server_monitor.hpp

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#pragma once
 
/// @file userver/server/handlers/server_monitor.hpp
/// @brief @copybrief server::handlers::ServerMonitor
 
#include <userver/server/handlers/http_handler_base.hpp>
#include <userver/utils/statistics/fwd.hpp>
 
USERVER_NAMESPACE_BEGIN
 
namespace server::handlers {
 
namespace impl {
enum class StatsFormat;
}
 
// clang-format off
 
/// @ingroup userver_components userver_http_handlers
///
/// @brief Handler that returns statistics data.
///
/// Additionally to the
/// @ref userver_http_handlers "common handler options" the component has
/// 'common-labels' option that should be a map of label name to label value.
/// Items of the map are added to each metric.
///
/// Default format can be set via 'format' option. Supported formats are: "prometheus", "prometheus-untyped", "graphite",
///   "json", "solomon", "pretty" and "internal". For more info see the documentation for utils::statistics::ToPrometheusFormat,
///   utils::statistics::ToPrometheusFormatUntyped, utils::statistics::ToGraphiteFormat, utils::statistics::ToJsonFormat,
///   utils::statistics::ToSolomonFormat, utils::statistics::ToPrettyFormat.
///
/// ## Static configuration example:
///
/// @snippet components/common_server_component_list_test.cpp  Sample handler server monitor component config
///
/// ## Scheme
///
/// Accepts a path arguments 'format', 'labels', 'path' and 'prefix':
/// * format - overrides default format option if it's present. Make sure that you provide
///   at least one of two formats.
/// * labels - filter out metrics without the provided labels. Parameter should
///   be a JSON dictionary in the form '{"label1":"value1", "label2":"value2"}'.
/// * path - return metrics on for the following path
/// * prefix - return metrics whose path starts from the specified prefix.
 
// clang-format on
class ServerMonitor final : public HttpHandlerBase {
 public:
  ServerMonitor(const components::ComponentConfig& config,
                const components::ComponentContext& component_context);
 
  /// @ingroup userver_component_names
  /// @brief The default name of server::handlers::ServerMonitor
  static constexpr std::string_view kName = "handler-server-monitor";
 
  std::string HandleRequestThrow(const http::HttpRequest& request,
                                 request::RequestContext&) const override;
 
  static yaml_config::Schema GetStaticConfigSchema();
 
 private:
  std::string GetResponseDataForLogging(
      const http::HttpRequest& request, request::RequestContext& context,
      const std::string& response_data) const override;
 
  utils::statistics::Storage& statistics_storage_;
 
  using CommonLabels = std::unordered_map<std::string, std::string>;
  const CommonLabels common_labels_;
  const std::optional<impl::StatsFormat> default_format_;
};
 
}  // namespace server::handlers
 
template <>
inline constexpr bool
    components::kHasValidate<server::handlers::ServerMonitor> = true;
 
USERVER_NAMESPACE_END