UNITS`, `FACES`, `ZERO_U_FACES`, `parse_frontmatter`, `load_rack_items`, `validate_item`, `check_overlaps`, `_esc`, `_sorted_items`, `render_svg`, `render_page`, `generate`, `main` — names and signatures match across tasks and tests. `generate` returns `int` (0/1); `render_*` return `str`; `validate_item`/`check_overlaps` return `None` and raise `SchemaError`. Consistent.