RPC框架-Thrift的使用

Apache Thrift

Thrift 是一种接口描述语言,通过二进制通信协议为多种编程语言定义和创建服务。Thrift是一种可扩展的跨语言服务的RPC框架,由Facebook开发并且开源。

应用

安装

MAC

brew install thrift

其他安装方式

下载安装包:http://www.apache.org/dyn/closer.cgi?path=/thrift/0.9.3/thrift-0.9.3.tar.gz

解压后进入目录执行:

./configure && make

编写IDL文件

安装好Thrift之后需要创建一个

.thrift

结尾的文件。该文件定义了thrift中的类型和服务。这些被定义的服务将被实现且能够被客户端调用。

IDL即:Interface definition language 接口描述语言,它是Thrift自己的一套接口定义语法。官方语法定义如下:

/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
*   http://www.apache.org/licenses/LICENSE-2.0 *
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/

# Thrift Tutorial
# Mark Slee (mcslee@facebook.com)
#
# This file aims to teach you how to use Thrift, in a .thrift file. Neato. The
# first thing to notice is that .thrift files support standard shell comments.
# This lets you make your thrift file executable and include your Thrift build
# step on the top line. And you can place comments like this anywhere you like.
#
# Before running this file, you will need to have installed the thrift compiler
# into /usr/local/bin.

/**
* The first thing to know about are types. The available types in Thrift are:
*
*  bool        Boolean, one byte
*  i8 (byte)   Signed 8-bit integer
*  i16         Signed 16-bit integer
*  i32         Signed 32-bit integer
*  i64         Signed 64-bit integer
*  double      64-bit floating point value
*  string      String
*  binary      Blob (byte array)
*  map<t1,t2>  Map from one type to another
*  list<t1>    Ordered list of one type
*  set<t1>     Set of unique elements of one type
*
* Did you also notice that Thrift supports C style comments?
*/

// Just in case you were wondering... yes. We support simple C comments too.

/**
* Thrift files can reference other Thrift files to include common struct
* and service definitions. These are found using the current path, or by
* searching relative to any paths specified with the -I compiler flag.
*
* Included objects are accessed using the name of the .thrift file as a
* prefix. i.e. shared.SharedObject
*/
include "shared.thrift"

/**
* Thrift files can namespace, package, or prefix their output in various
* target languages.
*/
namespace cpp tutorial
namespace d tutorial
namespace dart tutorial
namespace java tutorial
namespace php tutorial
namespace perl tutorial
namespace haxe tutorial

/**
* Thrift lets you do typedefs to get pretty names for your types. Standard
* C style here.
*/
typedef i32 MyInteger

/**
* Thrift also lets you define constants for use across languages. Complex
* types and structs are specified using JSON notation.
*/
const i32 INT32CONSTANT = 9853
const map<string,string> MAPCONSTANT = {'hello':'world', 'goodnight':'moon'}

/**
* You can define enums, which are just 32 bit integers. Values are optional
* and start at 1 if not supplied, C style again.
*/
enum Operation {
ADD = 1,
SUBTRACT = 2,
MULTIPLY = 3,
DIVIDE = 4
}

/**
* Structs are the basic complex data structures. They are comprised of fields
* which each have an integer identifier, a type, a symbolic name, and an
* optional default value.
*
* Fields can be declared "optional", which ensures they will not be included
* in the serialized output if they aren't set.  Note that this requires some
* manual management in some languages.
*/
struct Work {
1: i32 num1 = 0,
2: i32 num2,
3: Operation op,
4: optional string comment,
}

/**
* Structs can also be exceptions, if they are nasty.
*/
exception InvalidOperation {
1: i32 whatOp,
2: string why
}

/**
* Ahh, now onto the cool part, defining a service. Services just need a name
* and can optionally inherit from another service using the extends keyword.
*/
service Calculator extends shared.SharedService {

/**
* A method definition looks like C code. It has a return type, arguments,
* and optionally a list of exceptions that it may throw. Note that argument
* lists and exception lists are specified using the exact same syntax as
* field lists in struct or exception definitions.
*/

void ping(),

i32 add(1:i32 num1, 2:i32 num2),

i32 calculate(1:i32 logid, 2:Work w) throws (1:InvalidOperation ouch),

/**
* This method has a oneway modifier. That means the client only makes
* a request and does not listen for any response at all. Oneway methods
* must be void.
*/
oneway void zip()

}

/**
* That just about covers the basics. Take a look in the test/ folder for more
* detailed examples. After you run this file, your generated code shows up
* in folders with names gen-<language>. The generated code isn't too scary
* to look at. It even has pretty indentation.
*/

根据语法,编写简单的IDL文件如下:

文件名: exampleService.thrift

接口定义如下:

namespace java example
namespace php example

/**
* 异常代码
*/
enum ErrorCode {
/**
* 成功
*/
SUCCESS = 0,

/**
* 失败
*/
FAILED = -1,
}

/**
* 异常代码含义
*/
const map<i16,string> ERROR_CODE_MESSAGE = {
ErrorCode.SUCCESS: 'success',
ErrorCode.FAILED: 'failed',
}

/**
* 返回数据结构
*/
struct Data {
/**
* 加数
*/
1: i32 data_one,

/**
* 被加数
*/
2: i32 data_two,

/**
* 和
*/
3: i32 sum,
}

/**
* 服务返回结果
*/
struct Result {
1: i32 code;
2: string message;
3: optional Data data;
}

/**
* 服务
*/
service CalcService {
/**
* 计算两个数的和
*/
Result sum(1:i32 data_one, 2:i32 data_two),
}

接口定义完成之后生成响应语言的代码,执行:

thrift -r -gen php:server -v -strict -out /path/to/code/ /path/to/exampleService.thrift

服务实现

服务定义好之后,需要实现服务,实现服务的文件名称:

PhpService.php

,内容如下:

详细的代码请查看：thrift_example_code

<?php
namespace example;
error_reporting(E_ALL);

require __DIR__ . '/../vendor/autoload.php';
require_once __DIR__ . '/CalcService.php';
require_once __DIR__ . '/Types.php';

use Thrift\ClassLoader\ThriftClassLoader;

$loader = new ThriftClassLoader();
$loader->registerNamespace('Thrift', __DIR__ . '/../vendor/apache/thrift/lib/php/lib');
$loader->register();

if (php_sapi_name() == 'cli') {
ini_set("display_errors", "stderr");
}

use Thrift\Protocol\TBinaryProtocol;
use Thrift\Transport\TPhpStream;
use Thrift\Transport\TBufferedTransport;

class CalculatorHandler implements CalcServiceIf
{

/**
* 计算两个数的和
*
* @param int $data_one
* @param int $data_two
* @return \example\Result 服务返回结果
*
*/
public function sum($data_one, $data_two)
{
if (!is_numeric($data_one) || !is_numeric($data_two)) {
$error_code = ErrorCode::FAILED;
$messages = Constant::get('ERROR_CODE_MESSAGE');
$msg = $messages[$error_code];
$result = new Result();
$result->code = $error_code;
$result->message = $msg;
return $result;
}
$code = ErrorCode::SUCCESS;
$messages = Constant::get('ERROR_CODE_MESSAGE');
$msg = $messages[$code];
$result = new Result();
$result->code = $code;
$result->message = $msg;

$result_data = new Data();
$result_data->data_one = $data_one;
$result_data->data_two = $data_two;
$result_data->sum = $data_one + $data_two;

$result->data = $result_data;
return $result;
}
}

header('Content-Type', 'application/x-thrift');
if (php_sapi_name() == 'cli') {
echo "\r\n";
}

$handler = new CalculatorHandler();
$processor = new CalcServiceProcessor($handler);

$transport = new TBufferedTransport(new TPhpStream(TPhpStream::MODE_R | TPhpStream::MODE_W));
$protocol = new TBinaryProtocol($transport, true, true);

$transport->open();
$processor->process($protocol, $protocol);
$transport->close();

启动服务

在nginx配置中添加如下配置,监听服务:

server {
listen 8080;
server_name localhost;

location ~* ^/php/PhpServer {
rewrite . /index.php last;
}

location = /index.php {
internal;
fastcgi_pass localhost:9000;
fastcgi_param SCRIPT_FILENAME /path/to/PhpService.php;
include fastcgi_params;
}
}

其中的

fastcgi_param

参数的值是

PhpService.php

文件的绝对路径.

执行

nginx -s reload

重启nginx。

客户端代码

客户端文件名:PhpClient.php,内容如下:

详细的代码请查看：thrift_example_code

<?php

namespace example;

error_reporting(E_ALL);
require __DIR__ . '/../vendor/autoload.php';
require_once __DIR__ . '/CalcService.php';
require_once __DIR__ . '/Types.php';

use Thrift\ClassLoader\ThriftClassLoader;

$loader = new ThriftClassLoader();
$loader->registerNamespace('Thrift', __DIR__ . '/../thrift/lib/php/lib');
$loader->register();

use Thrift\Protocol\TBinaryProtocol;
use Thrift\Transport\THttpClient;
use Thrift\Transport\TBufferedTransport;
use Thrift\Exception\TException;

try {
$socket = new THttpClient('localhost', 8080, '/php/PhpServer');
$transport = new TBufferedTransport($socket, 1024, 1024);
$protocol = new TBinaryProtocol($transport);

/**
* @var CalcServiceIf
*/
$client = new CalcServiceClient($protocol);
$transport->open();

$sum = $client->sum(1, 2);
var_dump($sum);

$transport->close();
echo '<br /> DONE <br />';

} catch (TException $tx) {
print 'TException: ' . $tx->getMessage() . "\n";
}

执行客户端

执行客户端代码,请求服务。

在PhpStorm中执行PhpClient.php文件,会自动打开默认浏览器,通过浏览器执行POST请求,将请求发送到nginx。

打印输出如下:

object(example\Result)#9 (3) {
["code"]=> int(0)
["message"]=> string(7) "success"
["data"]=> object(example\Data)#10 (3) {
["data_one"]=> int(1)
["data_two"]=> int(2)
["sum"]=> int(3)
}
}

可以看到返回的数据结构和我们的thrift文件中定义的数据结构是一模一样的。

远程部署与访问

上面的服务端代码和客户端代码可以部署到不通的主机上,实现远程调用。而且,客户端代码可以有多种实现方式,比如JAVA,Python等。

问题

多个客户端如何保证服务端解析代码的一致性呢?

服务端代码和客户端代码该如何在应用中管理呢?

等等一致性问题都可以通过composer来管理。