micro/go-micro · error

failed to marshal stream request: %w

Error message

failed to marshal stream request: %w

What it means

Thrown in the OpenAI provider's Stream when json.Marshal(apiReq) fails while building the streaming request body. The apiReq is a map[string]any, so marshaling only fails for values that are not JSON-encodable (e.g. channels, funcs, cyclic structures) — rare in practice since options come from typed provider opts.

Source

Thrown at ai/openai/openai.go:211

	}
	if req.Prompt != "" {
		messages = append(messages, map[string]any{"role": "user", "content": req.Prompt})
	}
	apiReq := map[string]any{
		"model":          p.opts.Model,
		"messages":       messages,
		"stream":         true,
		"stream_options": map[string]any{"include_usage": true},
	}
	if p.opts.MaxTokens > 0 {
		apiReq["max_tokens"] = p.opts.MaxTokens
	}
	if p.opts.Effort != "" {
		apiReq["reasoning_effort"] = p.opts.Effort
	}
	reqBody, err := json.Marshal(apiReq)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal stream request: %w", err)
	}
	apiURL := strings.TrimRight(p.opts.BaseURL, "/") + "/v1/chat/completions"
	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, apiURL, bytes.NewReader(reqBody))
	if err != nil {
		return nil, fmt.Errorf("failed to create stream request: %w", err)
	}
	httpReq.Header.Set("Content-Type", "application/json")
	httpReq.Header.Set("Accept", "text/event-stream")
	httpReq.Header.Set("Authorization", "Bearer "+p.opts.APIKey)

	httpResp, err := http.DefaultClient.Do(httpReq)
	if err != nil {
		return nil, fmt.Errorf("stream API request failed: %w", err)
	}
	if httpResp.StatusCode != http.StatusOK {
		defer httpResp.Body.Close()
		respBody, _ := io.ReadAll(httpResp.Body)
		return nil, fmt.Errorf("stream API error (%s): %s", httpResp.Status, string(respBody))

View on GitHub (pinned to 24529f1404)

Solutions

1. Inspect the apiReq map contents for non-JSON-encodable values
2. Constrain options to strings, numbers, booleans, and slices/maps thereof
3. Ensure any middleware copying/deriving the map doesn't inject functions or channels
4. Log the map before marshaling to identify the offending key

Example fix

// before
apiReq["tools"] = someFunc // not JSON-encodable
// after
apiReq["tools"] = toolDefsJSONCompatible

func isJSONSafe(v any) bool {
    b, err := json.Marshal(v)
    return err == nil && json.Valid(b)
}
// call isJSONSafe(apiReq) before provider.Stream

When it happens

Trigger: Calling Stream() when the assembled apiReq map contains a value json.Marshal cannot encode — typically only possible if a caller injected a non-serializable value through custom options or a middleware mutating the request map.

Common situations: Custom option injection putting a func or unsupported type into the request map; a wrapping layer building the map dynamically with bad values; almost never hit with standard string/number options.

Understand the failure class

Background: json.Marshal / "failed to marshal" errors in Go: why "unsupported type" happens and how to fix it — this error's family across 22 libraries.

Related errors

• failed to parse stream chunk: %w
• failed to marshal request: %w
• failed to parse stream chunk: %w
• failed to marshal request: %w
• failed to marshal stream request: %w

AI-assisted analysis of micro/go-micro@24529f1404 (2026-09-01). Data as JSON: /api/errors/af62f42aceca2fbe. Report an issue: GitHub.