Set default timeout on curl handles (#66)

Co-authored-by: David Goffredo <david.goffredo@datadoghq.com>

Author: dmehala

src/datadog/curl.cpp

@@ -13,6 +13,7 @@
 #include <unordered_map>
 #include <unordered_set>
 
+#include "clock.h"
 #include "dict_reader.h"
 #include "dict_writer.h"
 #include "http_client.h"
@@ -95,6 +96,10 @@ CURLcode CurlLibrary::easy_setopt_writefunction(CURL *handle,
   return curl_easy_setopt(handle, CURLOPT_WRITEFUNCTION, on_write);
 }
 
+CURLcode CurlLibrary::easy_setopt_timeout_ms(CURL *handle, long timeout_ms) {
+  return curl_easy_setopt(handle, CURLOPT_TIMEOUT_MS, timeout_ms);
+}
+
 const char *CurlLibrary::easy_strerror(CURLcode error) {
   return curl_easy_strerror(error);
 }
@@ -162,6 +167,7 @@ class CurlImpl {
   std::mutex mutex_;
   CurlLibrary &curl_;
   const std::shared_ptr<Logger> logger_;
+  Clock clock_;
   CURLM *multi_handle_;
   std::unordered_set<CURL *> request_handles_;
   std::list<CURL *> new_handles_;
@@ -179,6 +185,7 @@ class CurlImpl {
     char error_buffer[CURL_ERROR_SIZE] = "";
     std::unordered_map<std::string, std::string> response_headers_lower;
     std::string response_body;
+    std::chrono::steady_clock::time_point deadline;
 
     ~Request();
   };
@@ -221,13 +228,14 @@ class CurlImpl {
   static StringView trim(StringView);
 
  public:
-  explicit CurlImpl(const std::shared_ptr<Logger> &, CurlLibrary &,
-                    const Curl::ThreadGenerator &);
+  explicit CurlImpl(const std::shared_ptr<Logger> &, const Clock &,
+                    CurlLibrary &, const Curl::ThreadGenerator &);
   ~CurlImpl();
 
   Expected<void> post(const URL &url, HeadersSetter set_headers,
                       std::string body, ResponseHandler on_response,
-                      ErrorHandler on_error);
+                      ErrorHandler on_error,
+                      std::chrono::steady_clock::time_point deadline);
 
   void drain(std::chrono::steady_clock::time_point deadline);
 };
@@ -242,22 +250,25 @@ void throw_on_error(CURLcode result) {
 
 }  // namespace
 
-Curl::Curl(const std::shared_ptr<Logger> &logger) : Curl(logger, libcurl) {}
+Curl::Curl(const std::shared_ptr<Logger> &logger, const Clock &clock)
+    : Curl(logger, clock, libcurl) {}
 
-Curl::Curl(const std::shared_ptr<Logger> &logger, CurlLibrary &curl)
-    : Curl(logger, curl,
+Curl::Curl(const std::shared_ptr<Logger> &logger, const Clock &clock,
+           CurlLibrary &curl)
+    : Curl(logger, clock, curl,
            [](auto &&func) { return std::thread(std::move(func)); }) {}
 
-Curl::Curl(const std::shared_ptr<Logger> &logger, CurlLibrary &curl,
-           const Curl::ThreadGenerator &make_thread)
-    : impl_(new CurlImpl{logger, curl, make_thread}) {}
+Curl::Curl(const std::shared_ptr<Logger> &logger, const Clock &clock,
+           CurlLibrary &curl, const Curl::ThreadGenerator &make_thread)
+    : impl_(new CurlImpl{logger, clock, curl, make_thread}) {}
 
 Curl::~Curl() { delete impl_; }
 
 Expected<void> Curl::post(const URL &url, HeadersSetter set_headers,
                           std::string body, ResponseHandler on_response,
-                          ErrorHandler on_error) {
-  return impl_->post(url, set_headers, body, on_response, on_error);
+                          ErrorHandler on_error,
+                          std::chrono::steady_clock::time_point deadline) {
+  return impl_->post(url, set_headers, body, on_response, on_error, deadline);
 }
 
 void Curl::drain(std::chrono::steady_clock::time_point deadline) {
@@ -268,10 +279,11 @@ nlohmann::json Curl::config_json() const {
   return nlohmann::json::object({{"type", "datadog::tracing::Curl"}});
 }
 
-CurlImpl::CurlImpl(const std::shared_ptr<Logger> &logger, CurlLibrary &curl,
-                   const Curl::ThreadGenerator &make_thread)
+CurlImpl::CurlImpl(const std::shared_ptr<Logger> &logger, const Clock &clock,
+                   CurlLibrary &curl, const Curl::ThreadGenerator &make_thread)
     : curl_(curl),
       logger_(logger),
+      clock_(clock),
       shutting_down_(false),
       num_active_handles_(0) {
   curl_.global_init(CURL_GLOBAL_ALL);
@@ -311,24 +323,35 @@ CurlImpl::~CurlImpl() {
   }
   log_on_error(curl_.multi_wakeup(multi_handle_));
   event_loop_.join();
+
+  log_on_error(curl_.multi_cleanup(multi_handle_));
+  curl_.global_cleanup();
 }
 
-Expected<void> CurlImpl::post(const HTTPClient::URL &url,
-                              HeadersSetter set_headers, std::string body,
-                              ResponseHandler on_response,
-                              ErrorHandler on_error) try {
+Expected<void> CurlImpl::post(
+    const HTTPClient::URL &url, HeadersSetter set_headers, std::string body,
+    ResponseHandler on_response, ErrorHandler on_error,
+    std::chrono::steady_clock::time_point deadline) try {
   if (multi_handle_ == nullptr) {
     return Error{Error::CURL_HTTP_CLIENT_NOT_RUNNING,
                  "Unable to send request via libcurl because the HTTP client "
                  "failed to start."};
   }
 
+  HeaderWriter writer{curl_};
+  set_headers(writer);
+  auto cleanup_list = [&](auto list) { curl_.slist_free_all(list); };
+  std::unique_ptr<curl_slist, decltype(cleanup_list)> headers{
+      writer.release(), std::move(cleanup_list)};
+
   auto request = std::make_unique<Request>();
 
   request->curl = &curl_;
+  request->request_headers = headers.get();
   request->request_body = std::move(body);
   request->on_response = std::move(on_response);
   request->on_error = std::move(on_error);
+  request->deadline = std::move(deadline);
 
   auto cleanup_handle = [&](auto handle) { curl_.easy_cleanup(handle); };
   std::unique_ptr<CURL, decltype(cleanup_handle)> handle{
@@ -339,6 +362,8 @@ Expected<void> CurlImpl::post(const HTTPClient::URL &url,
                  "unable to initialize a curl handle for request sending"};
   }
 
+  throw_on_error(
+      curl_.easy_setopt_httpheader(handle.get(), request->request_headers));
   throw_on_error(curl_.easy_setopt_private(handle.get(), request.get()));
   throw_on_error(
       curl_.easy_setopt_errorbuffer(handle.get(), request->error_buffer));
@@ -365,25 +390,17 @@ Expected<void> CurlImpl::post(const HTTPClient::URL &url,
         handle.get(), (url.scheme + "://" + url.authority + url.path).c_str()));
   }
 
-  HeaderWriter writer{curl_};
-  set_headers(writer);
-  auto cleanup_list = [&](auto list) { curl_.slist_free_all(list); };
-  std::unique_ptr<curl_slist, decltype(cleanup_list)> headers{
-      writer.release(), std::move(cleanup_list)};
-  request->request_headers = headers.get();
-  throw_on_error(
-      curl_.easy_setopt_httpheader(handle.get(), request->request_headers));
-
   std::list<CURL *> node;
   node.push_back(handle.get());
   {
     std::lock_guard<std::mutex> lock(mutex_);
     new_handles_.splice(new_handles_.end(), node);
 
-    headers.release();
-    handle.release();
-    request.release();
+    (void)headers.release();
+    (void)handle.release();
+    (void)request.release();
   }
+
   log_on_error(curl_.multi_wakeup(multi_handle_));
 
   return nullopt;
@@ -464,6 +481,7 @@ CURLMcode CurlImpl::log_on_error(CURLMcode result) {
 void CurlImpl::run() {
   int num_messages_remaining;
   CURLMsg *message;
+  const int max_wait_milliseconds = 10000;
   std::unique_lock<std::mutex> lock(mutex_);
 
   for (;;) {
@@ -478,16 +496,46 @@ void CurlImpl::run() {
                                             &num_messages_remaining))) {
       handle_message(*message, lock);
     }
-
-    const int max_wait_milliseconds = 10 * 1000;
     lock.unlock();
     log_on_error(curl_.multi_poll(multi_handle_, nullptr, 0,
                                   max_wait_milliseconds, nullptr));
     lock.lock();
 
     // New requests might have been added while we were sleeping.
     for (; !new_handles_.empty(); new_handles_.pop_front()) {
-      CURL *const handle = new_handles_.front();
+      CURL *handle = new_handles_.front();
+      char *user_data;
+      if (log_on_error(curl_.easy_getinfo_private(handle, &user_data)) !=
+          CURLE_OK) {
+        curl_.easy_cleanup(handle);
+        continue;
+      }
+
+      auto *request = reinterpret_cast<Request *>(user_data);
+      const auto timeout = request->deadline - clock_().tick;
+      if (timeout <= std::chrono::steady_clock::time_point::duration::zero()) {
+        std::string message;
+        message +=
+            "Request deadline exceeded before request was even added to "
+            "libcurl "
+            "event loop. Deadline was ";
+        message += std::to_string(
+            -std::chrono::duration_cast<std::chrono::nanoseconds>(timeout)
+                 .count());
+        message += " nanoseconds ago.";
+        request->on_error(
+            Error{Error::CURL_DEADLINE_EXCEEDED_BEFORE_REQUEST_START,
+                  std::move(message)});
+
+        curl_.easy_cleanup(handle);
+        delete request;
+
+        continue;
+      }
+
+      log_on_error(curl_.easy_setopt_timeout_ms(
+          handle, std::chrono::duration_cast<std::chrono::milliseconds>(timeout)
+                      .count()));
       log_on_error(curl_.multi_add_handle(multi_handle_, handle));
       request_handles_.insert(handle);
     }
@@ -510,8 +558,6 @@ void CurlImpl::run() {
   }
 
   request_handles_.clear();
-  log_on_error(curl_.multi_cleanup(multi_handle_));
-  curl_.global_cleanup();
 }
 
 void CurlImpl::handle_message(const CURLMsg &message,

src/datadog/curl.h

@@ -17,6 +17,7 @@
 #include <string>
 #include <thread>
 
+#include "clock.h"
 #include "http_client.h"
 #include "json_fwd.hpp"
 
@@ -59,6 +60,7 @@ class CurlLibrary {
   virtual CURLcode easy_setopt_url(CURL *handle, const char *url);
   virtual CURLcode easy_setopt_writedata(CURL *handle, void *data);
   virtual CURLcode easy_setopt_writefunction(CURL *handle, WriteCallback);
+  virtual CURLcode easy_setopt_timeout_ms(CURL *handle, long timeout_ms);
   virtual const char *easy_strerror(CURLcode error);
   virtual void global_cleanup();
   virtual CURLcode global_init(long flags);
@@ -86,16 +88,18 @@ class Curl : public HTTPClient {
  public:
   using ThreadGenerator = std::function<std::thread(std::function<void()> &&)>;
 
-  explicit Curl(const std::shared_ptr<Logger> &);
-  Curl(const std::shared_ptr<Logger> &, CurlLibrary &);
-  Curl(const std::shared_ptr<Logger> &, CurlLibrary &, const ThreadGenerator &);
+  explicit Curl(const std::shared_ptr<Logger> &, const Clock &);
+  Curl(const std::shared_ptr<Logger> &, const Clock &, CurlLibrary &);
+  Curl(const std::shared_ptr<Logger> &, const Clock &, CurlLibrary &,
+       const ThreadGenerator &);
   ~Curl();
 
   Curl(const Curl &) = delete;
 
   Expected<void> post(const URL &url, HeadersSetter set_headers,
                       std::string body, ResponseHandler on_response,
-                      ErrorHandler on_error) override;
+                      ErrorHandler on_error,
+                      std::chrono::steady_clock::time_point deadline) override;
 
   void drain(std::chrono::steady_clock::time_point deadline) override;
 

src/datadog/datadog_agent.cpp

@@ -134,17 +134,19 @@ std::variant<CollectorResponse, std::string> parse_agent_traces_response(
 DatadogAgent::DatadogAgent(
     const FinalizedDatadogAgentConfig& config,
     const std::shared_ptr<TracerTelemetry>& tracer_telemetry,
-    const Clock& clock, const std::shared_ptr<Logger>& logger)
+    const std::shared_ptr<Logger>& logger)
     : tracer_telemetry_(tracer_telemetry),
-      clock_(clock),
+      clock_(config.clock),
       logger_(logger),
       traces_endpoint_(traces_endpoint(config.url)),
       telemetry_endpoint_(telemetry_endpoint(config.url)),
       http_client_(config.http_client),
       event_scheduler_(config.event_scheduler),
       cancel_scheduled_flush_(event_scheduler_->schedule_recurring_event(
           config.flush_interval, [this]() { flush(); })),
-      flush_interval_(config.flush_interval) {
+      flush_interval_(config.flush_interval),
+      request_timeout_(config.request_timeout),
+      shutdown_timeout_(config.shutdown_timeout) {
   assert(logger_);
   assert(tracer_telemetry_);
   if (tracer_telemetry_->enabled()) {
@@ -185,7 +187,7 @@ DatadogAgent::DatadogAgent(
 }
 
 DatadogAgent::~DatadogAgent() {
-  const auto deadline = clock_().tick + std::chrono::seconds(2);
+  const auto deadline = clock_().tick + shutdown_timeout_;
   cancel_scheduled_flush_();
   flush();
   if (tracer_telemetry_->enabled()) {
@@ -208,17 +210,15 @@ Expected<void> DatadogAgent::send(
 }
 
 nlohmann::json DatadogAgent::config_json() const {
-  const auto flush_interval_milliseconds =
-      std::chrono::duration_cast<std::chrono::milliseconds>(flush_interval_)
-          .count();
-
   // clang-format off
   return nlohmann::json::object({
     {"type", "datadog::tracing::DatadogAgent"},
     {"config", nlohmann::json::object({
       {"traces_url", (traces_endpoint_.scheme + "://" + traces_endpoint_.authority + traces_endpoint_.path)},
       {"telemetry_url", (telemetry_endpoint_.scheme + "://" + telemetry_endpoint_.authority + telemetry_endpoint_.path)},
-      {"flush_interval_milliseconds", flush_interval_milliseconds},
+      {"flush_interval_milliseconds", std::chrono::duration_cast<std::chrono::milliseconds>(flush_interval_).count() },
+      {"request_timeout_milliseconds", std::chrono::duration_cast<std::chrono::milliseconds>(request_timeout_).count() },
+      {"shutdown_timeout_milliseconds", std::chrono::duration_cast<std::chrono::milliseconds>(shutdown_timeout_).count() },
       {"http_client", http_client_->config_json()},
       {"event_scheduler", event_scheduler_->config_json()},
     })},
@@ -324,9 +324,10 @@ void DatadogAgent::flush() {
   };
 
   tracer_telemetry_->metrics().trace_api.requests.inc();
-  auto post_result = http_client_->post(
-      traces_endpoint_, std::move(set_request_headers), std::move(body),
-      std::move(on_response), std::move(on_error));
+  auto post_result =
+      http_client_->post(traces_endpoint_, std::move(set_request_headers),
+                         std::move(body), std::move(on_response),
+                         std::move(on_error), clock_().tick + request_timeout_);
   if (auto* error = post_result.if_error()) {
     logger_->log_error(
         error->with_prefix("Unexpected error submitting traces: "));
@@ -335,9 +336,10 @@ void DatadogAgent::flush() {
 
 void DatadogAgent::send_app_started() {
   auto payload = tracer_telemetry_->app_started();
-  auto post_result = http_client_->post(
-      telemetry_endpoint_, telemetry_set_request_headers_, std::move(payload),
-      telemetry_on_response_, telemetry_on_error_);
+  auto post_result =
+      http_client_->post(telemetry_endpoint_, telemetry_set_request_headers_,
+                         std::move(payload), telemetry_on_response_,
+                         telemetry_on_error_, clock_().tick + request_timeout_);
   if (auto* error = post_result.if_error()) {
     logger_->log_error(error->with_prefix(
         "Unexpected error submitting telemetry app-started event: "));
@@ -346,9 +348,10 @@ void DatadogAgent::send_app_started() {
 
 void DatadogAgent::send_heartbeat_and_telemetry() {
   auto payload = tracer_telemetry_->heartbeat_and_telemetry();
-  auto post_result = http_client_->post(
-      telemetry_endpoint_, telemetry_set_request_headers_, std::move(payload),
-      telemetry_on_response_, telemetry_on_error_);
+  auto post_result =
+      http_client_->post(telemetry_endpoint_, telemetry_set_request_headers_,
+                         std::move(payload), telemetry_on_response_,
+                         telemetry_on_error_, clock_().tick + request_timeout_);
   if (auto* error = post_result.if_error()) {
     logger_->log_error(error->with_prefix(
         "Unexpected error submitting telemetry app-heartbeat event: "));
@@ -357,9 +360,10 @@ void DatadogAgent::send_heartbeat_and_telemetry() {
 
 void DatadogAgent::send_app_closing() {
   auto payload = tracer_telemetry_->app_closing();
-  auto post_result = http_client_->post(
-      telemetry_endpoint_, telemetry_set_request_headers_, std::move(payload),
-      telemetry_on_response_, telemetry_on_error_);
+  auto post_result =
+      http_client_->post(telemetry_endpoint_, telemetry_set_request_headers_,
+                         std::move(payload), telemetry_on_response_,
+                         telemetry_on_error_, clock_().tick + request_timeout_);
   if (auto* error = post_result.if_error()) {
     logger_->log_error(error->with_prefix(
         "Unexpected error submitting telemetry app-closing event: "));