Migrating Android projects to Cloud Endpoints Frameworks 2.0

This page describes migrating an existing Android Cloud Endpoints version 1.0 app to Endpoints Frameworks for App Engine. Note that this page refers to Endpoints version 1.0 as Endpoints Frameworks version 1.0 and new Endpoints Frameworks for App Engine as Endpoints Frameworks version 2.0.

Benefits

The new framework brings a number of benefits, including:

  • Reduced request latency
  • Better integration with App Engine features, such as custom domains.
  • Official support for Guice configurations
  • Optionally, new API management features

Endpoints Frameworks version 2.0 doesn't affect the interfaces to your API. Existing clients continue to work after migration without any client-side code changes.

Migrating Android multi-module projects to Endpoints Frameworks version 2.0

The following steps guide you through moving Android Studio Endpoints Frameworks version 1.0 projects to Endpoints Frameworks version 2.0. The guide migrates an Android Studio project with a Endpoints module.

Task list

Use the following high-level task list as you work through the migration guide. This migration guide assumes you have an existing Android project using a Google Cloud module.

  1. Before you begin.
  2. Setup the Google Cloud CLI.
  3. Optional: Download the sample code.
  4. Migrate to Endpoints Frameworks version 2.0.
  5. Deploy your backend module.
  6. Generate client libraries.

Before you begin

  1. Install Android Studio.
  2. Install Android SDK 26+.
  3. Install the gcloud CLI.

Set up the gcloud CLI

To setup the gcloud CLI:

  1. Initialize the gcloud CLI:

     gcloud init

  2. Use Application Default Credentials:

     gcloud auth application-default login

  3. Install the app-engine-java component:

     gcloud components install app-engine-java

Optional: Download the sample code

To clone the legacy and v2 sample projects from GitHub:

  1. Clone the sample repository to your local machine:

     git clone https://github.com/GoogleCloudPlatform/android-docs-samples

  2. Change to the directory containing the sample code for legacy and v2:

     cd android-docs-samples/endpoints-frameworks/

Migrate to Endpoints Frameworks version 2.0

Update the build.gradle file

Endpoints Frameworks version 2.0 dependencies use Guava 19 and Android Gradle build plugin com.android.tools.build:gradle:2.3.3 uses Guava 18. Add Guava 19 to the build script dependencies closure of the build.gradle to override this transitive dependency.

Legacy

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.3.3'
    }
}

v2

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        // V2: Include this dependency when using Endpoints Framework v2
        classpath 'com.google.guava:guava:19.0'

        classpath 'com.android.tools.build:gradle:2.3.3'
    }
}

Update the app/build.gradle file

In Endpoints version 1.0, you used the Gradle plugin, gradle-appengine-plugin, to generate an API Discovery Document. In Endpoints Frameworks version 2.0, you use the endpoints-framework-gradle-plugin to generate a Discovery Document.

This build script uses the client-side plugin, com.google.cloud.tools.endpoints-framework-client.

Legacy

apply plugin: 'com.android.application'

android {
    compileSdkVersion 26
    buildToolsVersion '26.0.1'
    defaultConfig {
        applicationId 'com.example.migration.endpoints.app'
        minSdkVersion 25
        targetSdkVersion 26
        versionCode 1
        versionName '1.0'
        testInstrumentationRunner 'android.support.test.runner.AndroidJUnitRunner'
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    configurations.all {
        resolutionStrategy.force 'com.google.code.findbugs:jsr305:2.0.1'
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])

    // androidTestCompile compiles instrumentation tests written using Espresso
    // used by Firebase Test Lab
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })

    compile 'com.android.support:appcompat-v7:26.+'
    compile 'com.android.support.constraint:constraint-layout:1.0.1'
    compile 'com.google.code.findbugs:jsr305:2.0.1'
    compile 'com.google.http-client:google-http-client-android:1.22.0'
    compile 'com.google.api-client:google-api-client:+'
    testCompile 'junit:junit:4.12'

    // LEGACY: Legacy compile :backend project
    compile project(path: ':backend', configuration: 'android-endpoints')
}

v2

apply plugin: 'com.android.application'

// V2: Apply the new Endpoints Framework client plugin
apply plugin: 'com.google.cloud.tools.endpoints-framework-client'

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        // V2: Add the new Endpoints Framework plugin dependencies
        classpath 'com.google.cloud.tools:endpoints-framework-gradle-plugin:1.0.2'
    }
}

android {
    compileSdkVersion 26
    buildToolsVersion '26.0.1'
    defaultConfig {
        applicationId 'com.example.migration.endpoints.app'
        minSdkVersion 25
        targetSdkVersion 26
        versionCode 1
        versionName '1.0'
        testInstrumentationRunner 'android.support.test.runner.AndroidJUnitRunner'
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    configurations.all {
        resolutionStrategy.force 'com.google.code.findbugs:jsr305:2.0.1'
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])

    // androidTestCompile compiles instrumentation tests written using Espresso
    // used by Firebase Test Lab
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })

    compile 'com.android.support:appcompat-v7:26.+'
    compile 'com.android.support.constraint:constraint-layout:1.0.1'
    compile 'com.google.code.findbugs:jsr305:2.0.1'
    testCompile 'junit:junit:4.12'

    // V2: Endpoints Framework v2 migration
    endpointsServer project(path: ':backend', configuration: 'endpoints')
    compile 'com.google.api-client:google-api-client:+'
    compile 'com.google.http-client:google-http-client-android:1.22.0'
}

Update the backend/build.gradle file

The App Engine standard environment Gradle tooling was updated. Endpoints Frameworks version 1.0 projects used the gradle-appengine-plugin in com.google.appengine, and Endpoints Frameworks version 2.0 projects use appengine-gradle-plugin.

This build script uses the server-side plugin, com.google.cloud.tools.endpoints-framework-server.

Legacy

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        // LEGACY: Deprecated App Engine plugin dependency
        classpath 'com.google.appengine:gradle-appengine-plugin:1.9.59'
    }
}

repositories {
    jcenter();
}

apply plugin: 'java'
apply plugin: 'war'

// LEGACY: Deprecated Apply App Engine plugin dependency
apply plugin: 'appengine'

sourceCompatibility = JavaVersion.VERSION_1_7
targetCompatibility = JavaVersion.VERSION_1_7

dependencies {
    // LEGACY: Deprecated App Engine plugin dependency
    appengineSdk 'com.google.appengine:appengine-java-sdk:1.9.59'

    // LEGACY: Legacy Endpoints Framework dependencies
    compile 'com.google.appengine:appengine-endpoints:1.9.59'
    compile 'com.google.appengine:appengine-endpoints-deps:1.9.59'

    compile 'javax.servlet:servlet-api:2.5'
}

appengine { // LEGACY: Deprecated App Engine plugin Tasks configuration
    downloadSdk = true
    appcfg {
        oauth2 = true

        // extraOptions is used for acceptance test and
        // is not required.
        def application = findProperty("appengine.deploy.application")
        def version = findProperty("appengine.deploy.version")
        def serviceAccount = findProperty("appengine.deploy.serviceAccount")

        extraOptions = ["--application=" + application, "--version=" + version,
            '--service_account_json_key_file=' + serviceAccount]
    }
    endpoints {
        getClientLibsOnBuild = true
        getDiscoveryDocsOnBuild = true
    }
}

v2

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        // V2: Add the new App Engine and Endpoints Frameworks plugin dependencies
        classpath 'com.google.cloud.tools:endpoints-framework-gradle-plugin:1.0.2'
        classpath 'com.google.cloud.tools:appengine-gradle-plugin:1.3.3'
    }
}

repositories {
    jcenter();
}

apply plugin: 'java'
apply plugin: 'war'

// V2: Apply new App Engine and Endpoints Framework server plugins
apply plugin: 'com.google.cloud.tools.appengine'
apply plugin: 'com.google.cloud.tools.endpoints-framework-server'

sourceCompatibility = JavaVersion.VERSION_1_7
targetCompatibility = JavaVersion.VERSION_1_7

dependencies {
    // V2: Endpoints Framework v2 migration
    compile 'com.google.endpoints:endpoints-framework:2.0.9'
    compile 'javax.inject:javax.inject:1'

    compile 'javax.servlet:servlet-api:2.5'
}

// V2: Define deployment configuration using the new App Engine plugin
// with the appengine closure
appengine {  // App Engine tasks configuration
    deploy {   // deploy configuration

        // The following is used for acceptance tests and
        // is not required for a migration.
        project = findProperty("appengine.deploy.project")
        version = findProperty("appengine.deploy.version")
        def promoteProp = findProperty("appengine.deploy.promote")
        if (promoteProp != null) {
            promote = new Boolean(promoteProp)
        }
    }
}

Update the web.xml file

In Endpoints Frameworks version 2.0, the servlet-class changed from SystemServiceServlet to EndpointsServlet.

The URL pattern was updated from /_ah/spi/* to /_ah/api/*.

Legacy

<servlet>
    <!-- LEGACY: Start of Legacy section -->
    <servlet-name>SystemServiceServlet</servlet-name>
    <servlet-class>com.google.api.server.spi.SystemServiceServlet</servlet-class>
    <!-- LEGACY: End of Legacy section -->
    <init-param>
        <param-name>services</param-name>
        <param-value>com.example.migration.endpoints.backend.MyEndpoint</param-value>
    </init-param>
</servlet>
<servlet-mapping>
    <!-- LEGACY: Start of legacy section -->
    <servlet-name>SystemServiceServlet</servlet-name>
    <url-pattern>/_ah/spi/*</url-pattern>
    <!-- LEGACY: End of legacy section -->
</servlet-mapping>

v2

<servlet>
    <!-- V2: Start of v2 section -->
    <servlet-name>EndpointsServlet</servlet-name>
    <servlet-class>com.google.api.server.spi.EndpointsServlet</servlet-class>
    <!-- V2: End of v2 section -->
    <init-param>
        <param-name>services</param-name>
        <param-value>com.example.migration.endpoints.backend.MyEndpoint</param-value>
    </init-param>
</servlet>
<servlet-mapping>
    <!-- V2: Start of v2 section -->
    <servlet-name>EndpointsServlet</servlet-name>
    <url-pattern>/_ah/api/*</url-pattern>
    <!-- V2: End of v2 section -->
</servlet-mapping>

Rebuild project

Finally, use the Android Studio build list to clean and rebuild the Android Studio project with the new dependencies.

Android Studio Rebuild

Deploy your backend module

The new Gradle App Engine plugin is now used to deploy the backend module by using the following Gradle task while in the backend module:

gradle appengineDeploy

Generate client libraries

To generate client libraries, use the following Gradle task while in the backend module:

gradle endpointsClientLibs

Learn more about the available tasks for the Endpoints Frameworks Gradle plugin.

Adding Endpoints API management

Endpoints Frameworks version 2.0 also lets you turn on API management features, including:

  • API key management
  • API sharing
  • User authentication
  • API metrics
  • API logs

To get started using these and other Cloud Endpoints Frameworks 2.0 features, go to the Java page about Endpoints Frameworks for App Engine.