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nodes/broker/vp_msg_broker_node.h

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+
+#pragma once
+
+#include "../vp_node.h"
+
+namespace vp_nodes {
+    // broke for what type of data (vp_frame_target, vp_frame_face_target or others)
+    enum class vp_broke_for {
+        NORMAL,  // vp_frame_target
+        FACE,    // vp_frame_face_target
+        TEXT,    // vp_frame_text_target
+        POSE     // vp_frame_pose_target
+                 // others to extend
+    };
+
+    // base node for message brokers, 
+    // used to serialize objects (inside vp_frame_meta) to structured data and then push them to external modules like kafka, file or sockets. 
+    // note: 
+    // 1. this node works asynchronously which would not block pipeline.
+    // 2. this class can not be initialized directly.
+    class vp_msg_broker_node: public vp_node
+    {
+    private:
+        // warning if cache size greater than threshold
+        int broking_cache_warn_threshold = 50;
+        bool broking_cache_warned = false;
+
+        // ignore if cache size greater than threshold (skip directly)
+        int broking_cache_ignore_threshold = 200;
+
+        // cache frames to be broked
+        std::queue<std::shared_ptr<vp_objects::vp_frame_meta>> frames_to_broke;
+        vp_utils::vp_semaphore broking_cache_semaphore;
+
+        // broking thread
+        std::thread broking_th;
+        // broking function
+        void broking_run();
+        bool broking = true;
+    protected:
+        virtual std::shared_ptr<vp_objects::vp_meta> handle_frame_meta(std::shared_ptr<vp_objects::vp_frame_meta> meta) override final;
+        virtual std::shared_ptr<vp_objects::vp_meta> handle_control_meta(std::shared_ptr<vp_objects::vp_control_meta> meta) override final;
+
+        // serialize objects to message which SHOULD be implemented in child class.
+        virtual void format_msg(const std::shared_ptr<vp_objects::vp_frame_meta>& meta, std::string& msg) = 0;
+        // broke message to external modules which SHOULD be implemented in child class.
+        virtual void broke_msg(const std::string& msg) = 0;
+        // wait thread exits in vp_msg_broker_node
+        void stop_broking();
+        // node applied for what type of target
+        vp_broke_for broke_for = vp_broke_for::NORMAL;
+
+        // string for broke_for
+        std::map<vp_broke_for, std::string> broke_fors = {{vp_broke_for::NORMAL, "normal"}, 
+                                                        {vp_broke_for::FACE, "face"}, 
+                                                        {vp_broke_for::TEXT, "text"}, 
+                                                        {vp_broke_for::POSE, "pose"}};
+    public:
+        vp_msg_broker_node(std::string node_name, 
+                        vp_broke_for broke_for = vp_broke_for::NORMAL, 
+                        int broking_cache_warn_threshold = 50, 
+                        int broking_cache_ignore_threshold = 200);
+        ~vp_msg_broker_node();
+    };
+}