一个最简单版本的mongocxx driver测试

安装

• 安装新版cmake3.1以上

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  wget https://cmake.org/files/v3.10/cmake-3.10.1-Linux-x86_64.tar.gz tar fxz cmake-3.10.1-Linux-x86_64.tar.gz ln -sf /home/xxxxx/cmake-3.10.1-Linux-x86_64/bin/cmake /usr/bin/cmake

• 安装libbson

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  wget https://github.com/mongodb/libbson/releases/download/1.9.0/libbson-1.9.0.tar.gz tar -xzf libbson-1.9.0.tar.gz cd libbson-1.9.0/ ./configure --enable-static make -j8 sudo make install

• 安装mongo c driver

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  wget https://github.com/mongodb/mongo-c-driver/releases/download/1.9.0/mongo-c-driver-1.9.0.tar.gz tar xzf mongo-c-driver-1.9.0.tar.gz cd mongo-c-driver-1.9.0 ./configure --enable-static --disable-automatic-init-and-cleanup make -j8 sudo make install

• 安装mongo cxx driver 3.1

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  wget https://github.com/mongodb/mongo-cxx-driver/archive/r3.1.3.tar.gz -O mongo-cxx-driver-r3.1.3.tar.gz tar fxz mongo-cxx-driver-r3.1.3.tar.gz cd mongo-cxx-driver-r3.1.3/build cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local -DLIBBSON_DIR=/usr/local -DLIBMONGOC_DIR=/usr/local .. sudo make -j8 sudo make install

最简单版本的main

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#include <iostream>
#include <mongocxx/client.hpp>
#include <mongocxx/instance.hpp>
#include <bsoncxx/builder/stream/document.hpp>
#include <bsoncxx/json.hpp>
typedef std::shared_ptr<mongocxx::client> MongoConnPtr;

int main( int argc, char * argv[] )
{
    mongocxx::instance instance{};
    mongocxx::uri uri("mongodb://username:pass@127.0.0.1:30000/?authSource=db_name&authMechanism=SCRAM-SHA-1");
    //mongocxx::client client(uri);
    MongoConnPtr pConn( new mongocxx::client(uri) );
	auto db = (*pConn)["tw2_commondb"];
	auto collection  = db["test"];

    auto cursor = collection.find({});
    for(auto doc : cursor)
        std::cout << bsoncxx::to_json(doc) << std::endl;
    std::cout << "end" << std::endl;
}

这个简单的测试程序是为了调试某个crash引起的

• 看起来很诡异，一开始以为是mongo连接不上，用户名密码authMechanism不对之类的引起的，但是用上面的最简单的代码测试又没问题

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  #0 0x00000000009452a8 in _mongoc_client_new_from_uri () (gdb) bt #0 0x00000000009452a8 in _mongoc_client_new_from_uri () #1 0x000000000090c445 in mongocxx::v_noabi::client::client(mongocxx::v_noabi::uri const&, mongocxx::v_noabi::options::client const&) () #2 0x000000000081862c in __base_dtor () at /usr/local/include/bsoncxx/v_noabi/bsoncxx/third_party/mnmlstc/core/optional.hpp:81 #3 __base_dtor () at /usr/local/include/bsoncxx/v_noabi/bsoncxx/third_party/mnmlstc/core/optional.hpp:194 #4 __base_dtor () at /usr/local/include/bsoncxx/v_noabi/bsoncxx/view_or_value.hpp:30 #5 __base_dtor () at /usr/local/include/bsoncxx/v_noabi/bsoncxx/string/view_or_value.hpp:36 #6 MongoDatabase::initMongoConnection() (this=0x152892c0) at mongo_database.cpp:667 #7 0x0000000000589884 in _M_dispose () at /usr/include/c++/4.9/bits/basic_string.h:240 #8 __base_dtor () at /usr/include/c++/4.9/bits/basic_string.h:547 #9 CommonMongoDatabase::startup(EntityDefs const&, bool, bool) (this=0x7ffcd0f7fc60, entityDefs=...) at mongo_database.cpp:3016 #10 0x0000000000502d42 in Database::init(bool, bool, DefsSyncMode) (this=0x7ffcd0f80b90, isRecover=<optimized out>, isUpgrade=<optimized out>, defsSyncMode=<optimized out>) at database.cpp:974 #11 0x00000000005048df in bwMain(int, char**) (argc=<optimized out>, argv=<optimized out>) at main.cpp:69 #12 0x00007f1dd39b6b45 in __libc_start_main () from /lib/x86_64-linux-gnu/libc.so.6 #13 0x00000000004d00cf in _start ()

• 最后发现这句mongocxx::instance instance{};在多线程中单例没有在所有链接初始化之前调用，就必定出现这个crash，出现在_mongoc_client_new_from_uri