Improve logging

client.go

@@ -215,6 +215,7 @@ func (this *Client) FlushRedisAndRespond() (err error) {
 
 	if redisConn.DatabaseId != this.DatabaseId {
 		if err = redisConn.SelectDatabase(this.DatabaseId); err != nil {
+			log.Error("Select database failed: %s", err)
 			return
 		}
 	}

connection/connection.go

@@ -98,7 +98,6 @@ func (c *Connection) ReconnectIfNecessary() (err error) {
 
 	c.connection, err = net.DialTimeout(c.protocol, c.endpoint, c.connectTimeout)
 	if err != nil {
-		log.Error("NewConnection: Error received from dial: %s", err)
 		c.connection = nil
 		return err
 	}
@@ -109,7 +108,7 @@ func (c *Connection) ReconnectIfNecessary() (err error) {
 	c.Reader = bufio.NewReader(netReadWriter)
 
 	if err = c.authenticate(); err != nil {
-		return err
+		return fmt.Errorf("authentication failed: %w", err)
 	}
 
 	c.nextReconnect = time.Now().Add(c.reconnectInterval)
@@ -121,42 +120,38 @@ func (c *Connection) ReconnectIfNecessary() (err error) {
 // Selects the given database, for the connection
 // If an error is returned, or if an invalid response is returned from the select, then this will return an error
 // If not, the connections internal database will be updated accordingly
-func (this *Connection) SelectDatabase(DatabaseId int) (err error) {
+func (this *Connection) SelectDatabase(DatabaseId int) error {
 	if this.connection == nil {
-		log.Error("SelectDatabase: Selecting on invalid connection")
-		return errors.New("Selecting database on an invalid connection")
+		return errors.New("selecting database on an invalid connection")
 	}
 
-	err = protocol.WriteLine([]byte(fmt.Sprintf("select %d", DatabaseId)), this.Writer, true)
+	err := protocol.WriteLine([]byte(fmt.Sprintf("select %d", DatabaseId)), this.Writer, true)
 	if err != nil {
-		log.Error("SelectDatabase: Error received from protocol.FlushLine: %s", err)
-		return err
+		return fmt.Errorf("flush line failed: %w", err)
 	}
 
 	if line, isPrefix, err := this.Reader.ReadLine(); err != nil || isPrefix || !bytes.Equal(line, protocol.OK_RESPONSE) {
 		if err == nil {
 			err = errors.New("unknown ReadLine error")
 		}
 
-		log.Error("SelectDatabase: Error while attempting to select database. Err:%q Response:%q isPrefix:%t", err, line, isPrefix)
 		this.Disconnect()
-		return errors.New("Invalid select response")
+		return fmt.Errorf("invalid select database response: err:%q Response:%q isPrefix:%t", err, line, isPrefix)
 	}
 
 	this.DatabaseId = DatabaseId
-	return
+	return nil
 }
 
 // Tries to authenticate the connection
 // If an error is returned, or if an invalid response is returned from the AUTH command, then this will return an error
-func (this *Connection) authenticate() (err error) {
+func (this *Connection) authenticate() error {
 	if this.connection == nil {
-		log.Error("authenticate: Using an invalid connection")
 		return errors.New("authenticating against an invalid connection")
 	}
 
 	if this.authPassword == "" {
-		return
+		return nil
 	}
 
 	authCommand := fmt.Sprintf("AUTH %s", this.authPassword)
@@ -165,10 +160,9 @@ func (this *Connection) authenticate() (err error) {
 		authCommand = fmt.Sprintf("AUTH %s %s", this.authUser, this.authPassword)
 	}
 
-	err = protocol.WriteLine([]byte(authCommand), this.Writer, true)
+	err := protocol.WriteLine([]byte(authCommand), this.Writer, true)
 	if err != nil {
-		log.Error("authenticate: Error received from protocol.FlushLine: %s", err)
-		return
+		return fmt.Errorf("flush line failed: %w", err)
 	}
 
 	line, isPrefix, err := this.Reader.ReadLine()
@@ -177,12 +171,10 @@ func (this *Connection) authenticate() (err error) {
 			err = errors.New("unknown ReadLine error")
 		}
 
-		log.Error("authenticate: Error while attempting to authenticate. Err:%q Response:%q isPrefix:%t",
-			err, line, isPrefix)
 		this.Disconnect()
-		return errors.New("invalid authentication response")
+		return fmt.Errorf("invalid authentication response: err:%q Response:%q isPrefix:%t", err, line, isPrefix)
 	}
-	return
+	return nil
 }
 
 // Checks if the current connection is up or not