Change default log verbosity to Error and add discovery example

ddsenabler/examples/CMakeLists.txt

@@ -20,6 +20,7 @@ install(
 
 # Add subdirectories for examples
 add_subdirectory(utils)
+add_subdirectory(discovery)
 add_subdirectory(publish)
 add_subdirectory(service)
 add_subdirectory(action)

ddsenabler/examples/discovery/CMakeLists.txt

@@ -0,0 +1,44 @@
+# Copyright 2026 Proyectos y Sistemas de Mantenimiento SL (eProsima).
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+cmake_minimum_required(VERSION 3.20)
+project(ddsenabler_example_discovery LANGUAGES CXX)
+
+# When built standalone (not as a subdirectory of the DDS Enabler project), the
+# 'ddsenabler' target does not exist yet, so locate the installed library. The
+# imported 'ddsenabler' target links transitively against the packages below, so
+# they must be found as well for the standalone build to configure and link.
+if(NOT TARGET ddsenabler)
+    find_package(cpp_utils REQUIRED)
+    find_package(ddspipe_core REQUIRED)
+    find_package(ddspipe_participants REQUIRED)
+    find_package(ddspipe_yaml REQUIRED)
+    find_package(ddsenabler_participants REQUIRED)
+    find_package(ddsenabler_yaml REQUIRED)
+    find_package(ddsenabler REQUIRED)
+endif()
+
+add_executable(ddsenabler_example_discovery main.cpp)
+
+target_link_libraries(ddsenabler_example_discovery PRIVATE ddsenabler)
+
+# Install rule
+install(TARGETS ddsenabler_example_discovery
+    RUNTIME DESTINATION examples/discovery
+)
+
+# Install the example configuration file
+install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/config.yml
+    DESTINATION examples/discovery
+)

ddsenabler/examples/discovery/README.md

@@ -0,0 +1,54 @@
+# Discovery Example README
+
+This is the simplest DDS Enabler example and a good starting point.
+It launches a DDS Enabler that listens to the DDS network and prints the **name** of every topic, service and action it discovers - nothing else (no types, no QoS, no data).
+
+The application keeps running until it is stopped with `Ctrl+C`.
+
+It registers only the three discovery notification callbacks of the `CallbackSet`:
+
+- `dds.topic_notification` → prints discovered topic names.
+- `service.service_notification` → prints discovered service names.
+- `action.action_notification` → prints discovered action names.
+
+## Compilation
+
+The example is compiled together with the DDS Enabler when the project is built with the `-DCOMPILE_EXAMPLES=ON` CMake option.
+It can also be compiled standalone against an already installed DDS Enabler.
+
+First, source the environment where the DDS Enabler is installed.
+
+```bash
+source <ddsenabler-installation-path>/install/setup.bash
+```
+
+Then configure and build the example from its own directory.
+
+```bash
+mkdir build
+cd build
+cmake ..
+cmake --build .
+```
+
+The `ddsenabler_example_discovery` executable is generated inside the `build` directory.
+
+## Example Command
+
+```bash
+./ddsenabler_example_discovery config.yml
+```
+
+Run it and then start any DDS / ROS 2 application (for instance the ROS 2 `talker`, or another DDS Enabler example such as `publish`, `service` or `action`).
+When a topic, service, or action is discovered, the application prints a line like:
+
+```
+[Discovery] Topic discovered: rt/chatter
+[Discovery] Service discovered: /add_two_ints
+[Discovery] Action discovered: /fibonacci
+```
+
+Press `Ctrl+C` to stop the application cleanly.
+
+An optional YAML configuration file may be passed as the first argument to customize the DDS behavior (domain, allow/deny topic lists, etc.).
+Without it, the Enabler uses its default configuration (DDS domain 0).

ddsenabler/examples/discovery/config.yml

@@ -0,0 +1,3 @@
+dds:
+  domain: 0
+

ddsenabler/examples/discovery/main.cpp

@@ -0,0 +1,113 @@
+// Copyright 2026 Proyectos y Sistemas de Mantenimiento SL (eProsima).
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/**
+ * @file main.cpp
+ *
+ * Minimal DDS Enabler example: print the name of every topic, service and action
+ * the Enabler discovers, and keep running until the user presses Ctrl+C.
+ */
+
+#include <condition_variable>
+#include <csignal>
+#include <iostream>
+#include <mutex>
+#include <string>
+
+#include "ddsenabler/dds_enabler_runner.hpp"
+#include "ddsenabler/DDSEnabler.hpp"
+
+// Synchronization used to keep the application alive until a stop signal arrives.
+std::mutex app_mutex;
+std::condition_variable app_cv;
+bool stop_app = false;
+
+// Called by the Enabler every time a new DDS topic is discovered.
+void on_topic_discovered(
+        const char* topic_name,
+        const eprosima::ddsenabler::participants::TopicInfo& /* topic_info */)
+{
+    std::cout << "[Discovery] Topic discovered: " << topic_name << std::endl;
+}
+
+// Called by the Enabler every time a new ROS 2 / DDS service is discovered.
+void on_service_discovered(
+        const char* service_name,
+        const eprosima::ddsenabler::participants::ServiceInfo& /* service_info */)
+{
+    std::cout << "[Discovery] Service discovered: " << service_name << std::endl;
+}
+
+// Called by the Enabler every time a new ROS 2 / DDS action is discovered.
+void on_action_discovered(
+        const char* action_name,
+        const eprosima::ddsenabler::participants::ActionInfo& /* action_info */)
+{
+    std::cout << "[Discovery] Action discovered: " << action_name << std::endl;
+}
+
+// Stops the application cleanly when Ctrl+C (or another termination signal) is received.
+void signal_handler(
+        int /* signum */)
+{
+    {
+        std::lock_guard<std::mutex> lock(app_mutex);
+        stop_app = true;
+    }
+    app_cv.notify_all();
+}
+
+int main(
+        int argc,
+        char** argv)
+{
+    using namespace eprosima::ddsenabler;
+
+    // Register only the discovery notification callbacks; everything else is left unset.
+    CallbackSet callbacks{};
+    callbacks.dds.topic_notification = on_topic_discovered;
+    callbacks.service.service_notification = on_service_discovered;
+    callbacks.action.action_notification = on_action_discovered;
+
+    // Create the Enabler. An optional YAML configuration file may be passed as the first argument.
+    std::shared_ptr<DDSEnabler> enabler;
+    bool enabler_created = (argc > 1)
+            ? create_dds_enabler(argv[1], callbacks, enabler)
+            : create_dds_enabler(yaml::EnablerConfiguration(""), callbacks, enabler);
+
+    if (!enabler_created)
+    {
+        std::cerr << "Failed to create DDSEnabler instance." << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    // Install signal handlers for a clean shutdown.
+    signal(SIGINT, signal_handler);
+    signal(SIGTERM, signal_handler);
+
+    std::cout << "DDS Enabler running. Listening for topics, services and actions. "
+              << "Press Ctrl+C to stop." << std::endl;
+
+    // Block until a stop signal is received.
+    {
+        std::unique_lock<std::mutex> lock(app_mutex);
+        app_cv.wait(lock, []
+                {
+                    return stop_app;
+                });
+    }
+
+    std::cout << "Stopping DDS Enabler..." << std::endl;
+    return EXIT_SUCCESS;
+}

ddsenabler_yaml/src/cpp/EnablerConfiguration.cpp

@@ -179,6 +179,12 @@ void EnablerConfiguration::load_ddsenabler_configuration_(
         enabler_configuration->id = "EnablerEnablerParticipant";
         enabler_configuration->app_id = "DDS_ENABLER";
 
+        /////
+        // Set the DDS Enabler default log verbosity to ERROR, so that INFO and WARNING traces
+        // (from both the Enabler and the underlying DDS Pipe) are silenced unless the user
+        // explicitly raises the verbosity through the logging configuration.
+        ddspipe_configuration.log_configuration.verbosity.set_value(utils::VerbosityKind::Error);
+
         /////
         // Get optional Enabler configuration options
         if (YamlReader::is_tag_present(yml, ENABLER_ENABLER_TAG))