feat: add node HTTP control, engine-to-node communication, connect-input/output API

- Node control server now accepts HTTP POST /cmd for command dispatch
  (in addition to existing WebSocket control)
- Added NodeControlClient: engine sends commands to nodes via HTTP POST
- New REST endpoints:
  POST /api/graph/nodes/:id/connect-input  - connect node input to MXL flow
  POST /api/graph/nodes/:id/connect-output - create new MXL flow + connect output
  POST /api/graph/nodes/:id/disconnect-port - remove reader/writer
  POST /api/graph/nodes/:id/command - send raw command to node
- Flow IDs now use proper UUID v4 format (MXL requires standard UUIDs)
- Flow definitions use NMOS format (urn:x-nmos:format:video)
- Engine passes --mxl-domain to node processes
- User-provided node IDs (via 'id' field in POST body)
- End-to-end verified: testsrc → passthrough → new MXL output flow

libs/dmf-engine/CMakeLists.txt

@@ -3,6 +3,7 @@ add_library(dmf-engine STATIC
     src/flow_manager.cpp
     src/process_manager.cpp
     src/api_server.cpp
+    src/node_control_client.cpp
 )
 
 target_include_directories(dmf-engine PUBLIC

libs/dmf-engine/include/dmf-engine/api_server.hpp

@@ -14,7 +14,7 @@ using RequestHandler = std::function<std::string(const std::string& method, cons
 
 class ApiServer {
 public:
-    ApiServer(uint16_t port, Graph& graph, class FlowManager& flow_manager, class ProcessManager& process_manager);
+    ApiServer(uint16_t port, Graph& graph, class FlowManager& flow_manager, class ProcessManager& process_manager, class NodeControlClient& control_client, const std::string& mxl_domain = "/dev/shm/mxl");
     ~ApiServer();
 
     ApiServer(const ApiServer&) = delete;

libs/dmf-engine/include/dmf-engine/node_control_client.hpp

@@ -0,0 +1,21 @@
+#pragma once
+
+#include <string>
+#include <unordered_map>
+#include <cstdint>
+
+namespace dmf_engine {
+
+class NodeControlClient {
+public:
+    bool send_command(uint16_t port, const std::string& json_cmd);
+
+    void register_node(const std::string& node_id, uint16_t port);
+    void unregister_node(const std::string& node_id);
+    uint16_t get_port(const std::string& node_id) const;
+
+private:
+    std::unordered_map<std::string, uint16_t> node_ports_;
+};
+
+} // namespace dmf_engine

libs/dmf-engine/src/api_server.cpp

@@ -2,6 +2,7 @@
 #include <dmf-engine/graph.hpp>
 #include <dmf-engine/flow_manager.hpp>
 #include <dmf-engine/process_manager.hpp>
+#include <dmf-engine/node_control_client.hpp>
 
 #include <libwebsockets.h>
 
@@ -19,6 +20,8 @@ struct ApiServerImpl {
     Graph* graph = nullptr;
     FlowManager* flow_manager = nullptr;
     ProcessManager* process_manager = nullptr;
+    NodeControlClient* control_client = nullptr;
+    std::string mxl_domain = "/dev/shm/mxl";
     struct lws_context* context = nullptr;
 };
 
@@ -84,6 +87,7 @@ static void handle_request(const std::string& method, const std::string& path,
         auto& graph = *g_impl->graph;
         auto& fm = *g_impl->flow_manager;
         auto& pm = *g_impl->process_manager;
+        auto& cc = *g_impl->control_client;
 
         if (path == "/api/graph" && method == "GET") {
             ok(graph.serialize());
@@ -93,11 +97,15 @@ static void handle_request(const std::string& method, const std::string& path,
             } else {
                 auto type = req_body["type"].get<std::string>();
                 auto config = req_body.value("config", nlohmann::json::object());
+                if (req_body.contains("id") && req_body["id"].is_string()) {
+                    config["id"] = req_body["id"];
+                }
                 auto id = graph.add_node(type, config);
                 created({{"id", id}});
             }
         } else if (path.find("/api/graph/nodes/") == 0 && method == "DELETE") {
             auto node_id = path.substr(std::string("/api/graph/nodes/").length());
+            cc.unregister_node(node_id);
             if (graph.remove_node(node_id)) {
                 ok({{"deleted", node_id}});
             } else {
@@ -116,11 +124,54 @@ static void handle_request(const std::string& method, const std::string& path,
                 auto flow_def = fm.create_v210_flow_def(flow_id, 1920, 1080, 50, 1);
 
                 auto edge_id = graph.add_edge(from_node, from_port, to_node, to_port, flow_id, flow_def);
+
+                auto from_port_num = cc.get_port(from_node);
+                auto to_port_num = cc.get_port(to_node);
+
+                if (from_port_num > 0) {
+                    nlohmann::json cmd;
+                    cmd["cmd"] = "add_writer";
+                    cmd["port_id"] = from_port;
+                    cmd["flow_id"] = flow_id;
+                    cmd["flow_def"] = flow_def;
+                    cc.send_command(from_port_num, cmd.dump());
+                }
+
+                if (to_port_num > 0) {
+                    nlohmann::json cmd;
+                    cmd["cmd"] = "add_reader";
+                    cmd["port_id"] = to_port;
+                    cmd["flow_id"] = flow_id;
+                    cc.send_command(to_port_num, cmd.dump());
+                }
+
                 created({{"id", edge_id}, {"flow_id", flow_id}});
             }
         } else if (path.find("/api/graph/edges/") == 0 && method == "DELETE") {
             auto edge_id = path.substr(std::string("/api/graph/edges/").length());
+            auto edges = graph.get_edges();
+            const GraphEdge* edge = nullptr;
+            for (auto& e : edges) {
+                if (e.id == edge_id) { edge = &e; break; }
+            }
+
             if (graph.remove_edge(edge_id)) {
+                if (edge) {
+                    auto from_port_num = cc.get_port(edge->from_node);
+                    auto to_port_num = cc.get_port(edge->to_node);
+                    if (from_port_num > 0) {
+                        nlohmann::json cmd;
+                        cmd["cmd"] = "remove_writer";
+                        cmd["port_id"] = edge->from_port;
+                        cc.send_command(from_port_num, cmd.dump());
+                    }
+                    if (to_port_num > 0) {
+                        nlohmann::json cmd;
+                        cmd["cmd"] = "remove_reader";
+                        cmd["port_id"] = edge->to_port;
+                        cc.send_command(to_port_num, cmd.dump());
+                    }
+                }
                 ok({{"deleted", edge_id}});
             } else {
                 error_resp(404, "Edge not found: " + edge_id);
@@ -129,15 +180,141 @@ static void handle_request(const std::string& method, const std::string& path,
             auto nodes = graph.get_nodes();
             uint16_t port = 9100;
             for (auto& node : nodes) {
-                pm.start_node(const_cast<GraphNode&>(node), "/dev/shm/mxl", port++);
+                pm.start_node(const_cast<GraphNode&>(node), g_impl->mxl_domain, port);
+                cc.register_node(node.id, port);
+                port++;
             }
+
+            for (auto& edge : graph.get_edges()) {
+                auto from_port_num = cc.get_port(edge.from_node);
+                auto to_port_num = cc.get_port(edge.to_node);
+
+                if (from_port_num > 0) {
+                    nlohmann::json cmd;
+                    cmd["cmd"] = "add_writer";
+                    cmd["port_id"] = edge.from_port;
+                    cmd["flow_id"] = edge.flow_id;
+                    cmd["flow_def"] = edge.flow_def;
+                    cc.send_command(from_port_num, cmd.dump());
+                }
+
+                if (to_port_num > 0) {
+                    nlohmann::json cmd;
+                    cmd["cmd"] = "add_reader";
+                    cmd["port_id"] = edge.to_port;
+                    cmd["flow_id"] = edge.flow_id;
+                    cc.send_command(to_port_num, cmd.dump());
+                }
+            }
+
             ok({{"status", "started"}});
         } else if (path == "/api/graph/stop" && method == "POST") {
             auto nodes = graph.get_nodes();
             for (auto& node : nodes) {
+                cc.unregister_node(node.id);
                 pm.stop_node(const_cast<GraphNode&>(node));
             }
             ok({{"status", "stopped"}});
+        } else if (path.find("/api/graph/nodes/") == 0 && path.find("/connect-input") != std::string::npos && method == "POST") {
+            auto prefix = std::string("/api/graph/nodes/");
+            auto suffix_start = path.find("/connect-input");
+            auto node_id = path.substr(prefix.length(), suffix_start - prefix.length());
+
+            if (!req_body.contains("flow_id") || !req_body.contains("port_id")) {
+                error_resp(400, "Missing flow_id/port_id");
+                return;
+            }
+
+            auto port_num = cc.get_port(node_id);
+            if (port_num == 0) {
+                error_resp(404, "Node not running or not found: " + node_id);
+                return;
+            }
+
+            nlohmann::json cmd;
+            cmd["cmd"] = "add_reader";
+            cmd["port_id"] = req_body["port_id"].get<std::string>();
+            cmd["flow_id"] = req_body["flow_id"].get<std::string>();
+
+            if (cc.send_command(port_num, cmd.dump())) {
+                ok({{"node_id", node_id}, {"connected_input", req_body["port_id"]}, {"flow_id", req_body["flow_id"]}});
+            } else {
+                error_resp(500, "Failed to send command to node");
+            }
+        } else if (path.find("/api/graph/nodes/") == 0 && path.find("/connect-output") != std::string::npos && method == "POST") {
+            auto prefix = std::string("/api/graph/nodes/");
+            auto suffix_start = path.find("/connect-output");
+            auto node_id = path.substr(prefix.length(), suffix_start - prefix.length());
+
+            auto port_id = req_body.value("port_id", "video_out");
+
+            auto port_num = cc.get_port(node_id);
+            if (port_num == 0) {
+                error_resp(404, "Node not running or not found: " + node_id);
+                return;
+            }
+
+            auto flow_id = fm.create_flow_id();
+            auto flow_def = fm.create_v210_flow_def(flow_id, 1920, 1080, 50, 1);
+
+            nlohmann::json cmd;
+            cmd["cmd"] = "add_writer";
+            cmd["port_id"] = port_id;
+            cmd["flow_id"] = flow_id;
+            cmd["flow_def"] = flow_def;
+
+            if (cc.send_command(port_num, cmd.dump())) {
+                ok({{"node_id", node_id}, {"connected_output", port_id}, {"flow_id", flow_id}});
+            } else {
+                error_resp(500, "Failed to send command to node");
+            }
+        } else if (path.find("/api/graph/nodes/") == 0 && path.find("/disconnect-port") != std::string::npos && method == "POST") {
+            auto prefix = std::string("/api/graph/nodes/");
+            auto suffix_start = path.find("/disconnect-port");
+            auto node_id = path.substr(prefix.length(), suffix_start - prefix.length());
+
+            if (!req_body.contains("port_id")) {
+                error_resp(400, "Missing port_id");
+                return;
+            }
+
+            auto port_id = req_body["port_id"].get<std::string>();
+            auto port_num = cc.get_port(node_id);
+            if (port_num == 0) {
+                error_resp(404, "Node not running or not found: " + node_id);
+                return;
+            }
+
+            auto direction = req_body.value("direction", "input");
+            nlohmann::json cmd;
+            if (direction == "output") {
+                cmd["cmd"] = "remove_writer";
+            } else {
+                cmd["cmd"] = "remove_reader";
+            }
+            cmd["port_id"] = port_id;
+
+            if (cc.send_command(port_num, cmd.dump())) {
+                ok({{"node_id", node_id}, {"disconnected", port_id}});
+            } else {
+                error_resp(500, "Failed to send command to node");
+            }
+        } else if (path.find("/api/graph/nodes/") == 0 && path.find("/command") != std::string::npos && method == "POST") {
+            auto prefix = std::string("/api/graph/nodes/");
+            auto suffix_start = path.find("/command");
+            auto node_id = path.substr(prefix.length(), suffix_start - prefix.length());
+
+            auto port_num = cc.get_port(node_id);
+            if (port_num == 0) {
+                error_resp(404, "Node not running or not found: " + node_id);
+                return;
+            }
+
+            if (cc.send_command(port_num, req_body.dump())) {
+                ok({{"node_id", node_id}, {"sent", true}});
+            } else {
+                error_resp(500, "Failed to send command to node");
+            }
         } else {
             error_resp(404, "Not found: " + method + " " + path);
         }
@@ -207,13 +384,15 @@ static const struct lws_protocols protocols[] = {
     {nullptr, nullptr, 0, 0},
 };
 
-ApiServer::ApiServer(uint16_t port, Graph& graph, FlowManager& flow_manager, ProcessManager& process_manager)
+ApiServer::ApiServer(uint16_t port, Graph& graph, FlowManager& flow_manager, ProcessManager& process_manager, NodeControlClient& control_client, const std::string& mxl_domain)
     : impl_(std::make_unique<Impl>()) {
     impl_->data = std::make_unique<ApiServerImpl>();
     impl_->data->port = port;
     impl_->data->graph = &graph;
     impl_->data->flow_manager = &flow_manager;
     impl_->data->process_manager = &process_manager;
+    impl_->data->control_client = &control_client;
+    impl_->data->mxl_domain = mxl_domain;
 
     g_impl = impl_->data.get();
 

libs/dmf-engine/src/flow_manager.cpp

@@ -9,18 +9,29 @@
 
 namespace dmf_engine {
 
-FlowManager::FlowManager() {
-    std::random_device rd;
-    flow_counter_ = static_cast<int>(rd());
-}
+FlowManager::FlowManager() = default;
 
 FlowId FlowManager::create_flow_id() {
+    std::random_device rd;
+    std::mt19937 gen(rd());
+    std::uniform_int_distribution<uint32_t> dist(0, 0xFFFFFFFF);
+
+    uint32_t a = dist(gen);
+    uint16_t b = dist(gen) & 0xFFFF;
+    uint16_t c = (dist(gen) & 0x0FFF) | 0x4000;
+    uint16_t d = (dist(gen) & 0x3FFF) | 0x8000;
+    uint32_t e1 = dist(gen);
+    uint16_t e2 = dist(gen) & 0xFFFF;
+
     std::stringstream ss;
-    ss << std::hex << (++flow_counter_);
+    ss << std::hex << std::setfill('0');
+    ss << std::setw(8) << a << "-";
+    ss << std::setw(4) << b << "-";
+    ss << std::setw(4) << c << "-";
+    ss << std::setw(4) << d << "-";
+    ss << std::setw(8) << e1 << std::setw(4) << e2;
+
     auto id = ss.str();
-    while (id.length() < 8) {
-        id = "0" + id;
-    }
     spdlog::info("FlowManager: created flow ID: {}", id);
     return id;
 }
@@ -30,17 +41,22 @@ nlohmann::json FlowManager::create_v210_flow_def(const FlowId& flow_id, int widt
 
     nlohmann::json flow_def;
     flow_def["id"] = flow_id;
-    flow_def["version"] = "v1.0";
     flow_def["label"] = "DMF Studio Flow " + flow_id;
     flow_def["description"] = "Auto-generated V210 flow";
+    flow_def["format"] = "urn:x-nmos:format:video";
     flow_def["grain_rate"] = {{"numerator", fps_numerator}, {"denominator", fps_denominator}};
-    flow_def["format"] = "video/v210";
-    flow_def["width"] = width;
-    flow_def["height"] = height;
-    flow_def["grain_size"] = grain_size;
-    flow_def["components"] = nlohmann::json::array();
+    flow_def["media_type"] = "video/v210";
+    flow_def["frame_width"] = width;
+    flow_def["frame_height"] = height;
+    flow_def["interlace_mode"] = "progressive";
+    flow_def["colorspace"] = "BT709";
+    flow_def["components"] = nlohmann::json::array({
+        {{"name", "Y"}, {"width", width}, {"height", height}, {"bit_depth", 10}},
+        {{"name", "Cb"}, {"width", width / 2}, {"height", height}, {"bit_depth", 10}},
+        {{"name", "Cr"}, {"width", width / 2}, {"height", height}, {"bit_depth", 10}},
+    });
     flow_def["tags"] = nlohmann::json::object();
-    flow_def["tags"]["grouphint"] = nlohmann::json::array({"DMF Studio:Video"});
+    flow_def["tags"]["urn:x-nmos:tag:grouphint/v1.0"] = nlohmann::json::array({"DMF Studio:Video"});
 
     return flow_def;
 }

libs/dmf-engine/src/node_control_client.cpp

@@ -0,0 +1,88 @@
+#include <dmf-engine/node_control_client.hpp>
+
+#include <spdlog/spdlog.h>
+
+#include <arpa/inet.h>
+#include <cstring>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#include <sstream>
+
+namespace dmf_engine {
+
+void NodeControlClient::register_node(const std::string& node_id, uint16_t port) {
+    node_ports_[node_id] = port;
+    spdlog::info("NodeControlClient: registered node '{}' on port {}", node_id, port);
+}
+
+void NodeControlClient::unregister_node(const std::string& node_id) {
+    node_ports_.erase(node_id);
+}
+
+uint16_t NodeControlClient::get_port(const std::string& node_id) const {
+    auto it = node_ports_.find(node_id);
+    return it != node_ports_.end() ? it->second : 0;
+}
+
+bool NodeControlClient::send_command(uint16_t port, const std::string& json_cmd) {
+    int fd = socket(AF_INET, SOCK_STREAM, 0);
+    if (fd < 0) {
+        spdlog::error("NodeControlClient: socket() failed: {}", strerror(errno));
+        return false;
+    }
+
+    struct timeval tv;
+    tv.tv_sec = 2;
+    tv.tv_usec = 0;
+    setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
+    setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
+
+    struct sockaddr_in addr;
+    std::memset(&addr, 0, sizeof(addr));
+    addr.sin_family = AF_INET;
+    addr.sin_port = htons(port);
+    inet_pton(AF_INET, "127.0.0.1", &addr.sin_addr);
+
+    if (connect(fd, reinterpret_cast<struct sockaddr*>(&addr), sizeof(addr)) < 0) {
+        spdlog::error("NodeControlClient: connect to port {} failed: {}", port, strerror(errno));
+        close(fd);
+        return false;
+    }
+
+    std::ostringstream req;
+    req << "POST /cmd HTTP/1.1\r\n"
+        << "Host: 127.0.0.1:" << port << "\r\n"
+        << "Content-Type: application/json\r\n"
+        << "Content-Length: " << json_cmd.size() << "\r\n"
+        << "Connection: close\r\n"
+        << "\r\n"
+        << json_cmd;
+
+    auto request = req.str();
+    auto sent = write(fd, request.data(), request.size());
+    if (sent != static_cast<ssize_t>(request.size())) {
+        spdlog::error("NodeControlClient: write failed on port {}", port);
+        close(fd);
+        return false;
+    }
+
+    char resp_buf[4096] = {};
+    auto n = read(fd, resp_buf, sizeof(resp_buf) - 1);
+    close(fd);
+
+    if (n <= 0) {
+        spdlog::error("NodeControlClient: read failed on port {}", port);
+        return false;
+    }
+
+    std::string resp(resp_buf, n);
+    bool ok = resp.find("200 OK") != std::string::npos || resp.find("201 Created") != std::string::npos;
+    if (!ok) {
+        spdlog::warn("NodeControlClient: command failed on port {}: {}", port, resp.substr(0, 100));
+    }
+    return ok;
+}
+
+} // namespace dmf_engine