windmill-labs/windmill · error

Failed to fetch resource types from hub: {}

Error message

Failed to fetch resource types from hub: {}

What it means

At startup, Windmill's main caches hub resource types by fetching them from hub.windmill.dev. If the HTTP response returns a non-2xx status, the server bails with the upstream status code. This reflects a hub-side or network/gateway problem, not a local data problem.

Source

Thrown at backend/src/main.rs:450

        skip_serializing_if = "Option::is_none"
    )]
    pub format_extension: Option<Option<String>>,
}

const HUB_RT_CACHE_FILE: &str = "resource_types.json";

async fn cache_hub_resource_types() -> anyhow::Result<()> {
    println!("Caching resource types from hub...");

    let response = HTTP_CLIENT
        .get(format!("{}/resource_types/list", DEFAULT_HUB_BASE_URL))
        .header("Accept", "application/json")
        .send()
        .await
        .with_context(|| "Failed to fetch resource types from hub")?;

    if !response.status().is_success() {
        anyhow::bail!(
            "Failed to fetch resource types from hub: {}",
            response.status()
        );
    }

    let raw_types: Vec<HubResourceTypeRaw> = response
        .json::<Vec<HubResourceTypeRaw>>()
        .await
        .with_context(|| "Failed to parse resource types from hub")?;

    // Parse schema strings into JSON values
    let resource_types: Vec<HubResourceType> = raw_types
        .into_iter()
        .filter_map(|rt| {
            let schema = match rt.schema {
                Some(s) => match serde_json::from_str(&s) {
                    Ok(v) => Some(v),
                    Err(e) => {

View on GitHub (pinned to e474e8803c)

Solutions

1. Retry later; this is typically transient hub unavailability
2. Check network/proxy egress to hub.windmill.dev from the server host
3. Verify the hub base URL configuration if customized
4. Run with self-contained resource types or skip hub sync if the deployment allows offline mode

let resp = loop {
  match client.get(hub_url).header("Accept", "application/json").send().await {
    Ok(r) if r.status().is_success() => break r,
    Ok(r) => { warn!("hub fetch failed: {}", r.status()); }
    Err(e) => warn!("hub fetch error: {e}"),
  }
  tokio::time::sleep(Duration::from_secs(30)).await;
};

When it happens

Trigger: `cache_hub_resource_types` in windmill_main sends a GET with Accept: application/json to the hub and receives 4xx/5xx (404, 429, 502, 503, etc.).

Common situations: Hub outage or maintenance, rate limiting, corporate proxies/firewalls returning error pages, DNS hijacking captive portals, or a misconfigured hub base URL pointing at a non-hub host.

Related errors

• Couldn't fetch resource types from hub ${hubBaseUrl}: ${(awa
• Couldn't fetch resource types from public hub:
• ApiError with mapped HTTP status message (e.g. "Not Found",
• Generic Error: status: ${errorStatus}; status text: ${errorS
• GET assets/graph -> ${res.status}: ${await res.text()}

AI-assisted analysis of windmill-labs/windmill@e474e8803c (2026-09-03). Data as JSON: /api/errors/2e073a35ab55d289. Report an issue: GitHub.