BoundaryML/baml · error

Failed to download checksum file: {e}

Error message

Failed to download checksum file: {e}

What it means

verify_sha256_checksum fetches the checksum file for the web-panel asset; this error wraps a reqwest transport-level failure of that GET request into "Failed to download checksum file: {e}". The asset itself may have downloaded fine, but the sidecar checksum file could not be fetched.

Source

Thrown at engine/playground-server/src/server.rs:259

        Ok(extract_root.to_string_lossy().to_string())
    }
}

async fn verify_sha256_checksum(
    file_bytes: &[u8],
    checksum_url: &str,
    client: &reqwest::Client,
) -> anyhow::Result<()> {
    tracing::info!("Downloading SHA256 checksum from: {}", checksum_url);

    // Download the checksum file
    tracing::info!("Downloading checksum file...");
    let checksum_resp = client
        .get(checksum_url)
        .header("User-Agent", "baml-playground-server")
        .send()
        .await
        .map_err(|e| anyhow::anyhow!("Failed to download checksum file: {e}"))?;

    if !checksum_resp.status().is_success() {
        return Err(anyhow::anyhow!(
            "Checksum download failed with status: {}",
            checksum_resp.status()
        ));
    }

    let checksum_text = checksum_resp.text().await?;

    // Parse the expected checksum (format: "hash filename" or just "hash")
    let expected_checksum = checksum_text
        .split_whitespace()
        .next()
        .ok_or_else(|| anyhow::anyhow!("Invalid checksum file format"))?
        .to_lowercase();

    // Calculate actual checksum

View on GitHub (pinned to bd85ce9dee)

Solutions

1. Test the checksum URL with curl; fix any DNS/firewall/proxy issue specific to that host.
2. Retry the operation — transport errors are often transient.
3. If checksums are hosted alongside the asset, ensure the release pipeline uploads the .sha256 file to the same origin as the asset.

curl -fsS "$CHECKSUM_URL" | head -c 64 && echo OK || echo unreachable

if let Err(e) = get_playground_dist().await {
    if e.to_string().contains("Failed to download checksum file") { retry_with_backoff(3); }
}

When it happens

Trigger: client.get(checksum_url).send().await returns Err while calling get_playground_dist -> verify_sha256_checksum: DNS failure, connection reset, TLS handshake error, or timeout on the checksum URL.

Common situations: Checksum file hosted at a URL that is blocked or unreachable from the server (firewalls allow the asset CDN but not the checksum host); intermittent network blips; wrong checksum_url configured in release metadata.

Related errors

• {err}
• Failed to download asset: {e}
• Failed to download library: {0}
• Checksum mismatch: expected {expected}, got {actual}
• Could not find an available port in range {}..{}

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/6740626647748c0f. Report an issue: GitHub.