jobqueue: Add AllRootJobIDs function to jobqueue

This lists the root job UUIDs (the jobs with no dependants).
Currently only implemented by fsjobqueue. The function for
dbjobqueue currently returns nil.

Related: RHEL-60120

internal/jobqueue/fsjobqueue/fsjobqueue.go

@@ -702,3 +702,27 @@ func jobMatchesCriteria(j *job, acceptedJobTypes []string, acceptedChannels []st
 
 	return contains(acceptedJobTypes, j.Type) && contains(acceptedChannels, j.Channel)
 }
+
+// AllRootJobIDs Return a list of all the top level(root) job uuids
+// This only includes jobs without any Dependents set
+func (q *fsJobQueue) AllRootJobIDs() ([]uuid.UUID, error) {
+	ids, err := q.db.List()
+	if err != nil {
+		return nil, err
+	}
+
+	jobIDs := []uuid.UUID{}
+	for _, id := range ids {
+		var j job
+		exists, err := q.db.Read(id, &j)
+		if err != nil {
+			return jobIDs, err
+		}
+		if !exists || len(j.Dependents) > 0 {
+			continue
+		}
+		jobIDs = append(jobIDs, j.Id)
+	}
+
+	return jobIDs, nil
+}

internal/jobqueue/fsjobqueue/fsjobqueue_test.go

@@ -3,13 +3,15 @@ package fsjobqueue_test
 import (
 	"os"
 	"path"
+	"sort"
 	"testing"
 
-	"github.com/osbuild/osbuild-composer/pkg/jobqueue"
+	"github.com/google/uuid"
 	"github.com/stretchr/testify/require"
 
 	"github.com/osbuild/osbuild-composer/internal/jobqueue/fsjobqueue"
 	"github.com/osbuild/osbuild-composer/internal/jobqueue/jobqueuetest"
+	"github.com/osbuild/osbuild-composer/pkg/jobqueue"
 )
 
 func TestJobQueueInterface(t *testing.T) {
@@ -42,3 +44,46 @@ func TestJobQueueBadJSON(t *testing.T) {
 	require.Nil(t, err)
 	require.NotNil(t, q)
 }
+
+func sortUUIDs(entries []uuid.UUID) {
+	sort.Slice(entries, func(i, j int) bool {
+		return entries[i].String() < entries[j].String()
+	})
+}
+
+func TestAllRootJobIDs(t *testing.T) {
+	dir := t.TempDir()
+	q, err := fsjobqueue.New(dir)
+	require.Nil(t, err)
+	require.NotNil(t, q)
+
+	var rootJobs []uuid.UUID
+
+	// root with no dependencies
+	jidRoot1, err := q.Enqueue("oneRoot", nil, nil, "OneRootJob")
+	require.Nil(t, err)
+	rootJobs = append(rootJobs, jidRoot1)
+
+	// root with 2 dependencies
+	jid1, err := q.Enqueue("twoDeps", nil, nil, "TwoDepJobs")
+	require.Nil(t, err)
+	jid2, err := q.Enqueue("twoDeps", nil, nil, "TwoDepJobs")
+	require.Nil(t, err)
+	jidRoot2, err := q.Enqueue("twoDeps", nil, []uuid.UUID{jid1, jid2}, "TwoDepJobs")
+	require.Nil(t, err)
+	rootJobs = append(rootJobs, jidRoot2)
+
+	// root with 2 dependencies, one shared with the previous root
+	jid3, err := q.Enqueue("sharedDeps", nil, nil, "SharedDepJobs")
+	require.Nil(t, err)
+	jidRoot3, err := q.Enqueue("sharedDeps", nil, []uuid.UUID{jid1, jid3}, "SharedDepJobs")
+	require.Nil(t, err)
+	rootJobs = append(rootJobs, jidRoot3)
+
+	sortUUIDs(rootJobs)
+	roots, err := q.AllRootJobIDs()
+	require.Nil(t, err)
+	require.Greater(t, len(roots), 0)
+	sortUUIDs(roots)
+	require.Equal(t, rootJobs, roots)
+}

pkg/jobqueue/dbjobqueue/dbjobqueue.go

@@ -903,3 +903,10 @@ func (q *DBJobQueue) jobDependents(ctx context.Context, conn connection, id uuid
 
 	return dependents, nil
 }
+
+// AllRootJobIDs returns a list of top level job UUIDs that the worker knows about
+func (q *DBJobQueue) AllRootJobIDs() ([]uuid.UUID, error) {
+	// TODO write this
+
+	return nil, nil
+}

pkg/jobqueue/jobqueue.go

@@ -95,6 +95,9 @@ type JobQueue interface {
 
 	// Deletes the worker
 	DeleteWorker(workerID uuid.UUID) error
+
+	// AllRootJobIDs returns a list of top level job UUIDs that the worker knows about
+	AllRootJobIDs() ([]uuid.UUID, error)
 }
 
 // SimpleLogger provides a structured logging methods for the jobqueue library.