SigNoz/signoz · error

err.Error()

Error message

err.Error()

What it means

The web router provider serves static dashboard assets; when os.Stat on the requested file errors with anything other than 'not exists' (e.g. EACCES permission denied, ELOOP, I/O error), it responds 500 with the raw err.Error() text.

Source

Thrown at pkg/web/routerweb/provider.go:94

	return nil
}

func (provider *provider) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
	// Join internally call path.Clean to prevent directory traversal
	path := filepath.Join(provider.config.Directory, req.URL.Path)

	// check whether a file exists or is a directory at the given path
	fi, err := os.Stat(path)
	if err != nil {
		// if the file doesn't exist, serve index.html
		if os.IsNotExist(err) {
			provider.serveIndex(rw)
			return
		}

		// if we got an error (that wasn't that the file doesn't exist) stating the
		// file, return a 500 internal server error and stop
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}

	if fi.IsDir() {
		// path is a directory, serve index.html
		provider.serveIndex(rw)
		return
	}

	// otherwise, use http.FileServer to serve the static file
	provider.fileHandler.ServeHTTP(rw, req)
}

func (provider *provider) serveIndex(rw http.ResponseWriter) {
	rw.Header().Set("Content-Type", "text/html; charset=utf-8")
	_, _ = rw.Write(provider.indexContents)
}

View on GitHub (pinned to 5069bf80b0)

Solutions

1. Check the response body: the text names the exact path and syscall error (e.g. 'permission denied')
2. Fix ownership/permissions on the web assets (chmod -R a+rX on the UI dist directory)
3. Verify symlinks and mount points if ELOOP/ENOENT-with-index-fallback misbehaves

if fi, err := os.Stat(assetPath); err != nil && !os.IsNotExist(err) {
    log.Printf("asset unreadable: %v", err)
}

When it happens

Trigger: GET requests to frontend assets where the embedded/filesystem asset is unreadable: wrong file permissions on the deployed UI directory, a broken symlink loop, or disk errors — a plain 404-miss does NOT take this path (that serves index.html).

Common situations: Container images built with restrictive file modes (assets owned by root, app runs non-root); volume mounts masking the dist directory; broken symlinks in extracted tarballs.

Related errors

• ErrCodeRoleInvalidInput
• CodeInvalidInput
• invalid_input
• invalid_request_query
• unsupported

AI-assisted analysis of SigNoz/signoz@5069bf80b0 (2026-08-28). Data as JSON: /api/errors/a2f421f048bceeca. Report an issue: GitHub.