dotnet/aspnetcore · error · Exception

Failed to download , Status Code

Error message

Failed to download {url}, Status Code: {response.status}

What it means

Raised by download_file when aiohttp returns a non-200 HTTP status for the requested URL. It captures the upstream status code so the operator can tell a 404 (wrong path) from a 403 (forbidden) or 5xx (server fault). Because it is raised inside the try, transient network errors are retried, but HTTP-level non-200 responses are not (they raise straight to the caller).

Solutions

1. Open the printed URL in a browser or curl -I to confirm the status code and adjust --mirror/--suite/--arch accordingly.
2. If 404, regenerate by pointing to a suite that still hosts the file (older stable point releases get archived under http://archive.debian.org).
3. If 403/451, switch mirrors or networks to bypass filtering.
4. If 5xx, retry shortly or fall back to a different mirror; do not change the script — the mirror is the fault.

Example fix

# before
python3 install-debs.py --mirror http://ftp.debian.org/debian --suite buster --arch amd64 --rootfsdir rootfs libc6
# HTTP 404: buster moved to archive

# after
python3 install-debs.py --mirror http://archive.debian.org/debian --suite buster --arch amd64 --rootfsdir rootfs libc6

# Validate the URL exists before the run for any package you care about:
for pkg in libc6 libc-bin; do
  url="$MIRROR/$(curl -fsS "$MIRROR/dists/$SUITE/main/binary-$ARCH/Packages.gz" | gzip -d | awk -v p=$pkg '$1=="Package:"{n=$2} $1=="Filename:"&&n==p{print $2}')"
  curl -fsS --head "$url" | head -1
done

When it happens

Trigger: session.get(url) returns a response whose .status is not 200 (404 for a package the index doesn't actually carry at that path, 403 from a firewall, 502/503 from an overloaded mirror).

Common situations: Stale Packages index referencing a .deb that was rotated off the mirror; wrong --arch (e.g. arm64 index pointing at a path only present for amd64); suite name typo; mirror with selective component availability (no 'universe'); geoblocking returning 403.

Related errors

• Failed to download after attempts.
• SHA256 mismatch for : expected , got
• SHA256 mismatch for : expected , got
• Could not find checksum for
• Could not find 'data.tar.*' in

AI-assisted analysis of dotnet/aspnetcore@3600ca084e (2026-08-11). Data as JSON: /api/errors/1b4aa6077aa208c5. Report an issue: GitHub.

Appendix: source

Thrown at eng/common/cross/install-debs.py:40

    attempt = 0
    while attempt < max_retries:
        try:
            async with session.get(url, timeout=aiohttp.ClientTimeout(total=timeout)) as response:
                if response.status == 200:
                    with open(dest_path, "wb") as f:
                        content = await response.read()

                        # verify checksum if provided
                        if checksum:
                            sha256 = hashlib.sha256(content).hexdigest()
                            if sha256 != checksum:
                                raise Exception(f"SHA256 mismatch for {url}: expected {checksum}, got {sha256}")

                        f.write(content)
                    print(f"Downloaded {url} at {dest_path}")
                    return
                else:
                    raise Exception(f"Failed to download {url}, Status Code: {response.status}")
        except (asyncio.CancelledError, asyncio.TimeoutError, aiohttp.ClientError) as e:
            print(f"Error downloading {url}: {type(e).__name__} - {e}. Retrying...")

        attempt += 1
        await asyncio.sleep(retry_delay)

    raise Exception(f"Failed to download {url} after {max_retries} attempts.")

async def download_deb_files_parallel(mirror, packages, tmp_dir):
    """Download .deb files in parallel."""
    os.makedirs(tmp_dir, exist_ok=True)

    tasks = []
    timeout = aiohttp.ClientTimeout(total=60)
    async with aiohttp.ClientSession(timeout=timeout) as session:
        for pkg, info in packages.items():
            filename = info.get("Filename")
            if filename:

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