Task Run Payload for HA Scheduler State

Problem

TaskRunSchedulerInfo is stored in-memory in Bus.sync.Map. This breaks HA:

• Lost on replica crash
• Not shared across replicas
• UI can't show why a task is waiting if the tracking replica dies

Solution

Add a payload JSONB column to task_run table, storing a TaskRunPayload proto that contains SchedulerInfo. Future fields can be added to the proto without schema changes.

Design

Proto

proto/store/store/task_run.proto:

message TaskRunPayload {
  SchedulerInfo scheduler_info = 1;
  // Future fields added here without schema changes
}

Schema

Migration backend/migrator/migration/3.14/0032##task_run_payload.sql:

ALTER TABLE task_run ADD COLUMN payload jsonb NOT NULL DEFAULT '{}';

Store Layer

backend/store/task_run.go:

• Add PayloadProto *storepb.TaskRunPayload to TaskRunMessage
• Read: Add payload to SELECT, unmarshal with protojson
• Write: UpdateTaskRunPayload(ctx, taskRunID, payload) method

Scheduler

backend/runner/taskrun/pending_scheduler.go:

• storeParallelLimitCause(): Write TaskRunPayload{SchedulerInfo: ...} to DB
• promoteTaskRun(): Write empty TaskRunPayload{} to clear

API

backend/api/v1/rollout_service_converter.go:

• Remove bus *bus.Bus parameter
• Read SchedulerInfo from taskRun.PayloadProto.SchedulerInfo

Cleanup

backend/component/bus/bus.go:

• Remove TaskRunSchedulerInfo sync.Map

Files to Modify

1. proto/store/store/task_run.proto - Add TaskRunPayload
2. backend/migrator/migration/3.14/0032##task_run_payload.sql - New
3. backend/migrator/migration/LATEST.sql - Add column
4. backend/migrator/migrator_test.go - Update version
5. backend/store/task_run.go - Add field and methods
6. backend/runner/taskrun/pending_scheduler.go - Use store
7. backend/api/v1/rollout_service_converter.go - Remove Bus
8. backend/api/v1/rollout_service.go - Update converter calls
9. backend/component/bus/bus.go - Remove field