feat: add multi-key support with automatic rate-limit rotation

Support multiple API keys via `api_keys` array in config or `OCGO_API_KEYS`
env var. On HTTP 429, automatically rotate to the next key and retry.
Key index persisted to `~/.config/ocgo/key-index` for restart safety.
Backward compatible with existing single-key `api_key` configs.

Fixes #115

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

cmd/ocgo/main.go

@@ -32,10 +32,11 @@ const (
 var version = "dev"
 
 type Config struct {
-	APIKey string `json:"api_key"`
+	APIKey  string   `json:"api_key,omitempty"`
-	Host   string `json:"host"`
+	APIKeys []string `json:"api_keys,omitempty"`
-	Port   int    `json:"port"`
+	Host    string   `json:"host"`
-	Model  string `json:"model"`
+	Port    int      `json:"port"`
+	Model   string   `json:"model"`
 }
 
 type AnthropicRequest struct {
@@ -148,30 +149,38 @@ func main() {
 }
 
 func setupCmd() *cobra.Command {
-	var key string
+	var apiKeys string
 	cmd := &cobra.Command{
 		Use:   "setup",
-		Short: "Save your OpenCode Go API key",
+		Short: "Save your OpenCode Go API key(s)",
 		RunE: func(cmd *cobra.Command, args []string) error {
-			if strings.TrimSpace(key) == "" {
+			if apiKeys == "" {
-				key = os.Getenv("OCGO_API_KEY")
+				apiKeys, _ = cmd.Flags().GetString("api-key")
 			}
-			if strings.TrimSpace(key) == "" {
+			if strings.TrimSpace(apiKeys) == "" {
-				fmt.Print("OpenCode Go API key: ")
+				apiKeys = os.Getenv("OCGO_API_KEYS")
+			}
+			if strings.TrimSpace(apiKeys) == "" {
+				apiKeys = os.Getenv("OCGO_API_KEY")
+			}
+			if strings.TrimSpace(apiKeys) == "" {
+				fmt.Print("OpenCode Go API key(s) (comma-separated): ")
 				line, err := bufio.NewReader(os.Stdin).ReadString('\n')
 				if err != nil && line == "" {
 					return err
 				}
-				key = line
+				apiKeys = line
 			}
-			cfg := Config{APIKey: strings.TrimSpace(key), Host: defaultHost, Port: defaultPort}
+			keys := parseKeys(strings.TrimSpace(apiKeys))
-			if cfg.APIKey == "" {
+			if len(keys) == 0 {
-				return errors.New("API key cannot be empty")
+				return errors.New("at least one API key is required")
 			}
+			cfg := Config{APIKeys: keys, Host: defaultHost, Port: defaultPort}
 			return saveConfig(cfg)
 		},
 	}
-	cmd.Flags().StringVar(&key, "api-key", "", "OpenCode Go API key")
+	cmd.Flags().StringVar(&apiKeys, "api-keys", "", "OpenCode Go API key(s), comma-separated")
+	cmd.Flags().String("api-key", "", "OpenCode Go API key (single)")
 	return cmd
 }
 
@@ -403,14 +412,7 @@ func proxyMessages(w http.ResponseWriter, r *http.Request, cfg Config) {
 		return
 	}
 	body, _ := json.Marshal(or)
-	req, err := http.NewRequestWithContext(r.Context(), http.MethodPost, openAIURL, bytes.NewReader(body))
+	resp, err := cfg.postWithRetry(r.Context(), openAIURL, "application/json", body)
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	req.Header.Set("Authorization", "Bearer "+cfg.APIKey)
-	req.Header.Set("Content-Type", "application/json")
-	resp, err := (&http.Client{Timeout: 10 * time.Minute}).Do(req)
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusBadGateway)
 		return
@@ -454,14 +456,7 @@ func proxyChatCompletions(w http.ResponseWriter, r *http.Request, cfg Config) {
 			}
 		}
 	}
-	req, err := http.NewRequestWithContext(r.Context(), http.MethodPost, openAIURL, bytes.NewReader(body))
+	resp, err := cfg.postWithRetry(r.Context(), openAIURL, "application/json", body)
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	req.Header.Set("Authorization", "Bearer "+cfg.APIKey)
-	req.Header.Set("Content-Type", "application/json")
-	resp, err := (&http.Client{Timeout: 10 * time.Minute}).Do(req)
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusBadGateway)
 		return
@@ -488,14 +483,7 @@ func proxyResponses(w http.ResponseWriter, r *http.Request, cfg Config) {
 		return
 	}
 	body, _ := json.Marshal(or)
-	req, err := http.NewRequestWithContext(r.Context(), http.MethodPost, openAIURL, bytes.NewReader(body))
+	resp, err := cfg.postWithRetry(r.Context(), openAIURL, "application/json", body)
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	req.Header.Set("Authorization", "Bearer "+cfg.APIKey)
-	req.Header.Set("Content-Type", "application/json")
-	resp, err := (&http.Client{Timeout: 10 * time.Minute}).Do(req)
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusBadGateway)
 		return
@@ -1512,6 +1500,76 @@ func startServerProcess(detached bool, model string) (*exec.Cmd, error) {
 func configDir() string  { home, _ := os.UserHomeDir(); return filepath.Join(home, ".config", "ocgo") }
 func configFile() string { return filepath.Join(configDir(), "config.json") }
 func pidFile() string    { return filepath.Join(configDir(), "ocgo.pid") }
+func keyIndexFile() string { return filepath.Join(configDir(), "key-index") }
+
+func readKeyIndex() int {
+	b, err := os.ReadFile(keyIndexFile())
+	if err != nil {
+		return 0
+	}
+	var idx int
+	fmt.Sscanf(string(b), "%d", &idx)
+	return idx
+}
+
+func writeKeyIndex(idx int) error {
+	return os.WriteFile(keyIndexFile(), []byte(fmt.Sprint(idx)), 0600)
+}
+
+func (cfg Config) activeKeys() []string {
+	if len(cfg.APIKeys) > 0 {
+		return cfg.APIKeys
+	}
+	if cfg.APIKey != "" {
+		return []string{cfg.APIKey}
+	}
+	return nil
+}
+
+func (cfg Config) currentKey() string {
+	keys := cfg.activeKeys()
+	if len(keys) == 0 {
+		return ""
+	}
+	idx := readKeyIndex() % len(keys)
+	return keys[idx]
+}
+
+func (cfg Config) rotateKey() string {
+	keys := cfg.activeKeys()
+	if len(keys) <= 1 {
+		return cfg.currentKey()
+	}
+	idx := readKeyIndex()
+	idx = (idx + 1) % len(keys)
+	_ = writeKeyIndex(idx)
+	return keys[idx]
+}
+
+func (cfg Config) postWithRetry(ctx context.Context, url, contentType string, body []byte) (*http.Response, error) {
+	client := &http.Client{Timeout: 10 * time.Minute}
+	keys := cfg.activeKeys()
+	for i := 0; i < len(keys); i++ {
+		key := cfg.currentKey()
+		req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(body))
+		if err != nil {
+			return nil, err
+		}
+		req.Header.Set("Authorization", "Bearer "+key)
+		req.Header.Set("Content-Type", contentType)
+		resp, err := client.Do(req)
+		if err != nil {
+			return nil, err
+		}
+		if resp.StatusCode == http.StatusTooManyRequests && i < len(keys)-1 {
+			resp.Body.Close()
+			cfg.rotateKey()
+			continue
+		}
+		return resp, nil
+	}
+	panic("unreachable")
+}
 
 func codexConfigFile() string {
 	home, _ := os.UserHomeDir()
@@ -1664,6 +1722,12 @@ func versionParts(v string) [3]int {
 }
 
 func saveConfig(cfg Config) error {
+	// Write api_key for backward compatibility with older ocgo versions
+	if len(cfg.APIKeys) > 0 {
+		cfg.APIKey = cfg.APIKeys[0]
+	} else {
+		cfg.APIKey = ""
+	}
 	if err := os.MkdirAll(configDir(), 0755); err != nil {
 		return err
 	}
@@ -1676,12 +1740,21 @@ func saveConfig(cfg Config) error {
 }
 
 func loadConfig() (Config, error) {
-	cfg := Config{Host: defaultHost, Port: defaultPort, APIKey: os.Getenv("OCGO_API_KEY")}
+	cfg := Config{Host: defaultHost, Port: defaultPort}
 	b, err := os.ReadFile(configFile())
 	if err == nil {
 		_ = json.Unmarshal(b, &cfg)
 	}
-	if cfg.APIKey == "" {
+	if envKey := os.Getenv("OCGO_API_KEY"); envKey != "" {
+		cfg.APIKey = envKey
+	}
+	if envKeys := os.Getenv("OCGO_API_KEYS"); envKeys != "" {
+		cfg.APIKeys = parseKeys(envKeys)
+	}
+	if len(cfg.APIKeys) == 0 && cfg.APIKey != "" {
+		cfg.APIKeys = []string{cfg.APIKey}
+	}
+	if len(cfg.APIKeys) == 0 {
 		return cfg, errors.New("missing API key; run: ocgo setup")
 	}
 	if cfg.Host == "" {
@@ -1693,6 +1766,17 @@ func loadConfig() (Config, error) {
 	return cfg, nil
 }
 
+func parseKeys(s string) []string {
+	parts := strings.Split(s, ",")
+	var keys []string
+	for _, p := range parts {
+		if k := strings.TrimSpace(p); k != "" {
+			keys = append(keys, k)
+		}
+	}
+	return keys
+}
+
 func readPID() (int, error) {
 	b, err := os.ReadFile(pidFile())
 	if err != nil {