Cocurrency otlp http session (open-telemetry#1274)

CHANGELOG.md

@@ -16,6 +16,7 @@ Increment the:
 ## [Unreleased]
 
 * [EXPORTER] Jaeger Exporter - Populate Span Links ([#1251](https://github.com/open-telemetry/opentelemetry-cpp/pull/1251))
+* [EXPORTER] OTLP http exporter allow concurrency session ([#1209](https://github.com/open-telemetry/opentelemetry-cpp/pull/1209))
 
 ## [1.2.0] 2022-01-31
 

api/include/opentelemetry/common/timestamp.h

@@ -169,5 +169,39 @@ class SteadyTimestamp
 private:
   int64_t nanos_since_epoch_;
 };
+
+class DurationUtil
+{
+public:
+  template <class Rep, class Period>
+  static std::chrono::duration<Rep, Period> AdjustWaitForTimeout(
+      std::chrono::duration<Rep, Period> timeout,
+      std::chrono::duration<Rep, Period> indefinite_value) noexcept
+  {
+    // Do not call now() when this duration is max value, now() may have a expensive cost.
+    if (timeout == std::chrono::duration<Rep, Period>::max())
+    {
+      return indefinite_value;
+    }
+
+    // std::future<T>::wait_for, std::this_thread::sleep_for, and std::condition_variable::wait_for
+    // may use steady_clock or system_clock.We need make sure now() + timeout do not overflow.
+    auto max_timeout = std::chrono::duration_cast<std::chrono::duration<Rep, Period>>(
+        std::chrono::steady_clock::time_point::max() - std::chrono::steady_clock::now());
+    if (timeout >= max_timeout)
+    {
+      return indefinite_value;
+    }
+    max_timeout = std::chrono::duration_cast<std::chrono::duration<Rep, Period>>(
+        std::chrono::system_clock::time_point::max() - std::chrono::system_clock::now());
+    if (timeout >= max_timeout)
+    {
+      return indefinite_value;
+    }
+
+    return timeout;
+  }
+};
+
 }  // namespace common
 OPENTELEMETRY_END_NAMESPACE

exporters/ostream/src/log_exporter.cc

@@ -180,7 +180,7 @@ sdk::common::ExportResult OStreamLogExporter::Export(
   return sdk::common::ExportResult::kSuccess;
 }
 
-bool OStreamLogExporter::Shutdown(std::chrono::microseconds timeout) noexcept
+bool OStreamLogExporter::Shutdown(std::chrono::microseconds) noexcept
 {
   const std::lock_guard<opentelemetry::common::SpinLockMutex> locked(lock_);
   is_shutdown_ = true;

exporters/otlp/include/opentelemetry/exporters/otlp/otlp_http_client.h

@@ -15,10 +15,15 @@
 
 #include "opentelemetry/exporters/otlp/otlp_environment.h"
 
+#include <atomic>
 #include <chrono>
+#include <condition_variable>
+#include <cstddef>
+#include <list>
 #include <memory>
 #include <mutex>
 #include <string>
+#include <unordered_map>
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace exporter
@@ -71,20 +76,25 @@ struct OtlpHttpClientOptions
   // Additional HTTP headers
   OtlpHeaders http_headers = GetOtlpDefaultHeaders();
 
+  // Concurrent sessions
+  std::size_t concurrent_sessions = 8;
+
   inline OtlpHttpClientOptions(nostd::string_view input_url,
                                HttpRequestContentType input_content_type,
                                JsonBytesMappingKind input_json_bytes_mapping,
                                bool input_use_json_name,
                                bool input_console_debug,
                                std::chrono::system_clock::duration input_timeout,
-                               const OtlpHeaders &input_http_headers)
+                               const OtlpHeaders &input_http_headers,
+                               std::size_t input_concurrent_sessions = 8)
       : url(input_url),
         content_type(input_content_type),
         json_bytes_mapping(input_json_bytes_mapping),
         use_json_name(input_use_json_name),
         console_debug(input_console_debug),
         timeout(input_timeout),
-        http_headers(input_http_headers)
+        http_headers(input_http_headers),
+        concurrent_sessions(input_concurrent_sessions)
   {}
 };
 
@@ -99,6 +109,8 @@ class OtlpHttpClient
    */
   explicit OtlpHttpClient(OtlpHttpClientOptions &&options);
 
+  ~OtlpHttpClient();
+
   /**
    * Export
    * @param message message to export, it should be ExportTraceServiceRequest,
@@ -114,19 +126,33 @@ class OtlpHttpClient
    */
   bool Shutdown(std::chrono::microseconds timeout = std::chrono::microseconds(0)) noexcept;
 
+  /**
+   * @brief Release the lifetime of specify session.
+   *
+   * @param session the session to release
+   */
+  void ReleaseSession(const opentelemetry::ext::http::client::Session &session) noexcept;
+
 private:
-  // Stores if this HTTP client had its Shutdown() method called
-  bool is_shutdown_ = false;
+  /**
+   * Add http session and hold it's lifetime.
+   * @param session the session to add
+   * @param event_handle the event handle of this session
+   */
+  void addSession(
+      std::shared_ptr<opentelemetry::ext::http::client::Session> session,
+      std::unique_ptr<opentelemetry::ext::http::client::EventHandler> &&event_handle) noexcept;
 
-  // The configuration options associated with this HTTP client.
-  const OtlpHttpClientOptions options_;
+  /**
+   * @brief Real delete all sessions and event handles.
+   * @note This function is called in the same thread where we create sessions and handles
+   *
+   * @return return true if there are more sessions to delete
+   */
+  bool cleanupGCSessions() noexcept;
 
-  // Object that stores the HTTP sessions that have been created
-  std::shared_ptr<ext::http::client::HttpClient> http_client_;
-  // Cached parsed URI
-  std::string http_uri_;
-  mutable opentelemetry::common::SpinLockMutex lock_;
   bool isShutdown() const noexcept;
+
   // For testing
   friend class OtlpHttpExporterTestPeer;
   friend class OtlpHttpLogExporterTestPeer;
@@ -138,6 +164,51 @@ class OtlpHttpClient
    */
   OtlpHttpClient(OtlpHttpClientOptions &&options,
                  std::shared_ptr<ext::http::client::HttpClient> http_client);
+
+  struct HttpSessionData
+  {
+    std::shared_ptr<opentelemetry::ext::http::client::Session> session;
+    std::unique_ptr<opentelemetry::ext::http::client::EventHandler> event_handle;
+
+    inline HttpSessionData() = default;
+
+    inline explicit HttpSessionData(
+        std::shared_ptr<opentelemetry::ext::http::client::Session> &&input_session,
+        std::unique_ptr<opentelemetry::ext::http::client::EventHandler> &&input_handle)
+    {
+      session.swap(input_session);
+      event_handle.swap(input_handle);
+    }
+
+    inline explicit HttpSessionData(HttpSessionData &&other)
+    {
+      session.swap(other.session);
+      event_handle.swap(other.event_handle);
+    }
+  };
+
+  // Stores if this HTTP client had its Shutdown() method called
+  bool is_shutdown_;
+
+  // The configuration options associated with this HTTP client.
+  const OtlpHttpClientOptions options_;
+
+  // Object that stores the HTTP sessions that have been created
+  std::shared_ptr<ext::http::client::HttpClient> http_client_;
+
+  // Cached parsed URI
+  std::string http_uri_;
+
+  // Running sessions and event handles
+  std::unordered_map<const opentelemetry::ext::http::client::Session *, HttpSessionData>
+      running_sessions_;
+  // Sessions and event handles that are waiting to be deleted
+  std::list<HttpSessionData> gc_sessions_;
+  // Lock for running_sessions_, gc_sessions_ and http_client_
+  std::recursive_mutex session_manager_lock_;
+  // Condition variable and mutex to control the concurrency count of running sessions
+  std::mutex session_waker_lock_;
+  std::condition_variable session_waker_;
 };
 }  // namespace otlp
 }  // namespace exporter

exporters/otlp/include/opentelemetry/exporters/otlp/otlp_http_exporter.h

@@ -11,6 +11,7 @@
 #include "opentelemetry/exporters/otlp/otlp_environment.h"
 
 #include <chrono>
+#include <cstddef>
 #include <memory>
 #include <string>
 
@@ -50,6 +51,9 @@ struct OtlpHttpExporterOptions
 
   // Additional HTTP headers
   OtlpHeaders http_headers = GetOtlpDefaultHeaders();
+
+  // Concurrent sessions
+  std::size_t concurrent_sessions = 8;
 };
 
 /**

exporters/otlp/include/opentelemetry/exporters/otlp/otlp_http_log_exporter.h

@@ -11,6 +11,7 @@
 #  include "opentelemetry/exporters/otlp/otlp_environment.h"
 
 #  include <chrono>
+#  include <cstddef>
 #  include <memory>
 #  include <string>
 
@@ -50,6 +51,9 @@ struct OtlpHttpLogExporterOptions
 
   // Additional HTTP headers
   OtlpHeaders http_headers = GetOtlpDefaultLogHeaders();
+
+  // Concurrent sessions
+  std::size_t concurrent_sessions = 8;
 };
 
 /**