Exemplo n.º 1
0
// sendRPC sends an RPC out to the wire.
// Returns the response (for now, as the call is synchronous).
func (c *Client) sendRPC(rpc hrpc.Call) error {
	// Header.
	c.id++
	reqheader := &pb.RequestHeader{
		CallId:       &c.id,
		MethodName:   proto.String(rpc.GetName()),
		RequestParam: proto.Bool(true),
	}

	payload, err := rpc.Serialize()
	if err != nil {
		return fmt.Errorf("Failed to serialize RPC: %s", err)
	}
	payloadLen := proto.EncodeVarint(uint64(len(payload)))

	headerData, err := proto.Marshal(reqheader)
	if err != nil {
		return fmt.Errorf("Failed to marshal Get request: %s", err)
	}

	buf := make([]byte, 5, 4+1+len(headerData)+len(payloadLen)+len(payload))
	binary.BigEndian.PutUint32(buf, uint32(cap(buf)-4))
	buf[4] = byte(len(headerData))
	buf = append(buf, headerData...)
	buf = append(buf, payloadLen...)
	buf = append(buf, payload...)

	c.sentRPCsMutex.Lock()
	c.sentRPCs[c.id] = rpc
	c.sentRPCsMutex.Unlock()

	err = c.write(buf)
	if err != nil {
		return UnrecoverableError{err}
	}

	return nil
}
Exemplo n.º 2
0
// sendRPC takes an RPC call, and will send it to the correct region server. If
// the correct region server is offline or otherwise unavailable, sendRPC will
// continually retry until the deadline set on the RPC's context is exceeded.
func (c *Client) sendRPC(rpc hrpc.Call) (proto.Message, error) {
	log.WithFields(log.Fields{
		"Type":  rpc.GetName(),
		"Table": string(rpc.Table()),
		"Key":   string(rpc.Key()),
	}).Debug("Sending RPC")
	err := c.queueRPC(rpc)
	if err == ErrDeadline {
		return nil, err
	} else if err != nil {
		log.WithFields(log.Fields{
			"Type":  rpc.GetName(),
			"Table": string(rpc.Table()),
			"Key":   string(rpc.Key()),
		}).Debug("We hit an error queuing the RPC. Resending.")
		// There was an error locating the region for the RPC, or the client
		// for the region encountered an error and has shut down.
		return c.sendRPC(rpc)
	}
	if err == nil {
		var res hrpc.RPCResult
		resch := rpc.GetResultChan()

		select {
		case res = <-resch:
		case <-rpc.GetContext().Done():
			return nil, ErrDeadline
		}

		err := res.Error
		log.WithFields(log.Fields{
			"Type":   rpc.GetName(),
			"Table":  string(rpc.Table()),
			"Key":    string(rpc.Key()),
			"Result": res.Msg,
			"Error":  err,
		}).Debug("Successfully sent RPC. Returning.")

		if _, ok := err.(region.RetryableError); ok {
			return c.sendRPC(rpc)
		} else if _, ok := err.(region.UnrecoverableError); ok {
			// Prevents dropping into the else block below,
			// error handling happens a few lines down
		} else {
			return res.Msg, res.Error
		}
	}

	// There was an issue related to the network, so we're going to mark the
	// region as unavailable, and generate the channel used for announcing
	// when it's available again
	region := rpc.GetRegion()

	log.WithFields(log.Fields{
		"Type":  rpc.GetName(),
		"Table": string(rpc.Table()),
		"Key":   string(rpc.Key()),
	}).Debug("Encountered a network error. Region unavailable?")

	if region != nil {
		succ := region.MarkUnavailable()
		if succ {
			go c.reestablishRegion(region)
		}
	}
	log.WithFields(log.Fields{
		"Type":  rpc.GetName(),
		"Table": string(rpc.Table()),
		"Key":   string(rpc.Key()),
	}).Debug("Retrying sendRPC")
	return c.sendRPC(rpc)
}