> ## Documentation Index
> Fetch the complete documentation index at: https://rive.app/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Logging

export const Apple = {
  currentRuntimeName: "New Runtime",
  legacyRuntimeName: "Legacy Runtime"
};

This Rive runtime includes logging capabilities to help with debugging. These logs are *only* for debugging purposes; nothing is sent over the network, and no personally identifiable information (PII) is logged.

The table below showcases the runtimes that support logging.

<Tabs>
  <Tab title={Apple.currentRuntimeName}>
    The new runtime supports logging via the `RiveLog` type. To enable logging, set the `RiveLog.logger` property to a `RiveLog.Logger` implementation. The new runtime defaults to no logging, which can be set at any time by setting `RiveLog.logger` to `RiveLog.none`. The new runtime ships with a default implementation that logs to the console, which can be set by using the `RiveLog.system(levels:)` helper function. When using the system logger, any logs that are not emitted at the levels specified will be suppressed.

    ```swift theme={null}
    // To enable the default logging implementation, which uses os.Logger
    RiveLog.logger = RiveLog.system(levels: .default)

    // To disable logging (the default)
    RiveLog.logger = RiveLog.none
    ```

    ### Levels

    Logs will be logged at various levels, which are inspired by `OSLogType` . These levels can be used to additionally filter logs to be logged at certain levels only. Available levels are:

    * **Notice**: important informational logs
    * **Debug**: commonly used to aid with debugging
    * **Trace**: highly detailed and potentially verbose diagnostic logs, including operations like advancing that may emit at least one log per frame
    * **Info**: logs that provide additional information
    * **Error**: used when an error occurs
    * **Warning**: used when a potential issue is detected
    * **Fault**: used when a severe error occurs
    * **Critical**: used when a fatal error occurs

    Convenience presets are also available:

    * **.default**: `.debug`, `.warning`, `.error`, `.fault`, `.critical`
    * **.all**: all levels (`.notice`, `.debug`, `.trace`, `.info`, `.error`, `.warning`, `.fault`, `.critical`)

    ### Custom Logger

    You can also implement your own custom logger by implementing the `RiveLog.Logger` protocol. This allows you to log to any desired sink, such as a file, a network endpoint, or a custom console.

    ```swift theme={null}
    nonisolated public protocol Logger: Sendable {
        nonisolated func notice(tag: Tag, _ message: @escaping () -> String)
        nonisolated func debug(tag: Tag, _ message: @escaping () -> String)
        nonisolated func trace(tag: Tag, _ message: @escaping () -> String)
        nonisolated func info(tag: Tag, _ message: @escaping () -> String)
        nonisolated func error(tag: Tag, error _: (any Error)?, _ message: @escaping () -> String)
        nonisolated func warning(tag: Tag, _ message: @escaping () -> String)
        nonisolated func fault(tag: Tag, _ message: @escaping () -> String)
        nonisolated func critical(tag: Tag, _ message: @escaping () -> String)
    }
    ```

    Once you have implemented your own logger, you can set it to the `RiveLog.logger` property.

    ```swift theme={null}
    RiveLog.logger = MyLogger()
    ```
  </Tab>

  <Tab title={Apple.legacyRuntimeName}>
    ```
    RiveLogger.isEnabled = true // Enable logging; false by default
    RiveLogger.levels = [.debug] // Filter logs; all by default
    RiveLogger.categories = [.viewModel] // Filter categories; all by default
    RiveLogger.isVerbose = true // Include verbose logs; false by default
    ```
  </Tab>
</Tabs>