fix(self-host): stop tracing idle polls

.changeset/untraced-event-poll.md

@@ -0,0 +1,8 @@
+---
+"@executor-js/sdk": patch
+---
+
+Self-host and local check for due event deliveries every two seconds. That
+check no longer records traces when it finds nothing to deliver; each delivery
+attempt and each subscription it expires is still traced. An idle self-host
+instance no longer fills the bundled Motel store with polling spans.

.changeset/untraced-idle-polls.md

@@ -0,0 +1,11 @@
+---
+"@executor-js/sdk": patch
+"@executor-js/hosted-server": patch
+---
+
+The scheduler's check for due runs, every second on self-host and local, and
+self-host's check for queued provisioning jobs, every second, no longer record
+traces when they find nothing to do. Each scheduled operation a check finds is
+still traced, in its own `schedule.dispatch` trace, and so is each provisioning
+job. An idle self-host instance no longer fills the bundled Motel store with
+polling spans.

apps/hosted/server/src/implementation/provisioning.ts

@@ -210,6 +210,8 @@ export const drainProvisioning = (services: ProvisioningServices) =>
       Effect.flatMap(
         Schema.decodeUnknownEffect(Schema.Array(Schema.Struct({ id: Schema.String }))),
       ),
+      // Self-host polls every second. The poll records nothing; the jobs it finds are traced.
+      Effect.withTracerEnabled(false),
     );
     for (const job of jobs)
       yield* provision(job.id, services).pipe(

packages/sdk/src/implementation/event-worker.ts

@@ -12,7 +12,8 @@ export const deliverEvents = (executor: Executor) =>
     yield* Effect.flatten(ScheduleHostReady);
     yield* executor.events.deliver({ maxDeliveries: batch }).pipe(
       Effect.repeat({ while: (more) => more }),
-      Effect.withSpan("events.dispatch"),
+      // A pass runs every two seconds; one that finds nothing to deliver records nothing.
+      Effect.withTracerEnabled(false),
       Effect.catch(() => Effect.logError("Event delivery failed")),
       Effect.repeat(Schedule.spaced("2 seconds")),
     );

packages/sdk/src/implementation/events.ts

@@ -808,7 +808,11 @@ export const makeEvents = (input: {
           limit: 100,
         }),
       );
-      for (const row of lapsed) yield* stopWith(EventSubscriptionId.make(row.id), "expired");
+      // A host may poll without tracing; the work a pass finds is traced all the same.
+      for (const row of lapsed)
+        yield* stopWith(EventSubscriptionId.make(row.id), "expired").pipe(
+          Effect.withTracerEnabled(true),
+        );
       const due = yield* query(() =>
         db.findMany("eventDeliveries", {
           where: (b) =>
@@ -825,7 +829,11 @@ export const makeEvents = (input: {
         due,
         (row) =>
           claim(row.id).pipe(
-            Effect.flatMap((claimed) => (claimed === null ? Effect.void : attempt(claimed))),
+            Effect.flatMap((claimed) =>
+              claimed === null
+                ? Effect.void
+                : attempt(claimed).pipe(Effect.withTracerEnabled(true)),
+            ),
             Effect.catch(() => Effect.logWarning("Event delivery attempt failed")),
           ),
         { concurrency: 8, discard: true },

packages/sdk/src/implementation/schedule-worker.ts

@@ -23,11 +23,18 @@ export const startScheduleWorker = (
         runner: config.runner,
         maxCandidates: config.concurrency,
         authorize,
-        execute: (operation) => pool.withPermitsIfAvailable(1)(operation).pipe(Effect.asVoid),
+        // Each operation a pass finds is one trace, rooted in a dispatch as a Cloud
+        // coordinator's pass is.
+        execute: (operation) =>
+          pool
+            .withPermitsIfAvailable(1)(
+              operation.pipe(Effect.withSpan("schedule.dispatch"), Effect.withTracerEnabled(true)),
+            )
+            .pipe(Effect.asVoid),
       })
       .pipe(
-        // Each pass is one trace, as a Cloud coordinator's dispatch is.
-        Effect.withSpan("schedule.dispatch"),
+        // A pass runs every second; one that finds nothing to run records nothing.
+        Effect.withTracerEnabled(false),
         Effect.catch(() => Effect.logError("Scheduled dispatch failed")),
         Effect.forkIn(scope),
         Effect.asVoid,