[NOD-323] Move rpc-client to separate package (#402)

apiserver/connect.go

@@ -1,40 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"github.com/daglabs/btcd/apiserver/config"
-	"github.com/daglabs/btcd/rpcclient"
-	"io/ioutil"
-)
-
-func connectToServer(cfg *config.Config) (*apiServerClient, error) {
-	var cert []byte
-	if !cfg.DisableTLS {
-		var err error
-		cert, err = ioutil.ReadFile(cfg.RPCCert)
-		if err != nil {
-			return nil, fmt.Errorf("Error reading certificates file: %s", err)
-		}
-	}
-
-	connCfg := &rpcclient.ConnConfig{
-		Host:       cfg.RPCServer,
-		Endpoint:   "ws",
-		User:       cfg.RPCUser,
-		Pass:       cfg.RPCPassword,
-		DisableTLS: cfg.DisableTLS,
-	}
-
-	if !cfg.DisableTLS {
-		connCfg.Certificates = cert
-	}
-
-	client, err := newAPIServerClient(connCfg)
-	if err != nil {
-		return nil, fmt.Errorf("Error connecting to address %s: %s", cfg.RPCServer, err)
-	}
-
-	log.Infof("Connected to server %s", cfg.RPCServer)
-
-	return client, nil
-}

apiserver/jsonrpc/client.go

@@ -1,7 +1,11 @@
-package main
+package jsonrpc
 
 import (
+	"errors"
 	"fmt"
+	"io/ioutil"
+
+	"github.com/daglabs/btcd/apiserver/config"
 	"github.com/daglabs/btcd/util/daghash"
 
 	"github.com/daglabs/btcd/rpcclient"
@@ -9,12 +13,24 @@ import (
 	"github.com/daglabs/btcd/wire"
 )
 
-type apiServerClient struct {
+// Client represents a connection to the JSON-RPC API of a full node
+type Client struct {
 	*rpcclient.Client
 	onBlockAdded   chan *blockAddedMsg
 	onChainChanged chan *chainChangedMsg
 }
 
+var client *Client
+
+// GetClient returns an instance of the JSON-RPC client, in case we have an active connection
+func GetClient() (*Client, error) {
+	if client == nil {
+		return nil, errors.New("JSON-RPC is not connected")
+	}
+
+	return client, nil
+}
+
 type blockAddedMsg struct {
 	chainHeight uint64
 	header      *wire.BlockHeader
@@ -25,8 +41,50 @@ type chainChangedMsg struct {
 	addedChainBlocks        []*rpcclient.ChainBlock
 }
 
-func newAPIServerClient(connCfg *rpcclient.ConnConfig) (*apiServerClient, error) {
-	client := &apiServerClient{
+// Close closes the connection to the JSON-RPC API server
+func Close() {
+	if client == nil {
+		return
+	}
+
+	client.Disconnect()
+	client = nil
+}
+
+// Connect initiates a connection to the JSON-RPC API Server
+func Connect(cfg *config.Config) error {
+	var cert []byte
+	if !cfg.DisableTLS {
+		var err error
+		cert, err = ioutil.ReadFile(cfg.RPCCert)
+		if err != nil {
+			return fmt.Errorf("Error reading certificates file: %s", err)
+		}
+	}
+
+	connCfg := &rpcclient.ConnConfig{
+		Host:       cfg.RPCServer,
+		Endpoint:   "ws",
+		User:       cfg.RPCUser,
+		Pass:       cfg.RPCPassword,
+		DisableTLS: cfg.DisableTLS,
+	}
+
+	if !cfg.DisableTLS {
+		connCfg.Certificates = cert
+	}
+
+	var err error
+	client, err = newClient(connCfg)
+	if err != nil {
+		return fmt.Errorf("Error connecting to address %s: %s", cfg.RPCServer, err)
+	}
+
+	return nil
+}
+
+func newClient(connCfg *rpcclient.ConnConfig) (*Client, error) {
+	client = &Client{
 		onBlockAdded:   make(chan *blockAddedMsg),
 		onChainChanged: make(chan *chainChangedMsg),
 	}
@@ -58,5 +116,6 @@ func newAPIServerClient(connCfg *rpcclient.ConnConfig) (*apiServerClient, error)
 	if err = client.NotifyChainChanges(); err != nil {
 		return nil, fmt.Errorf("Error while registering client %s for chain changes notifications: %s", client.Host(), err)
 	}
+
 	return client, nil
 }

apiserver/main.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"github.com/daglabs/btcd/apiserver/config"
 	"github.com/daglabs/btcd/apiserver/database"
+	"github.com/daglabs/btcd/apiserver/jsonrpc"
 	"github.com/daglabs/btcd/apiserver/server"
 	"github.com/daglabs/btcd/logger"
 	"github.com/daglabs/btcd/signal"
@@ -32,21 +33,15 @@ func main() {
 		}
 	}()
 
-	client, err := connectToServer(cfg)
+	err = jsonrpc.Connect(cfg)
 	if err != nil {
 		panic(fmt.Errorf("Error connecting to servers: %s", err))
 	}
+	defer jsonrpc.Close()
+
 	shutdownServer := server.Start(cfg.HTTPListen)
-	defer func() {
-		shutdownServer()
-		disconnectFromNode(client)
-	}()
+	defer shutdownServer()
 
 	interrupt := signal.InterruptListener()
 	<-interrupt
 }
-
-func disconnectFromNode(client *apiServerClient) {
-	log.Infof("Disconnecting client")
-	client.Disconnect()
-}