Line data    Source code

       1             : #pragma once
       2             : 
       3             : #include <functional>
       4             : #include <string>
       5             : 
       6             : #include "envoy/common/optref.h"
       7             : #include "envoy/common/pure.h"
       8             : #include "envoy/http/header_map.h"
       9             : 
      10             : #include "absl/strings/string_view.h"
      11             : #include "absl/types/optional.h"
      12             : 
      13             : namespace Envoy {
      14             : namespace Tracing {
      15             : 
      16             : class TraceContextHandler;
      17             : 
      18             : /**
      19             :  * Protocol-independent abstraction for traceable stream. It hides the differences between different
      20             :  * protocol and provides tracer driver with common methods for obtaining and setting the tracing
      21             :  * context.
      22             :  */
      23             : class TraceContext {
      24             : public:
      25         251 :   virtual ~TraceContext() = default;
      26             : 
      27             :   using IterateCallback = std::function<bool(absl::string_view key, absl::string_view val)>;
      28             : 
      29             :   /**
      30             :    * Get context protocol.
      31             :    *
      32             :    * @return A string view representing the protocol of the traceable stream behind the context.
      33             :    */
      34             :   virtual absl::string_view protocol() const PURE;
      35             : 
      36             :   /**
      37             :    * Get context host.
      38             :    *
      39             :    * @return The host of traceable stream. It typically should be domain, VIP, or service name that
      40             :    * used to represents target service instances.
      41             :    */
      42             :   virtual absl::string_view host() const PURE;
      43             : 
      44             :   /**
      45             :    * Get context path.
      46             :    *
      47             :    * @return The path of traceable stream. The content and meaning of path are determined by
      48             :    * specific protocol itself.
      49             :    */
      50             :   virtual absl::string_view path() const PURE;
      51             : 
      52             :   /**
      53             :    * Get context method.
      54             :    *
      55             :    * @return The method of traceable stream. The content and meaning of method are determined by
      56             :    * specific protocol itself.
      57             :    */
      58             :   virtual absl::string_view method() const PURE;
      59             : 
      60             :   /**
      61             :    * Iterate over all context entry.
      62             :    *
      63             :    * @param callback supplies the iteration callback.
      64             :    */
      65             :   virtual void forEach(IterateCallback callback) const PURE;
      66             : 
      67             :   /**
      68             :    * Get tracing context value by key.
      69             :    *
      70             :    * @param key The context key of string view type.
      71             :    * @return The optional context value of string_view type.
      72             :    */
      73             :   virtual absl::optional<absl::string_view> get(absl::string_view key) const PURE;
      74             : 
      75             :   /**
      76             :    * Set new tracing context key/value pair.
      77             :    *
      78             :    * @param key The context key of string view type.
      79             :    * @param val The context value of string view type.
      80             :    */
      81             :   virtual void set(absl::string_view key, absl::string_view val) PURE;
      82             : 
      83             :   /**
      84             :    * Removes the following key and its associated values from the tracing
      85             :    * context.
      86             :    *
      87             :    * @param key The key to remove if it exists.
      88             :    */
      89             :   virtual void remove(absl::string_view key) PURE;
      90             : 
      91             : private:
      92             :   friend class TraceContextHandler;
      93             : 
      94             :   /**
      95             :    * Optional HTTP request headers map. This is valid for HTTP protocol or any protocol that
      96             :    * that provides HTTP request headers.
      97             :    */
      98           0 :   virtual OptRef<Http::RequestHeaderMap> requestHeaders() { return {}; };
      99           0 :   virtual OptRef<const Http::RequestHeaderMap> requestHeaders() const { return {}; };
     100             : };
     101             : 
     102             : } // namespace Tracing
     103             : } // namespace Envoy