# use_logger_service

*This file is ai generated. Do not edit this file directly. Instead, edit the node source code and run the generate-node-docs command to update this file.*

## Description

A ROS2 demonstration showing how to enable and control logger levels dynamically using logger services. The demo includes two nodes: `LoggerServiceNode` which has the logger service enabled, and `TestNode` which remotely changes the logger level and sends test messages. This demonstrates runtime control of log verbosity without restarting nodes.

## Publishers

- **Topic**: `/output`
  - **Type**: `example_interfaces/msg/String`
  - **QoS**: Queue size of 10
  - **Description**: TestNode publishes test messages to this topic

## Subscribers

- **Topic**: `/output`
  - **Type**: `example_interfaces/msg/String`
  - **QoS**: Queue size of 10
  - **Description**: LoggerServiceNode subscribes and logs messages at different levels

## Services

- **Service Server**: `/LoggerServiceNode/get_logger_levels`
  - **Type**: `rcl_interfaces/srv/GetLoggerLevels`
  - **Description**: Returns current logger level configuration

- **Service Server**: `/LoggerServiceNode/set_logger_levels`
  - **Type**: `rcl_interfaces/srv/SetLoggerLevels`
  - **Description**: Sets logger level for the node

## Example Usage

```bash
# Run the complete demo
ros2 run demo_nodes_py use_logger_service
```

The demo will automatically:
1. Output messages with default logger level (INFO)
2. Get current logger level (Unset/0)
3. Set to DEBUG level and output test message
4. Get logger level (DEBUG/10)
5. Set to WARN level and output test message
6. Get logger level (WARN/30)
7. Set to ERROR level and output test message
8. Get logger level (ERROR/40)

Expected output:
```
[INFO] [TestNode]: Output with default logger level:
[INFO] [LoggerServiceNode]: Output 1 with INFO logger level.
[WARN] [LoggerServiceNode]: Output 1 with WARN logger level.
[ERROR] [LoggerServiceNode]: Output 1 with ERROR logger level.
[INFO] [TestNode]: Current logger level: 0
[INFO] [TestNode]: Output with debug logger level:
[DEBUG] [LoggerServiceNode]: Output 2 with DEBUG logger level.
[INFO] [LoggerServiceNode]: Output 2 with INFO logger level.
...
```

To manually control logger level:
```bash
# Terminal 1: Run a node with logger service enabled
# (use a modified version or another node)

# Terminal 2: Get current logger level
ros2 service call /LoggerServiceNode/get_logger_levels \
    rcl_interfaces/srv/GetLoggerLevels "{names: ['LoggerServiceNode']}"

# Terminal 3: Set logger level to DEBUG
ros2 service call /LoggerServiceNode/set_logger_levels \
    rcl_interfaces/srv/SetLoggerLevels \
    "{levels: [{name: 'LoggerServiceNode', level: 10}]}"
```