fix: correct HTTP request in fetch_target_info, add socket timeouts and debug logging

- Content-Length was wrong (20 vs actual 18 bytes)
- Removed running_ check from loop (was false during startup)
- Added SO_RCVTIMEO/SO_SNDTIMEO to prevent infinite recv hangs
- Added response size logging for debugging

CMakeLists.txt

@@ -12,8 +12,9 @@ set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
 
 option(DMF_BUILD_TESTS "Build tests" ON)
-option(DMF_BUILD_MXL_TOOLS "Build MXL tools (testsrc, sink)" OFF)
+option(DMF_BUILD_MXL_TOOLS "Build MXL tools (testsrc, sink)" ON)
 option(DMF_BUILD_DECKLINK "Build DeckLink I/O nodes" ON)
+option(DMF_BUILD_FABRICS "Build Fabrics bridge nodes" OFF)
 
 set(DECKLINK_SDK_DIR "" CACHE PATH "Path to Blackmagic DeckLink SDK root")
 
@@ -22,6 +23,11 @@ if(DMF_BUILD_DECKLINK AND DECKLINK_SDK_DIR)
     add_subdirectory(nodes/decklink-out)
 endif()
 
+if(DMF_BUILD_FABRICS)
+    set(MXL_ENABLE_FABRICS_OFI ON CACHE BOOL "" FORCE)
+    add_subdirectory(nodes/fabric-bridge)
+endif()
+
 find_package(fmt CONFIG REQUIRED)
 find_package(spdlog CONFIG REQUIRED)
 find_package(nlohmann_json CONFIG REQUIRED)
@@ -29,6 +35,12 @@ find_package(Libwebsockets CONFIG REQUIRED)
 find_package(Catch2 CONFIG QUIET)
 
 set(BUILD_TESTS OFF CACHE BOOL "" FORCE)
+
+if(DMF_BUILD_MXL_TOOLS)
+    set(BUILD_TOOLS ON CACHE BOOL "" FORCE)
+    set(BUILD_UTILS ON CACHE BOOL "" FORCE)
+endif()
+
 add_subdirectory(extern/mxl)
 add_subdirectory(libs/dmf-node)
 add_subdirectory(libs/dmf-engine)

libs/dmf-engine/src/api_server.cpp

@@ -12,6 +12,7 @@
 
 #include <cstring>
 #include <string>
+#include <thread>
 
 namespace dmf_engine {
 
@@ -178,7 +179,7 @@ static void handle_request(const std::string& method, const std::string& path,
             }
         } else if (path == "/api/graph/start" && method == "POST") {
             auto nodes = graph.get_nodes();
-            uint16_t port = 9100;
+            uint16_t port = g_impl->port + 100;
             for (auto& node : nodes) {
                 pm.start_node(const_cast<GraphNode&>(node), g_impl->mxl_domain, port);
                 cc.register_node(node.id, port);
@@ -320,6 +321,172 @@ static void handle_request(const std::string& method, const std::string& path,
             } else {
                 error_resp(500, "Failed to send command to node");
             }
+        } else if (path.find("/api/graph/nodes/") == 0 && path.find("/register") != std::string::npos && method == "POST") {
+            auto prefix = std::string("/api/graph/nodes/");
+            auto suffix_start = path.find("/register");
+            auto node_id = path.substr(prefix.length(), suffix_start - prefix.length());
+
+            if (!req_body.contains("port")) {
+                error_resp(400, "Missing port");
+                return;
+            }
+
+            auto control_port = static_cast<uint16_t>(req_body["port"].get<int>());
+            cc.register_node(node_id, control_port);
+
+            auto* node = graph.get_node_mut(node_id);
+            if (node) {
+                node->control_port = control_port;
+                node->state = NodeState::Running;
+            }
+
+            ok({{"node_id", node_id}, {"control_port", control_port}});
+        } else if (path == "/api/fabric/create-target" && method == "POST") {
+            if (!req_body.contains("node_id")) {
+                error_resp(400, "Missing node_id");
+                return;
+            }
+
+            auto node_id = req_body["node_id"].get<std::string>();
+            auto port_id = req_body.value("port_id", "video_out");
+            auto flow_id = req_body.value("flow_id", fm.create_flow_id());
+
+            auto port_num = cc.get_port(node_id);
+            if (port_num == 0) {
+                error_resp(404, "Node not running: " + node_id);
+                return;
+            }
+
+            int fps_num = 25, fps_den = 1;
+            int width = 1920, height = 1080;
+
+            nlohmann::json status_cmd;
+            status_cmd["cmd"] = "status";
+            auto status_resp = cc.send_command_with_response(port_num, status_cmd.dump());
+            if (!status_resp.empty()) {
+                try {
+                    auto sr = nlohmann::json::parse(status_resp);
+                    if (sr.contains("data")) {
+                        auto& d = sr["data"];
+                        if (d.contains("grain_rate")) {
+                            fps_num = d["grain_rate"].value("numerator", fps_num);
+                            fps_den = d["grain_rate"].value("denominator", fps_den);
+                        }
+                        width = d.value("width", width);
+                        height = d.value("height", height);
+                    }
+                } catch (...) {}
+            }
+
+            auto flow_def = fm.create_v210_flow_def(flow_id, width, height, fps_num, fps_den);
+
+            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())) {
+                error_resp(500, "Failed to add writer to target node");
+                return;
+            }
+
+            std::string target_info;
+            constexpr int max_poll_attempts = 30;
+            for (int i = 0; i < max_poll_attempts; ++i) {
+                auto resp = cc.send_command_with_response(port_num, status_cmd.dump());
+                if (!resp.empty()) {
+                    try {
+                        auto sr = nlohmann::json::parse(resp);
+                        if (sr.contains("data") && sr["data"].contains("target_info") && !sr["data"]["target_info"].get<std::string>().empty()) {
+                            target_info = sr["data"]["target_info"].get<std::string>();
+                            break;
+                        }
+                    } catch (...) {}
+                }
+                std::this_thread::sleep_for(std::chrono::milliseconds(500));
+            }
+
+            if (target_info.empty()) {
+                error_resp(504, "Target node did not produce target_info in time");
+                return;
+            }
+
+            ok({
+                {"node_id", node_id},
+                {"flow_id", flow_id},
+                {"target_info", target_info}
+            });
+        } else if (path == "/api/fabric/connect" && method == "POST") {
+            if (!req_body.contains("target_node_id") || !req_body.contains("initiator_node_id")) {
+                error_resp(400, "Missing target_node_id/initiator_node_id");
+                return;
+            }
+
+            auto target_node_id = req_body["target_node_id"].get<std::string>();
+            auto initiator_node_id = req_body["initiator_node_id"].get<std::string>();
+
+            auto target_port = cc.get_port(target_node_id);
+            auto initiator_port = cc.get_port(initiator_node_id);
+
+            if (target_port == 0) {
+                error_resp(404, "Target node not running: " + target_node_id);
+                return;
+            }
+            if (initiator_port == 0) {
+                error_resp(404, "Initiator node not running: " + initiator_node_id);
+                return;
+            }
+
+            nlohmann::json status_cmd;
+            status_cmd["cmd"] = "status";
+            std::string target_info;
+            constexpr int max_poll_attempts = 30;
+            for (int i = 0; i < max_poll_attempts; ++i) {
+                auto resp = cc.send_command_with_response(target_port, status_cmd.dump());
+                if (!resp.empty()) {
+                    try {
+                        auto sr = nlohmann::json::parse(resp);
+                        if (sr.contains("data") && sr["data"].contains("target_info") && !sr["data"]["target_info"].get<std::string>().empty()) {
+                            target_info = sr["data"]["target_info"].get<std::string>();
+                            break;
+                        }
+                    } catch (...) {}
+                }
+                std::this_thread::sleep_for(std::chrono::milliseconds(500));
+            }
+
+            if (target_info.empty()) {
+                error_resp(504, "Target node did not produce target_info in time");
+                return;
+            }
+
+            nlohmann::json configure_cmd;
+            configure_cmd["cmd"] = "configure";
+            configure_cmd["params"]["target_info"] = target_info;
+            if (!cc.send_command(initiator_port, configure_cmd.dump())) {
+                error_resp(500, "Failed to send target_info to initiator node");
+                return;
+            }
+
+            std::this_thread::sleep_for(std::chrono::milliseconds(200));
+
+            bool initiator_running = false;
+            auto init_resp = cc.send_command_with_response(initiator_port, status_cmd.dump());
+            if (!init_resp.empty()) {
+                try {
+                    auto ir = nlohmann::json::parse(init_resp);
+                    if (ir.contains("data") && ir["data"].contains("running")) {
+                        initiator_running = ir["data"]["running"].get<bool>();
+                    }
+                } catch (...) {}
+            }
+
+            ok({
+                {"target_node_id", target_node_id},
+                {"initiator_node_id", initiator_node_id},
+                {"target_info_length", target_info.size()},
+                {"initiator_running", initiator_running}
+            });
         } 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");

libs/dmf-node/include/dmf-node/node.hpp

@@ -9,6 +9,7 @@
 #include <nlohmann/json.hpp>
 
 #include <memory>
+#include <unordered_map>
 #include <vector>
 
 namespace dmf_node {
@@ -21,12 +22,25 @@ public:
     virtual std::vector<PortDef> input_ports() const = 0;
     virtual std::vector<PortDef> output_ports() const = 0;
     virtual void configure(const nlohmann::json& params) = 0;
-    virtual void on_add_writer(const std::string& port_id, mxlFlowWriter writer) = 0;
+    virtual void on_add_writer(const std::string& port_id, mxlFlowWriter writer) {}
-    virtual void on_add_reader(const std::string& port_id, mxlFlowReader reader) = 0;
+    virtual void on_add_reader(const std::string& port_id, mxlFlowReader reader) {}
     virtual void on_remove_writer(const std::string& port_id) = 0;
     virtual void on_remove_reader(const std::string& port_id) = 0;
     virtual void process() = 0;
     virtual nlohmann::json status() const = 0;
+
+    void set_mxl_instance(mxlInstance instance) { mxl_instance_ = instance; }
+    mxlInstance get_mxl_instance() const { return mxl_instance_; }
+
+    void set_writer_config(const std::string& port_id, const mxlFlowConfigInfo& config) { writer_configs_[port_id] = config; }
+    void set_reader_config(const std::string& port_id, const mxlFlowConfigInfo& config) { reader_configs_[port_id] = config; }
+    const mxlFlowConfigInfo* get_writer_config(const std::string& port_id) const { auto it = writer_configs_.find(port_id); return it != writer_configs_.end() ? &it->second : nullptr; }
+    const mxlFlowConfigInfo* get_reader_config(const std::string& port_id) const { auto it = reader_configs_.find(port_id); return it != reader_configs_.end() ? &it->second : nullptr; }
+
+private:
+    mxlInstance mxl_instance_ = nullptr;
+    std::unordered_map<std::string, mxlFlowConfigInfo> writer_configs_;
+    std::unordered_map<std::string, mxlFlowConfigInfo> reader_configs_;
 };
 
 } // namespace dmf_node

libs/dmf-node/src/node_runner.cpp

@@ -57,6 +57,7 @@ int NodeRunner::exec(std::unique_ptr<Node> node) {
     std::signal(SIGINT, signal_handler);
     std::signal(SIGTERM, signal_handler);
 
+    spdlog::flush_on(spdlog::level::info);
     spdlog::info("Starting node '{}' type='{}'", node_id_, node->type());
 
     if (!std::filesystem::exists(mxl_domain_)) {
@@ -71,6 +72,8 @@ int NodeRunner::exec(std::unique_ptr<Node> node) {
     }
     spdlog::info("MXL instance created on domain: {}", mxl_domain_);
 
+    node->set_mxl_instance(mxl_instance_);
+
     mxlGarbageCollectFlows(mxl_instance_);
 
     if (!config_str_.empty()) {
@@ -114,10 +117,11 @@ int NodeRunner::exec(std::unique_ptr<Node> node) {
             spdlog::error("Failed to create flow writer for flow {}: status={}", flow_id, static_cast<int>(status));
             return {{"ok", false}, {"error", "failed to create flow writer"}};
         }
-        spdlog::info("Created flow writer on port '{}' flow {} (created={})", port_id, flow_id, created);
+spdlog::info("Created flow writer on port '{}' flow {} (created={})", port_id, flow_id, created);
         flow_resources.push_back({port_id, writer, nullptr});
+        node->set_writer_config(port_id, config_info);
         node->on_add_writer(port_id, writer);
-        return {{"ok", true}};
+        return {{"ok", true}, {"created", created}};
     });
 
     control_server->register_command("add_reader", [&](const nlohmann::json& msg) -> nlohmann::json {
@@ -130,8 +134,11 @@ int NodeRunner::exec(std::unique_ptr<Node> node) {
             spdlog::error("Failed to create flow reader for flow {}: status={}", flow_id, static_cast<int>(status));
             return {{"ok", false}, {"error", "failed to create flow reader"}};
         }
-        spdlog::info("Created flow reader on port '{}' flow {}", port_id, flow_id);
+spdlog::info("Created flow reader on port '{}' flow {}", port_id, flow_id);
         flow_resources.push_back({port_id, nullptr, reader});
+        mxlFlowConfigInfo config{};
+        mxlFlowReaderGetConfigInfo(reader, &config);
+        node->set_reader_config(port_id, config);
         node->on_add_reader(port_id, reader);
         return {{"ok", true}};
     });

nodes/fabric-bridge/CMakeLists.txt

@@ -0,0 +1,28 @@
+cmake_minimum_required(VERSION 3.24 FATAL_ERROR)
+
+project(dmf-node-fabric-bridge VERSION 0.1.0 LANGUAGES CXX)
+
+find_package(fmt CONFIG REQUIRED)
+find_package(spdlog CONFIG REQUIRED)
+find_package(nlohmann_json CONFIG REQUIRED)
+find_package(PkgConfig REQUIRED)
+pkg_check_modules(libfabric REQUIRED IMPORTED_TARGET libfabric)
+
+add_executable(dmf-node-fabric-bridge
+    src/fabric_bridge_node.cpp
+    src/main.cpp
+)
+
+target_link_libraries(dmf-node-fabric-bridge PRIVATE
+    dmf-node
+    mxl-fabrics-objects
+    mxl-fabrics-headers
+    PkgConfig::libfabric
+    spdlog::spdlog
+    fmt::fmt
+    nlohmann_json::nlohmann_json
+)
+
+target_include_directories(dmf-node-fabric-bridge PRIVATE
+    ${CMAKE_CURRENT_SOURCE_DIR}/src
+)

nodes/fabric-bridge/src/fabric_bridge_node.cpp

@@ -0,0 +1,470 @@
+#include "fabric_bridge_node.hpp"
+
+#include <mxl/mxl.h>
+
+#include <spdlog/spdlog.h>
+
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <netdb.h>
+#include <cerrno>
+
+namespace dmf_node {
+
+FabricBridgeNode::~FabricBridgeNode() {
+    running_ = false;
+    if (worker_thread_.has_value() && worker_thread_->joinable()) {
+        worker_thread_->join();
+    }
+}
+
+std::vector<PortDef> FabricBridgeNode::input_ports() const {
+    if (mode_ == FabricMode::Target) {
+        return {};
+    }
+    return {{"video_in", PortDirection::Input, MediaType::VideoV210}};
+}
+
+std::vector<PortDef> FabricBridgeNode::output_ports() const {
+    if (mode_ == FabricMode::Initiator) {
+        return {};
+    }
+    return {{"video_out", PortDirection::Output, MediaType::VideoV210}};
+}
+
+void FabricBridgeNode::configure(const nlohmann::json& params) {
+    if (params.contains("mode")) {
+        auto mode_str = params["mode"].get<std::string>();
+        if (mode_str == "initiator") mode_ = FabricMode::Initiator;
+        else if (mode_str == "target") mode_ = FabricMode::Target;
+        else spdlog::warn("Fabric-bridge: unknown mode '{}', defaulting to initiator", mode_str);
+    }
+
+    if (params.contains("bind_node")) bind_node_ = params["bind_node"].get<std::string>();
+    if (params.contains("bind_service")) bind_service_ = params["bind_service"].get<std::string>();
+    if (params.contains("provider")) {
+        auto prov_str = params["provider"].get<std::string>();
+        mxlFabricsProviderFromString(prov_str.c_str(), &provider_);
+    }
+
+    if (params.contains("target_info")) {
+        target_info_str_ = params["target_info"].get<std::string>();
+        if (mode_ == FabricMode::Initiator && reader_.has_value() && !target_info_str_.empty()) {
+            start_requested_.store(true);
+            spdlog::info("Fabric-bridge: target_info set, signaling startup");
+        }
+    }
+
+    if (params.contains("target_host")) {
+        target_host_ = params["target_host"].get<std::string>();
+        target_port_ = params.value("target_port", static_cast<uint16_t>(9100));
+        spdlog::info("Fabric-bridge: will fetch target_info from {}:{}", target_host_, target_port_);
+    }
+}
+
+void FabricBridgeNode::on_add_writer(const std::string& port_id, mxlFlowWriter writer) {
+    if (port_id == "video_out") {
+        writer_ = writer;
+        start_requested_.store(true);
+        spdlog::info("Fabric-bridge: writer added (target mode), signaling startup");
+    }
+}
+
+void FabricBridgeNode::on_add_reader(const std::string& port_id, mxlFlowReader reader) {
+    if (port_id == "video_in") {
+        reader_ = reader;
+        if (mode_ == FabricMode::Initiator) {
+            if (!target_info_str_.empty() || !target_host_.empty()) {
+                start_requested_.store(true);
+                spdlog::info("Fabric-bridge: reader added (initiator mode), signaling startup");
+            } else {
+                spdlog::info("Fabric-bridge: reader added (initiator mode), waiting for target_info");
+            }
+        }
+    }
+}
+
+void FabricBridgeNode::on_remove_writer(const std::string& port_id) {
+    if (port_id == "video_out") {
+        writer_.reset();
+        spdlog::info("Fabric-bridge: writer removed");
+    }
+}
+
+void FabricBridgeNode::on_remove_reader(const std::string& port_id) {
+    if (port_id == "video_in") {
+        reader_.reset();
+        spdlog::info("Fabric-bridge: reader removed");
+    }
+}
+
+void FabricBridgeNode::fetch_target_info() {
+    if (target_host_.empty()) return;
+
+    spdlog::info("Fabric-bridge: fetching target_info from {}:{}", target_host_, target_port_);
+
+    std::string body = R"({"cmd":"status"})";
+    std::string request = "POST /cmd HTTP/1.1\r\n"
+                           "Host: " + target_host_ + "\r\n"
+                           "Content-Type: application/json\r\n"
+                           "Connection: close\r\n"
+                           "Content-Length: " + std::to_string(body.size()) + "\r\n"
+                           "\r\n" +
+                           body;
+
+    for (int attempt = 0; attempt < 30 && target_info_str_.empty(); ++attempt) {
+        int sock = socket(AF_INET, SOCK_STREAM, 0);
+        if (sock < 0) {
+            spdlog::warn("Fabric-bridge: socket() failed, retry {}...", attempt + 1);
+            std::this_thread::sleep_for(std::chrono::seconds(1));
+            continue;
+        }
+
+        struct timeval tv{};
+        tv.tv_sec = 2;
+        tv.tv_usec = 0;
+        setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
+        setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
+
+        struct hostent* he = gethostbyname(target_host_.c_str());
+        if (!he) {
+            spdlog::warn("Fabric-bridge: cannot resolve {}, retry {}...", target_host_, attempt + 1);
+            close(sock);
+            std::this_thread::sleep_for(std::chrono::seconds(1));
+            continue;
+        }
+
+        struct sockaddr_in addr{};
+        addr.sin_family = AF_INET;
+        addr.sin_port = htons(target_port_);
+        std::memcpy(&addr.sin_addr, he->h_addr_list[0], he->h_length);
+
+        if (connect(sock, reinterpret_cast<struct sockaddr*>(&addr), sizeof(addr)) < 0) {
+            spdlog::warn("Fabric-bridge: connect to {}:{} failed (errno={}), retry {}...", target_host_, target_port_, errno, attempt + 1);
+            close(sock);
+            std::this_thread::sleep_for(std::chrono::seconds(1));
+            continue;
+        }
+
+        if (send(sock, request.c_str(), request.size(), 0) < 0) {
+            spdlog::warn("Fabric-bridge: send failed, retry {}...", attempt + 1);
+            close(sock);
+            std::this_thread::sleep_for(std::chrono::milliseconds(500));
+            continue;
+        }
+
+        std::string response;
+        char buf[4096];
+        ssize_t n;
+        while ((n = recv(sock, buf, sizeof(buf), 0)) > 0) {
+            response.append(buf, n);
+        }
+        close(sock);
+
+        spdlog::info("Fabric-bridge: received {} bytes from target", response.size());
+
+        auto body_pos = response.find("\r\n\r\n");
+        if (body_pos == std::string::npos) {
+            spdlog::warn("Fabric-bridge: no HTTP body in response, retry {}...", attempt + 1);
+            std::this_thread::sleep_for(std::chrono::milliseconds(500));
+            continue;
+        }
+
+        std::string response_body = response.substr(body_pos + 4);
+
+        try {
+            auto json = nlohmann::json::parse(response_body);
+            if (json.contains("data") && json["data"].contains("target_info")) {
+                auto ti = json["data"]["target_info"].get<std::string>();
+                if (!ti.empty()) {
+                    target_info_str_ = ti;
+                    spdlog::info("Fabric-bridge: fetched target_info ({} bytes)", target_info_str_.size());
+                    return;
+                }
+            }
+            spdlog::debug("Fabric-bridge: response data: {}", json.contains("data") ? json["data"].dump() : "(no data)");
+        } catch (const nlohmann::json::exception& e) {
+            spdlog::warn("Fabric-bridge: JSON parse error: {}", e.what());
+        }
+
+        spdlog::info("Fabric-bridge: target_info not ready yet, retry {}...", attempt + 1);
+        std::this_thread::sleep_for(std::chrono::milliseconds(500));
+    }
+
+    if (target_info_str_.empty()) {
+        spdlog::error("Fabric-bridge: failed to fetch target_info after 30 attempts");
+    }
+}
+
+void FabricBridgeNode::process() {
+    if (!worker_thread_.has_value() && start_requested_.load()) {
+        if (mode_ == FabricMode::Initiator && reader_.has_value() && !target_host_.empty() && target_info_str_.empty()) {
+            fetch_target_info();
+        }
+        if (start_requested_.load()) {
+            running_ = true;
+            spdlog::info("Fabric-bridge: starting worker thread (mode={})", mode_ == FabricMode::Initiator ? "initiator" : "target");
+            if (mode_ == FabricMode::Initiator) {
+                worker_thread_ = std::thread(&FabricBridgeNode::run_initiator, this);
+            } else {
+                worker_thread_ = std::thread(&FabricBridgeNode::run_target, this);
+            }
+        }
+    }
+    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+}
+
+void FabricBridgeNode::run_initiator() {
+    spdlog::info("Fabric-bridge: starting initiator mode");
+
+    auto instance = get_mxl_instance();
+    if (!instance) {
+        spdlog::error("Fabric-bridge: no MXL instance");
+        running_ = false;
+        return;
+    }
+
+    spdlog::info("Fabric-bridge: creating fabrics instance...");
+    mxlFabricsInstance fab_inst = nullptr;
+    auto status = mxlFabricsCreateInstance(instance, nullptr, &fab_inst);
+    spdlog::info("Fabric-bridge: mxlFabricsCreateInstance returned {}", static_cast<int>(status));
+    if (status != MXL_STATUS_OK || !fab_inst) {
+        spdlog::error("Fabric-bridge: failed to create fabrics instance: {}", static_cast<int>(status));
+        running_ = false;
+        return;
+    }
+    fabrics_instance_ = fab_inst;
+
+    spdlog::info("Fabric-bridge: creating initiator...");
+    mxlFabricsInitiator initiator = nullptr;
+    status = mxlFabricsCreateInitiator(fab_inst, &initiator);
+    spdlog::info("Fabric-bridge: mxlFabricsCreateInitiator returned {}", static_cast<int>(status));
+    if (status != MXL_STATUS_OK || !initiator) {
+        spdlog::error("Fabric-bridge: failed to create initiator: {}", static_cast<int>(status));
+        mxlFabricsDestroyInstance(fab_inst);
+        running_ = false;
+        return;
+    }
+    initiator_ = initiator;
+
+    mxlFlowConfigInfo config{};
+    mxlFlowReaderGetConfigInfo(*reader_, &config);
+    grain_rate_ = config.common.grainRate;
+
+    mxlFabricsInitiatorConfig init_cfg{};
+    init_cfg.version = MXL_FABRICS_API_VERSION;
+    init_cfg.interface.version = MXL_FABRICS_API_VERSION;
+    init_cfg.interface.provider = provider_;
+    init_cfg.interface.address.node = bind_node_.c_str();
+    init_cfg.interface.address.service = bind_service_.c_str();
+    init_cfg.reader = *reader_;
+
+    spdlog::info("Fabric-bridge: calling mxlFabricsInitiatorSetup on {}:{}", bind_node_, bind_service_);
+    status = mxlFabricsInitiatorSetup(initiator, &init_cfg, nullptr);
+    if (status != MXL_STATUS_OK) {
+        spdlog::error("Fabric-bridge: initiator setup failed: {}", static_cast<int>(status));
+        mxlFabricsDestroyInitiator(fab_inst, initiator);
+        mxlFabricsDestroyInstance(fab_inst);
+        running_ = false;
+        return;
+    }
+
+    if (target_info_str_.empty()) {
+        spdlog::error("Fabric-bridge: no target_info available, cannot add target");
+        mxlFabricsDestroyInitiator(fab_inst, initiator);
+        mxlFabricsDestroyInstance(fab_inst);
+        running_ = false;
+        return;
+    }
+
+    mxlFabricsTargetInfo target_info = nullptr;
+    spdlog::info("Fabric-bridge: parsing target_info ({} bytes)", target_info_str_.size());
+    status = mxlFabricsTargetInfoFromString(target_info_str_.c_str(), &target_info);
+    if (status != MXL_STATUS_OK || !target_info) {
+        spdlog::error("Fabric-bridge: failed to parse target_info: {}", static_cast<int>(status));
+        mxlFabricsDestroyInitiator(fab_inst, initiator);
+        mxlFabricsDestroyInstance(fab_inst);
+        running_ = false;
+        return;
+    }
+
+    status = mxlFabricsInitiatorAddTarget(initiator, target_info);
+    if (status != MXL_STATUS_OK) {
+        spdlog::error("Fabric-bridge: failed to add target: {}", static_cast<int>(status));
+        mxlFabricsFreeTargetInfo(target_info);
+        mxlFabricsDestroyInitiator(fab_inst, initiator);
+        mxlFabricsDestroyInstance(fab_inst);
+        running_ = false;
+        return;
+    }
+
+    spdlog::info("Fabric-bridge: waiting for connection...");
+    do {
+        status = mxlFabricsInitiatorMakeProgressBlocking(initiator, 250);
+    } while (status == MXL_ERR_NOT_READY && running_);
+
+    auto now = mxlGetTime();
+    read_index_ = mxlTimestampToIndex(&grain_rate_, now) - 2;
+
+    spdlog::info("Fabric-bridge: initiator started, grain_rate={}/{}", grain_rate_.numerator, grain_rate_.denominator);
+
+    while (running_) {
+        auto deadline = mxlIndexToTimestamp(&grain_rate_, read_index_ + 1);
+        mxlSleepUntil(deadline);
+
+        mxlGrainInfo grain_info{};
+        uint8_t* payload = nullptr;
+        auto grain_status = mxlFlowReaderGetGrain(*reader_, read_index_, 5000000ULL, &grain_info, &payload);
+        if (grain_status != MXL_STATUS_OK) {
+            if (grain_status == MXL_ERR_OUT_OF_RANGE_TOO_LATE || grain_status == MXL_ERR_OUT_OF_RANGE_TOO_EARLY) {
+                auto ts = mxlGetTime();
+                read_index_ = mxlTimestampToIndex(&grain_rate_, ts) - 2;
+                continue;
+            }
+            read_index_++;
+            continue;
+        }
+
+        auto transfer_status = mxlFabricsInitiatorTransferGrain(initiator, read_index_, 0, grain_info.validSlices);
+        if (transfer_status != MXL_STATUS_OK) {
+            spdlog::warn("Fabric-bridge: transfer grain {} failed: {}", read_index_, static_cast<int>(transfer_status));
+            read_index_++;
+            continue;
+        }
+
+        do {
+            status = mxlFabricsInitiatorMakeProgressBlocking(initiator, 10);
+        } while (status == MXL_ERR_NOT_READY && running_);
+
+        read_index_++;
+        grains_transferred_++;
+
+        if (grains_transferred_ == 1) {
+            spdlog::info("Fabric-bridge: first grain transferred, index={}", read_index_ - 1);
+        }
+    }
+
+    mxlFabricsInitiatorRemoveTarget(initiator, target_info);
+    mxlFabricsFreeTargetInfo(target_info);
+    mxlFabricsDestroyInitiator(fab_inst, initiator);
+    mxlFabricsDestroyInstance(fab_inst);
+    spdlog::info("Fabric-bridge: initiator stopped");
+}
+
+void FabricBridgeNode::run_target() {
+    spdlog::info("Fabric-bridge: starting target mode");
+
+    auto instance = get_mxl_instance();
+    if (!instance) {
+        spdlog::error("Fabric-bridge: no MXL instance");
+        running_ = false;
+        return;
+    }
+
+    spdlog::info("Fabric-bridge: creating fabrics instance...");
+    mxlFabricsInstance fab_inst = nullptr;
+    auto status = mxlFabricsCreateInstance(instance, nullptr, &fab_inst);
+    spdlog::info("Fabric-bridge: mxlFabricsCreateInstance returned {}", static_cast<int>(status));
+    if (status != MXL_STATUS_OK || !fab_inst) {
+        spdlog::error("Fabric-bridge: failed to create fabrics instance: {}", static_cast<int>(status));
+        running_ = false;
+        return;
+    }
+    fabrics_instance_ = fab_inst;
+
+    spdlog::info("Fabric-bridge: creating target...");
+    mxlFabricsTarget tgt = nullptr;
+    status = mxlFabricsCreateTarget(fab_inst, &tgt);
+    spdlog::info("Fabric-bridge: mxlFabricsCreateTarget returned {}", static_cast<int>(status));
+    if (status != MXL_STATUS_OK || !tgt) {
+        spdlog::error("Fabric-bridge: failed to create target: {}", static_cast<int>(status));
+        mxlFabricsDestroyInstance(fab_inst);
+        running_ = false;
+        return;
+    }
+    target_ = tgt;
+
+    auto* config = get_writer_config("video_out");
+    if (config) {
+        grain_rate_ = config->common.grainRate;
+        spdlog::info("Fabric-bridge: target grain_rate={}/{}", grain_rate_.numerator, grain_rate_.denominator);
+    } else {
+        spdlog::warn("Fabric-bridge: no writer config, using default grain_rate");
+    }
+
+    mxlFabricsTargetConfig target_cfg{};
+    target_cfg.version = MXL_FABRICS_API_VERSION;
+    target_cfg.interface.version = MXL_FABRICS_API_VERSION;
+    target_cfg.interface.provider = provider_;
+    target_cfg.interface.address.node = bind_node_.c_str();
+    target_cfg.interface.address.service = bind_service_.c_str();
+    target_cfg.writer = *writer_;
+
+    spdlog::info("Fabric-bridge: calling mxlFabricsTargetSetup on {}:{}", bind_node_, bind_service_);
+    mxlFabricsTargetInfo target_info = nullptr;
+    status = mxlFabricsTargetSetup(tgt, &target_cfg, nullptr, &target_info);
+    if (status != MXL_STATUS_OK || !target_info) {
+        spdlog::error("Fabric-bridge: target setup failed: {}", static_cast<int>(status));
+        mxlFabricsDestroyTarget(fab_inst, tgt);
+        mxlFabricsDestroyInstance(fab_inst);
+        running_ = false;
+        return;
+    }
+
+    size_t info_size = 0;
+    mxlFabricsTargetInfoToString(target_info, nullptr, &info_size);
+    std::vector<char> info_buf(info_size);
+    mxlFabricsTargetInfoToString(target_info, info_buf.data(), &info_size);
+    target_info_str_ = std::string(info_buf.data(), info_size);
+
+    spdlog::info("Fabric-bridge: target ready, target_info length={}", target_info_str_.size());
+    spdlog::info("Fabric-bridge: TARGET_INFO={}", target_info_str_);
+
+    while (running_) {
+        uint64_t grain_index = 0;
+        status = mxlFabricsTargetReadGrain(tgt, 200, &grain_index);
+        if (status == MXL_ERR_TIMEOUT || status == MXL_ERR_NOT_READY) {
+            continue;
+        }
+        if (status != MXL_STATUS_OK) {
+            spdlog::warn("Fabric-bridge: target read grain failed: {}", static_cast<int>(status));
+            continue;
+        }
+
+        mxlGrainInfo grain_info{};
+        uint8_t* dummy_payload = nullptr;
+        auto open_status = mxlFlowWriterOpenGrain(*writer_, grain_index, &grain_info, &dummy_payload);
+        if (open_status == MXL_STATUS_OK) {
+            grain_info.validSlices = grain_info.totalSlices;
+            mxlFlowWriterCommitGrain(*writer_, &grain_info);
+            grains_transferred_++;
+            if (grains_transferred_ == 1) {
+                spdlog::info("Fabric-bridge: first grain committed, index={}", grain_index);
+            }
+        } else {
+            spdlog::warn("Fabric-bridge: open grain {} failed: {}", grain_index, static_cast<int>(open_status));
+        }
+    }
+
+    mxlFabricsFreeTargetInfo(target_info);
+    mxlFabricsDestroyTarget(fab_inst, tgt);
+    mxlFabricsDestroyInstance(fab_inst);
+    spdlog::info("Fabric-bridge: target stopped");
+}
+
+nlohmann::json FabricBridgeNode::status() const {
+    return {
+        {"type", "fabric-bridge"},
+        {"mode", mode_ == FabricMode::Initiator ? "initiator" : "target"},
+        {"grains_transferred", grains_transferred_},
+        {"running", running_.load()},
+        {"has_reader", reader_.has_value()},
+        {"has_writer", writer_.has_value()},
+        {"target_info_length", target_info_str_.size()},
+        {"target_info", target_info_str_},
+    };
+}
+
+} // namespace dmf_node

nodes/fabric-bridge/src/fabric_bridge_node.hpp

@@ -0,0 +1,68 @@
+#pragma once
+
+#include <dmf-node/node.hpp>
+#include <mxl/flow.h>
+#include <mxl/fabrics.h>
+#include <mxl/time.h>
+
+#include <atomic>
+#include <optional>
+#include <string>
+#include <thread>
+
+namespace dmf_node {
+
+enum class FabricMode { Initiator, Target };
+
+class FabricBridgeNode : public Node {
+public:
+    FabricBridgeNode() = default;
+    ~FabricBridgeNode();
+
+    std::string type() const override { return "fabric-bridge"; }
+
+    std::vector<PortDef> input_ports() const override;
+    std::vector<PortDef> output_ports() const override;
+
+    void configure(const nlohmann::json& params) override;
+    void on_add_writer(const std::string& port_id, mxlFlowWriter writer) override;
+    void on_add_reader(const std::string& port_id, mxlFlowReader reader) override;
+    void on_remove_writer(const std::string& port_id) override;
+    void on_remove_reader(const std::string& port_id) override;
+
+    void process() override;
+    nlohmann::json status() const override;
+
+private:
+    void run_initiator();
+    void run_target();
+
+    FabricMode mode_ = FabricMode::Initiator;
+
+    std::string bind_node_ = "0.0.0.0";
+    std::string bind_service_ = "0";
+    mxlFabricsProvider provider_ = MXL_FABRICS_PROVIDER_ANY;
+
+    std::optional<mxlFlowReader> reader_;
+    std::optional<mxlFlowWriter> writer_;
+    mxlRational grain_rate_{50, 1};
+    uint64_t read_index_ = 0;
+    uint64_t grains_transferred_ = 0;
+
+    std::string target_info_str_;
+
+    std::string target_host_;
+    uint16_t target_port_ = 9100;
+
+    void fetch_target_info();
+
+    mxlFabricsInstance fabrics_instance_ = nullptr;
+    mxlFabricsInitiator initiator_ = nullptr;
+    mxlFabricsTarget target_ = nullptr;
+
+    std::optional<std::thread> worker_thread_;
+    std::atomic<bool> running_{false};
+    std::atomic<bool> start_requested_{false};
+};
+
+} // namespace dmf_node

nodes/fabric-bridge/src/main.cpp

@@ -0,0 +1,6 @@
+#include "fabric_bridge_node.hpp"
+#include <dmf-node/node_runner.hpp>
+
+int main(int argc, char* argv[]) {
+    return dmf_node::NodeRunner::run<dmf_node::FabricBridgeNode>(argc, argv);
+}