Gradle Plugin (Android)

The Emerge Gradle plugin is the recommended way to integrate with Emerge on Android. Its main features are:

  • Uploading builds to Emerge for size analysis, snapshot testing, reaper & performance analysis.
  • Automatically run snapshot tests for all Compose Previews
  • Integrate Reaper, Emerge's dead code detection SDK, with your app
  • Debug & run performance and snapshot tests locally

Quick setup (~10 minutes)

Add the Gradle plugin portal to your plugin repositories

The Emerge Gradle plugin is hosted by the Gradle plugin portal. In new projects it should already be part of the plugin repositories. If not, you'll need to add it in settings.gradle(.kts):

pluginManagement {
  repositories {
    gradlePluginPortal()
  }
}

Add the Gradle plugin dependency

Add the gradle plugin dependency to your lib.versions.toml plugin dependency definitions.

[versions]
emergeGradlePlugin = "<latest_version>"

[plugins]
emerge = { id = "com.emergetools.android", version.ref = "emergeGradlePlugin"}

Latest gradle plugin version: Gradle Plugin Portal Version

Apply the Emerge Gradle plugin to your application module

In your application module's build.gradle(.kts):

plugins {
  id("com.emergetools.android")
}

emerge {
  // Emerge uses the EMERGE_API_TOKEN env variable by default if no value is set
  apiToken.set(System.getenv("EMERGE_API_TOKEN"))
}

Obtain an API key

Follow our guide on obtaining an API key.

We recommend storing this token in a secrets store, an environment variable, or a Gradle property file. The example in this guide uses the EMERGE_API_TOKEN environment variable, which the Emerge plugin will pick up and set as the default value. for apiToken.

Run a preflight check

Let's check that everything's setup properly by running one of Emerge's preflight tasks for size analysis, snapshots or Reaper. Run ./gradlew :<app>:tasks to see all available tasks. For demo purposes, we'll run a size analysis preflight task:

./gradlew :<app>:emergeSizeAnalysisPreflightRelease

Which will give detailed output about the Emerge integration:

› ./gradlew :app:emergeSizeAnalysisPreflightRelease

> Task :app:emergeSizeAnalysisPreflightRelease

╔════════════════════════════════════════════════════╗
║ Size analysis preflight check was successful (2/2) ║
╠════════════════════════════════════════════════════╝
╠═ ✅ Emerge API token set
╚═ ✅ Size analysis enabled


╔═════════════════════════════════════╗
║ VCS Info check was successful (4/4) ║
╠═════════════════════════════════════╝
╠═ ✅ SHA: 123456789..
╠═ ✅ Base SHA: 987654321..
╠═ ✅ Branch name: main
╚═ ✅ PR number: 123

Size analysis preflight was successful!
Upload & run size analysis on Emerge with ./gradlew :app:emergeUploadReleaseAab

If there are any issues or warnings, the preflight tasks should help you identify and address them before uploading to Emerge. Let the Emerge team know if you have any unexpected issues.

👍

All done!

You're ready to start using the Emerge Gradle plugin. Read on for some commonly used tasks.

Tasks

Emerge offers numerous tasks to help facilitate common use cases. We recommend running these in CI to get the full functionality Emerge offers.

Size

TaskDescription
emergeSizeAnalysisPreflight{Variant}Run a preflight check to validate if size analysis is properly set up for the specific variant.
emergeUpload{Variant}ApkUpload an APK matching the specified variant to Emerge for size analysis.
emergeUpload{Variant}AabUpload an AAB matching the specified variant to Emerge for size analysis.

Snapshots

TaskDescription
emergeSnapshotsPreflight{Variant}Run a preflight check to validate if snapshots are properly set up for the specific variant.
emergeUploadSnapshotBundle{Variant}Builds & uploads target & test APKs for the specified variant. Snapshots will be generated & saved in Emerge's cloud snapshot offering.
emergeLocalSnapshots{Variant}Run snapshot tests locally.

Note: The local snapshots task relies on ADB to run. Ensure a device or emulator is
connected/running and ANDROID_HOME set to the location of the Android SDK is on your PATH.

Reaper

TaskDescription
emergeReaperPreflight{Variant}Run a preflight check to validate if reaper is properly set up for the specific variant.

Reaper hooks into the default AGP bundle{Variant} task to upload the app to Emerge. Reaper requires the release app to be uploaded so Emerge can determine all classes present within the app to associate with reports. For full reaper details, see Reaper Android.

Performance

TaskDescription
emergeGeneratePerformanceProjectCreate a pre-configured Emerge performance module. Only available if perfProjectPath value is set and doesn't yet exist .
emergeUpload{Variant}PerfBundleUpload an AAB matching the specified variant to Emerge packaged with the perfProjectPath's test APK.
emergeLocal{Variant}TestRun performance tests from perfProjectPath locally for debugging & testing.

Note: If wanting to run size & custom performance tests for an upload, you can just use the emergeUpload{variant}PerfBundle task. We'll automatically run size analysis for the release build as well 😄

Configuration

The Emerge Gradle plugin is designed to be configured in the application-level build.gradle(.kts) file of your project.

Depending on your configuration, in your project's root build.gradle(.kts) file, you might need to include the Emerge gradle plugin, but not apply it, to ensure the plugin is available in your project's classpath:

// root-level build.gradle.kts
plugins {
  // ..
  id("com.emergetools.android") version "<latest_version>" apply false
}

Latest gradle plugin version: Gradle Plugin Portal Version

Full configuration

// app-module build.gradle.kts
plugins {
  id("com.emergetools.android")
}

emerge {
  // If not explicitly set, Emerge uses the EMERGE_API_TOKEN env variable
  apiToken.set(System.getenv("EMERGE_API_TOKEN"))

  // Defaults to true, if true, dependency info (module & third party) is included in upload to Emerge
  includeDependencyInformation.set(true)

  // Optional, defaults to false, use to execute tasks without uploading to Emerge
  dryRun.set(false)

  verbose.set(false)

  vcs {
    // Optional, will attempt to set automatically using Git information.
    sha.set("..")
    // Optional, will attempt to set automatically using Git information.
    baseSha.set("..")
    // Optional, will attempt to set automatically using Git information.
    branchName.set("my-feature")

    prNumber.set("123")

    gitHub {
      // Required for CI status checks (only if using GitHub) - Emerge will attempt to set with GitHub event info
      repoOwner.set("..")
      // Required for CI status checks (only if using GitHub) - Emerge will attempt to set with GitHub event info
      repoName.set("..")
      // Optional, defaults to true, include GitHub event data in upload for debugging
      includeEventInformation.set(true)
    }

    gitLab {
      // Required for CI status checks (only if using GitLab)
      projectId.set("..")
    }
  }

  size {
    // Optional, defaults to 'release'
    tag.set("release")
    // Alternatively, use `setFromVariant()` to set the tag from the Android build variant name
    tag.setFromVariant()

    // If size tasks/project configuration are enabled.
    enabled.set(true)
  }

  snapshots {
    // Storage of locally generated snapshots
    snapshotsStorageDirectory.set("/src/main/snapshots")
    // Android API version to run snapshots on, must be 29, 31, 33 or 34.
    apiVersion.set(33)
    // Include private previews in snapshot generation - defaults to true
    includePrivatePreviews.set(false)

    // Optional, snapshots use debug builds, we recommend using a separate tag.
    tag.set("snapshots")
    // Alternatively, use `setFromVariant()` to set the tag from the Android build variant name
    tag.setFromVariant()

    // If snapshot tasks/project configuration are enabled.
    enabled.set(true)
  }

  reaper {
    // The build variants Reaper is enabled for.
    // When Reaper is enabled the application bytecode will be instrumented to support Reaper.
    enabledVariants.set(listOf("release", "releaseVariant2"))
    // The key used to identify Reaper reports for your organization. Emerge recommends setting this as an environment variable
    // Note: This key is not the same as the API key used for uploading to Emerge - you can find this
    publishableApiKey.set(System.getenv("REAPER_API_TOKEN"))

    // Optional, defaults to 'release'
    tag.set("release")
    // Alternatively, use `setFromVariant()` to set the tag from the Android build variant name
    tag.setFromVariant()

  }

  performance {
    // Required for performance testing
    projectPath.set(":perf")

    // Optional, defaults to 'release'
    tag.set("release")
    // Alternatively, use `setFromVariant()` to set the tag from the Android build variant
    tag.setFromVariant()

    // If performance tasks/project configuration are enabled.
    enabled.set(true)
  }
}

VCS

Emerge works best as part of your CI workflow for diffing and comparing size, snapshots and
performance. To ensure these comparisons are accurate, Emerge leverages VCS information to
accurately determine the proper comparison builds.

By default, Emerge attempts to set necessary Git values automatically for you. If you need to override these
values, you can do so using the vcs extension.

emerge {
  vcs {
    sha.set("...") // Optional, will be set automatically using Git information.
    baseSha.set("...") // Optional, will be set automatically using Git information.
    branchName.set("my-feature") // Optional, will be set automatically using Git information.
    prNumber.set("123") // Required for PR status checks & comments, not set automatically.
  }
}
Properties
FieldTypeDefaultDescription
shaStringHEAD branch commit shaThe Git sha of the HEAD build.
baseShaStringbase branch commit shaThe Git sha of the base build to compare against.
branchNameStringCurrent branch nameThe name of the branch being built.
prNumberStringThe number of the pull request being built.
gitHub.repoOwnerStringRepo ID before '/'The owner of the GitHub repository.
gitHub.repoNameStringRepo ID after '/'The name of the GitHub repository.
gitHub.includeEventInformationbooleantrueWhether to include GitHub event data for debugging.
gitLab.projectIdStringThe ID of the GitLab repository.

GitHub

The GitHub sub-extension can be used to set GitHub-specific values. These are set automatically
using repoId information from git's remoteUrl if not specified.

These are used for CI integrations, like posting GitHub comments and status checks.

emerge {
  vcs {
    ..

    gitHub {
      repoOwner.set("...") // Required for CI status checks (only if using GitHub)
      repoName.set("...") // Required for CI status checks (only if using GitHub)
      
      includeEventInformation.set(true) // Default true, whether to include GitHub event data for debugging.
    }
  }
}

GitLab

The GitLab sub-extension can be used to set GitLab-specific values. Unlike GitHub values, these
are not set automatically and will need to be set manually for GitLab CI integration.

emerge {
  vcs {
    ..

    gitLab {
      projectId.set("...") // Required for CI status checks (only if using GitLab)
    }
  }
}

Size

The size extension allows you to configure size-specific properties.

emerge {
  ...

  size {
    tag.set("release") // Optional, tag to use for grouping builds in the Emerge dashboard
    // Alternatively, use `setFromVariant()` to set the tag from the Android build variant
    tag.setFromVariant()

    // If size tasks/project configuration are enabled.
    enabled.set(true)
  }
}
Properties
FieldTypeDefaultDescription
tagStringreleaseThe tag to use for grouping builds in the Emerge dashboard.
enabledBooleantrueIf size tasks/project configuration are enabled.

Snapshots

See the Emerge Snapshots documentation for all info on setting up snapshot testing.

emerge {
  ...

  snapshots {
    // Path to local snapshot image storage, defaults to `/build/emerge/snapshots/outputs`
    snapshotsStorageDirectory.set("/src/main/snapshots")

    // Android API version to run snapshots on, must be 29, 31, 33 or 34.
    apiVersion.set(33)

    // Include private previews in snapshot generation - defaults to true
    includePrivatePreviews.set(false)

    // Tag to use for grouping builds in the Emerge dashboard
    tag.set("snapshots")
    // Alternatively, use `setFromVariant()` to set the tag from the Android build variant
    tag.setFromVariant()

    // If performance tasks/project configuration are enabled.
    enabled.set(true)
  }
}
Properties
FieldTypeDefaultDescription
snapshotsStorageDirectoryString/build/emerge/snapshots/outputsPath to local snapshot image storage
apiVersionInt34The Android API version to use for snapshot generation. Must be an int value in 29, 31, 33 or 34.
includePrivatePreviewsbooleantrueInclude private previews in snapshot generation
tagStringreleaseThe tag to use for grouping builds in the Emerge dashboard.
enabledBooleantrueIf snapshot tasks/project configuration are enabled.

Reaper

The reaper extension allows you to configure reaper-specific fields.

By default, Reaper will hook into the default bundle<variant> task for any enabledVariants to
upload the built app to Emerge for detecting all classes. See the Reaper docs for more information.

emerge {
  ...

  reaper {
    // The build variants Reaper is enabled for.
    // When Reaper is enabled the application bytecode will be instrumented to support Reaper.
    enabledVariants.set(listOf("release", "releaseVariant2"))
    // The key used to identify Reaper reports for your organization. Emerge recommends setting this as an environment variable
    // Note: This key is not the same as the API key used for uploading to Emerge - you can find this
    publishableApiKey.set(System.getenv("REAPER_API_TOKEN"))

    // Optional, defaults to 'release'
    tag.set("release")
    // Alternatively, use `setFromVariant()` to set the tag from the Android build variant name
    tag.setFromVariant()
  }
}
Properties
FieldTypeDefaultDescription
enabledVariantsList<String>The build variants Reaper is enabled for.
publishableApiKeyStringThis key is used to identify Reaper reports sent from your application for your organization. It is safe to include in client-side code. The key can be found at here.
tagStringreleaseThe tag to use for grouping builds in the Emerge dashboard.
enabledBooleanfalseInstruments compiled bytecode to support Reaper and auto-initializes Reaper at runtime.

Performance

By default, Emerge will automatically add the necessary build configuration needed for the
specified perfProjectPath module.

Additionally, the performance extension allows you to configure perf-specific properties.

emerge {
  ...

  performance {
    perfProjectPath.set(":perf") // Required, Module path to the Emerge performance module
    tag.set("release") // Optional, tag to use for grouping builds in the Emerge dashboard
    // Alternatively, use `setFromVariant()` to set the tag from the Android build variant
    tag.setFromVariant()
  }
}
Properties
FieldTypeDefaultDescription
perfProjectPathStringThe module path to the Emerge performance module.
tagStringreleaseThe tag to use for grouping builds in the Emerge dashboard.
enabledBooleantrueIf performance tasks/project configuration are enabled.

Configuration cache support

The 2.0 release of the Emerge gradle plugin supports the Gradle configuration cache. All future versions should be fully compliant. Let us know if you experience a configuration cache violation or open an issue in the [emerge-android repo](https://github.com/EmergeTools/emerge-android)!

Migrating from older plugin versions

2.X

  • buildType has been removed in favor of tag. No functional changes other than naming need to be done to update.