Add percent-based rollout of clickhouse logs

Author: ericallam

apps/webapp/app/env.server.ts

@@ -1120,6 +1120,7 @@ const EnvironmentSchema = z
     EVENTS_CLICKHOUSE_COMPRESSION_REQUEST: z.string().default("1"),
     EVENTS_CLICKHOUSE_BATCH_SIZE: z.coerce.number().int().default(1000),
     EVENTS_CLICKHOUSE_FLUSH_INTERVAL_MS: z.coerce.number().int().default(1000),
+    EVENT_REPOSITORY_CLICKHOUSE_ROLLOUT_PERCENT: z.coerce.number().optional(),
     EVENT_REPOSITORY_DEFAULT_STORE: z.enum(["postgres", "clickhouse"]).default("postgres"),
     EVENTS_CLICKHOUSE_MAX_TRACE_SUMMARY_VIEW_COUNT: z.coerce.number().int().default(250_000),
 

apps/webapp/app/v3/eventRepository/index.server.ts

@@ -20,17 +20,39 @@ export function resolveEventRepositoryForStore(store: string | undefined): IEven
 export async function getEventRepository(
   featureFlags: Record<string, unknown> | undefined
 ): Promise<{ repository: IEventRepository; store: string }> {
-  const taskEventRepository = await flags({
+  const taskEventRepository = await resolveTaskEventRepositoryFlag(featureFlags);
+
+  if (taskEventRepository === "clickhouse") {
+    return { repository: clickhouseEventRepository, store: "clickhouse" };
+  }
+
+  return { repository: eventRepository, store: getTaskEventStore() };
+}
+
+async function resolveTaskEventRepositoryFlag(
+  featureFlags: Record<string, unknown> | undefined
+): Promise<"clickhouse" | "postgres"> {
+  const flag = await flags({
     key: FEATURE_FLAG.taskEventRepository,
     defaultValue: env.EVENT_REPOSITORY_DEFAULT_STORE,
     overrides: featureFlags,
   });
 
-  if (taskEventRepository === "clickhouse") {
-    return { repository: clickhouseEventRepository, store: "clickhouse" };
+  if (flag === "clickhouse") {
+    return "clickhouse";
   }
 
-  return { repository: eventRepository, store: getTaskEventStore() };
+  if (env.EVENT_REPOSITORY_CLICKHOUSE_ROLLOUT_PERCENT) {
+    const rolloutPercent = env.EVENT_REPOSITORY_CLICKHOUSE_ROLLOUT_PERCENT;
+
+    const randomNumber = Math.random();
+
+    if (randomNumber < rolloutPercent) {
+      return "clickhouse";
+    }
+  }
+
+  return flag;
 }
 
 export async function recordRunDebugLog(