Overview

If you experience unexpected behavior with Datadog React Native RUM, use this guide to resolve issues quickly. If you continue to have trouble, contact Datadog Support for further assistance.

No data is being sent to Datadog

Follow these instructions in order when the SDK has been installed and the app compiles, but no data is received by Datadog.

Check the configuration

Sometimes, no data is sent due to a small misstep in the configuration.

Here are some common things to check for:

• Ensure your clientToken and applicationId are correct.
• Make sure you have not set sessionSamplingRate to something other than 100 (100 is the default value), or else your session might be sent.
• If you’ve set up a Proxy in the Datadog configuration, check that it has been correctly configured.
• Check that you are tracking views (all events must be attached to a view) and sending events.

Review SDK logs in React Native

• Set config.verbosity = SdkVerbosity.DEBUG, which imports SdkVerbosity from @datadog/mobile-react-native.

• Logs start appearing in the JavaScript console, like the following output:

  INFO  DATADOG: Datadog SDK was initialized
  INFO  DATADOG: Datadog SDK is tracking interactions
  INFO  DATADOG: Datadog SDK is tracking XHR resources
  INFO  DATADOG: Datadog SDK is tracking errors
  DEBUG  DATADOG: Starting RUM View "Products" #Products-oaZlP_FVwGM5vtPoup_rT
  DEBUG  DATADOG: Adding RUM Action "RCTView" (TAP)
  

  Note: In this example, the first four logs indicate that the SDK has been correctly configured and the last two lines are events that were sent.

Possible cause

If you are on iOS and see some DEBUG logs indicating that logs or RUM events were sent before the initialization logs, this may be why the SDK is not sending events.

You cannot send events before initialization, and attempting to do so puts the SDK in a state where it cannot send any data.

Solution

Review native logs

Reviewing native logs can give you more input on what could be going wrong.

On iOS

• Open your project in Xcode by running xed ios.

• Build your project for a simulator or a device.

• Native logs start appearing on the bottom right corner:

You can filter logs by “DATADOG” and look for any error.

If you are indeed sending events, you should see the following logs:

[DATADOG SDK] 🐶 → 10:02:47.398 [DEBUG] ⏳ (rum) Uploading batch...
[DATADOG SDK] 🐶 → 10:02:47.538 [DEBUG]    → (rum) accepted, won't be retransmitted: [response code: 202 (accepted), request ID: AAAABBBB-1111-2222-3333-777788883333]

The first log indicates that some data is being sent, and the second log indicates that the data has been received.

Possible cause

If you see the log below, it means that you have called a RUM method before initializing the SDK.

[DATADOG SDK] 🐶 → 10:09:13.621 [WARN] The `Global.rum` was called but no `RUMMonitor` is registered. Configure and register the RUM Monitor globally before invoking the feature:

Solution

On Android

• For a better debugging experience, Datadog recommends installing pidcat.

  • pidcat filters the device logs (obtained by adb logcat) to only show the one from your application.
  • See this issue for M1 users who don’t have Python 2.

• Modify node_modules/@datadog/mobile-react-native/android/src/main/kotlin/com/datadog/reactnative/DdSdk.kt to enable verbose logging from the native SDK:

  fun initialize(configuration: ReadableMap, promise: Promise) {
      // ...
  
      datadog.initialize(appContext, credentials, nativeConfiguration, trackingConsent)
      datadog.setVerbosity(Log.VERBOSE) // Add this line
  
      // ...
  }
  

• Run the app on a phone connected in debug mode to your laptop (should appear when running adb devices), or from an emulator.

• Run pidcat my.app.package.name or adb logcat from your laptop.

• Look for any error mentioning Datadog.

Pidcat output looks like this:

In this example, the last log indicates that the batch of RUM data was sent successfully.

Undefined symbols: Swift

If you see the following error message:

Undefined symbols for architecture x86_64:
  "static Foundation.JSONEncoder.OutputFormatting.withoutEscapingSlashes.getter : Foundation.JSONEncoder.OutputFormatting", referenced from:
      static (extension in Datadog):Foundation.JSONEncoder.default() -> Foundation.JSONEncoder in libDatadogSDK.a(JSONEncoder.o)
...

Open Xcode, go to the Build Settings of your project (not your app target), and make sure Library Search Paths have the following settings:

LIBRARY_SEARCH_PATHS = (
  "\"$(TOOLCHAIN_DIR)/usr/lib/swift/$(PLATFORM_NAME)\"",
  "\"/usr/lib/swift\"",
  "\"$(inherited)\"",
);

Undefined symbols: _RCTModule

If you see an undefined _RCTModule symbol, it may be related to this change in the react-native v0.63 changelog.

You can make the following change to fix it:

// DdSdk.m
// instead of
#import <React/RCTBridgeModule.h>
// maybe that:
@import React // or @import React-Core

Infinite loop-like error messages

If you run into an issue where your React Native project displays a stream of error messages and significantly raises your CPU usage, try creating a new React Native project.

Android build failures with SDK version 2.*

Unable to make field private final java.lang.String java.io.File.path accessible

If your Android build fails with an error like:

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:processReleaseMainManifest'.
> Unable to make field private final java.lang.String java.io.File.path accessible: module java.base does not "opens java.io" to unnamed module @1bbf7f0e

You are using Java 17, which is not compatible with your React Native version. Switch to Java 11 to solve the issue.

java.lang.UnsupportedClassVersionError

If your Android build fails with an error like:

java.lang.UnsupportedClassVersionError: com/datadog/android/lint/DatadogIssueRegistry has been compiled by a more recent version of the Java Runtime (class file version 61.0), this version of the Java Runtime only recognizes class file versions up to 55.0

You are using a version of Java that is too old. Switch to Java 17 to solve the issue.

Unsupported class file major version 61

If your Android build fails with an error like:

FAILURE: Build failed with an exception.

* What went wrong:
Could not determine the dependencies of task ':app:lintVitalRelease'.
> Could not resolve all artifacts for configuration ':app:debugRuntimeClasspath'.
   > Failed to transform dd-sdk-android-core-2.0.0.aar (com.datadoghq:dd-sdk-android-core:2.0.0) to match attributes {artifactType=android-manifest, org.gradle.category=library, org.gradle.dependency.bundling=external, org.gradle.libraryelements=aar, org.gradle.status=release, org.gradle.usage=java-runtime}.
      > Execution failed for JetifyTransform: /Users/me/.gradle/caches/modules-2/files-2.1/com.datadoghq/dd-sdk-android-core/2.0.0/a97f8a1537da1de99a86adf32c307198b477971f/dd-sdk-android-core-2.0.0.aar.
         > Failed to transform '/Users/me/.gradle/caches/modules-2/files-2.1/com.datadoghq/dd-sdk-android-core/2.0.0/a97f8a1537da1de99a86adf32c307198b477971f/dd-sdk-android-core-2.0.0.aar' using Jetifier. Reason: IllegalArgumentException, message: Unsupported class file major version 61. (Run with --stacktrace for more details.)

You are using a version of Android Gradle Plugin below 5.0. To fix the issue, add in your android/gradle.properties file:

android.jetifier.ignorelist=dd-sdk-android-core

Duplicate class kotlin.collections.jdk8.*

If your Android build fails with an error like:

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:checkReleaseDuplicateClasses'.
> A failure occurred while executing com.android.build.gradle.internal.tasks.CheckDuplicatesRunnable
   > Duplicate class kotlin.collections.jdk8.CollectionsJDK8Kt found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.20)
     Duplicate class kotlin.internal.jdk7.JDK7PlatformImplementations found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20)

You need to set a Kotlin version for your project to avoid clashes among Kotlin dependencies. In your android/build.gradle file, specify the kotlinVersion:

buildscript {
    ext {
        // targetSdkVersion = ...
        kotlinVersion = "1.8.21"
    }
}

Alternatively, you can add the following rules to your build script in your android/app/build.gradle file:

dependencies {
    constraints {
        implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.8.21") {
            because("kotlin-stdlib-jdk7 is now a part of kotlin-stdlib")
        }
        implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.8.21") {
            because("kotlin-stdlib-jdk8 is now a part of kotlin-stdlib")
        }
    }
}

Sending data when device is offline

RUM ensures availability of data when your user device is offline. In cases of low-network areas, or when the device battery is too low, all RUM events are first stored on the local device in batches. They are sent as soon as the network is available, and the battery is high enough to ensure the React Native RUM SDK does not impact the end user’s experience. If the network is not available with your application running in the foreground, or if an upload of data fails, the batch is kept until it can be sent successfully.

This means that even if users open your application while offline, no data is lost.

Note: The data on the disk is automatically deleted if it gets too old to ensure the React Native RUM SDK does not use too much disk space.

Further Reading

Additional helpful documentation, links, and articles:

Source code for dd-sdk-reactnativeSOURCE CODE Datadog Real User MonitoringDOCUMENTATION