Intro to claire-protorpc@fanyu83

What is claire-protorpc

● protobuf-based RPC library● non-blocking● event-driving● multi-core ready● modern C++● for x86-64 Linux● BSD license

Tutorial: echo

● In computer telecommunications, echo is the display or return of sent data at or to the sending end of a transmission. ------ from wikipedia

● Use claire-protorpc develop application and services should do:○ define a .proto file which declared the rpc message

structure and methods○ use generated stub to call echo methods through

RpcChannel○ implement echo services, and register it to RpcServer

Echo Client/Server

Stubs

RpcChannel

HttpClient

Services

RpcServer

HttpServer

HttpConnection

echo.proto

● echo.proto define message and service.

● Use protoc compile the echo.proto○ generate echo.pb.h

and echo.pb.cc

// protoc --plugin=protoc-rpc-gen --rpc_out . echo.proto

package echo;

option cc_generic_services = true;

message EchoRequest {

required string str = 1;

}

message EchoResponse {

required string str = 1;

}

service EchoService {

rpc Echo (EchoRequest) returns (EchoResponse);

}

Echo client

● echo.pb.h define Stub which can call Echo service

● It need RpcChannel to communicate remote server.

int main(int argc, char* argv[])

{

EventLoop loop;

InetAddress server_address(argv[1], 8080);

RpcChannel channel(&loop);

channel.Connect(server_address);

echo::EchoService::Stub stub(&channel);

RpcControllerPtr controller(new RpcController());

echo::EchoRequest request;

request.set_str("0123456789ABCDEF");

stub.Echo(controller, request, boost::bind(&replied, _1, _2));

loop.loop();

}

Echo server

● echo.pb.h define Abstract interface EchoService, server side need implement it.

● EchoService need register to RpcServer.

int main(int argc, char* argv[])

{

::google::ParseCommandLineFlags(&argc, &argv, true);

InitClaireLogging(argv[0]);

EventLoop loop;

InetAddress listen_address(8080);

echo::EchoServiceImpl impl;

RpcServer server(&loop, listen_address);

server.set_num_threads(FLAGS_num_threads);

server.RegisterService(&impl);

server.Start();

loop.loop();

}

Benefits of claire-protorpc

● claire-protorpc provide:○ Define a service only need a function.○ Generate stub to call remote service.○ Automatic message encode/decode.○ Checksum for each message.○ Compress data if user set.○ Very good performance, at least no obvious

bottleneck.

Concept● protobuf provide server declaration but no implementation, it suggest

“provide code generator plugins which generate code specific to the particular RPC implementation.”

● claire-protorpc is one implementation of protobuf-based rpc, and supply itself plugin to generate code for claire-protorpc only.

● It implement 3 important concept of protobuf rpc:○ RpcController○ RpcChannel○ RpcServer

● But we do not use Google defined interface directly, instead claire-version!

Service● Services themselves are abstract interfaces (implemented either by servers

or as stubs), but they subclass this base interface. The methods of this interface can be used to call the methods of the Service without knowing its exact type at compile time (analogous to Reflection).

● claire-protorpc use protoc-rpc-gen to generate the rpc service which inherited from Service class(claire-protorpc’s version)

RpcController

● “An RpcController mediates a single method call. The primary purpose of the controller is to provide a way to manipulate settings specific to the RPC implementation and to find out about RPC-level errors.”

● Now it used to declare caller specific option and get error information.

RpcChannel

● “An RpcChannel represents a communication line to a Service which can be used to call that Service's methods. The Service may be running on another machine. Normally, you should not call an RpcChannel directly, but instead construct a stub Service wrapping it.”

● Now it used to communicate to RpcServer, it do message encode/decode, health detection, compress/uncompress,loadbalance, address resolverm, .etc .

RpcServer

● RpcServer used to store all registered service, and response to all request.○ It also provide monitor, debug, profile, flags

management features, user no need write one line code to use these

Wire Formatm

message RpcMessage {

required MessageType type = 1;

required fixed64 id = 2;

optional string service = 3;

optional string method = 4;

optional bytes request = 5;

optional bytes response = 6;

optional ErrorCode error = 7;

optional string reason = 8;

optional CompressType compress_type = 9;

}

meesage length

checksum

RpcMessage

4 bytes

4 bytes

Architecture

Logging

Symbolizer

EventLoop

Thread

Metrics

Time

String

File

protobuf

tcmalloc

profiler

snappy

ctemplate

rapidjson

boost

gflagsc-ares

RpcController

gtest

RpcChannel

ProtobufIO

RpcServer

System

BuiltInService

HttpConnection

TcpConnection

HttpClient

TcpClient

HttpServer

TcpServer

Resolver

Inspector

protoc-rpc-gen

gen-assets

claire-protorpc

claire-netty

claire-common

external

LoadBalancer

Features

● Health Detection● LoadBalancer(Random, .etc)● Address Resolver(Dns, .etc)● Compress transport● Flags view/modify● Internal statistics view/collection● Online profile● Methods form for test/debug● All built-on Http

/flags

● claire use gflags manage configures.● Through /flags, user can view and modify flags.● Easy for modify flags of a lot of machines through /flags

post method.

/flags

Metrics

● claire-protorpc supply powerful metrics type:○ counter

■ A counter is a value that never decreases. Examples might be "sent bytes" or "receied bytes". You just increment the counter each time a countable event happens, and graphing utilities usually graph the deltas over time.

○ histogram■ A metric is tracked via distribution, and is usually used for

timings.● claire-protorpc support graphing pages & json interface together

/couters

/histograms

/form

● /form page show all register services & method on running server, user can post form to server as post protobuf message

● Easy for test and debug

/form

/pprof

● claire-protorpc integrate with gperftools, so it support online profiling.○ support /pprof/profile, /pprof/heap, /pprof/growth○ also support profile without binary file, through

/pprof/symbol & /pprof cmdlind○ will support /pprof/contension later

/pprof

Question

github.com/robbinfan/claire-protorpc