oven-sh/bun · error · Error

Failed to download Packer: ${response.status}

Error message

Failed to download Packer: ${response.status}

What it means

Thrown by scripts/machine.mjs while installing HashiCorp Packer for Windows Azure image builds. The script fetches a pinned release zip (packer_1.15.0_<platform>_<arch>.zip) from releases.hashicorp.com and this error means the HTTP response completed but response.ok was false. The numeric status is embedded so you can tell a 404 (bad URL) from a 5xx/proxy failure.

Source

Thrown at scripts/machine.mjs:1346

  }

  // Check if we have a local copy
  const localPacker = join(tmpdir(), "packer");
  if (existsSync(localPacker)) {
    return localPacker;
  }

  // Download Packer
  const version = "1.15.0";
  const platform = process.platform === "win32" ? "windows" : process.platform;
  const packerArch = process.arch === "arm64" ? "arm64" : "amd64";
  const url = `https://releases.hashicorp.com/packer/${version}/packer_${version}_${platform}_${packerArch}.zip`;

  console.log(`[packer] Downloading Packer ${version}...`);
  const zipPath = join(tmpdir(), "packer.zip");

  const response = await fetch(url);
  if (!response.ok) throw new Error(`Failed to download Packer: ${response.status}`);
  const buffer = Buffer.from(await response.arrayBuffer());
  writeFileSync(zipPath, buffer);

  // Extract
  await spawnSafe(["unzip", "-o", zipPath, "-d", tmpdir()], { stdio: "inherit" });
  chmodSync(localPacker, 0o755);

  console.log(`[packer] Installed Packer ${version}`);
  return localPacker;
}

async function main() {
  const { positionals } = parseArgs({
    allowPositionals: true,
    strict: false,
  });

  const [command] = positionals;

View on GitHub (pinned to 8c5296ac45)

Solutions

1. curl -fL the exact URL printed by the `[packer] Downloading` log line to see the real status code
2. Verify the runner maps to a published release: process.platform win32→'windows', arch arm64→'arm64' else 'amd64'; check the release listing for 1.15.0
3. Fix network/proxy (HTTPS_PROXY/HTTP_PROXY) or re-run — the CDN is occasionally transient
4. Pre-install Packer on PATH or place it at the local cache path so the function returns before reaching the download

Example fix

// before
const response = await fetch(url);
if (!response.ok) throw new Error(`Failed to download Packer: ${response.status}`);

// after — retry transient failures, fail fast on 4xx
let response: Response | undefined;
for (let attempt = 0; attempt < 3 && !response?.ok; attempt++) {
  response = await fetch(url);
  if (response.status >= 500 && attempt < 2) continue;
}
if (!response?.ok) throw new Error(`Failed to download Packer: ${response.status}`);

import { existsSync } from "node:fs";
import { localPacker } from "./machine.mjs"; // or replicate its path

// Skip the download branch entirely when Packer is already usable.
if (!existsSync(localPacker)) {
  const url = "https://releases.hashicorp.com/packer/1.15.0/packer_1.15.0_linux_amd64.zip";
  const head = await fetch(url, { method: "HEAD" });
  if (!head.ok) throw new Error(`Packer release unreachable (HTTP ${head.status}) — fix network or URL`);
}

try {
  await ensurePacker();
} catch (err) {
  if (/Failed to download Packer: (5\d\d|429)/.test(String(err))) {
    await sleep(5_000); // simple backoff, then one retry
    return ensurePacker();
  }
  throw err; // 4xx (bad URL/platform) will not heal — rethrow
}

When it happens

Trigger: Running `machine.mjs create-image/publish-image` for Azure + windows when no usable Packer is already installed locally (the download branch only runs then). A 404 happens when the computed platform/arch pair has no published release; 403/5xx happen behind corporate proxies or when the release CDN is flaky.

Common situations: CI runner without outbound internet or with an HTTPS_PROXY that blocks releases.hashicorp.com; the pinned version 1.15.0 lacking a build for the runner's platform (e.g. an unusual arch mapping); transient CDN errors during CI.

Related errors

• [azure] Failed to get public IP for ${vmName}
• Packer template not found: ${templateFile}
• packer build exited with ${signal ? `signal ${signal}` : `co
• Azure secret not found: ${name}
• [azure] Operation poll failed after ${fetchErrors} fetch err

AI-assisted analysis of oven-sh/bun@8c5296ac45 (2026-08-16). Data as JSON: /api/errors/922ab4f1de1387ee. Report an issue: GitHub.