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Android CI
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| #Android and CI and Gradle (A How-To) | |
| There are tech stacks in this world that make it dead simple to integrate a <abbr title="Continuous Integration">CI</abbr> build system. <br> | |
| The Android platform is not one of them. | |
| Although Gradle is getting better, it's still a bit non-deterministic, and some of the fixes you'll need will start to feel more like black magic than any sort of programming. | |
| But fear not! It can be done! | |
| Before we embark on our journey, you'll need a few things to run locally: | |
| 1. A (working) Gradle build | |
| 2. Automated tests (JUnit, Espresso, etc.) | |
| If you don't have Gradle set up for your build system, it is highly recommend that you move your projects over. Android Studio has a built-in migration tool, and the [Android Dev Tools website](http://tools.android.com/tech-docs/new-build-system/intellij_to_gradle) has an excellent guide on how to migrate over to the Gradle build system, whether you're on Maven, Ant, or some unholy combination of all three. | |
| A very general example of a `build.gradle` file follows: | |
| ```gradle | |
| //build.gradle in /app | |
| apply plugin: 'com.android.application' | |
| buildscript { | |
| repositories { | |
| mavenCentral() | |
| } | |
| dependencies { | |
| classpath 'com.android.tools.build:gradle:0.13.2' | |
| } | |
| } | |
| //See note below | |
| task wrapper(type: Wrapper) { | |
| gradleVersion = '2.1' | |
| } | |
| android { | |
| compileSdkVersion 19 | |
| buildToolsVersion "20.0.0" | |
| defaultConfig { | |
| applicationId "com.example.originate" | |
| minSdkVersion 14 | |
| targetSdkVersion 19 | |
| versionCode 1 | |
| versionName "1.0" | |
| testApplicationId "com.example.originate.tests" | |
| testInstrumentationRunner "android.test.InstrumentationTestRunner" | |
| } | |
| buildTypes { | |
| debug { | |
| debuggable true | |
| } | |
| release { | |
| debuggable false | |
| } | |
| } | |
| } | |
| dependencies { | |
| compile project(':libProject') | |
| compile com.android.support:support-v4:21.0.+ | |
| } | |
| ``` | |
| *(**NOTE**: the Gradle Wrapper task isn't strictly necessary, but a highly recommended way of ensuring you always know what version of Gradle you're using - both for futureproofing and for regressions)* | |
| Check out the [Android Developers website](http://developer.android.com/sdk/installing/studio-build.html) for some good explanations and samples. | |
| ##Choose your weapon | |
| Personally, I'm a fan of [CircleCI](circleci.com). They sport a clean, easy-to-use interface, support more languages than you could possibly care about. Plus, they are [free for open source Github projects!](http://blog.circleci.com/a-step-into-open-source/)<br> | |
| (Other options include [TravisCI](https://travis-ci.org/), [Jenkins](http://jenkins-ci.org/), and [Bamboo](https://www.atlassian.com/software/bamboo)) | |
| In this guide, we'll be using CircleCI, but these instructions should translate readily to TravisCI. | |
| ##Configure all the things! | |
| In order to use CircleCI to build/test your Android library, there's some configuration necessary. | |
| Below are some snippets of some of the basis configurations you might want/do. About half of this comes from the [CircleCI docs](https://circleci.com/docs/android) and half of it comes from my blood, sweat, and tears. | |
| At the end of this section, I'll include a complete `circle.yml` file. | |
| ###Machine | |
| First, the code: | |
| ```yml | |
| machine: | |
| environment: | |
| ANDROID_HOME: /home/ubuntu/android | |
| java: | |
| version: oraclejdk6 | |
| ``` | |
| 1. The setting of the `ANDROID_HOME` environment variable is necessary for the Android SDKs to function properly. It'll also be useful for booting up the emulator in later steps. | |
| 2. Although setting the JDK version isn't strictly necessary, it's nice to ensure that it doesn't change behind-the-scenes and possibly surprise-bork your build. | |
| ###Dependencies + Caching | |
| ```yml | |
| dependencies: | |
| cache_directories: | |
| - ~/.android | |
| - ~/android | |
| override: | |
| - (source scripts/environmentSetup.sh && getAndroidSDK) | |
| ``` | |
| 1. By default, CircleCI will cache nothing. You might think this a non-issue right now, but you'll reconsider when each build takes 10+ minutes to inform you that you dropped a semicolon in your log statement. | |
| <br>By caching `~/.android` and `~/android`, you can shave precious minutes off of your build time. | |
| 2. Android provides us with a nifty command-line utility called...`android` (inventive!). We can use this in little Bash script that we'll write in just a second. For now, just know that `scripts/environmentSetup.sh` can be whatever you want, as can the Bash function `getAndroidSDK`. | |
| ####Bash Scripts - a Jaunt into the CLI | |
| Gradle is good at a lot of things, but it isn't yet a complete build system. Sometimes, you just need some good ol'fashioned bash scripting. | |
| In this round, we'll download Android API 19 (Android 4.4 Jelly Bean) and create a hardware-accelerated Android AVD (Android Virtual Device - aka "emulator) image. | |
| Note: If `android` commands confuse/scare you, check out the [`android` documentation](http://developer.android.com/tools/help/android.html). | |
| ```bash | |
| #!/bin/bash | |
| # Fix the CircleCI path | |
| function getAndroidSDK(){ | |
| export PATH="$ANDROID_HOME/platform-tools:$ANDROID_HOME/tools:$PATH" | |
| DEPS="$ANDROID_HOME/installed-dependencies" | |
| if [ ! -e $DEPS ]; then | |
| cp -r /usr/local/android-sdk-linux $ANDROID_HOME && | |
| echo y | android update sdk -u -a -t android-19 && | |
| echo y | android update sdk -u -a -t platform-tools && | |
| echo y | android update sdk -u -a -t build-tools-20.0.0 && | |
| echo y | android update sdk -u -a -t sys-img-x86-android-19 && | |
| #echo y | android update sdk -u -a -t addon-google_apis-google-19 && | |
| echo no | android create avd -n testAVD -f -t android-19 --abi default/x86 && | |
| touch $DEPS | |
| fi | |
| } | |
| ``` | |
| 1. The `export PATH` line is to ensure we have access to all of the Android CLI tools we'll need later in the script. | |
| 2. The `DEPS=...` is used in the `if/then` block to determine if CircleCI has already provided us with cached dependencies. If so, there's no to download anything! | |
| 3. Note that we're explicitly requesting the x86 version of the Android 19 emulator image (`sys-img-x86-android-19`). The emulator is notoriously slow, and we should use the hardware-accelerated version if at all possible. | |
| 4. We create the AVD with the line `android create avd ...`, with a `target` of Android 19 and a name of `testAVD`. | |
| 5. If you don't need the Google APIs (e.g., Maps, Play Store, etc.), you don't need to download `addon-google_apis-google-19` - hence why it's commented out! | |
| **CAVEAT** - Because of the way this caching works, if you ever change which version of Android you compile/run against, you need to click the "Rebuild & Clear Cache" button in CircleCI. If you don't, you'll never actually start compiling against the new SDK. You have been warned. | |
| ###You shall not pass! (until your tests have run) | |
| This section will vary greatly depending on your testing setup, so, moreso than with the rest of this post, YMMV. <br>This section is assuming you're using a plain vanilla Android JUnit test suite. | |
| ```yml | |
| test: | |
| pre: | |
| - $ANDROID_HOME/tools/emulator -avd testAVD -no-skin -no-audio -no-window: | |
| background: true | |
| - (./gradlew assembleDebug): | |
| timeout: 1200 | |
| - (./gradlew assembleDebugTest): | |
| timeout: 1200 | |
| - (source scripts/environmentSetup.sh && waitForAVD) | |
| override: | |
| - (./gradlew connectedAndroidTest) | |
| ``` | |
| 1. The `$ANDROID_HOME/tools/emulator` starts a "headless" emulator - namely the one we just created. <br> | |
| a. Running the emulator from the terminal is a blocking command. That's why we are setting the `background: true` attribute on the emulator command. Without this, we would have to wait anywhere between 2-7 minutes for the emulator to start and THEN build the APK, etc. | |
| This way, we kick off the emulator and can get back to building. | |
| 2. The two subsequent `./gradlew` commands use the [Gradle wrapper](http://www.gradle.org/docs/current/userguide/gradle_wrapper.html) (**gradle** +<b>w</b>rapper) to build the code from your `/app` and `androidTest` directories, respectively. | |
| 3. See below for `environmentSetup.sh` Part II. Essentially, after building both the app and the test suite, we cannot continue without the emulator being ready. And so we wait. | |
| 4. Once the emulator is up and running, we run `gradlew connectedAndroidTest`, which, as its name suggests, run the tests on the connected Android device. If you're using Espresso or other test libraries, those commands would go here. <br> | |
| 4a. The CircleCI Android docs say that the "standard" way to run your tests is through ADB - ignore them. Gradle is the future and it elides all of those thorny problems that ADB tests have. | |
| ####Bash Round 2 | |
| As mentioned above, after Gradle has finished building your app and test suite, you'll kind of need the emulator to...y'know...run your tests. | |
| This script relies on the currently-booting AVD's `init.svc.bootanim` property, which essentially tells us whether the boot animation has finished. Sometimes, it seems like it'll go on forever...<br> | |
|  | |
| <br><sup>*will the madness never stop?!*</sup> | |
| This snippet can go in the same file as your previous bash script - in that case, you only need one `#!/bin/bash` - at the top of your file. | |
| ```bash | |
| #!/bin/bash | |
| function waitAVD { | |
| ( | |
| local bootanim="" | |
| export PATH=$(dirname $(dirname $(which android)))/platform-tools:$PATH | |
| until [[ "$bootanim" =~ "stopped" ]]; do | |
| sleep 5 | |
| bootanim=$(adb -e shell getprop init.svc.bootanim 2>&1) | |
| echo "emulator status=$bootanim" | |
| done | |
| ) | |
| } | |
| ``` | |
| Note: This script was adapted from [this busy-wait script](http://blog.crowdint.com/2013/05/17/android-builds-on-travis-ci-with-maven.html). | |
| ###Results | |
| By default, CircleCI will be fairly vague regarding your tests' successes and/or failures. You'll have to go hunting through the very ~~chatty~~ verbose Gradle loggings in order to determine exactly which tests failed. Fortunately, there's a better way - thanks to Gradle! | |
| When you run `gradlew connectedAndroidTests`, Gradle, when finished, will create a folder called `/build/outputs/reports/**testFolderName**/connected` in whichever folder you have a `build.gradle` script in. <br> | |
| So, for example, if your repo was in `~/username/awesomerepo`, with a local library in `awesome_repo/lib` and an app in `/awesome_repo/app`, the Gradle test artifacts should be in `/awesome_repo/app/build/outputs/reports/**testFolderName**/connected`. | |
| In this directory, you'll find a little website that Gradle has generated, showing you which test packages and specific tests passed/failed. | |
| If you like, you can tell CircleCI to grab this by placing the following at the top of your `circle.yml` file: | |
| ```yml | |
| general: | |
| artifacts: | |
| -/home/ubuntu/**repo_name**/build/outputs/reports/**testFolderName**/connected | |
| ``` | |
| You can then peruse your overwhelming success under the **Artifacts** tab for your CircleCI build - just click on `index.html`. | |
| It should pull up something like this: | |
|  | |
| ##Security, Signing, and Keystores | |
| The astute among you will notice that I haven't gone much into the process of signing an Android app. This is mainly for the reason that people trying to set up APK signing fall into 2 categories - Simple and Enterprise. | |
| **Enterprise:** If you're programming Android for a company, you probably have some protocol regarding where your keystores/passwords can and cannot live - so a general guide such as this won't be much help for you. | |
| **Simple:** If you're not Enterprise and you're not currently wearing a tinfoil hat, your security protocol is probably a little more lax. | |
| In either case, [Google and StackOverflow are your friends](http://stackoverflow.com/questions/18328730/how-to-create-a-release-signed-apk-file-using-gradle#comment27871848_18329835). | |
| My final word of advice is that CircleCI can encrypt things like keystore passphrases - stuff you might consider passing in plain-text in your buildscript files. Check out [CircleCI's Environment Variables doc](https://circleci.com/docs/environment-variables). | |
| ##Finally, | |
| Go into your CircleCI settings, add a hook for your Github repo, and then do a `git push origin branchName`. If the Gradle Gods have smiled upon you, Circle should detect your config files and start building and testing! | |
| Depending on your test suite, tests can take as little as a few minutes or as much as a half-hour to run. Try not to [slack off](http://xkcd.com/303/) in the meanwhile, but rejoice in having some solid continuous integration! | |
| Stay tuned for a future blog post about using CircleCI to automagically deploy to MavenCentral! | |
| ##Flipping to the back of the book... | |
| Below is the full `circle.yml` as well as `environmentSetup.sh` for your viewing/copying pleasure: | |
| ```yml | |
| # Build configuration file for Circle CI | |
| # needs to be named `circle.yml` and should be in the top level dir of the repo | |
| general: | |
| artifacts: | |
| -/home/ubuntu/**repo_name**/build/outputs/reports/**testFolderName**/connected | |
| machine: | |
| environment: | |
| ANDROID_HOME: /home/ubuntu/android | |
| java: | |
| version: oraclejdk6 | |
| dependencies: | |
| cache_directories: | |
| - ~/.android | |
| - ~/android | |
| override: | |
| - (echo "Downloading Android SDK v19 now!") | |
| - (source scripts/environmentSetup.sh && getAndroidSDK) | |
| test: | |
| pre: | |
| - $ANDROID_HOME/tools/emulator -avd testAVD -no-skin -no-audio -no-window: | |
| background: true | |
| - (./gradlew assembleDebug): | |
| timeout: 1200 | |
| - (./gradlew assembleDebugTest): | |
| timeout: 1200 | |
| - (source scripts/environmentSetup.sh && waitForAVD) | |
| override: | |
| - (echo "Running JUnit tests!") | |
| - (./gradlew connectedAndroidTest) | |
| ``` | |
| And the accompanying shell scripts: | |
| ```bash | |
| #!/bin/bash | |
| # Fix the CircleCI path | |
| function getAndroidSDK(){ | |
| export PATH="$ANDROID_HOME/platform-tools:$ANDROID_HOME/tools:$PATH" | |
| DEPS="$ANDROID_HOME/installed-dependencies" | |
| if [ ! -e $DEPS ]; then | |
| cp -r /usr/local/android-sdk-linux $ANDROID_HOME && | |
| echo y | android update sdk -u -a -t android-19 && | |
| echo y | android update sdk -u -a -t platform-tools && | |
| echo y | android update sdk -u -a -t build-tools-20.0.0 && | |
| echo y | android update sdk -u -a -t sys-img-x86-android-19 && | |
| #echo y | android update sdk -u -a -t addon-google_apis-google-18 && | |
| echo no | android create avd -n testAVD -f -t android-19 --abi default/x86 && | |
| touch $DEPS | |
| fi | |
| } | |
| function waitForAVD { | |
| ( | |
| local bootanim="" | |
| export PATH=$(dirname $(dirname $(which android)))/platform-tools:$PATH | |
| until [[ "$bootanim" =~ "stopped" ]]; do | |
| sleep 5 | |
| bootanim=$(adb -e shell getprop init.svc.bootanim 2>&1) | |
| echo "emulator status=$bootanim" | |
| done | |
| ) | |
| } | |
| ``` | |
| ##References | |
| - [Android Dev Tools - Migrating to Gradle](http://tools.android.com/tech-docs/new-build-system/intellij_to_gradle) | |
| - [Android-Gradle Plugin User Guide](http://tools.android.com/tech-docs/new-build-system/user-guide) | |
| - [Android Developers Gradle Project walkthrough](http://developer.android.com/sdk/installing/studio-build.html) | |
| - [`android` CLI tool](http://developer.android.com/tools/help/android.html) | |
| - [Gradle Wrapper docs](http://www.gradle.org/docs/current/userguide/gradle_wrapper.html) | |
| - [CircleCI Android Docs](https://circleci.com/docs/android) | |
| - [CircleCI background processes](https://circleci.com/docs/background-process) | |
| - [`circle.yml` dissected](https://circleci.com/docs/configuration) | |
| - [StackOverflow.com](http://stackoverflow.com/) |
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