feat(backend): allow specifying PostHog host

Author: pan93412

cmd/backend/dependencies.go

@@ -52,15 +52,15 @@ func ApqCache(redisClient rueidis.Client) graphql.Cache[string] {
 }
 
 func PostHogClient(lifecycle fx.Lifecycle, cfg config.Config) (posthog.Client, error) {
-	if cfg.PostHog.APIKey == nil {
-		slog.Warn("PostHog client is not initialized, because you did not configure a PostHog API key.")
+	if cfg.PostHog.APIKey == nil || cfg.PostHog.Host == nil {
+		slog.Warn("PostHog client is not initialized, because you did not configure a PostHog API key and a host.")
 		return nil, nil
 	}
 
 	client, err := posthog.NewWithConfig(
 		*cfg.PostHog.APIKey,
 		posthog.Config{
-			Endpoint: "https://us.i.posthog.com",
+			Endpoint: *cfg.PostHog.Host,
 		},
 	)
 	if err != nil {

docs/config.md

@@ -65,3 +65,5 @@ PostHog 是一個產品統計平台。這個專案使用 [posthog-go](https://po
 如果不填寫 API Key 則代表不送出任何統計。
 
 - `POSTHOG_API_KEY`: PostHog 的 API key。可以在 PostHog 的 Settings > Project > General > Project API key 中取得。
+- `POSTHOG_HOST`: PostHog API 的主機。可以在 PostHog 的 Settings > Project > General > Web snippet 中的 `api_host` 取得。
+  - e.g. `https://us.i.posthog.com`

internal/config/models.go

@@ -157,12 +157,17 @@ func (c SqlRunnerConfig) Validate() error {
 
 type PostHogConfig struct {
 	APIKey *string `env:"API_KEY"`
+	Host   *string `env:"HOST"`
 }
 
 func (c PostHogConfig) Validate() error {
 	if c.APIKey != nil && *c.APIKey == "" {
 		return errors.New("POSTHOG_API_KEY cannot be empty")
 	}
 
+	if c.Host != nil && *c.Host == "" {
+		return errors.New("POSTHOG_HOST cannot be empty")
+	}
+
 	return nil
 }