AOSP Integration Guide

The following guide will walk you through step-by-step how to integrate and validate Memfault's Android SDK in your custom AOSP project.

1. Create a Project

Create a Project and get a Project Key

Go to app.memfault.com and from the "Select A Project" dropdown, click on "Create Project" to setup your first project. Choose a name that reflects your product, such as "smart-sink-dev".

Select "Android (AOSP)" as your Project Type.

By default, the Device's Serial Number is used as the Device ID, collected from the ro.serialno system property. Make sure that it is unique for every device in the same Project.

See our reference documentation on Hardware and Software Versions for further details about how to choose the right versions for your project. Note that these settings cannot be changed once the project is created!

Once you've created your project, you'll be automatically taken to an page that includes your project key. Copy the key and follow the rest of this guide.

2. Build your AOSP project with the Android SDK integrated

i. Clone the Android SDK into your project

Using a Git client, clone the bort repository from:

git clone https://github.com/memfault/bort.git

Add this repo to your tree at vendor/memfault/bort (i.e. add it to your repo manifest).

ii. Include the Memfault Android SDK into your project Makefiles

note

We recommend placing the includes below at the end of the respective Makefiles. This is because include directives are used to append to variables in the build script; placing them at the end of the file reduces the chances that subsequent lines in the Makefile do not redefine those variables and discard the effect of the include. If it is not possible to place the include at the end of the file, ensure that the respective variables are not redefined (look for the := syntax).

Add this line to your device.mk file to get the components included in your build; this appends to the PRODUCT_PACKAGES variable:

include vendor/memfault/bort/product.mk

Add this line to your BoardConfig.mk file to get the sepolicy files picked up by the build system; this appends to the BOARD_SEPOLICY_DIRS and BOARD_PLAT_PRIVATE_SEPOLICY_DIR variables:

include vendor/memfault/bort/BoardConfig.mk

iii. Patch AOSP

Before Memfault Android SDK version 5.0, it is required to apply patches to the AOSP source code in order to integrate the Android SDK. After 5.0, patches are only required for the SDK to function on Android 8. Not all patches are required - some enhance enable/enhanced specific SDK features:

AOSP Version	Memfault Android SDK Version	Required AOSP Patches
8	All	build/core/tasks / system/sepolicy
11+	< 5.0	build/make/target/product/mainline

For full details, see AOSP Patches.

Apply using the bort_cli.py tool (requires Python 3.6+). Be sure to call this using the correct Android OS version (--android-release) for your build.

vendor/memfault/bort/bort_cli.py patch-aosp \
  --android-release 14 \
  <AOSP_ROOT>

iv. Patch Bort's application ID

Decide on an application ID for the Bort application. We recommend placing the application under your domain, and appending bort to your reverse domain name in some fashion. For example, com.mycorp.bort.

If you're using the OTA Update Client, the OTA application ID must also be set. For example, com.mycorp.bort.ota.

note

OTA must be explicitly enabled — instructions here.

Patch Bort with your own application IDs:

vendor/memfault/bort/bort_cli.py patch-bort \
  --bort-app-id <YOUR_BORT_APPLICATION_ID> \
  --bort-ota-app-id <YOUR_BORT_OTA_APPLICATION_ID> \
  <AOSP_ROOT>/vendor/memfault/bort/MemfaultPackages

This command will patch bort.properties, setting the BORT_APPLICATION_ID (and BORT_OTA_APPLICATION_ID) properties to <YOUR_BORT_APPLICATION_ID> and YOUR_BORT_OTA_APPLICATION_ID.

v. Configure bort.properties

You must set your Project Key in the Bort app. This is set in MemfaultPackages/bort.properties; the app will not compile without this property.

If your devices will have Google Mobile Services (GMS) and must run the Compatibility Test Suite (CTS), you may need to update the target SDK version to match the API level of your OS. This can be done by updating the TARGET_SDK_VERSION property in MemfaultPackages/bort.properties.

Additional settings can be configured via the Android SDK over-the-air SDK settings system.

vi. Create a keystore for the Android SDK

Bort app

The Bort app requires a Java keystore file so that the app can be signed.

To generate a keystore, run the following command in the <AOSP_ROOT>/vendor/memfault/bort/MemfaultPackages directory:

$JAVA_HOME/bin/keytool -genkeypair -alias release_key -keypass secretPassword -keystore bort_keystore.jks -storepass secretPassword -validity 10000 -keyalg rsa

Make sure to change the secretPassword to a uniquely generated password and store that password securely. Please note that the -keypass and -storepass must be the same.

Alternatively, instructions on how to create a keystore in Android Studio can be found here. If you plan to update the app via the Play Store, you may wish to follow the additional instructions on that page.

important

• The key that is used to sign the Bort app must NOT be the platform signing key, otherwise the SDK will not function correctly.
• The key must ONLY be used to sign the Bort app and no other apps. Special permissions are assigned to Bort app based on the signing certificate.

Once you have a keystore, set up a keystore.properties file and provide the path to it via the bort.properties file:

BORT_KEYSTORE_PROPERTIES_PATH=keystore.properties

The keystore.properties file must contain these properties with the appropriate values:

keyAlias=release_key # e.g. key0
keyPassword=secretPassword
storeFile=bort_keystore.jks
storePassword=secretPassword

OTA Update Client app

note

This step is only required if you are using the OTA Update Client.

If using the OTA Update Client, a separate keystore should be created, following the same steps as for the Bort app.

Once you have a keystore, set up a ota_keystore.properties file and provide the path to it via the bort.properties file:

BORT_OTA_KEYSTORE_PROPERTIES_PATH=ota_keystore.properties

If using OTA, then this must be explicitly enabled - instructions here.

vii. Build the Android SDK APKs

Build the Bort APK

The MemfaultBort app is built using gradle. Building the release APK will automatically invoke a task to copy the resulting APK and place it in the root directory where it will be picked up by the AOSP build system.

Building the Bort app with gradle requires the Android SDK location to be configured. This can either be set with the ANDROID_HOME environment variable, or by opening the project with Android Studio (e.g. opening the root build.gradle) which will auto-generate a local.properties file with the sdk.dir property. We recommend installing Android Studio, which will automatically install many Android SDK tools.

cd MemfaultPackages && ./gradlew :bort:assembleRelease

This will create a signed MemfaultBort.apk and MemfaultBort.x509.pem file. The pem file is a public certificate used by the system when enforcing the SE policy.

Build the OTA Update Client APK

The MemfaultBortOta app is built using gradle. Building the release APK will automatically invoke a task to copy the resulting APK and place it in the root directory where it will be picked up by the AOSP build system.

cd MemfaultPackages && ./gradlew :bort-ota:assembleRelease

This will create a signed MemfaultBortOta.apk and MemfaultBortOta.x509.pem file. The pem file is a public certificate used by the system when enforcing the SE policy.

Build the UsageReporter APK

The MemfaultUsageReporter app is built using gradle. Building the release APK will automatically invoke a task to copy the resulting APK and place it in the root directory where it will be picked up by the AOSP build system.

cd MemfaultPackages && ./gradlew :reporter:assembleRelease

Build all APKs at once (Recommended)

All of the above APKs can be built using a single command! We recommend using the full command and letting gradle automatically optimize the recompilation.

cd MemfaultPackages && ./gradlew assembleRelease

viii. Compile and run the AOSP image on your device

After the APKs are built and the Makefiles are included in your AOSP project, compile your AOSP image, and flash it to your device.

By default, Memfault expects the MemfaultBort.apk, MemfaultUsageReporter.apk, and MemfaultBort.x509.pem files to exist in the vendor/memfault/bort/MemfaultPackages folder, so the Bort and UsageReporter apps can be installed in the AOSP image.

If using OTA, the MemfaultBortOta.apk and MemfaultBortOta.x509.pem must also exist in that folder.

Building these APKs using gradle will automatically copy the apk and certificates to the correct location, but you can define your own process as long as those files are written to that location before the image AOSP is built.

3. Validate the AOSP integration

The bort_cli.py tool can also be used to check for issues with the SDK installation. To use it, install a build containing the Android SDK on a device that you wish to validate. Connect that device via ADB (verify via adb devices) and run the script:

./bort_cli.py validate-sdk-integration --bort-app-id your.app.id

If using the Bort OTA client, then run the validation tool with an additional argument for the OTA app ID. This is supported from Android SDK 4.12.0 onwards:

./bort_cli.py validate-sdk-integration --bort-app-id your.app.id --bort-ota-app-id your.ota.app.id

info

We recommend running the validation tool with a userdebug system image. A user image does not allow all checks to be run, which may result in Bort configuration issues being missed.

If you have multiple devices connected, use the --device flag to specify the target device. For more information on the different options, run the command with the -h flag:

./bort_cli.py validate-sdk-integration -h

4. Collect your first device metrics

i. Enable the Android SDK

By default, the Android SDK will only run after being explicitly enabled at runtime (RUNTIME_ENABLE_REQUIRED=true) — this is to ensure no data is collected without user consent.

Additional information on enabling the SDK can be found in the Enabling the SDK at Runtime section of the Android SDK documentation.

For the purposes of testing the SDK on a development device, the SDK can be enabled via ADB using the CLI tool:

./bort_cli.py enable-bort --bort-app-id your.app.id

The enable-bort command runs this ADB command under the hood:

adb shell am broadcast --receiver-include-background \
  -a com.memfault.intent.action.BORT_ENABLE \
  -n your.app.id/com.memfault.bort.receivers.ShellControlReceiver \
  --ez com.memfault.intent.extra.BORT_ENABLED true

ii. Trigger metrics collection from the Android SDK manually

You can request a Metrics collection using the bort_cli.py tool as well. To enable these debugging utilities, we must first enable Developer Mode.

Developer Mode (since Android SDK 4.2.0)

On local development/test devices, the Android SDK can be placed into developer mode. This can be useful for testing the AOSP integration or testing newly added Custom Metrics.

Once in developer mode:

• Random upload jitter is removed (this is helpful to see diagnostic information in the Memfault dashboard immediately).
• mar files are uploaded immediately (instead of waiting to be bundled in a single upload, as it normally would).
• Metrics collection can be triggered on-demand. This will trigger Bort to collect batterystats and Metrics - useful for validating new calls to the Reporting APIs.
• Device configuration update can also be requested on-demand. This will trigger the Android SDK to update settings from the Memfault server, including the fleet-sampling configuration.
• From Android SDK 4.5.0 onwards: All client-side rate limits are bypassed. Server-side rate-limits may still be in effect.

To enable developer mode (change true to false to disable):

./bort_cli.py dev-mode --bort-app-id your.app.id --enabled true

Then, request a metrics collection using:

./bort_cli.py request-metrics --bort-app-id your.app.id

Server-side rate limiting will apply to the device you're using to work on the integration process. Once you can see the device on the Memfault Web App, consider enabling Server-Side Developer Mode for it on the Memfault Web App to temporarily bypass these limits.

Next Steps

Activate your first OTA update

Collect your first Metrics

Request a test bug report

Once the SDK has been enabled, you can manually trigger a bug report to be generated. Once generated, it will be automatically uploaded to Memfault:

./bort_cli.py request-bug-report --bort-app-id your.app.id

More information on triggering a bug report can be found in Triggering A Bug Report Programmatically; more information on when bug reports are automatically captured can be found in Bug Report Capture Period.

Once the bug report has been generated, uploaded and processed successfully, you will be able to find it in Memfault by navigating to the Fleet → Devices view and finding the device that uploaded the bug report.

If you do not see the bug report, you can check your project's Processing Log under the "Integration Hub" sub-menu. The Processing Log contains details on what data has been received and processed by Memfault, as well as any error that may have occurred.

A bug report's status will remain as Stored if the maximum number of bug reports that will be analyzed from a device per day is reached. Quotas can be accessed from Settings → Quotas. When a bug report is Processed, the results of analysis can be viewed from the respective Issue page.

Troubleshooting

See Troubleshooting.