Shared content across namespaces

Update content ingests to use content from another namespace.
Ingests must be committed to make content available and the
client will see the sharing as an ingest which has already
been fully written to, but not completed.

Updated the database version to change the ingest record in
the database from a link key to an object with a link and
expected value. This expected value is used to indicate that
the content already exists and an underlying writer may
not yet exist.

Signed-off-by: Derek McGowan <derek@mcgstyle.net>

metadata/db_test.go

@@ -86,6 +86,27 @@ func TestInit(t *testing.T) {
 }
 
 func TestMigrations(t *testing.T) {
+	testRefs := []struct {
+		ref  string
+		bref string
+	}{
+		{
+			ref:  "k1",
+			bref: "bk1",
+		},
+		{
+			ref:  strings.Repeat("longerkey", 30), // 270 characters
+			bref: "short",
+		},
+		{
+			ref:  "short",
+			bref: strings.Repeat("longerkey", 30), // 270 characters
+		},
+		{
+			ref:  "emptykey",
+			bref: "",
+		},
+	}
 	migrationTests := []struct {
 		name  string
 		init  func(*bolt.Tx) error
@@ -183,6 +204,48 @@ func TestMigrations(t *testing.T) {
 					}
 				}
 
+				return nil
+			},
+		},
+		{
+			name: "IngestUpdate",
+			init: func(tx *bolt.Tx) error {
+				bkt, err := createBucketIfNotExists(tx, bucketKeyVersion, []byte("testing"), bucketKeyObjectContent, deprecatedBucketKeyObjectIngest)
+				if err != nil {
+					return err
+				}
+
+				for _, s := range testRefs {
+					if err := bkt.Put([]byte(s.ref), []byte(s.bref)); err != nil {
+						return err
+					}
+				}
+
+				return nil
+			},
+			check: func(tx *bolt.Tx) error {
+				bkt := getIngestsBucket(tx, "testing")
+				if bkt == nil {
+					return errors.Wrap(errdefs.ErrNotFound, "ingests bucket not found")
+				}
+
+				for _, s := range testRefs {
+					sbkt := bkt.Bucket([]byte(s.ref))
+					if sbkt == nil {
+						return errors.Wrap(errdefs.ErrNotFound, "ref does not exist")
+					}
+
+					bref := string(sbkt.Get(bucketKeyRef))
+					if bref != s.bref {
+						return errors.Errorf("unexpected reference key %q, expected %q", bref, s.bref)
+					}
+				}
+
+				dbkt := getBucket(tx, bucketKeyVersion, []byte("testing"), bucketKeyObjectContent, deprecatedBucketKeyObjectIngest)
+				if dbkt != nil {
+					return errors.New("deprecated ingest bucket still exists")
+				}
+
 				return nil
 			},
 		},