windmill-labs/windmill · error

Couldn't write inventory: {}

Error message

Couldn't write inventory: {}

What it means

write_file_at_user_defined_location failed while persisting the inventory file into the job directory; the executor wraps the io/path error with this message. Failure here usually means the filename derived from inventory.name is unusable (illegal characters, too long) or a filesystem-level error occurred in the job dir.

Source

Thrown at backend/windmill-worker/src/ansible_executor.rs:2278

                .map_err(|e| anyhow!("Failed to parse inventory arg: {}", e))?;

            if content == serde_json::value::Value::Null {
                Err(anyhow!("The inventory argument was left empty. If you do not wish to specify an inventory for this script, remove the `inventory:` section from the yaml."))?;
            }
        }

        let validated_path = write_file_at_user_defined_location(
            job_dir,
            &inventory.name,
            content
                .get("content")
                .and_then(|v| v.as_str())
                .ok_or(anyhow!(
                    "Invalid inventory resource, `content` field absent or invalid"
                ))?,
            None,
        )
        .map_err(|e| anyhow!("Couldn't write inventory: {}", e))?;

        nsjail_mounts.push(
            define_nsjail_mount(job_dir, &validated_path)
                .map_err(|e| anyhow!("Inventory path (a.k.a. `name`) is invalid: {}", e))?,
        );

        logs.push_str(&format!("\nCreated inventory `{}`", inventory.name));
    }

    for file_res in &r.file_resources {
        let r =
            get_resource_or_variable_content(client, &file_res.resource_path, job_id.to_string())
                .await?;
        let path = file_res.target_path.clone();
        let validated_path =
            write_file_at_user_defined_location(job_dir, path.as_str(), &r, file_res.mode)
                .map_err(|e| anyhow!("Couldn't write text file at {}: {}", path, e))?;

View on GitHub (pinned to e474e8803c)

Solutions

1. Rename the inventory `name` in the yaml to a simple filesystem-safe identifier (letters, digits, `-`, `_`).
2. Check worker disk space (`df` on the job/tmp dir) and permissions of the job directory.
3. Look at the inner error in this message to distinguish path validation vs I/O failure.
4. Retry the job once disk/permission issues are fixed.

Example fix

// before
inventory: { name: "prod/web servers" }
// after
inventory: { name: "prod-web-servers" }

function isFilenameSafe(name) {
  return /^[A-Za-z0-9._-]+$/.test(name) && !name.includes('..');
}
if (!isFilenameSafe(inventoryName)) throw new Error('inventory name must be a flat safe filename');

function isSafeFilename(s) { return typeof s === 'string' && /^[A-Za-z0-9._-]{1,128}$/.test(s); }

// surface the inner io error and fail fast
match write_inventory().await {
    Err(e) if e.to_string().contains("Couldn't write inventory") => bail!("check worker disk space and inventory name: {e}"),
    other => other,
}

When it happens

Trigger: create_file_resources calls write_file_at_user_defined_location(job_dir, &inventory.name, content, None) and it errors — bad path chars in `inventory.name` (slashes, `..`), permission issues on the worker's temp dir, or disk full — via handle_ansible_job.

Common situations: Inventory name containing `/`, spaces, or unusual unicode; name exceeding filesystem filename limits; worker tmpfs full; read-only job directory after a mount misconfiguration.

Understand the failure class

Background: "failed to write file", "Could not save figure", "Error saving remote file" — file write failed: causes and fixes across languages and libraries — this error's family across 38 libraries.

Related errors

• Directory '{}' already exists and is not empty
• Invalid inventory definition
• Specified inventory was missing in the script arguments
• Failed to parse inventory arg: {}
• The inventory argument was left empty. If you do not wish to

AI-assisted analysis of windmill-labs/windmill@e474e8803c (2026-09-03). Data as JSON: /api/errors/1faac971b8739919. Report an issue: GitHub.