Rename Agent to Server (#316)

Initially, we had a plan to install Yorkie on the nodes where MongoDB
is installed, so we named it Agent.

However, we implemented Agents like normal Servers and the name
of Agent is confusing. So this commit renames it as Server.

README.md

@@ -17,7 +17,7 @@ documents(CRDT) with optional types.
 Yorkie consists of three main components: Client, Document and Agent.
 
  ```
-  Client "A" (Go)                 Agent                        MemDB or MongoDB
+  Client "A" (Go)                 Server                       MemDB or MongoDB
 ┌───────────────────┐           ┌────────────────────────┐   ┌───────────┐
 │  Document "D-1"   │◄─Changes─►│  Collection "C-1"      │   │ Changes   │
 │  { a: 1, b: {} }  │           │ ┌───────────────────┐  │◄─►│ Snapshots │

api/converter/from_pb.go

@@ -28,7 +28,7 @@ import (
 	"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/yorkie/backend/sync"
+	"github.com/yorkie-team/yorkie/server/backend/sync"
 )
 
 // FromProjects converts the given Protobuf formats to model format.

api/converter/to_pb.go

@@ -29,7 +29,7 @@ import (
 	"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/yorkie/backend/sync"
+	"github.com/yorkie-team/yorkie/server/backend/sync"
 )
 
 // ToProjects converts the given model to Protobuf.

api/types/client.go

@@ -6,7 +6,7 @@ import (
 	"github.com/yorkie-team/yorkie/pkg/document/time"
 )
 
-// Client represents the Client that communicates with the Agent.
+// Client represents the Client that communicates with the Server.
 type Client struct {
 	ID           *time.ActorID
 	MetadataInfo MetadataInfo

api/types/event.go

@@ -1,6 +1,6 @@
 package types
 
-// DocEventType represents the event that the Agent delivers to the client.
+// DocEventType represents the event that the Server delivers to the client.
 type DocEventType string
 
 const (

client/client.go

@@ -62,9 +62,9 @@ type Attachment struct {
 	peers map[string]types.MetadataInfo
 }
 
-// Client is a normal client that can communicate with the agent.
+// Client is a normal client that can communicate with the server.
 // It has documents and sends changes of the document in local
-// to the agent to synchronize with other replicas in remote.
+// to the server to synchronize with other replicas in remote.
 type Client struct {
 	conn        *grpc.ClientConn
 	client      api.YorkieClient
@@ -184,8 +184,8 @@ func (c *Client) Close() error {
 	return c.conn.Close()
 }
 
-// Activate activates this client. That is, it registers itself to the agent
-// and receives a unique ID from the agent. The given ID is used to distinguish
+// Activate activates this client. That is, it registers itself to the server
+// and receives a unique ID from the server. The given ID is used to distinguish
 // different clients.
 func (c *Client) Activate(ctx context.Context) error {
 	if c.status == activated {
@@ -228,7 +228,7 @@ func (c *Client) Deactivate(ctx context.Context) error {
 	return nil
 }
 
-// Attach attaches the given document to this client. It tells the agent that
+// Attach attaches the given document to this client. It tells the server that
 // this client will synchronize the given document.
 func (c *Client) Attach(ctx context.Context, doc *document.Document) error {
 	if c.status != activated {
@@ -277,7 +277,7 @@ func (c *Client) Attach(ctx context.Context, doc *document.Document) error {
 }
 
 // Detach detaches the given document from this client. It tells the
-// agent that this client will no longer synchronize the given document.
+// server that this client will no longer synchronize the given document.
 //
 // To collect garbage things like CRDT tombstones left on the document, all the
 // changes should be applied to other replicas before GC time. For this, if the
@@ -319,8 +319,8 @@ func (c *Client) Detach(ctx context.Context, doc *document.Document) error {
 	return nil
 }
 
-// Sync pushes local changes of the attached documents to the Agent and
-// receives changes of the remote replica from the agent then apply them to
+// Sync pushes local changes of the attached documents to the server and
+// receives changes of the remote replica from the server then apply them to
 // local documents.
 func (c *Client) Sync(ctx context.Context, keys ...key.Key) error {
 	if len(keys) == 0 {

cmd/yorkie/agent.go → cmd/yorkie/server.go

@@ -25,10 +25,10 @@ import (
 
 	"github.com/spf13/cobra"
 
-	"github.com/yorkie-team/yorkie/yorkie"
-	"github.com/yorkie-team/yorkie/yorkie/backend/db/mongo"
-	"github.com/yorkie-team/yorkie/yorkie/backend/sync/etcd"
-	"github.com/yorkie-team/yorkie/yorkie/logging"
+	"github.com/yorkie-team/yorkie/server"
+	"github.com/yorkie-team/yorkie/server/backend/db/mongo"
+	"github.com/yorkie-team/yorkie/server/backend/sync/etcd"
+	"github.com/yorkie-team/yorkie/server/logging"
 )
 
 var (
@@ -57,13 +57,13 @@ var (
 	etcdPassword      string
 	etcdLockLeaseTime time.Duration
 
-	conf = yorkie.NewConfig()
+	conf = server.NewConfig()
 )
 
-func newAgentCmd() *cobra.Command {
+func newServerCmd() *cobra.Command {
 	return &cobra.Command{
-		Use:   "agent [options]",
-		Short: "Start yorkie agent",
+		Use:   "server [options]",
+		Short: "Start Yorkie server",
 		RunE: func(cmd *cobra.Command, args []string) error {
 			conf.Backend.AuthWebhookMaxWaitInterval = authWebhookMaxWaitInterval.String()
 			conf.Backend.AuthWebhookCacheAuthTTL = authWebhookCacheAuthTTL.String()
@@ -93,7 +93,7 @@ func newAgentCmd() *cobra.Command {
 
 			// If config file is given, command-line arguments will be overwritten.
 			if flagConfPath != "" {
-				parsed, err := yorkie.NewConfigFromFile(flagConfPath)
+				parsed, err := server.NewConfigFromFile(flagConfPath)
 				if err != nil {
 					return err
 				}
@@ -104,7 +104,7 @@ func newAgentCmd() *cobra.Command {
 				return err
 			}
 
-			y, err := yorkie.New(conf)
+			y, err := server.New(conf)
 			if err != nil {
 				return err
 			}
@@ -122,7 +122,7 @@ func newAgentCmd() *cobra.Command {
 	}
 }
 
-func handleSignal(r *yorkie.Yorkie) int {
+func handleSignal(r *server.Yorkie) int {
 	sigCh := make(chan os.Signal, 1)
 	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP)
 
@@ -159,7 +159,7 @@ func handleSignal(r *yorkie.Yorkie) int {
 }
 
 func init() {
-	cmd := newAgentCmd()
+	cmd := newServerCmd()
 	cmd.Flags().StringVarP(
 		&flagConfPath,
 		"config",
@@ -177,7 +177,7 @@ func init() {
 	cmd.Flags().IntVar(
 		&conf.RPC.Port,
 		"rpc-port",
-		yorkie.DefaultRPCPort,
+		server.DefaultRPCPort,
 		"RPC port",
 	)
 	cmd.Flags().StringVar(
@@ -195,13 +195,13 @@ func init() {
 	cmd.Flags().Uint64Var(
 		&conf.RPC.MaxRequestBytes,
 		"rpc-max-requests-bytes",
-		yorkie.DefaultRPCMaxRequestsBytes,
+		server.DefaultRPCMaxRequestsBytes,
 		"Maximum client request size in bytes the server will accept.",
 	)
 	cmd.Flags().IntVar(
 		&conf.Profiling.Port,
 		"profiling-port",
-		yorkie.DefaultProfilingPort,
+		server.DefaultProfilingPort,
 		"Profiling port",
 	)
 	cmd.Flags().BoolVar(
@@ -213,19 +213,19 @@ func init() {
 	cmd.Flags().DurationVar(
 		&housekeepingInterval,
 		"housekeeping-interval",
-		yorkie.DefaultHousekeepingInterval,
+		server.DefaultHousekeepingInterval,
 		"housekeeping interval between housekeeping runs",
 	)
 	cmd.Flags().DurationVar(
 		&housekeepingDeactivateThreshold,
 		"housekeeping-deactivate-threshold",
-		yorkie.DefaultHousekeepingDeactivateThreshold,
+		server.DefaultHousekeepingDeactivateThreshold,
 		"time after which clients are considered deactivate",
 	)
 	cmd.Flags().IntVar(
 		&conf.Housekeeping.CandidatesLimit,
 		"housekeeping-candidates-limit",
-		yorkie.DefaultHousekeepingCandidateLimit,
+		server.DefaultHousekeepingCandidateLimit,
 		"candidates limit for a single housekeeping run",
 	)
 	cmd.Flags().StringVar(
@@ -237,19 +237,19 @@ func init() {
 	cmd.Flags().DurationVar(
 		&mongoConnectionTimeout,
 		"mongo-connection-timeout",
-		yorkie.DefaultMongoConnectionTimeout,
+		server.DefaultMongoConnectionTimeout,
 		"Mongo DB's connection timeout",
 	)
 	cmd.Flags().StringVar(
 		&mongoYorkieDatabase,
 		"mongo-yorkie-database",
-		yorkie.DefaultMongoYorkieDatabase,
+		server.DefaultMongoYorkieDatabase,
 		"Yorkie's database name in MongoDB",
 	)
 	cmd.Flags().DurationVar(
 		&mongoPingTimeout,
 		"mongo-ping-timeout",
-		yorkie.DefaultMongoPingTimeout,
+		server.DefaultMongoPingTimeout,
 		"Mongo DB's ping timeout",
 	)
 	cmd.Flags().StringSliceVar(
@@ -285,51 +285,51 @@ func init() {
 	cmd.Flags().BoolVar(
 		&conf.Backend.UseDefaultProject,
 		"backend-use-default-project",
-		yorkie.DefaultUseDefaultProject,
+		server.DefaultUseDefaultProject,
 		"Whether to use the default project. Even if public key is not provided from the client, "+
 			"the default project will be used for the request.",
 	)
 	cmd.Flags().Uint64Var(
 		&conf.Backend.SnapshotThreshold,
 		"backend-snapshot-threshold",
-		yorkie.DefaultSnapshotThreshold,
+		server.DefaultSnapshotThreshold,
 		"Threshold that determines if changes should be sent with snapshot when the number "+
 			"of changes is greater than this value.",
 	)
 	cmd.Flags().Uint64Var(
 		&conf.Backend.SnapshotInterval,
 		"backend-snapshot-interval",
-		yorkie.DefaultSnapshotInterval,
+		server.DefaultSnapshotInterval,
 		"Interval of changes to create a snapshot.",
 	)
 	cmd.Flags().Uint64Var(
 		&conf.Backend.AuthWebhookMaxRetries,
 		"auth-webhook-max-retries",
-		yorkie.DefaultAuthWebhookMaxRetries,
+		server.DefaultAuthWebhookMaxRetries,
 		"Maximum number of retries for an authorization webhook.",
 	)
 	cmd.Flags().DurationVar(
 		&authWebhookMaxWaitInterval,
 		"auth-webhook-max-wait-interval",
-		yorkie.DefaultAuthWebhookMaxWaitInterval,
+		server.DefaultAuthWebhookMaxWaitInterval,
 		"Maximum wait interval for authorization webhook.",
 	)
 	cmd.Flags().IntVar(
 		&conf.Backend.AuthWebhookCacheSize,
 		"auth-webhook-cache-size",
-		yorkie.DefaultAuthWebhookCacheSize,
+		server.DefaultAuthWebhookCacheSize,
 		"The cache size of the authorization webhook.",
 	)
 	cmd.Flags().DurationVar(
 		&authWebhookCacheAuthTTL,
 		"auth-webhook-cache-auth-ttl",
-		yorkie.DefaultAuthWebhookCacheAuthTTL,
+		server.DefaultAuthWebhookCacheAuthTTL,
 		"TTL value to set when caching authorized webhook response.",
 	)
 	cmd.Flags().DurationVar(
 		&authWebhookCacheUnauthTTL,
 		"auth-webhook-cache-unauth-ttl",
-		yorkie.DefaultAuthWebhookCacheUnauthTTL,
+		server.DefaultAuthWebhookCacheUnauthTTL,
 		"TTL value to set when caching unauthorized webhook response.",
 	)
 

pkg/document/json/root.go

@@ -28,7 +28,7 @@ type ElementPair struct {
 
 // Root is a structure represents the root of JSON. It has a hash table of
 // all JSON elements to find a specific element when applying remote changes
-// received from agent.
+// received from server.
 //
 // Every element has a unique time ticket at creation, which allows us to find
 // a particular element.

yorkie/admin/cluster_server.go → server/admin/cluster_server.go

@@ -23,11 +23,11 @@ import (
 	"github.com/yorkie-team/yorkie/api/converter"
 	"github.com/yorkie-team/yorkie/api/types"
 	"github.com/yorkie-team/yorkie/pkg/document/time"
-	"github.com/yorkie-team/yorkie/yorkie/backend"
-	"github.com/yorkie-team/yorkie/yorkie/logging"
+	"github.com/yorkie-team/yorkie/server/backend"
+	"github.com/yorkie-team/yorkie/server/logging"
 )
 
-// clusterServer is a normal server that processes the broadcast by the agent.
+// clusterServer is a normal server that processes the broadcast by the server.
 type clusterServer struct {
 	backend *backend.Backend
 }

yorkie/admin/server.go → server/admin/server.go

@@ -27,10 +27,10 @@ import (
 	"github.com/yorkie-team/yorkie/api"
 	"github.com/yorkie-team/yorkie/api/converter"
 	"github.com/yorkie-team/yorkie/api/types"
-	"github.com/yorkie-team/yorkie/yorkie/backend"
-	"github.com/yorkie-team/yorkie/yorkie/documents"
-	"github.com/yorkie-team/yorkie/yorkie/logging"
-	"github.com/yorkie-team/yorkie/yorkie/projects"
+	"github.com/yorkie-team/yorkie/server/backend"
+	"github.com/yorkie-team/yorkie/server/documents"
+	"github.com/yorkie-team/yorkie/server/logging"
+	"github.com/yorkie-team/yorkie/server/projects"
 )
 
 // ErrInvalidAdminPort occurs when the port in the config is invalid.