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。

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。