Android/iOS App in Flutter Instrumentation

This documentation contains instructions on how to set up OpenTelemetry(OTel) instrumentation in your Android/iOS mobile application built using Flutter. OpenTelemetry, also known as OTel for short, is an open-source observability framework that can help you generate and collect telemetry data - traces, metrics, and logs from your Flutter application.

Once the telemetry data is generated, you can configure an exporter to send the data to SigNoz for monitoring and visualization.

There are three major steps to using OpenTelemetry:

• Instrumenting your iOS application with OpenTelemetry
• Configuring the exporter to send data to SigNoz
• Validating the configuration to ensure that data is being sent as expected.

In this tutorial, we will instrument an Android/iOS Mobile application for traces and send it to SigNoz.

Requirements

Flutter

Send traces directly to SigNoz cloud

Step 1 : Instrument your application with OpenTelemetry

To configure your Flutter application to send traces to OpenTelemetry you need to install opentelemetry

For that,run the following command.

flutter pub add opentelemetry

Step 2: Initialize the tracer

To enable tracing and send traces to the SigNoz cloud, you need to initialize the tracer as follows:

Import the packages

import 'package:opentelemetry/api.dart';
import 'package:opentelemetry/sdk.dart';

Put the following in main.dart file.

final headers = {
    //INGESTION KEY HERE VARIABLE
    'signoz-ingestion-key': '<SIGNOZ_INGESTION_KEY>',
  };

  final exporter = CollectorExporter(
    //enter ingestion url here VARIABLE
    Uri.parse('ingest.[REGION].signoz.cloud:<PORT>/v1/traces'),
    headers: headers,
  );

  // Set up span processors
  final processor = BatchSpanProcessor(exporter);
  final provider = TracerProviderBase(
    processors: [processor],
    //enter service name here VARIABLE
    resource: Resource( [Attribute.fromString("service.name", "<SERVICE_NAME>")]),
  );

  registerGlobalTracerProvider(provider);

  void _createSpan() {
    final inputText = _controller.text;

    // Start a root span
    final rootSpan = _tracer.startSpan('root-span');
    try {
      // Create a child span with the input text
      final childSpan = _tracer.startSpan('child-span', kind: SpanKind.client);
      try {
        // Set attribute for the child span
        childSpan.setAttribute(Attribute.fromString('input.name', inputText));

        // Simulate a remote procedure call (this could be a real async call)
        remoteProcedureCall();

        // Add an event to the child span
        childSpan.addEvent('Processed input: $inputText');
      } catch (e) {
        childSpan.recordException(e);
      } finally {
        childSpan.end();
      }
    } catch (e) {
      // Handle any exceptions that may occur while starting spans
      print('Error creating span: $e');
    } finally {
      // End the root span
      rootSpan.end();
    }
  }

  Future<void> remoteProcedureCall() async {
    final headers = <String, String>{};
    W3CTraceContextPropagator().inject(Context.current, headers, _TextMapSetter());
  }

Ensure to replace <SIGNOZ_INGESTION_KEY>, <PORT>, and <REGION> with your actual SigNoz ingestion key, Port, and region, respectively.

You can find your Ingestion Key in the following places:

• mail which you recieved from SigNoz after signing up.
• inside settings on SigNoz dashboard

Depending on the choice of your region for SigNoz cloud, the ingest endpoint will vary according to this table.

These are the variables you need to replace :

Step 3: Send Telemetry data to SigNoz

To send telemetry data to SigNoz, you can use the _createSpan function which we created above.

_createSpan()

Step 4: Run app

Run your application from Android Studio to see the output & you can verify the sent span in SigNoz .