Build properties Gradle plugin

Sometimes you need to inspect information about the current build in your app code. The conventional way is to use custom fields in a BuildConfig or resource values.

android {
  buildTypes {
    release {
      buildConfigField("String", "GIT_COMMIT", "\"${commit}\"")
      resValue("string", "git_commit", "${commit}")
    }
    debug {
      // To avoid rebuilding
      buildConfigField("String", "GIT_COMMIT", "\"_\"")
      resValue("string", "git_commit", "_")
    }
  }
}

BuildConfig and R classes are used to compile the code. Any changes harm incremental compilation and build caching. This is a known problem: unstable task inputs.

To mitigate this issue the plugin uses assets to store properties. This approach is less harmful for incremental compilation and build caching.

Getting started

1. Apply the plugin in the Android module's build script

plugins {
    id("com.avito.android.build-properties")
}

Setup plugins

In the settings.gradle:

pluginManagement {
    repositories {
        mavenCentral()
    }
    resolutionStrategy {
        eachPlugin {
            String pluginId = requested.id.id
            if (pluginId.startsWith("com.avito.android")) {
                def artifact = pluginId.replace("com.avito.android.", "")
                useModule("com.avito.android:$artifact:$avitoToolsVersion")
            }
        }
    }
}

avitoToolsVersion could be exact version, or property in project's gradle.properties. The latest version could be found on project's release page.

2. Define properties in a build script

Kotlin

build.gradle.kts

buildProperties {
    buildProperty("GIT_COMMIT", commit)
}

Groovy

build.gradle

buildProperties {
    buildProperty("GIT_COMMIT", commit)
}

3. Add auto-generated file to the .gitignore config

Content of this file depends on the build. It's no use to store it in VCS.

build-info.properties

4. Read properties in the code

val properties = Properties()
context.assets.open("build-info.properties").use {
    properties.load(it)
}
val gitCommit = properties.getProperty("GIT_COMMIT")