Vaadin Package Scanner Gradle Plugin

WORK IN PROGRESS

Generate the setting vaadin.whitelisted-packages in src/main/resources/application.properties for Vaadin Flow/Spring projects.

In a Vaadin Flow project, on startup there is intensive search for annotations, that influence the application. E.g. Vaadin tries to find CSS and JavaScript files to include into the build or looks for NPM packages to download.

In a growing project, this is a growing overhead on each start, especially while developing. There even is a warning in the dev server, when this takes longer than 10 seconds, which is an unacceptable long time especially if you don't have hot-reload available.

To limit the locations where to look for the annotations, there are two settings to allow or deny a list of package names. Since adding or creating new components is the rarest event, that needs changing this lists, recreating the allow-list when needed, is the most efficient way to deal with this.

And this is what is plugin for:

• Add the plugin in your build.gradle file, where Vaadin Flow is used.
• Optionally configure the plugin.
• Run ./gradlew vaadinScanPackages to re-create the allow-list from the current class-path.
• When adding new deps or creating new components yourself, re-run the task to update the setting.

Setup

Add the plugin in your build.gradle

plugins {
    // ...
    id 'net.ofnir.gradle.vaadin-package-scanner' version "${vaadinPackageScannerPluginVersion}"
}

Usage

Run:

# ./gradlew vaadinScanPackages
...
> Task :vaadinScanPackages
Updated Vaadin package allow list (vaadin.whitelisted-packages) in .../src/main/resources/application.properties

Configuration

The default configuration aims to work out of the box with the current LTS version (23 as of this writing).

vaadinScanPackages {
    // Gradle source set to search for deps; should represent the
    // effective runtime classpath
    sourceSetName = 'main'
    // The full qualified class name, that Vaadin uses itself to load
    // deps (usually the one with `HandlesTypes`
    markerClassName = 'com.vaadin.base.devserver.startup.DevModeStartupListener'
    // Annotation on marker class, that contains the list of interface
    // to look for deps
    handlesTypesAnnotationClassName = 'javax.servlet.annotation.HandlesTypes'
    // Ignored packages, that never get added to the allow list;
    // By default `com.vaadin.flow.component` as it's always in included
    // by Vaadin
    alwaysBlockRegexp = /^com\.vaadin\.flow\.component($|\..*)/
    // File to create/append the allow-list too
    applicationProperties = "${projectDir}/src/main/resources/application.properties"
    // Key of the property inside the properties file, to set the
    // allow-list too
    vaadinProperty = 'vaadin.whitelisted-packages'
}

Vaadin 23

Defaults will suffice.

Vaadin 14

• Different markerClassName

vaadinScanPackages {
    markerClassName = 'com.vaadin.flow.server.startup.DevModeInitializer'
}