implement ota updates

backend/app/services/android_updates.py

@@ -0,0 +1,373 @@
+"""The Android OTA feed, read from this repository's Gitea Actions artifacts.
+
+The Gitea repository is private, so the phone cannot read Actions artifacts
+itself. This module is the only place that touches the Gitea token: it finds the
+newest successful build from the configured branch, reads the small metadata
+artifact, and pulls the APK out of the matching artifact zip on demand.
+
+Nothing here trusts the metadata blindly. Every field falls back to what the
+Gitea run itself reports, so an older artifact that predates `update.json` still
+produces a usable answer instead of a 500.
+"""
+
+from __future__ import annotations
+
+import json
+import logging
+import shutil
+import tempfile
+import threading
+import time
+import zipfile
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Any
+
+import httpx
+
+from app.config import EnvSettings, env_settings
+
+log = logging.getLogger(__name__)
+
+METADATA_ARTIFACT = "kadence-update-metadata"
+APK_ARTIFACT = "kadence-release-apk"
+
+_METADATA_TTL_SECONDS = 60.0
+_HTTP_TIMEOUT = 30.0
+_DOWNLOAD_TIMEOUT = 120.0
+_MAX_METADATA_BYTES = 1_000_000
+_CACHE_DIR = Path(tempfile.gettempdir()) / "kadence-updates"
+
+
+class UpdateUnavailable(RuntimeError):
+    """The feed cannot be built right now."""
+
+
+class UpdateNotConfigured(UpdateUnavailable):
+    """No Gitea token was supplied, so there is nothing to read."""
+
+
+class UpdateNotFound(UpdateUnavailable):
+    """There is no successful artifact for the configured branch."""
+
+
+@dataclass(frozen=True, slots=True)
+class ResolvedUpdate:
+    metadata: dict[str, Any]
+    apk_artifact_id: int
+
+
+@dataclass(frozen=True, slots=True)
+class Artifact:
+    id: int
+    name: str
+    created_at: str
+    size_bytes: int
+    expired: bool
+    run_id: int
+    run_number: int
+    branch: str
+    commit: str
+    conclusion: str
+
+
+_lock = threading.Lock()
+_resolved_cache: tuple[float, ResolvedUpdate] | None = None
+_apk_cache: dict[int, Path] = {}
+
+
+def reset_cache() -> None:
+    """Drop the in-process caches. Tests use this between Gitea responses."""
+    global _resolved_cache
+    with _lock:
+        _resolved_cache = None
+        _apk_cache.clear()
+
+
+# ---- Gitea reads -----------------------------------------------------------
+
+
+def _settings() -> EnvSettings:
+    settings = env_settings()
+    if not settings.gitea_token:
+        raise UpdateNotConfigured(
+            "Android updates are not configured: set GITEA_TOKEN on the backend."
+        )
+    if not settings.gitea_repo or "/" not in settings.gitea_repo:
+        raise UpdateNotConfigured("Android updates need GITEA_REPO as owner/repository.")
+    return settings
+
+
+def _client(settings: EnvSettings, *, timeout: float = _HTTP_TIMEOUT) -> httpx.Client:
+    return httpx.Client(
+        base_url=settings.gitea_url.rstrip("/"),
+        headers={
+            "Authorization": f"token {settings.gitea_token}",
+            "Accept": "application/json",
+        },
+        timeout=timeout,
+        follow_redirects=True,
+    )
+
+
+def _api(settings: EnvSettings, path: str) -> str:
+    return f"/api/v1/repos/{settings.gitea_repo}{path}"
+
+
+def _artifact(raw: Any) -> Artifact | None:
+    if not isinstance(raw, dict):
+        return None
+    run = raw.get("workflow_run")
+    run = run if isinstance(run, dict) else {}
+    try:
+        artifact_id = int(raw.get("id") or 0)
+    except (TypeError, ValueError):
+        return None
+    if artifact_id <= 0:
+        return None
+    return Artifact(
+        id=artifact_id,
+        name=str(raw.get("name") or ""),
+        created_at=str(raw.get("created_at") or ""),
+        size_bytes=int(raw.get("size_in_bytes") or 0),
+        expired=bool(raw.get("expired")),
+        run_id=int(run.get("id") or 0),
+        run_number=int(run.get("run_number") or 0),
+        branch=str(run.get("head_branch") or ""),
+        commit=str(run.get("head_sha") or ""),
+        conclusion=str(run.get("conclusion") or ""),
+    )
+
+
+def _list_artifacts(
+    client: httpx.Client, settings: EnvSettings, name: str
+) -> list[Artifact]:
+    try:
+        response = client.get(_api(settings, "/actions/artifacts"), params={"name": name})
+        response.raise_for_status()
+        payload = response.json()
+    except (httpx.HTTPError, ValueError) as exc:
+        raise UpdateUnavailable(f"Could not read Gitea artifacts: {exc}") from exc
+
+    entries = payload.get("artifacts") if isinstance(payload, dict) else None
+    if not isinstance(entries, list):
+        return []
+    return [artifact for raw in entries if (artifact := _artifact(raw)) is not None]
+
+
+def _successful(artifacts: list[Artifact], branch: str) -> list[Artifact]:
+    """Newest first, and only successful builds from the requested branch."""
+    usable = [
+        artifact
+        for artifact in artifacts
+        if not artifact.expired
+        and artifact.conclusion == "success"
+        and artifact.branch == branch
+    ]
+    # `run_number` is the monotonic number Android uses as `versionCode`. The
+    # created_at string is the tie-breaker for older Gitea runs that report 0.
+    return sorted(usable, key=lambda item: (item.run_number, item.created_at), reverse=True)
+
+
+def _download_artifact(client: httpx.Client, settings: EnvSettings, artifact: Artifact) -> Path:
+    """Download one artifact zip to a temporary file and return its path."""
+    _CACHE_DIR.mkdir(parents=True, exist_ok=True)
+    target = _CACHE_DIR / f"artifact-{artifact.id}.zip"
+    if target.is_file() and target.stat().st_size > 0:
+        return target
+
+    temporary = target.with_suffix(".zip.part")
+    try:
+        with client.stream(
+            "GET",
+            _api(settings, f"/actions/artifacts/{artifact.id}/zip"),
+            timeout=_DOWNLOAD_TIMEOUT,
+        ) as response:
+            response.raise_for_status()
+            with temporary.open("wb") as handle:
+                for chunk in response.iter_bytes():
+                    handle.write(chunk)
+        if temporary.stat().st_size == 0:
+            raise UpdateUnavailable("Gitea returned an empty artifact archive.")
+        temporary.replace(target)
+    except (httpx.HTTPError, OSError) as exc:
+        temporary.unlink(missing_ok=True)
+        raise UpdateUnavailable(f"Could not download the Gitea artifact: {exc}") from exc
+    return target
+
+
+def _member(zf: zipfile.ZipFile, basename: str) -> zipfile.ZipInfo | None:
+    for info in zf.infolist():
+        if not info.is_dir() and Path(info.filename).name == basename:
+            return info
+    return None
+
+
+def _read_metadata(client: httpx.Client, settings: EnvSettings, artifact: Artifact) -> dict[str, Any]:
+    archive = _download_artifact(client, settings, artifact)
+    try:
+        with zipfile.ZipFile(archive) as zf:
+            info = _member(zf, "update.json")
+            if info is None:
+                raise UpdateUnavailable("The update metadata artifact has no update.json.")
+            if info.file_size > _MAX_METADATA_BYTES:
+                raise UpdateUnavailable("The update metadata artifact is unexpectedly large.")
+            raw = json.loads(zf.read(info).decode("utf-8"))
+    except (zipfile.BadZipFile, OSError, UnicodeDecodeError, ValueError) as exc:
+        raise UpdateUnavailable(f"Could not read the update metadata: {exc}") from exc
+    return raw if isinstance(raw, dict) else {}
+
+
+def _int(value: Any, fallback: int = 0) -> int:
+    try:
+        return int(value)
+    except (TypeError, ValueError):
+        return fallback
+
+
+def _metadata_from_artifact(raw: dict[str, Any], artifact: Artifact) -> dict[str, Any]:
+    run_number = artifact.run_number
+    return {
+        "version_code": _int(raw.get("version_code"), run_number),
+        "version_name": str(
+            raw.get("version_name") or f"0.1.0-master.{run_number or artifact.run_id}"
+        ),
+        "commit": str(raw.get("commit") or artifact.commit),
+        "built_at": str(raw.get("built_at") or artifact.created_at),
+        "size_bytes": _int(raw.get("size_bytes"), artifact.size_bytes),
+        "sha256": str(raw.get("sha256") or ""),
+        "signer_sha256": str(raw.get("signer_sha256") or ""),
+        "run_number": run_number,
+    }
+
+
+def _derive_metadata(artifact: Artifact) -> dict[str, Any]:
+    """For artifacts built before the metadata artifact existed."""
+    return _metadata_from_artifact({}, artifact)
+
+
+def _apk_for_run(artifacts: list[Artifact], update: Artifact) -> Artifact | None:
+    for artifact in artifacts:
+        if artifact.run_id and artifact.run_id == update.run_id and not artifact.expired:
+            return artifact
+    # Defensive fallback for an instance that omits workflow_run.id on an
+    # artifact but keeps the run number.
+    if update.run_number:
+        for artifact in artifacts:
+            if artifact.run_number == update.run_number and not artifact.expired:
+                return artifact
+    return None
+
+
+def _resolve(settings: EnvSettings) -> ResolvedUpdate:
+    global _resolved_cache
+
+    now = time.monotonic()
+    with _lock:
+        cached = _resolved_cache
+    if cached is not None and now - cached[0] < _METADATA_TTL_SECONDS:
+        return cached[1]
+
+    with _client(settings) as client:
+        metadata_artifacts = _successful(
+            _list_artifacts(client, settings, METADATA_ARTIFACT),
+            settings.gitea_update_branch,
+        )
+        apk_artifacts = _list_artifacts(client, settings, APK_ARTIFACT)
+        usable_apk = _successful(apk_artifacts, settings.gitea_update_branch)
+
+        resolved: ResolvedUpdate | None = None
+        for artifact in metadata_artifacts:
+            apk = _apk_for_run(usable_apk, artifact)
+            if apk is None:
+                continue
+            resolved = ResolvedUpdate(
+                metadata=_metadata_from_artifact(
+                    _read_metadata(client, settings, artifact), artifact
+                ),
+                apk_artifact_id=apk.id,
+            )
+            break
+
+        # Before the first build after this feature landed there is no metadata
+        # artifact. The run number is the versionCode, so the newest APK
+        # artifact is still enough to offer an update.
+        if resolved is None and usable_apk:
+            newest = usable_apk[0]
+            resolved = ResolvedUpdate(
+                metadata=_derive_metadata(newest),
+                apk_artifact_id=newest.id,
+            )
+
+    if resolved is None:
+        raise UpdateNotFound(
+            f"No successful {settings.gitea_update_branch} build with an APK was found."
+        )
+
+    with _lock:
+        _resolved_cache = (time.monotonic(), resolved)
+    return resolved
+
+
+def _apk_file(client: httpx.Client, settings: EnvSettings, artifact_id: int) -> Path:
+    with _lock:
+        cached = _apk_cache.get(artifact_id)
+    if cached is not None and cached.is_file() and cached.stat().st_size > 0:
+        return cached
+
+    # The artifact list does not carry the APK's own record here, so fetch it by
+    # id. The id is enough for both the zip URL and the cache key.
+    artifact = Artifact(
+        id=artifact_id,
+        name=APK_ARTIFACT,
+        created_at="",
+        size_bytes=0,
+        expired=False,
+        run_id=0,
+        run_number=0,
+        branch="",
+        commit="",
+        conclusion="success",
+    )
+    archive = _download_artifact(client, settings, artifact)
+    _CACHE_DIR.mkdir(parents=True, exist_ok=True)
+    target = _CACHE_DIR / f"kadence-{artifact_id}.apk"
+    temporary = target.with_suffix(".apk.part")
+    try:
+        with zipfile.ZipFile(archive) as zf:
+            info = _member(zf, "app-release.apk")
+            if info is None:
+                raise UpdateUnavailable("The APK artifact has no app-release.apk.")
+            with zf.open(info) as source, temporary.open("wb") as destination:
+                shutil.copyfileobj(source, destination)
+        if temporary.stat().st_size == 0:
+            raise UpdateUnavailable("The APK inside the artifact is empty.")
+        temporary.replace(target)
+    except (zipfile.BadZipFile, OSError) as exc:
+        temporary.unlink(missing_ok=True)
+        raise UpdateUnavailable(f"Could not extract the APK: {exc}") from exc
+    except UpdateUnavailable:
+        temporary.unlink(missing_ok=True)
+        raise
+
+    with _lock:
+        _apk_cache[artifact_id] = target
+    return target
+
+
+# ---- the public feed -------------------------------------------------------
+
+
+def latest_android() -> dict[str, Any]:
+    """The newest successful build, as JSON-ready metadata."""
+    settings = _settings()
+    return _resolve(settings).metadata
+
+
+def android_apk() -> tuple[Path, dict[str, Any]]:
+    """The APK for the newest build, along with its metadata."""
+    settings = _settings()
+    resolved = _resolve(settings)
+    with _client(settings) as client:
+        path = _apk_file(client, settings, resolved.apk_artifact_id)
+    return path, resolved.metadata