2 files changed, 67 insertions, 1 deletions
diff --git a/packages/trpc/index.ts b/packages/trpc/index.ts
index 555ca3ba..178703f0 100644
--- a/packages/trpc/index.ts
+++ b/packages/trpc/index.ts
@@ -6,6 +6,7 @@ import type { db } from "@karakeep/db";
 import serverConfig from "@karakeep/shared/config";
 
 import { createRateLimitMiddleware } from "./lib/rateLimit";
+import { createTracingMiddleware } from "./lib/tracing";
 import {
   apiErrorsTotalCounter,
   apiRequestDurationSummary,
@@ -86,7 +87,9 @@ export const procedure = t.procedure
     });
     end();
     return res;
-  });
+  })
+  // OpenTelemetry tracing middleware
+  .use(createTracingMiddleware());
 
 // Default public procedure rate limiting
 export const publicProcedure = procedure.use(
diff --git a/packages/trpc/lib/tracing.ts b/packages/trpc/lib/tracing.ts
new file mode 100644
index 00000000..7b4fb39f
--- /dev/null
+++ b/packages/trpc/lib/tracing.ts
@@ -0,0 +1,63 @@
+import { SpanKind } from "@opentelemetry/api";
+
+import {
+  getTracer,
+  setSpanAttributes,
+  withSpan,
+} from "@karakeep/shared-server";
+import serverConfig from "@karakeep/shared/config";
+
+import type { Context } from "../index";
+
+const tracer = getTracer("@karakeep/trpc");
+
+/**
+ * tRPC middleware that creates a span for each procedure call.
+ * This integrates OpenTelemetry tracing into the tRPC layer.
+ */
+export function createTracingMiddleware() {
+  return async function tracingMiddleware<T>(opts: {
+    ctx: Context;
+    type: "query" | "mutation" | "subscription";
+    path: string;
+    input: unknown;
+    next: () => Promise<T>;
+  }): Promise<T> {
+    // Skip if tracing is disabled
+    if (!serverConfig.tracing.enabled) {
+      return opts.next();
+    }
+
+    const spanName = `trpc.${opts.type}.${opts.path}`;
+
+    return withSpan(
+      tracer,
+      spanName,
+      {
+        kind: SpanKind.SERVER,
+        attributes: {
+          "rpc.system": "trpc",
+          "rpc.method": opts.path,
+          "rpc.type": opts.type,
+          "user.id": opts.ctx.user?.id ?? "anonymous",
+          "user.role": opts.ctx.user?.role ?? "none",
+        },
+      },
+      async () => {
+        return await opts.next();
+      },
+    );
+  };
+}
+
+/**
+ * Helper to add tracing attributes within a tRPC procedure.
+ * Use this to add custom attributes to the current span.
+ */
+export function addTracingAttributes(
+  attributes: Record<string, string | number | boolean>,
+): void {
+  if (serverConfig.tracing.enabled) {
+    setSpanAttributes(attributes);
+  }
+}