Manager: fetch jobs of tasks in FetchTasksOfWorkerInStatus()

The task state machine expects that `task.Job` is set correctly. Since
SQLC does not automatically fill this field (and rightfully so), I've added
a bit of Go code that fetches the job in a separate query.

A TODO is added as a reminder that it would be better for the task state
machine itself to fetch the job when needed.

internal/manager/persistence/jobs.go

@@ -650,14 +650,32 @@ func (db *DB) FetchTasksOfWorkerInStatus(ctx context.Context, worker *Worker, ta
 		return nil, taskError(err, "finding tasks of worker %s in status %q", worker.UUID, taskStatus)
 	}
 
+	jobCache := make(map[uint]*Job)
+
 	result := make([]*Task, len(rows))
 	for i := range rows {
-		gormTask, err := convertSqlcTask(rows[i].Task, rows[i].JobUUID.String, worker.UUID)
+		jobUUID := rows[i].JobUUID.String
+		gormTask, err := convertSqlcTask(rows[i].Task, jobUUID, worker.UUID)
 		if err != nil {
 			return nil, err
 		}
 		gormTask.Worker = worker
 		gormTask.WorkerID = &worker.ID
+
+		// Fetch the job, either from the cache or from the database. This is done
+		// here because the task_state_machine functionality expects that task.Job
+		// is set.
+		// TODO: make that code fetch the job details it needs, rather than fetching
+		// the entire job here.
+		job := jobCache[gormTask.JobID]
+		if job == nil {
+			job, err = db.FetchJob(ctx, jobUUID)
+			if err != nil {
+				return nil, jobError(err, "finding job %s of task %s", jobUUID, gormTask.UUID)
+			}
+		}
+		gormTask.Job = job
+
 		result[i] = gormTask
 	}
 	return result, nil

internal/manager/task_state_machine/task_state_machine.go

@@ -59,9 +59,8 @@ func (sm *StateMachine) taskStatusChangeOnly(
 	task *persistence.Task,
 	newTaskStatus api.TaskStatus,
 ) error {
-	job := task.Job
-	if job == nil {
-		log.Panic().Str("task", task.UUID).Msg("task without job, cannot handle this")
+	if task.JobUUID == "" {
+		log.Panic().Str("task", task.UUID).Msg("task without job UUID, cannot handle this")
 		return nil // Will not run because of the panic.
 	}
 
@@ -70,7 +69,7 @@ func (sm *StateMachine) taskStatusChangeOnly(
 
 	logger := log.With().
 		Str("task", task.UUID).
-		Str("job", job.UUID).
+		Str("job", task.JobUUID).
 		Str("taskStatusOld", string(oldTaskStatus)).
 		Str("taskStatusNew", string(newTaskStatus)).
 		Logger()
@@ -83,7 +82,7 @@ func (sm *StateMachine) taskStatusChangeOnly(
 	if oldTaskStatus != newTaskStatus {
 		// logStorage already logs any error, and an error here shouldn't block the
 		// rest of the function.
-		_ = sm.logStorage.WriteTimestamped(logger, job.UUID, task.UUID,
+		_ = sm.logStorage.WriteTimestamped(logger, task.JobUUID, task.UUID,
 			fmt.Sprintf("task changed status %s -> %s", oldTaskStatus, newTaskStatus))
 	}
 
@@ -101,9 +100,13 @@ func (sm *StateMachine) updateJobAfterTaskStatusChange(
 	ctx context.Context, task *persistence.Task, oldTaskStatus api.TaskStatus,
 ) error {
 	job := task.Job
+	if job == nil {
+		log.Panic().Str("task", task.UUID).Msg("task without job, cannot handle this")
+		return nil // Will not run because of the panic.
+	}
 
 	logger := log.With().
-		Str("job", job.UUID).
+		Str("job", task.JobUUID).
 		Str("task", task.UUID).
 		Str("taskStatusOld", string(oldTaskStatus)).
 		Str("taskStatusNew", string(task.Status)).

internal/manager/task_state_machine/task_state_machine_test.go

@@ -473,6 +473,7 @@ func taskWithStatus(jobStatus api.JobStatus, taskStatus api.TaskStatus) *persist
 		Model: persistence.Model{ID: 327},
 		UUID:  "testtask-0001-4e28-aeea-8cbaf2fc96a5",
 
+		JobUUID: job.UUID,
 		JobID:   job.ID,
 		Job:     &job,
 
@@ -488,6 +489,7 @@ func taskOfSameJob(task *persistence.Task, taskStatus api.TaskStatus) *persisten
 	return &persistence.Task{
 		Model:   persistence.Model{ID: newTaskID},
 		UUID:    fmt.Sprintf("testtask-%04d-4e28-aeea-8cbaf2fc96a5", newTaskID),
+		JobUUID: task.JobUUID,
 		JobID:   task.JobID,
 		Job:     task.Job,
 		Status:  taskStatus,