TSeerServer不稳定 core

[troycheng]

目前试用中还是会遇到 TSeerServer 不稳定 core 的问题，目前还没有找出稳定复现的条件，会继续尝试。
现将 core 信息贴出，期望能获得一些有效信息，最终解决这个问题：

core文件1：

#0  0x00007f95ce5ccec5 in _IO_vfscanf_internal () from /lib64/libc.so.6
#1  0x00007f95ce5e1685 in vsscanf () from /lib64/libc.so.6
#2  0x00007f95ce5db6e8 in sscanf () from /lib64/libc.so.6
#3  0x00007f95ce615152 in __tzset_parse_tz () from /lib64/libc.so.6
#4  0x00007f95ce61632e in __tzfile_compute () from /lib64/libc.so.6
#5  0x00007f95ce615cb7 in __tz_convert () from /lib64/libc.so.6
#6  0x000000000046eba1 in tars::TC_Logger<tars::RollWriteT, tars::TC_RollBySize>::stream(int) ()
    at /home/tcheng/tools/TSeer/thirdparty/tars/include/util/tc_logger.h:727
#7  0x000000000046ed3e in tars::TC_Logger<tars::RollWriteT, tars::TC_RollBySize>::debug() ()
    at /home/tcheng/tools/TSeer/thirdparty/tars/include/util/tc_logger.h:689
#8  0x00000000004957ec in RequestEtcdCallback::responseClient(int, long, std::vector<Tseer::RouterData, std::allocator<Tseer::RouterData> > const&) () at /home/tcheng/tools/TSeer/TseerServer/src/RequestEtcdCallback.cpp:1299
#9  0x00000000004a1b8c in RequestEtcdCallback::onResponse(bool, tars::TC_HttpResponse&) ()
    at /home/tcheng/tools/TSeer/TseerServer/src/RequestEtcdCallback.cpp:168
#10 0x0000000000609a81 in tars::TC_HttpAsync::AsyncRequest::doReceive() ()
    at /home/tcheng/tools/TSeer/build/Tars/cpp/util/src/tc_http_async.cpp:264
#11 0x0000000000609be1 in tars::TC_HttpAsync::process(tars::TC_AutoPtr<tars::TC_HttpAsync::AsyncRequest>&, int) ()
    at /home/tcheng/tools/TSeer/build/Tars/cpp/util/src/tc_http_async.cpp:462
#12 0x0000000000609d2d in tars::TC_HttpAsync::run() () at /home/tcheng/tools/TSeer/build/Tars/cpp/util/src/tc_http_async.cpp:505
#13 0x0000000000610acf in tars::TC_ThreadPool::ThreadWorker::run() ()
    at /home/tcheng/tools/TSeer/build/Tars/cpp/util/src/tc_thread_pool.cpp:60
#14 0x00000000005f7e7a in tars::TC_Thread::threadEntry(tars::TC_Thread*) ()
    at /home/tcheng/tools/TSeer/build/Tars/cpp/util/src/tc_thread.cpp:93
#15 0x00007f95cf0b6aa1 in start_thread () from /lib64/libpthread.so.0
#16 0x00007f95ce660aad in clone () from /lib64/libc.so.6

core 文件2：

#0  std::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) ()
    at /usr/local/include/c++/4.8.3/bits/basic_string.h:716
#1  0x00000000004a314a in EtcdReqStr(EtcdReqestInfo const&) () at /home/tcheng/tools/TSeer/TseerServer/src/RequestEtcdCallback.h:284
#2  0x00000000004957af in RequestEtcdCallback::responseClient(int, long, std::vector<Tseer::RouterData, std::allocator<Tseer::RouterData> > const&) () at /home/tcheng/tools/TSeer/TseerServer/src/RequestEtcdCallback.cpp:1299
#3  0x0000000000499291 in RequestEtcdCallback::doGetSeerAgentResponse(rapidjson::GenericDocument<rapidjson::UTF8<char>, rapidjson::MemoryPoolAllocator<rapidjson::CrtAllocator>, rapidjson::CrtAllocator> const&) ()
    at /home/tcheng/tools/TSeer/TseerServer/src/RequestEtcdCallback.cpp:316
#4  0x00000000004a207b in RequestEtcdCallback::onResponse(bool, tars::TC_HttpResponse&) ()
    at /home/tcheng/tools/TSeer/TseerServer/src/RequestEtcdCallback.cpp:120
#5  0x0000000000609a81 in tars::TC_HttpAsync::AsyncRequest::doReceive() ()
    at /home/tcheng/tools/TSeer/build/Tars/cpp/util/src/tc_http_async.cpp:264
#6  0x0000000000609be1 in tars::TC_HttpAsync::process(tars::TC_AutoPtr<tars::TC_HttpAsync::AsyncRequest>&, int) ()
    at /home/tcheng/tools/TSeer/build/Tars/cpp/util/src/tc_http_async.cpp:462
#7  0x0000000000609d2d in tars::TC_HttpAsync::run() () at /home/tcheng/tools/TSeer/build/Tars/cpp/util/src/tc_http_async.cpp:505
#8  0x0000000000610acf in tars::TC_ThreadPool::ThreadWorker::run() ()
    at /home/tcheng/tools/TSeer/build/Tars/cpp/util/src/tc_thread_pool.cpp:60
#9  0x00000000005f7e7a in tars::TC_Thread::threadEntry(tars::TC_Thread*) ()
    at /home/tcheng/tools/TSeer/build/Tars/cpp/util/src/tc_thread.cpp:93
#10 0x00007f0febe71aa1 in start_thread () from /lib64/libpthread.so.0
#11 0x00007f0feb41baad in clone () from /lib64/libc.so.6

入口都是 tars::TC_HttpAsync::AsyncRequest::doReceive()，中间路径略有由不同，看起来是字符串的处理上有点儿问题，但简单 debug 了一下没有找出原因。

[troycheng]

/home/tcheng/tools/TSeer/TseerServer/src/RequestEtcdCallback.cpp:1299 就是一个日志输出语句：

ETCDPROC_LOG << ETCDFILE_FUN << "|response,ret= " << ret << "|retryTime= " << retryTime << endl;

其中ETCDFILE_FUN是一个宏定义：

#define ETCDFILE_FUN FILE_FUN <<EtcdReqStr(_etcdReqInfo)<<"|"

而EtcdReqStr这个函数，就是一个字符串拼接：

273 inline string EtcdReqStr(const EtcdReqestInfo& etcdReqInfo)
274 {
275     string client;
276     if (etcdReqInfo.current)
277     {
278         client = etcdReqInfo.current->getIp();
279     }
280     else
281     {
282         client = "NULL";
283     }
284     return "client=" + client + "|" + \
285             ActionStr(etcdReqInfo.etcdAction) + "|" +\
286             etcdReqInfo.moduletype + "." + \
287             etcdReqInfo.application + "." + \
288             etcdReqInfo.service_name + "|" + \
289             etcdReqInfo.node_name + "_" + \
290             etcdReqInfo.container_name + "|etcdhost=" + \
291             etcdReqInfo.etcdHost + ":" + \
292             TC_Common::tostr(etcdReqInfo.etcdPort) + "|" + \
293             MSTIMEINSTR(etcdReqInfo.startTime);
294 }

其中etcdReqInfo.current->getIp();也是直接返回_ip这个字符串，这个字符串初始值也是“NULL”，整个过程看起来并没有什么问题。目前是改写了一下这个函数，新加了一些日志，期望下次 core 的时候能有额外的发现

[troycheng]

回头来继续看了一下这个问题，对最近的几次 core 分析，代码有修改，位置也有所不同，都最终都是 core 在
ETCDPROC_LOG << ETCDFILE_FUN << "|response,ret= " << ret << "|retryTime= " << retryTime << endl;
这一句里，只是每次断点位置不太一样，鉴于其它部分都是字符串拼接，这个 logger有问题的可能性比较大。其中一次的断点位置在 LoggerStream 的析构函数里，目前触发条件仍未理清，但感觉排查方向应该是对了

#0  0x00007fe20422aa1c in free () from /lib64/libc.so.6
#1  0x000000000063c7eb in std::ios_base::~ios_base() () at ../../../.././libstdc++-v3/src/c++98/ios.cc:93
#2  0x00000000004b6f56 in tars::LoggerStream::~LoggerStream() () at /mnt/homework/gcc/gcc/include/c++/4.8.2/bits/basic_ios.h:276