Micronaut Control Panel

The Micronaut Control Panel module provides a web UI that allows you to view and manage the state of your Micronaut application, typically in a development environment.

Version: 1.4.0

1 Introduction

The Micronaut Control Panel module provides a web UI that allows you to view and manage the state of your Micronaut application, typically in a development environment.

2 Release History

For this project, you can find a list of releases (with release notes) here:

https://github.com/micronaut-projects/micronaut-control-panel/releases

3 Quick Start

To get started, add the UI module as a runtime dependency:

developmentOnly("io.micronaut.controlpanel:micronaut-control-panel-ui")

<dependency>
    <groupId>io.micronaut.controlpanel</groupId>
    <artifactId>micronaut-control-panel-ui</artifactId>
    <scope>provided</scope>
</dependency>

Then, add the control panel modules that you want. For example, if you already have the io.micronaut:micronaut-management module, you can add the micronaut-control-panel-management module:

developmentOnly("io.micronaut.controlpanel:micronaut-control-panel-management")

<dependency>
    <groupId>io.micronaut.controlpanel</groupId>
    <artifactId>micronaut-control-panel-management</artifactId>
    <scope>provided</scope>
</dependency>

By default, the Control Panel is only enabled in the dev or test environments. You can change this and other settings in your configuration file:

🔗

Table 1. Configuration Properties for ControlPanelModuleConfiguration
Property	Type	Description
`micronaut.control-panel.enabled`	boolean	Enables/disables the control panel module. Default value: "true".
`micronaut.control-panel.allowed-environments`	java.util.Set	Configures the environments where the control panel module is enabled. By default, it is only enabled in the "dev" and "test" environments.
`micronaut.control-panel.path`	java.lang.String	Configures the path where the control panel can be accessed. Default value: "/control-panel".

Therefore, make sure you activate the appropriate environments when running locally, for example, using default environments:

# For Maven:
MICRONAUT_ENVIRONMENTS=dev ./mvnw mn:run

# For Gradle:
MICRONAUT_ENVIRONMENTS=dev ./gradlew run

Once the application is running, you can access the control panel at http://localhost:8080/control-panel.

4 Available Control Panels

All Control Panels are configurable with the following properties:

🔗

Table 1. Configuration Properties for ControlPanelConfiguration
Property	Type	Description
`micronaut.control-panel.panels.*.enabled`	boolean	Enables/disables this control panel. Default value: true.
`micronaut.control-panel.panels.*.order`	int	Sets the order of this control panel, since they will be displayed sorted by order.
`micronaut.control-panel.panels.*.title`	java.lang.String	The title is displayed in the header of the card UI element.
`micronaut.control-panel.panels.*.icon`	java.lang.String	Icon class of the card UI element.
`micronaut.control-panel.panels.*.name`	java.lang.String	The unique name of the control panel. Can be used in URLs.

For example, to disable the routes control panel, set the property micronaut.control-panel.panels.routes.enabled to false.

Beyond displaying the available panels, the control panel also allows to perform 2 additional actions, provided that the corresponding endpoints are enabled and non-sensitive:

Refresh: refreshing the application will cause all @Refreshable beans in the context to be destroyed and re-instantiated upon further requests. This requires the Refresh Endpoint to be enabled and non-sensitive.
Stop: will shut down the application. This requires the Stop Endpoint to be enabled and non-sensitive.

Micronaut Endpoints require having the io.micronaut:micronaut-management dependency on the classpath.

4.1 Built-in

The following control panels are available by default with the UI module:

routes: displays information about the available HTTP routes.

4.2 Management

To add the management panels, include the following dependency:

developmentOnly("io.micronaut.controlpanel:micronaut-control-panel-management")

<dependency>
    <groupId>io.micronaut.controlpanel</groupId>
    <artifactId>micronaut-control-panel-management</artifactId>
    <scope>provided</scope>
</dependency>

Note that you also need the Management module:

runtimeOnly("io.micronaut.:micronaut-management")

<dependency>
    <groupId>io.micronaut.</groupId>
    <artifactId>micronaut-management</artifactId>
    <scope>runtime</scope>
</dependency>

The following panels are available:

health: Application Health
env: Environment Properties
beans: Bean Definitions
loggers: Logging Configuration

Application Heath

This panel displays the health information of your application, and relies on the Health Endpoint to display its information. Note that, by default, the health endpoint only displays the details to authenticated users. To be able to see the details in the control panel, you need to configure the health endpoint to expose the details to unauthenticated users:

Make sure this is done in an environment-specific configuration file, for example, application-dev.yml.

Configuring the Health Endpoint to expose details to anonymous users

endpoints.health.details-visible=ANONYMOUS

endpoints:
  health:
    details-visible: ANONYMOUS

[endpoints]
  [endpoints.health]
    details-visible="ANONYMOUS"

endpoints {
  health {
    detailsVisible = "ANONYMOUS"
  }
}

{
  endpoints {
    health {
      details-visible = "ANONYMOUS"
    }
  }
}

{
  "endpoints": {
    "health": {
      "details-visible": "ANONYMOUS"
    }
  }
}

Environment Properties

This panel displays all the configuration properties resolved, and relies on the Environment Endpoint to display all the properties. This endpoint is disabled and sensitive (requires authentication to display the information) by default, so you need to configure it to be enabled and accessible to anonymous users in the environments where the control panel is enabled:

Make sure this is done in an environment-specific configuration file, for example, application-dev.yml.

Configuring the Environment Endpoint

endpoints.env.enabled=true
endpoints.env.sensitive=false

endpoints:
  env:
    enabled: true
    sensitive: false

[endpoints]
  [endpoints.env]
    enabled=true
    sensitive=false

endpoints {
  env {
    enabled = true
    sensitive = false
  }
}

{
  endpoints {
    env {
      enabled = true
      sensitive = false
    }
  }
}

{
  "endpoints": {
    "env": {
      "enabled": true,
      "sensitive": false
    }
  }
}

Also, by default, all the values will be masked. If you want to see the actual configuration values in the control panel, you need to provide an implementation of the EnvironmentEndpointFilter interface and register it as a bean. For example:

Displaying the actual configuration values

@Singleton
@Requires(env = Environment.DEVELOPMENT)
public class AllPlainEnvironmentEndpointFilter implements EnvironmentEndpointFilter {

    @Override
    public void specifyFiltering(@NonNull EnvironmentFilterSpecification specification) {
        specification.legacyMasking();
    }
}

This will show all values apart from those that contain the words password, credential, certificate, key, secret or token anywhere in their name.

Bean Definitions

This panel displays all the beans, and their relationships, grouped by packages. It relies on the Beans Endpoint to display all the bean definitions. This endpoint is sensitive by default, so if you want to see the bean definitions in the control panel, you need to configure the endpoint to be accessible to anonymous users in the environments where the control panel is enabled:

Make sure this is done in an environment-specific configuration file, for example, application-dev.yml.

Configuring the Beans Endpoint

endpoints.beans.sensitive=false

endpoints:
  beans:
    sensitive: false

[endpoints]
  [endpoints.beans]
    sensitive=false

endpoints {
  beans {
    sensitive = false
  }
}

{
  endpoints {
    beans {
      sensitive = false
    }
  }
}

{
  "endpoints": {
    "beans": {
      "sensitive": false
    }
  }
}

Logging Configuration

This panel allows you to view and re-configure the logging levels without restarting the application. It relies on the Loggers Endpoint to display and update the logging levels. This endpoint is disabled by default, so if you want to manage the logging configuration in the control panel, you need to enable the endpoint. Also, by default, the endpoint is read-only, so you need to configure it to be writable:

Make sure this is done in an environment-specific configuration file, for example, application-dev.yml.

Configuring the Loggers Endpoint

endpoints.loggers.enabled=true
endpoints.loggers.write-sensitive=false

endpoints:
  loggers:
    enabled: true
    write-sensitive: false

[endpoints]
  [endpoints.loggers]
    enabled=true
    write-sensitive=false

endpoints {
  loggers {
    enabled = true
    writeSensitive = false
  }
}

{
  endpoints {
    loggers {
      enabled = true
      write-sensitive = false
    }
  }
}

{
  "endpoints": {
    "loggers": {
      "enabled": true,
      "write-sensitive": false
    }
  }
}

5 Creating Custom Control Panels

You can add your own control panels to the Control Panel UI. Creating custom panels requires the following:

An implementation of the ControlPanel interface.
Some configuration values.
The views.

The Control Panel UI uses the open-source AdminLTE template, including Bootstrap and Font Awesome.

The categories are used to group the control panels in the UI. Categories are rendered as left side menu items. There is a default category called Dashboard that is used for all control panels that don’t specify a category.

Control Panel Implementation

The easiest way to implement a custom panel is to extend from AbstractControlPanel. For example:

@Singleton
public class MyApplicationControlPanel extends AbstractControlPanel<String> { // (1)

    private static final String NAME = "my-application"; // (2)

    public MyApplicationControlPanel(@Named(NAME) ControlPanelConfiguration configuration) {
        super(NAME, configuration); // (3)
    }

    @Override
    public String getBody() {
        return "This is an application-provided control panel. This text is coming from the body.";
    }

    @Override
    public Category getCategory() {
        return new Category(NAME, "My Application", "fa-copy"); // (4)
    }
}

1	The `String` type parameter indicates the object type of the body. You can use your own classes or records to return custom data to the view. In this example, the control panel only returns a message.
2	Unique name for your control panel. This is used for the configuration properties prefix. In this case: `micronaut.control-panel.panels.my-application`.
3	Call the parent constructor. You could inject any other beans in this constructor.
4	The category under which the control panel will be displayed, if other than the default.

Check the ControlPanel interface to see the other methods that can be overridden, for example, to display a badge in the control panel header.

Configuration

There are some values for the UI that can be configured:

micronaut.control-panel.panels.my-application.title=My Application Control Panel
micronaut.control-panel.panels.my-application.icon=fa-plug
micronaut.control-panel.panels.my-application.order=10

micronaut:
  control-panel:
    panels:
      my-application:
        title: My Application Control Panel # (1)
        icon: fa-plug # (2)
        order: 10 # (3)

[micronaut]
  [micronaut.control-panel]
    [micronaut.control-panel.panels]
      [micronaut.control-panel.panels.my-application]
        title="My Application Control Panel"
        icon="fa-plug"
        order=10

micronaut {
  controlPanel {
    panels {
      myApplication {
        title = "My Application Control Panel"
        icon = "fa-plug"
        order = 10
      }
    }
  }
}

{
  micronaut {
    control-panel {
      panels {
        my-application {
          title = "My Application Control Panel"
          icon = "fa-plug"
          order = 10
        }
      }
    }
  }
}

{
  "micronaut": {
    "control-panel": {
      "panels": {
        "my-application": {
          "title": "My Application Control Panel",
          "icon": "fa-plug",
          "order": 10
        }
      }
    }
  }
}

1	Title to be displayed in the control panel headeer.
2	Icon class (from Font Awesome) of the control panel.
3	The order in which the control panel will be displayed in the UI.

Views

For rendering the views, the Control Panel uses Micronaut Views with Handlebars.java templates.

Each control panel needs to provide 2 views: one for the control panel list, that can contain a summary of the information to be displayed, and another one for the detailed view. The must be placed in a views/<panel-name> directory on the classpath, and names body.hbs and detail.hbs, respectively. For example, in the above example:

src/main/resources/views/my-application/body.hbs.

<p class="card-text">
    This is the body of the application-provided control panel
</p>

The ControlPanel instance (MyApplicationControlPanel in this case) is stored on the Handlebars context, so you can implicitly access its methods and properties. For example, to access the badge:

src/main/resources/views/my-application/body.hbs.

<p class="card-text">
    <strong>{{badge}}</strong> bean definitions active.
</p>

In the case of the detail view, the control panel instance is passed as an implicit controlPanel variable. For example, to access the body of our control panel example:

src/main/resources/views/my-application/detail.hbs.

{{ controlPanel.body }}

6 Repository

You can find the source code of this project in this repository:

https://github.com/micronaut-projects/micronaut-control-panel

Table of Contents

Micronaut Control Panel

1 Introduction

2 Release History

3 Quick Start

4 Available Control Panels

4.1 Built-in

4.2 Management

Application Heath

Environment Properties

Bean Definitions

Logging Configuration

5 Creating Custom Control Panels

Control Panel Implementation

Configuration

Views

6 Repository