feat: Add open telemetry (#2318)

* feat: add OpenTelemetry tracing infrastructure

Introduce distributed tracing capabilities using OpenTelemetry:

- Add @opentelemetry packages to shared-server for tracing
- Create tracing utility module with span helpers (withSpan, addSpanEvent, etc.)
- Add tRPC middleware for automatic span creation on API calls
- Initialize tracing in API and workers entry points
- Add demo instrumentation to bookmark creation and crawler worker
- Add configuration options (OTEL_TRACING_ENABLED, OTEL_EXPORTER_OTLP_ENDPOINT, etc.)
- Document tracing configuration in environment variables docs

When enabled, traces are collected for tRPC calls, bookmark creation flow,
and crawler operations, with support for any OTLP-compatible backend (Jaeger, Tempo, etc.)

* refactor: remove tracing from workers for now

Keep tracing infrastructure but remove worker instrumentation:
- Remove tracing initialization from workers entry point
- Remove tracing instrumentation from crawler worker
- Fix formatting in tracing files

The tracing infrastructure remains available for future use.

* add hono and next tracing

* remove extra span logging

* more fixes

* update config

* some fixes

* upgrade packages

* remove unneeded packages

---------

Co-authored-by: Claude <noreply@anthropic.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/packages/shared/config.ts b/packages/shared/config.ts
index c10634e2..28dcc624 100644
--- a/packages/shared/config.ts
+++ b/packages/shared/config.ts
@@ -211,6 +211,12 @@ const allEnv = z.object({
 
   // Database configuration
   DB_WAL_MODE: stringBool("false"),
+
+  // OpenTelemetry tracing configuration
+  OTEL_TRACING_ENABLED: stringBool("false"),
+  OTEL_EXPORTER_OTLP_ENDPOINT: z.string().url().optional(),
+  OTEL_SERVICE_NAME: z.string().default("karakeep"),
+  OTEL_SAMPLE_RATE: z.coerce.number().min(0).max(1).default(1.0),
 });
 
 const serverConfigSchema = allEnv.transform((val, ctx) => {
@@ -413,6 +419,12 @@ const serverConfigSchema = allEnv.transform((val, ctx) => {
     database: {
       walMode: val.DB_WAL_MODE,
     },
+    tracing: {
+      enabled: val.OTEL_TRACING_ENABLED,
+      otlpEndpoint: val.OTEL_EXPORTER_OTLP_ENDPOINT,
+      serviceName: val.OTEL_SERVICE_NAME,
+      sampleRate: val.OTEL_SAMPLE_RATE,
+    },
   };
   if (obj.auth.emailVerificationRequired && !obj.email.smtp) {
     ctx.addIssue({