Dexcount Gradle Plugin

A Gradle plugin to report the number of method references in your APK on every build.

This helps you keep tabs on the growth of your app, with an eye to staying under the 65,536 method-reference limit, and avoiding the headache of eliminating methods or enabling multidex.

Usage

in app/build.gradle

buildscript {
    repositories {
        mavenCentral() // or jcenter()
    }

    dependencies {
        classpath 'com.getkeepsafe.dexcount:dexcount-gradle-plugin:0.6.2'
    }
}

// make sure this line comes *after* you apply the Android plugin
apply plugin: 'com.getkeepsafe.dexcount'

Note

dexcount-gradle-plugin "requires" Java 8 to run. "Requires" means that, while it will technically work if Gradle is being run on Java 7, there are situations where it may crash. This is caused by dependencies we don't bundle targeting JRE 8; these cannot be loaded on older runtimes. Attempting to load them will crash Gradle. This currently applies only to counting .aar library projects, but as time goes by the JRE-8-only surface area will only increase.

Sample output

> ./gradlew assembleDebug

...buildspam...
:app:compileDebugSources
:app:preDexDebug UP-TO-DATE
:app:dexDebug
:app:packageDebug
:app:zipalignDebug
:app:assembleDebug
Total methods in MyApp-debug.apk: 58930 (89.92% used)
Total fields in MyApp-debug.apk:  27507 (41.97% used)
Methods remaining in MyApp-debug.apk: 6605
Fields remaining in MyApp-debug.apk:  38028


BUILD SUCCESSFUL

Total time: 33.017 secs

Detailed method counts

By default, a breakdown of method references by package and class will be written to a file under ${buildDir}/outputs/dexcount/${variant}.

For example, an excerpt from our own app (in app/build/outputs/dexcount/debug.txt):

methods  fields   package/class name
5037     1103     android.support.v4
29       1        android.support.v4.accessibilityservice
57       16       android.support.v4.animation
931      405      android.support.v4.app
87       31       android.support.v4.content
139      12       android.support.v4.graphics
116      11       android.support.v4.graphics.drawable
74       9        android.support.v4.internal
74       9        android.support.v4.internal.view
194      35       android.support.v4.media
11       0        android.support.v4.media.routing
156      26       android.support.v4.media.session

Configuration

Dexcount is configurable via a Gradle extension (shown with default values):

in app/build.gradle:

dexcount {
    format = "list"
    includeClasses = false
    includeFieldCount = true
    includeTotalMethodCount = false
    orderByMethodCount = false
    verbose = false
    maxTreeDepth = Integer.MAX_VALUE
    teamCityIntegration = false
    enableForInstantRun = false
    teamCitySlug = null
    runOnEachAssemble = true
}

Each flag controls some aspect of the printed output:

• format: The format of the method count output, either "list", "tree", "json", or "yaml".
• includeClasses: When true, individual classes will be include in the package list - otherwise, only packages are included.
• includeFieldCount: When true, the number of fields in a package or class will be included in the printed output.
• includeTotalMethodCount: When true, the total number of methods in the application will be included in the printed output.
• orderByMethodCount: When true, packages will be sorted in descending order by the number of methods they contain.
• verbose: When true, the output file will also be printed to the build's standard output.
• maxTreeDepth: Sets the max number of package segments in the output - i.e. when set to 2, counts stop at com.google, when set to 3 you get com.google.android, etc. "Unlimited" by default.
• teamCityIntegration: When true, Team City integration strings will be printed.
• enableForInstantRun: When true, count methods even for Instant Run builds. False by default.
• teamCitySlug: A string which, if specified, will be added to TeamCity stat names. Null by default.
• runOnEachAssemble: When false, does not run count method during assemble task

Use with Jenkins Plot Plugin

A common use-case is to plot method and field counts across builds. The Jenkins Plot plugin is a general-purpose tool that graphs per-build scalar values through time. It reads java .properties files, CSV files, and XML files. Dexcount generates two files for each variant - a full package list, and a summary CSV file. The summary file is usable as-is with the Jenkins Plot Plugin. You can find it in app/build/outputs/variant.csv (note the .csv extension).

Consult the plugin documentation for details on how to configure it.

Use with Team City

Common case is to enable integration with teamCityIntegration option and add custom statistic graphs in Team City. Key name is generated by pattern DexCount_${variant}_MethodCount and DexCount_${variant}_FieldCount

Technically special strings like ##teamcity[buildStatisticValue key='DexCount_universalDebug_MethodCount' value='62362'] will be printed.

More about integration in Team City doc

If you have multiple products within one project using Dexcount, the default stat names will conflict with each other. In this case, the teamCitySlug configuration option can be useful. It is a string that, if specified, will be added to stat names according to the following scheme: DexCount_${teamCitySlug}_${variant}_${statName}. Note that you can assign a dynamically-evaluated property, e.g. teamCitySlug = project.name.

Note on Instant Run

By default, dexcount-gradle-plugin does not apply to Instant Run builds in Android Studio. Instant Run is implemented in such a way that it makes method counts very inaccurate: it adds generated code to your APK as well as disabling Proguard. Additionally, method counting can take anywhere from half a second to several seconds. A drop in the bucket for full builds, but Instant Run builds can take as little as three seconds, making dexcount relatively quite expensive. For these reason, the plugin is disabled by default.

If, bearing in mind that counts will be wrong, you still wish to count methods on Instant Run, setting enableForInstantRun in the plugin configuration will make that happen.

Snapshot Builds

We host snapshots in the Sonatype OSS repo. They are updated on each commit. As snapshots, they are inherently unstable - use at your own risk! To use them, add the Sonatype Snapshot repo to your repositories:

buildscript {
  repositories {
    // other repos should come first
    maven { url 'https://oss.sonatype.org/content/repositories/snapshots' }
  }

  dependencies {
    classpath 'com.getkeepsafe.dexcount:dexcount-gradle-plugin:0.6.2-SNAPSHOT'
  }
}

Building

./gradlew build

Pushing artifacts to Sonatype requires membership in the KeepSafe Sonatype org, which is by employment only. Once you have a login, put it in your private global Gradle file (e.g. ~/.gradle/gradle.properties, along with a valid GPG signing configuration.

Minutia

This plugin creates a task per output file, per variant, and configures each task to run after that variant's assemble task. This means that if the assemble task does not run, no method count will be reported. This also means that counts are done after Proguard is run, if minification is enabled. Dexcount will use the resulting mapping file to de-obfuscate class and package names.

Credits

The Java code from the com.android.dexdeps package is sourced from the Android source tree. Inspired by Mihail Parparita's dex-method-counts project, to whom much credit is due.

Copyright 2015-2016 Keepsafe Software, Inc