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Enable verbose logging for input events (Components v1)

Adding extra logging for input event dispatch allows you to see what (and how) components are handling event dispatch.

To enable vebose logging for components that use fxl to parse their args, add the --verbose flag to its invocation. For example, Root Presenter and Scenic components can issue verbose logging.

The following sample code shows the component manifest (.cmx) of a test that starts a Scenic component in its injected-services clause:

  "facets": {
    "fuchsia.test": {
      "injected-services": {
        "fuchsia.ui.scenic.Scenic": "fuchsia-pkg://",

To add extra logging for input event dispatch, modify the fuchsia.ui.scenic.Scenic line in the following way:

"fuchsia.ui.scenic.Scenic": [ "fuchsia-pkg://", "--verbose=2" ],

Each service instance of Scenic (or Root Presenter) must be modified, unless you know that service is invoked first.

In most ways, this is identical to modifying a sysmgr services configuration file.