initial commit: docker test-build toolchain

Extracted from the .extras/ dir of the sbo-slackbuilds package repo, where it
grew from a throwaway helper into a standalone tool. Git history starts fresh;
the original 41-commit development log is preserved in HISTORY.md.

Contents: the test-build CLI (resolves a local SlackBuild's deps from a
configured SBo tree and builds it in a throwaway container, lints, caches deps),
the image-builder chain that produces the images it consumes, their pure-logic
self-checks, design specs/plans, an install.sh for ~/bin, and docs.

Licensed GPLv2-only.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

1 files changed, 216 insertions, 0 deletions

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+# sbo-testbuild image builder — design
+
+Date: 2026-07-13
+Status: approved (design)
+
+## Purpose
+
+Produce and serve the docker images the `.extras/test-build` tool consumes.
+`.extras/test-build` verifies a published SBo package still builds on a target
+Slackware version inside a throwaway container; it does **not** build the
+images, it only checks image presence by tag and errors if absent. This is the
+missing image-builder job.
+
+Images produced (x86_64 only for now):
+
+- `sbo-testbuild:current` — Slackware -current, full install + sbopkg +
+  sbo-maintainer-tools
+- `sbo-testbuild:15.0` — Slackware 15.0, same
+
+Served from a LAN docker registry so `.extras/test-build`'s `require_image`
+can `docker pull` them, and so `installed_in_base` can later query the image's
+package db.
+
+## Infrastructure
+
+Self-hosted on a Slackware VM (proxmox node), fully offline from the public
+internet for the Slackware bits:
+
+- **Host**: `docker.noland.dnx` (LAN DNS), Slackware x86_64, 4 vCPU / 4 GB RAM
+  / 80 GB disk.
+- **NAS trees**: two standard Slackware mirror trees NFS-mounted read-only:
+  - `/mnt/nas/slackware64-current`
+  - `/mnt/nas/slackware64-15.0`
+  Each is a full mirror tree (`PACKAGES.TXT`, `ChangeLog.txt`, `slackware64/`
+  series dirs, `patches/`, `extra/`).
+- **Registry**: `registry:2` container on the VM, port 5000, plain HTTP (LAN
+  only). Pull path `docker.noland.dnx:5000/sbo-testbuild:{tag}`.
+- **Local .txz drop**: `/opt/sbo-testbuild/pkgs/` holds `sbopkg-*.txz` and
+  `sbo-maintainer-tools-*.txz`, provided by the user (sbopkg packaged from the
+  user's SBo repo). Installed into the image, not built in it (hermetic, no
+  build-time deps).
+
+Both `docker.noland.dnx` and every client that pulls (this dev box, the
+`buildsystem` VM) need the registry marked insecure in
+`/etc/docker/daemon.json`:
+`{"insecure-registries":["docker.noland.dnx:5000"]}`, then `docker` restarted.
+
+i586 is out of scope for now; the variant list is written to extend to it
+later without restructuring.
+
+## Architecture
+
+Three scripts, chained, adapted from the forge repo
+`slackware/docker-images` (`scripts/bootstrap.sh`, `build-full-image.sh`,
+`build-builder-image.sh`). The forge `build-builder-image.sh` is **not** used:
+the full image already ships the toolchain (series d, kde, x, etc.), so a
+separate builder layer is redundant here.
+
+```
+bootstrap.sh              FROM scratch; installpkg base pkgs read from NAS
+  → sbo-base:{ver}          via file://; configure rootfs for container use.
+
+build-full-image.sh       FROM sbo-base:{ver}; slackpkg install every series
+  → sbo-full:{ver}          (a ap d e f k kde l n t tcl x xap xfce y).
+
+build-sbo-testbuild.sh    FROM sbo-full:{ver}; installpkg sbopkg +
+  → sbo-testbuild:{ver}     sbo-maintainer-tools from /opt/sbo-testbuild/pkgs.
+```
+
+All three push to `docker.noland.dnx:5000`.
+
+### Namespacing
+
+Forge scripts push to `registry.slackware.nl/slackware/slackware*`. Re-namespace
+to the LAN registry with our own image names:
+
+- `docker.noland.dnx:5000/sbo-base:{ver}`
+- `docker.noland.dnx:5000/sbo-full:{ver}`
+- `docker.noland.dnx:5000/sbo-testbuild:{ver}`
+
+`sbo-base` and `sbo-full` are intermediate; `.extras/test-build` only pulls
+`sbo-testbuild`.
+
+## Configuration
+
+Single shared file `config`, sourced by all scripts and the test:
+
+```sh
+REGISTRY=docker.noland.dnx:5000
+MIRROR=file:///mnt/nas
+VARIANTS=(current 15.0)          # x86_64 only for now
+PKGDIR=/opt/sbo-testbuild/pkgs   # sbopkg + sbo-maintainer-tools .txz
+```
+
+The forge scripts hardcode `MIRROR=https://slackware.nl/slackware` and
+`REGISTRY=registry.slackware.nl/...`; both move to the shared config.
+
+### NAS path mapping
+
+bootstrap derives the per-variant repo dir as `slackware64-${VERSION}` for
+x86_64 (`DIRSUFFIX=64`). With `MIRROR=file:///mnt/nas` this resolves to
+`file:///mnt/nas/slackware64-current/...` and `.../slackware64-15.0/...`,
+matching the mount points. Mounts must be named to match.
+
+## Patches to the forge scripts
+
+1. **`file://`-aware fetch.** Forge downloads `PACKAGES.TXT` and packages with
+   `curl` over http. Replace with one helper in `lib.sh` that detects a
+   `file://` (or bare-local) MIRROR and uses `cp`, otherwise `curl`. curl's
+   own `file://` support is unreliable across builds, so branch explicitly.
+2. **Drop i586.** `ALL_VARIANTS` becomes the config `VARIANTS` (x86_64 only).
+   All the `ARCH_SUFFIX`/`-i586` machinery collapses to the x86_64 path.
+3. **Re-namespace + LAN registry** (see Namespacing).
+4. **MIRROR → `file:///mnt/nas`** (see config).
+
+## Data flow and rebuild gating
+
+Nightly cron on the VM (root; `bootstrap` needs `installpkg`):
+
+```cron
+ 0 4 * * *  bootstrap.sh
+15 4 * * *  build-full-image.sh
+30 4 * * *  build-sbo-testbuild.sh
+```
+
+Rebuild gating (kept from the forge scripts, extended):
+
+- **bootstrap**: sha256 of the NAS `ChangeLog.txt` (read via `file://`)
+  compared to a stored hash under `HASH_DIR`; skip the variant if unchanged.
+- **build-full-image**: base image digest recorded as a label on the full
+  image; pull base, compare, skip if unchanged.
+- **build-sbo-testbuild**: full image digest label, same pattern; **plus** a
+  hash of the `.txz` set in `PKGDIR`, so a sbopkg / sbo-maintainer-tools bump
+  forces a rebuild even when the full image is unchanged.
+
+Net effect: a quiet NAS tree makes the whole chain no-op in seconds; a
+-current churn cascades base → full → testbuild.
+
+### Local-registry digest consistency
+
+The forge scripts read the base/full digest via `docker inspect RepoDigests`
+after `docker pull`. Self-hosted, those intermediate images live in the LAN
+registry, so pull-then-inspect must target `docker.noland.dnx:5000`. Since
+every image name is derived from `REGISTRY`, re-namespacing handles this with
+no extra logic.
+
+## Error handling
+
+- `set -euo pipefail` in every script (forge already has it).
+- **Missing NAS mount**: guard `[[ -d /mnt/nas/slackware64-$ver ]]` first;
+  `_err` if absent.
+- **Missing `.txz`**: `build-sbo-testbuild` errors before building if
+  `PKGDIR` lacks a `sbopkg-*.txz` or `sbo-maintainer-tools-*.txz` — never push
+  a testbuild image missing sbopkg.
+- **Registry unreachable**: `docker push` fails under `set -e`; the chain
+  aborts. The base/full may already be built locally; cron retries next night.
+  Acceptable.
+- **Per-variant isolation**: one variant failing (e.g. current) must not block
+  the other (15.0). Each variant runs wrapped; log the failure, continue, and
+  exit non-zero at the end so cron logs surface it.
+
+## Testing
+
+Pure-logic pieces get a `test-image-builder.sh` self-check, matching the
+existing `.extras/test-build` pattern (`.extras/test-logic.sh`, assert-based,
+no framework). No docker daemon in tests — hermetic.
+
+- **`file://` fetch helper**: local file resolves via cp; missing local file
+  errors; an http MIRROR still routes to curl.
+- **`.txz`-set hash**: stable across file reordering; changes when a file's
+  content changes.
+- **variant guard**: a missing mount dir yields non-zero.
+
+The real end-to-end chain is verified by a manual first run on the VM (the user
+runs it and reports back), the same division of labor as `.extras/test-build`
+Task 10.
+
+## Layout
+
+```
+.extras/image-builder/
+├── config                    REGISTRY, MIRROR, VARIANTS, PKGDIR
+├── lib.sh                    shared: _log/_warn/_err, fetch, txz_hash, guards
+├── bootstrap.sh              base image (root; installpkg from NAS)
+├── build-full-image.sh       full image (slackpkg all series)
+├── build-sbo-testbuild.sh    testbuild image (installpkg sbopkg + tools)
+├── test-image-builder.sh     pure-logic self-check
+└── README                    VM-side setup, reproducible
+```
+
+Lives in `.extras/` for now (per the user), relocatable later.
+
+The README carries the user-side checklist so it is reproducible and not
+trapped in chat:
+
+- VM specs (4/4/80), Slackware x86_64, docker installed.
+- Two NFS mounts (ro), root-readable, named `slackware64-current` /
+  `slackware64-15.0` under `/mnt/nas`.
+- `registry:2` container: `-v /opt/registry/data:/var/lib/registry`,
+  `--restart=always`, port 5000.
+- `/etc/docker/daemon.json` insecure-registry entry on the VM **and** on every
+  pulling client (this dev box, `buildsystem`), docker restarted.
+- Drop `sbopkg-*.txz` and `sbo-maintainer-tools-*.txz` into
+  `/opt/sbo-testbuild/pkgs/`.
+- Install the three cron lines.
+- VM static IP / LAN DNS for `docker.noland.dnx`.
+
+## Out of scope
+
+- i586 images (extensible later via `VARIANTS` / arch machinery).
+- Building sbopkg / sbo-maintainer-tools from source in the image (installed
+  from prebuilt `.txz`).
+- The forge `build-builder-image.sh` toolchain layer (redundant with full).
+- `installed_in_base` implementation in `.extras/test-build` — unblocked by
+  this work (queries the built image's package db) but tracked separately.
+- Registry auth / TLS (LAN-only plain HTTP).