client.hpp

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#pragma once
 
/// @file userver/clients/http/client.hpp
/// @brief @copybrief clients::http::Client
 
#ifdef USERVER_TVM2_HTTP_CLIENT
#error Use clients::Http from clients/http.hpp instead
#endif
 
#include <memory>
 
#include <userver/moodycamel/concurrentqueue_fwd.h>
 
#include <userver/clients/dns/resolver_fwd.hpp>
#include <userver/clients/http/config.hpp>
#include <userver/clients/http/plugin.hpp>
#include <userver/clients/http/request.hpp>
#include <userver/engine/task/task_processor_fwd.hpp>
#include <userver/rcu/rcu.hpp>
#include <userver/utils/fast_pimpl.hpp>
#include <userver/utils/not_null.hpp>
#include <userver/utils/periodic_task.hpp>
#include <userver/utils/swappingsmart.hpp>
#include <userver/yaml_config/fwd.hpp>
 
USERVER_NAMESPACE_BEGIN
 
namespace tracing {
class TracingManagerBase;
}  // namespace tracing
 
namespace curl {
class easy;
class multi;
class ConnectRateLimiter;
}  // namespace curl
 
namespace engine::ev {
class ThreadPool;
}  // namespace engine::ev
 
namespace clients::http {
namespace impl {
class EasyWrapper;
}  // namespace impl
 
struct TestsuiteConfig;
class Statistics;
struct PoolStatistics;
struct InstanceStatistics;
class DestinationStatistics;
 
/// @ingroup userver_clients
///
/// @brief HTTP client that returns a HTTP request builder from
/// CreateRequest().
///
/// Usually retrieved from components::HttpClient component.
///
/// ## Example usage:
///
/// @snippet clients/http/client_test.cpp  Sample HTTP Client usage
class Client final {
 public:
  Client(ClientSettings settings, engine::TaskProcessor& fs_task_processor,
         impl::PluginPipeline&& plugin_pipeline);
 
  ~Client();
 
  /// @brief Returns a HTTP request builder type with preset values of
  /// User-Agent, Proxy and some of the Testsuite suff (if any).
  ///
  /// @note This method is thread-safe despite being non-const.
  Request CreateRequest();
 
  /// Providing CreateNonSignedRequest() function for the clients::Http alias.
  ///
  /// @note This method is thread-safe despite being non-const.
  Request CreateNotSignedRequest() { return CreateRequest(); }
 
  /// @cond
  // For internal use only.
  void SetMultiplexingEnabled(bool enabled);
 
  // For internal use only.
  void SetMaxHostConnections(size_t max_host_connections);
 
  // For internal use only.
  PoolStatistics GetPoolStatistics() const;
 
  // Set max number of automatically created destination metrics.
  // For internal use only.
  void SetDestinationMetricsAutoMaxSize(size_t max_size);
 
  // For internal use only.
  const http::DestinationStatistics& GetDestinationStatistics() const;
 
  // For internal use only.
  void SetTestsuiteConfig(const TestsuiteConfig& config);
 
  // For internal use only.
  void SetAllowedUrlsExtra(std::vector<std::string>&& urls);
 
  // For internal use only.
  void SetConfig(const impl::Config&);
  /// @endcond
 
  /// @brief Sets User-Agent headers for all the requests or removes that
  /// header.
  ///
  /// By default User-Agent is set by components::HttpClient to the
  /// userver identity string.
  void ResetUserAgent(std::optional<std::string> user_agent = std::nullopt);
 
  /// @brief Returns the current proxy that is automatically used for each
  /// request.
  ///
  /// @warning The value may become immediately obsolete as the proxy could be
  /// concurrently changed from runtime config.
  std::string GetProxy() const;
 
  /// @brief Sets the DNS resolver to use.
  ///
  /// If given nullptr, the default resolver will be used
  /// (most likely getaddrinfo).
  void SetDnsResolver(clients::dns::Resolver* resolver);
 
 private:
  void ReinitEasy();
 
  InstanceStatistics GetMultiStatistics(size_t n) const;
 
  size_t FindMultiIndex(const curl::multi*) const;
 
  // Functions for EasyWrapper that must be noexcept, as they are called from
  // the EasyWrapper destructor.
  friend class impl::EasyWrapper;
  void IncPending() noexcept { ++pending_tasks_; }
  void DecPending() noexcept { --pending_tasks_; }
  void PushIdleEasy(std::shared_ptr<curl::easy>&& easy) noexcept;
 
  std::shared_ptr<curl::easy> TryDequeueIdle() noexcept;
 
  std::atomic<std::size_t> pending_tasks_{0};
 
  const DeadlinePropagationConfig deadline_propagation_config_;
  CancellationPolicy cancellation_policy_;
 
  std::shared_ptr<DestinationStatistics> destination_statistics_;
  std::unique_ptr<engine::ev::ThreadPool> thread_pool_;
  std::vector<Statistics> statistics_;
  std::vector<std::unique_ptr<curl::multi>> multis_;
 
  static constexpr size_t kIdleQueueSize = 616;
  static constexpr size_t kIdleQueueAlignment = 8;
  using IdleQueueTraits = moodycamel::ConcurrentQueueDefaultTraits;
  using IdleQueueValue = std::shared_ptr<curl::easy>;
  using IdleQueue =
      moodycamel::ConcurrentQueue<IdleQueueValue, IdleQueueTraits>;
  utils::FastPimpl<IdleQueue, kIdleQueueSize, kIdleQueueAlignment> idle_queue_;
 
  engine::TaskProcessor& fs_task_processor_;
  std::optional<std::string> user_agent_;
  rcu::Variable<std::string> proxy_;
 
  utils::SwappingSmart<const curl::easy> easy_;
  utils::PeriodicTask easy_reinit_task_;
 
  // Testsuite support
  std::shared_ptr<const TestsuiteConfig> testsuite_config_;
  rcu::Variable<std::vector<std::string>> allowed_urls_extra_;
 
  std::shared_ptr<curl::ConnectRateLimiter> connect_rate_limiter_;
 
  clients::dns::Resolver* resolver_{nullptr};
  utils::NotNull<const tracing::TracingManagerBase*> tracing_manager_;
  impl::PluginPipeline plugin_pipeline_;
};
 
}  // namespace clients::http
 
USERVER_NAMESPACE_END