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Configuration

As we've seen in the Quickstart example, a simple call to Invirt() wires the framework with its default configuration. However, you can customise the behaviour of the framework by passing an InvirtConfig object to this initialisation call.

The Invirt configuration object controls how the framework behaves in different environments, and allows you to customise the Pebble template engine used by Invirt.

Below is the configuration object with its default values. There are a set of sensible defaults which you can override as needed.

data class InvirtConfig(
    val developmentMode: Boolean = Environment.ENV.developmentMode,
    val pebble: InvirtPebbleConfig = InvirtPebbleConfig()
)

data class InvirtPebbleConfig(
    val classpathLocation: String = "webapp/views",
    val hotReloadDirectory: String = "src/main/resources/webapp/views",
    val extensions: List<Extension> = emptyList(),
    val globalVariables: Map<String, Any> = emptyMap()
)

Development mode​

The flag InvirtConfig.developmentMode is used to enable hot reload capabilities when running the application locally. By default, this flag is read from the DEVELOPMENT_MODE environment variable as discussed here.

When set to true, the framework will look for templates in the InvirtPebbleConfig.hotReloadDirectory path, and any template edits will be immediately visible (for example via a browser refresh). This is typically useful on a local development environment.

When set to false, the framework will look for templates in the InvirtPebbleConfig.classpathLocation path with additional caching capabilities using http4k's built-in components. This is typically used when deploying the application in production.

Pebble configuration​

The InvirtPebbleConfig object allows you to customise the Pebble template engine used by Invirt.

  • classpathLocation is the path where the framework will look for templates when developmentMode is false.
  • hotReloadDirectory is the path where the framework will look for templates when developmentMode is true.
  • extensions is a list of custom Pebble extensions that you can use to expose custom Pebble capabilities to your template rendering. See this example for an application using a custom Pebble extension.
  • globalVariables is a map of global variables that will be available in all Pebble templates. Particularly useful for exposing application-wide configuration or constants like a static assets version, for example.