Generating a keystore

You can create a keystore for signing your release builds with the Java Keytool utility by running the following command:

keytool -genkey -v -keystore codemagic.keystore -storetype JKS \
        -keyalg RSA -keysize 2048 -validity 10000 -alias codemagic

Keytool then prompts you to enter your personal details for creating the certificate, as well as provide passwords for the keystore and the key. It then generates the keystore as a file called codemagic.keystore in the directory you’re in. The key is valid for 10,000 days.

Uploading a keystore

1. Open your Codemagic Team settings, and go to codemagic.yaml settings > Code signing identities.
2. Open Android keystores tab.
3. Upload the keystore file by clicking on Choose a file or by dragging it into the indicated frame.
4. Enter the Keystore password, Key alias and Key password values as indicated.
5. Enter the keystore Reference name. This is a unique name used to reference the file in codemagic.yaml
6. Click the Add keystore button to add the keystore.

For each of the added keystore, its common name, issuer, and expiration date are displayed.

Referencing keystores in codemagic.yaml

To tell Codemagic to fetch the uploaded keystores from the Code signing identities section during the build, list the reference of the uploaded keystore under the android_signing field.

Add the following code to the environment section of your codemagic.yaml file:

workflows:
  android-workflow:
    name: Android Workflow
    # ....
    environment:
      android_signing:
        - keystore_reference

Default environment variables are assigned by Codemagic for the values on the build machine:

• Keystore path: CM_KEYSTORE_PATH
• Keystore password: CM_KEYSTORE_PASSWORD
• Key alias: CM_KEY_ALIAS
• Key alias password: CM_KEY_PASSWORD

Signing Android apps using Gradle

To sign your Android app, simply modify your android/app/build.gradle as follows:

...
  android {
      ...
      defaultConfig { ... }
      signingConfigs {
          release {
              if (System.getenv()["CI"]) { // CI=true is exported by Codemagic
                  storeFile file(System.getenv()["CM_KEYSTORE_PATH"])
                  storePassword System.getenv()["CM_KEYSTORE_PASSWORD"]
                  keyAlias System.getenv()["CM_KEY_ALIAS"]
                  keyPassword System.getenv()["CM_KEY_PASSWORD"]
              } else {
                  keyAlias keystoreProperties['keyAlias']
                  keyPassword keystoreProperties['keyPassword']
                  storeFile keystoreProperties['storeFile'] ? file(keystoreProperties['storeFile']) : null
                  storePassword keystoreProperties['storePassword']
              }
          }
      }
      buildTypes {
          release {
              ...
              signingConfig signingConfigs.release
          }
      }
  }
  ...

One very useful method of calculating the code version is to use Codemagic command line tools to get the latest build number from Google Play and increment it by one.

You can find the full sample project with the instructions on alternative ways to perform Android build versioning in our repository.

The prerequisite is a valid Google Cloud Service Account. Plese follow these steps:

1. Go to this guide and complete the steps in the Google Play section.
2. Skip to the Creating a service account section in the same guide and complete those steps also.
3. You now have a JSON file with the credentials.
4. Open Codemagic UI and create a new Environment variable GCLOUD_SERVICE_ACCOUNT_CREDENTIALS.
5. Paste the content of the downloaded JSON file in the Value field, set the group name (e.g. google_play) and make sure the Secure option is checked.

6. Add the google_play variable group to the codemagic.yaml

   workflows:
     android-workflow-id:
       # ....
       environment:
         groups:
           - google_play

7. Modify the build script to calculate the build number and use it as gradlew arguments.

   scripts:
       # ....
     - name: Build Android release
       script: | 
         LATEST_GOOGLE_PLAY_BUILD_NUMBER=$(google-play get-latest-build-number --package-name "$PACKAGE_NAME")
         if [ -z $LATEST_GOOGLE_PLAY_BUILD_NUMBER ]; then
           # fallback in case no build number was found from Google Play.
           # Alternatively, you can `exit 1` to fail the build
           # BUILD_NUMBER is a Codemagic built-in variable tracking the number
           # of times this workflow has been built
             UPDATED_BUILD_NUMBER=$BUILD_NUMBER
         else
             UPDATED_BUILD_NUMBER=$(($LATEST_GOOGLE_PLAY_BUILD_NUMBER + 1))
         fi
         cd android
         ./gradlew bundleRelease \
             -PversionCode=$UPDATED_BUILD_NUMBER \
             -PversionName=1.0.$UPDATED_BUILD_NUMBER

8. Modify the android/app/build.gradle file to get the build number values and apply them:

   // get version code from the specified property argument `-PversionCode` during the build call
   def getMyVersionCode = { ->
       return project.hasProperty('versionCode') ? versionCode.toInteger() : -1
   }
   
   // get version name from the specified property argument `-PversionName` during the build call
   def getMyVersionName = { ->
       return project.hasProperty('versionName') ? versionName : "1.0"
   }
   
   ....
   android {
       ....
       defaultConfig {
           ...
           versionCode getMyVersionCode()
           versionName getMyVersionName()

Publishing apps to Google Play requires you to set up a service account in Google Play Console and save the content of the JSON key file to a secure environment variable as explained above in Android Build Versioning steps 1-5. Configuring Google Play publishing is simple as you only need to provide credentials and choose the desired track. If the app is in draft status, please also include the submit_as_draft: true or promote the app status in Google Play.

react-native-android:
  # ... 
  publishing:
    # ...
    google_play:
      credentials: $GCLOUD_SERVICE_ACCOUNT_CREDENTIALS
      track: internal
      submit_as_draft: true