Address comment (#487)

* Address comment

* Update src/c++/perf_analyzer/client_backend/openai/openai_client.cc

* Update src/c++/perf_analyzer/client_backend/openai/http_client.cc

* formatting

---------

Co-authored-by: Timothy Gerdes <50968584+tgerdesnv@users.noreply.github.com>
Co-authored-by: tgerdes <tgerdes@nvidia.com>

src/c++/perf_analyzer/client_backend/openai/http_client.cc

@@ -76,19 +76,25 @@ HttpRequest::GetNextInput(uint8_t* buf, size_t size, size_t* input_bytes)
   }
 }
 
+std::mutex HttpClient::curl_init_mtx_{};
 HttpClient::HttpClient(
     const std::string& server_url, bool verbose,
     const HttpSslOptions& ssl_options)
     : url_(server_url), verbose_(verbose), ssl_options_(ssl_options)
 {
-  auto* ver = curl_version_info(CURLVERSION_NOW);
-  if (ver->features & CURL_VERSION_THREADSAFE == 0) {
-    throw std::runtime_error(
-        "HTTP client has dependency on CURL library to have thread-safe "
-        "support (CURL_VERSION_THREADSAFE set)");
-  }
-  if (curl_global_init(CURL_GLOBAL_ALL) != 0) {
-    throw std::runtime_error("CURL global initialization failed");
+  // [TODO TMA-1670] uncomment below and remove class-wise mutex once confirm
+  // curl >= 7.84.0 will always be used
+  // auto* ver = curl_version_info(CURLVERSION_NOW);
+  // if (ver->features & CURL_VERSION_THREADSAFE == 0) {
+  //   throw std::runtime_error(
+  //       "HTTP client has dependency on CURL library to have thread-safe "
+  //       "support (CURL_VERSION_THREADSAFE set)");
+  // }
+  {
+    std::lock_guard<std::mutex> lk(curl_init_mtx_);
+    if (curl_global_init(CURL_GLOBAL_ALL) != 0) {
+      throw std::runtime_error("CURL global initialization failed");
+    }
   }
 
   multi_handle_ = curl_multi_init();
@@ -114,7 +120,10 @@ HttpClient::~HttpClient()
   }
   curl_multi_cleanup(multi_handle_);
 
-  curl_global_cleanup();
+  {
+    std::lock_guard<std::mutex> lk(curl_init_mtx_);
+    curl_global_cleanup();
+  }
 }
 
 const std::string&

src/c++/perf_analyzer/client_backend/openai/http_client.h

@@ -168,5 +168,6 @@ class HttpClient {
  private:
   const std::string& ParseSslKeyType(HttpSslOptions::KEYTYPE key_type);
   const std::string& ParseSslCertType(HttpSslOptions::CERTTYPE cert_type);
+  static std::mutex curl_init_mtx_;
 };
 }}}}  // namespace triton::perfanalyzer::clientbackend::openai

src/c++/perf_analyzer/client_backend/openai/openai_client.cc

@@ -114,8 +114,21 @@ size_t
 ChatCompletionClient::ResponseHandler(
     void* contents, size_t size, size_t nmemb, void* userp)
 {
-  // [WIP] verify if the SSE responses received are complete, or the response
-  // need to be stitched first
+  // [TODO TMA-1666] verify if the SSE responses received are complete, or the
+  // response need to be stitched first. To verify, print out the received
+  // responses from SendResponse() to make sure the OpenAI server doesn't chunk
+  // the HTTP responses in the way that misaligns with the SSE responses. Reason
+  // of not stitching responses now is that it is a bit complicated that to make
+  // the write callback bulletproof is to assume the response can be chunked at
+  // arbitrary position, then bake in checking for SSE style (data:.*\n\n) by
+  // iterating all received buffer character by character.
+  size_t result_bytes = size * nmemb;
+  // return early if the response is empty as the response handling is
+  // triggered by the content of the response.
+  if (result_bytes == 0) {
+    return result_bytes;
+  }
+
   auto request = reinterpret_cast<ChatCompletionRequest*>(userp);
   if (request->timer_.Timestamp(
           triton::client::RequestTimers::Kind::RECV_START) == 0) {
@@ -124,7 +137,6 @@ ChatCompletionClient::ResponseHandler(
   }
 
   char* buf = reinterpret_cast<char*>(contents);
-  size_t result_bytes = size * nmemb;
   request->response_buffer_.append(buf, result_bytes);
   // Send response now if streaming, otherwise wait until request has been
   // completed