jobqueue: Add JobArgs() method

JobArgs() returns the arguments submitted with a job in raw form.
Since the structure of the args are opaque to job queue, it's the
responsibility of the caller to deserialize the arguments.

Args retrieval is added to the existing TestArgs() function.

internal/jobqueue/fsjobqueue/fsjobqueue.go

@@ -287,6 +287,16 @@ func (q *fsJobQueue) JobStatus(id uuid.UUID) (result json.RawMessage, queued, st
 	return
 }
 
+func (q *fsJobQueue) JobArgs(id uuid.UUID) (args json.RawMessage, err error) {
+	j, err := q.readJob(id)
+	if err != nil {
+		return
+	}
+
+	args = j.Args
+	return
+}
+
 // Reads job with `id`. This is a thin wrapper around `q.db.Read`, which
 // returns the job directly, or and error if a job with `id` does not exist.
 func (q *fsJobQueue) readJob(id uuid.UUID) (*job, error) {

internal/jobqueue/fsjobqueue/fsjobqueue_test.go

@@ -103,6 +103,11 @@ func TestArgs(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, twoargs, parsedArgs)
 
+	// Read args after Dequeue
+	jargs, err := q.JobArgs(id)
+	require.NoError(t, err)
+	require.Equal(t, args, jargs)
+
 	id, deps, typ, args, err = q.Dequeue(context.Background(), []string{"fish"})
 	require.NoError(t, err)
 	require.Equal(t, one, id)
@@ -111,6 +116,14 @@ func TestArgs(t *testing.T) {
 	err = json.Unmarshal(args, &parsedArgs)
 	require.NoError(t, err)
 	require.Equal(t, oneargs, parsedArgs)
+
+	// Read args directly after Dequeue
+	jargs, err = q.JobArgs(id)
+	require.NoError(t, err)
+	require.Equal(t, args, jargs)
+
+	_, err = q.JobArgs(uuid.New())
+	require.Error(t, err)
 }
 
 func TestJobTypes(t *testing.T) {

internal/jobqueue/jobqueue.go

@@ -59,6 +59,9 @@ type JobQueue interface {
 	//
 	// Lastly, the IDs of the jobs dependencies are returned.
 	JobStatus(id uuid.UUID) (result json.RawMessage, queued, started, finished time.Time, canceled bool, deps []uuid.UUID, err error)
+
+	// Returns the job's arguments in Raw form.
+	JobArgs(id uuid.UUID) (args json.RawMessage, err error)
 }
 
 var (