init claude-code

services/analytics/sink.ts

@@ -0,0 +1,114 @@
+/**
+ * Analytics sink implementation
+ *
+ * This module contains the actual analytics routing logic and should be
+ * initialized during app startup. It routes events to Datadog and 1P event
+ * logging.
+ *
+ * Usage: Call initializeAnalyticsSink() during app startup to attach the sink.
+ */
+
+import { trackDatadogEvent } from './datadog.js'
+import { logEventTo1P, shouldSampleEvent } from './firstPartyEventLogger.js'
+import { checkStatsigFeatureGate_CACHED_MAY_BE_STALE } from './growthbook.js'
+import { attachAnalyticsSink, stripProtoFields } from './index.js'
+import { isSinkKilled } from './sinkKillswitch.js'
+
+// Local type matching the logEvent metadata signature
+type LogEventMetadata = { [key: string]: boolean | number | undefined }
+
+const DATADOG_GATE_NAME = 'tengu_log_datadog_events'
+
+// Module-level gate state - starts undefined, initialized during startup
+let isDatadogGateEnabled: boolean | undefined = undefined
+
+/**
+ * Check if Datadog tracking is enabled.
+ * Falls back to cached value from previous session if not yet initialized.
+ */
+function shouldTrackDatadog(): boolean {
+  if (isSinkKilled('datadog')) {
+    return false
+  }
+  if (isDatadogGateEnabled !== undefined) {
+    return isDatadogGateEnabled
+  }
+
+  // Fallback to cached value from previous session
+  try {
+    return checkStatsigFeatureGate_CACHED_MAY_BE_STALE(DATADOG_GATE_NAME)
+  } catch {
+    return false
+  }
+}
+
+/**
+ * Log an event (synchronous implementation)
+ */
+function logEventImpl(eventName: string, metadata: LogEventMetadata): void {
+  // Check if this event should be sampled
+  const sampleResult = shouldSampleEvent(eventName)
+
+  // If sample result is 0, the event was not selected for logging
+  if (sampleResult === 0) {
+    return
+  }
+
+  // If sample result is a positive number, add it to metadata
+  const metadataWithSampleRate =
+    sampleResult !== null
+      ? { ...metadata, sample_rate: sampleResult }
+      : metadata
+
+  if (shouldTrackDatadog()) {
+    // Datadog is a general-access backend — strip _PROTO_* keys
+    // (unredacted PII-tagged values meant only for the 1P privileged column).
+    void trackDatadogEvent(eventName, stripProtoFields(metadataWithSampleRate))
+  }
+
+  // 1P receives the full payload including _PROTO_* — the exporter
+  // destructures and routes those keys to proto fields itself.
+  logEventTo1P(eventName, metadataWithSampleRate)
+}
+
+/**
+ * Log an event (asynchronous implementation)
+ *
+ * With Segment removed the two remaining sinks are fire-and-forget, so this
+ * just wraps the sync impl — kept to preserve the sink interface contract.
+ */
+function logEventAsyncImpl(
+  eventName: string,
+  metadata: LogEventMetadata,
+): Promise<void> {
+  logEventImpl(eventName, metadata)
+  return Promise.resolve()
+}
+
+/**
+ * Initialize analytics gates during startup.
+ *
+ * Updates gate values from server. Early events use cached values from previous
+ * session to avoid data loss during initialization.
+ *
+ * Called from main.tsx during setupBackend().
+ */
+export function initializeAnalyticsGates(): void {
+  isDatadogGateEnabled =
+    checkStatsigFeatureGate_CACHED_MAY_BE_STALE(DATADOG_GATE_NAME)
+}
+
+/**
+ * Initialize the analytics sink.
+ *
+ * Call this during app startup to attach the analytics backend.
+ * Any events logged before this is called will be queued and drained.
+ *
+ * Idempotent: safe to call multiple times (subsequent calls are no-ops).
+ */
+export function initializeAnalyticsSink(): void {
+  attachAnalyticsSink({
+    logEvent: logEventImpl,
+    logEventAsync: logEventAsyncImpl,
+  })
+}