feat: add Python-alpine Dockerfile for enhanced build process and testing with id-configurator

Signed-off-by: d9pouces <github@19pouces.net>

tests/dockerfiles/repos/build_test_cargo_package.py

@@ -0,0 +1,94 @@
+"""Build a minimal, offline, hand-rolled crate and its sparse registry index
+entry, for integration-testing the `rust` module of id-configurator.
+
+No network access and no build backend (cargo) is used: the crate is a
+plain gzipped tar assembled with the standard library only, so this script
+can run in a minimal Python image with nothing installed.
+
+See https://doc.rust-lang.org/cargo/reference/registries.html#index-format
+for the sparse registry index/config.json format this reproduces.
+"""
+
+from __future__ import annotations
+
+import hashlib
+import io
+import json
+import pathlib
+import tarfile
+
+CRATE = "idconfiguratortestpkg"
+VERSION = "0.0.1"
+CRATE_FILE = f"{CRATE}-{VERSION}.crate"
+OUT_DIR = pathlib.Path("/srv")
+
+CARGO_TOML = f"""[package]
+name = "{CRATE}"
+version = "{VERSION}"
+edition = "2021"
+"""
+LIB_RS = "// test-only crate served by the id-configurator integration tests\n"
+
+
+def _add_file(archive: tarfile.TarFile, name: str, content: bytes) -> None:
+    info = tarfile.TarInfo(name=f"{CRATE}-{VERSION}/{name}")
+    info.size = len(content)
+    archive.addfile(info, io.BytesIO(content))
+
+
+def build_crate() -> bytes:
+    buffer = io.BytesIO()
+    with tarfile.open(fileobj=buffer, mode="w:gz") as archive:
+        _add_file(archive, "Cargo.toml", CARGO_TOML.encode("utf-8"))
+        _add_file(archive, "src/lib.rs", LIB_RS.encode("utf-8"))
+    return buffer.getvalue()
+
+
+def index_path(name: str) -> pathlib.Path:
+    """Mirror cargo's sparse index path convention for a crate name."""
+    if len(name) <= 2:
+        return pathlib.Path(str(len(name))) / name
+    if len(name) == 3:
+        return pathlib.Path("3") / name[0] / name
+    return pathlib.Path(name[0:2]) / name[2:4] / name
+
+
+def write_index(out_dir: pathlib.Path, crate: bytes) -> None:
+    entry = {
+        "name": CRATE,
+        "vers": VERSION,
+        "deps": [],
+        "cksum": hashlib.sha256(crate).hexdigest(),
+        "features": {},
+        "yanked": False,
+    }
+    path = out_dir / index_path(CRATE)
+    path.parent.mkdir(parents=True, exist_ok=True)
+    path.write_text(json.dumps(entry) + "\n", encoding="utf-8")
+
+
+def write_config_json(out_dir: pathlib.Path) -> None:
+    # Cargo requires a fully-qualified "dl" download template, so this bakes
+    # in a placeholder that nginx's sub_filter rewrites to the real
+    # https://<host used by the client>/ at request time (see
+    # cargo-repo.nginx.conf) - the host and port this fixture is actually
+    # reached on aren't known at image-build time.
+    config = {
+        "dl": "__BASE_URL__/api/v1/crates/{crate}/{version}/download",
+        "api": "__BASE_URL__",
+    }
+    (out_dir / "config.json").write_text(json.dumps(config), encoding="utf-8")
+
+
+def main() -> None:
+    OUT_DIR.mkdir(parents=True, exist_ok=True)
+    crate = build_crate()
+    download_path = OUT_DIR / "api/v1/crates" / CRATE / VERSION / "download"
+    download_path.parent.mkdir(parents=True, exist_ok=True)
+    download_path.write_bytes(crate)
+    write_index(OUT_DIR, crate)
+    write_config_json(OUT_DIR)
+
+
+if __name__ == "__main__":
+    main()