Change the structure of WatchDocument API (#491)

1. Change to use ID instead of Key in WatchDocument
  - By introducing RemoveDocument API, multiple IDs can be mapped to a
    single key(multiple removed IDs and one active ID)
2. Change WatchDocuments API to WatchDocument API
  - In the cluster mode conversion task, one document is mapped to one
    server, and single document mapping is a simplified cluster
  - This can cause Changing the structure where the client maintains
    one WatchDocuments stream to maintain multiple streams.
3. Remove unnecessary types due to the change in step 2
  - The implementation was simplified by changing the structure in
    step 2, so unnecessary data types were cleaned up.

Co-authored-by: hackerwins <hackerwins@gmail.com>

api/converter/converter_test.go

@@ -212,12 +212,9 @@ func TestConverter(t *testing.T) {
 		assert.Equal(t, cli.ID.Bytes(), decodedCli.ID.Bytes())
 		assert.Equal(t, cli.PresenceInfo, decodedCli.PresenceInfo)
 
-		pbClientsMap := converter.ToClientsMap(map[string][]types.Client{
-			"test": {cli},
-		})
+		pbClients := converter.ToClients([]types.Client{cli})
 
-		pbCli = pbClientsMap["test"].Clients[0]
-		decodedCli, err = converter.FromClient(pbCli)
+		decodedCli, err = converter.FromClient(pbClients[0])
 		assert.NoError(t, err)
 		assert.Equal(t, cli.ID.Bytes(), decodedCli.ID.Bytes())
 		assert.Equal(t, cli.PresenceInfo, decodedCli.PresenceInfo)

api/converter/from_pb.go

@@ -211,13 +211,24 @@ func fromChangeID(id *api.ChangeID) (change.ID, error) {
 	), nil
 }
 
-// FromDocumentKeys converts the given Protobuf formats to model format.
-func FromDocumentKeys(pbKeys []string) []key.Key {
-	var keys []key.Key
-	for _, pbKey := range pbKeys {
-		keys = append(keys, key.Key(pbKey))
+// FromDocumentKey converts the given Protobuf formats to model format.
+func FromDocumentKey(pbKey string) (key.Key, error) {
+	k := key.Key(pbKey)
+	if err := k.Validate(); err != nil {
+		return "", err
 	}
-	return keys
+
+	return k, nil
+}
+
+// FromDocumentID converts the given Protobuf formats to model format.
+func FromDocumentID(pbID string) (types.ID, error) {
+	id := types.ID(pbID)
+	if err := id.Validate(); err != nil {
+		return "", err
+	}
+
+	return id, nil
 }
 
 // FromEventType converts the given Protobuf formats to model format.
@@ -247,17 +258,22 @@ func FromDocEvent(docEvent *api.DocEvent) (*sync.DocEvent, error) {
 		return nil, err
 	}
 
+	documentID, err := FromDocumentID(docEvent.DocumentId)
+	if err != nil {
+		return nil, err
+	}
+
 	return &sync.DocEvent{
-		Type:         eventType,
-		Publisher:    *client,
-		DocumentKeys: FromDocumentKeys(docEvent.DocumentKeys),
+		Type:       eventType,
+		Publisher:  *client,
+		DocumentID: documentID,
 	}, nil
 }
 
 // FromClients converts the given Protobuf formats to model format.
-func FromClients(pbClients *api.Clients) ([]*types.Client, error) {
+func FromClients(pbClients []*api.Client) ([]*types.Client, error) {
 	var clients []*types.Client
-	for _, pbClient := range pbClients.Clients {
+	for _, pbClient := range pbClients {
 		client, err := FromClient(pbClient)
 		if err != nil {
 			return nil, err

api/converter/to_pb.go

@@ -26,7 +26,6 @@ import (
 	api "github.com/yorkie-team/yorkie/api/yorkie/v1"
 	"github.com/yorkie-team/yorkie/pkg/document/change"
 	"github.com/yorkie-team/yorkie/pkg/document/crdt"
-	"github.com/yorkie-team/yorkie/pkg/document/key"
 	"github.com/yorkie-team/yorkie/pkg/document/operations"
 	"github.com/yorkie-team/yorkie/pkg/document/time"
 	"github.com/yorkie-team/yorkie/server/backend/sync"
@@ -173,31 +172,13 @@ func ToChangeID(id change.ID) *api.ChangeID {
 	}
 }
 
-// ToDocumentKeys converts the given model format to Protobuf format.
-func ToDocumentKeys(keys []key.Key) []string {
-	var keyList []string
-	for _, k := range keys {
-		keyList = append(keyList, k.String())
+// ToClients converts the given model to Protobuf format.
+func ToClients(clients []types.Client) []*api.Client {
+	var pbClients []*api.Client
+	for _, client := range clients {
+		pbClients = append(pbClients, ToClient(client))
 	}
-	return keyList
-}
-
-// ToClientsMap converts the given model to Protobuf format.
-func ToClientsMap(clientsMap map[string][]types.Client) map[string]*api.Clients {
-	pbClientsMap := make(map[string]*api.Clients)
-
-	for k, clients := range clientsMap {
-		var pbClients []*api.Client
-		for _, client := range clients {
-			pbClients = append(pbClients, ToClient(client))
-		}
-
-		pbClientsMap[k] = &api.Clients{
-			Clients: pbClients,
-		}
-	}
-
-	return pbClientsMap
+	return pbClients
 }
 
 // ToDocEventType converts the given model format to Protobuf format.
@@ -224,9 +205,9 @@ func ToDocEvent(docEvent sync.DocEvent) (*api.DocEvent, error) {
 	}
 
 	return &api.DocEvent{
-		Type:         eventType,
-		Publisher:    ToClient(docEvent.Publisher),
-		DocumentKeys: ToDocumentKeys(docEvent.DocumentKeys),
+		Type:       eventType,
+		Publisher:  ToClient(docEvent.Publisher),
+		DocumentId: docEvent.DocumentID.String(),
 	}, nil
 }
 

api/yorkie/v1/resources.proto

@@ -252,10 +252,6 @@ message Client {
   Presence presence = 2;
 }
 
-message Clients {
-  repeated Client clients = 1;
-}
-
 message Checkpoint {
   int64 server_seq = 1 [jstype = JS_STRING];
   uint32 client_seq = 2;
@@ -299,5 +295,5 @@ enum DocEventType {
 message DocEvent {
   DocEventType type = 1;
   Client publisher = 2;
-  repeated string document_keys = 3;
+  string document_id = 3;
 }