US08-02: Build a Reproducible Application Image (#97)

docker/fetch-immich-go.py

@@ -0,0 +1,72 @@
+"""Download one pinned immich-go release and verify it before unpacking (US08-02).
+
+Run at image build time by the `uploader` stage, with the interpreter that is already
+in the base image: no curl, no wget, and no download tooling in the layer that ships.
+The checksum is not advisory — a release asset that does not match the pinned digest
+is a failed build, not a warning, because the uploader's flags and report format are
+what the upload parser is written against (concept §15).
+"""
+
+from __future__ import annotations
+
+import argparse
+import hashlib
+import platform
+import tarfile
+import tempfile
+import urllib.request
+from pathlib import Path
+
+RELEASE_URL = "https://github.com/simulot/immich-go/releases/download/v{version}/{asset}"
+# Debian/BuildKit architecture as the interpreter sees it → release asset name.
+ASSETS = {
+    "x86_64": ("immich-go_Linux_x86_64.tar.gz", "amd64"),
+    "amd64": ("immich-go_Linux_x86_64.tar.gz", "amd64"),
+    "aarch64": ("immich-go_Linux_arm64.tar.gz", "arm64"),
+    "arm64": ("immich-go_Linux_arm64.tar.gz", "arm64"),
+}
+TIMEOUT_SECONDS = 300
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--version", required=True, help="immich-go release, without the v")
+    parser.add_argument("--sha256-amd64", required=True)
+    parser.add_argument("--sha256-arm64", required=True)
+    parser.add_argument("--into", default="/usr/local/bin")
+    args = parser.parse_args()
+
+    machine = platform.machine().lower()
+    if machine not in ASSETS:
+        raise SystemExit(f"unsupported architecture: {machine}")
+    asset, arch = ASSETS[machine]
+    expected = {"amd64": args.sha256_amd64, "arm64": args.sha256_arm64}[arch]
+    url = RELEASE_URL.format(version=args.version, asset=asset)
+
+    with urllib.request.urlopen(url, timeout=TIMEOUT_SECONDS) as response:  # noqa: S310
+        payload = response.read()
+    digest = hashlib.sha256(payload).hexdigest()
+    if digest != expected:
+        raise SystemExit(f"checksum mismatch for {url}: {digest} != {expected}")
+
+    target = Path(args.into)
+    target.mkdir(parents=True, exist_ok=True)
+    with tempfile.TemporaryDirectory() as work:
+        archive = Path(work) / asset
+        archive.write_bytes(payload)
+        with tarfile.open(archive) as tar:
+            member = tar.getmember("immich-go")
+            # Extract exactly the one file this pin is about, by name, so nothing
+            # else in the archive can decide where it lands.
+            extracted = tar.extractfile(member)
+            if extracted is None:
+                raise SystemExit("release archive contains no immich-go binary")
+            binary = target / "immich-go"
+            binary.write_bytes(extracted.read())
+            binary.chmod(0o755)
+    print(f"immich-go {args.version} ({arch}) verified {digest}")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())