LangChain4j Tracing

dependencies {
    // OpenInference instrumentation
    implementation project(path: ':instrumentation:openinference-instrumentation-langchain4j')

    // LangChain4j
    implementation "dev.langchain4j:langchain4j:${langchain4jVersion}"
    implementation "dev.langchain4j:langchain4j-open-ai:${langchain4jVersion}"

    // OpenTelemetry
    implementation "io.opentelemetry:opentelemetry-sdk"
    implementation "io.opentelemetry:opentelemetry-exporter-otlp"
    implementation "io.opentelemetry:opentelemetry-exporter-logging"
}

private static void initializeOpenTelemetry() {
        // Create resource with service name
        Resource resource = Resource.getDefault()
                .merge(Resource.create(Attributes.of(
                        AttributeKey.stringKey("service.name"), "langchain4j",
                        AttributeKey.stringKey(SEMRESATTRS_PROJECT_NAME), "langchain4j-project",
                        AttributeKey.stringKey("service.version"), "0.1.0")));

        String apiKey = System.getenv("PHOENIX_API_KEY");
        OtlpGrpcSpanExporterBuilder otlpExporterBuilder = OtlpGrpcSpanExporter.builder()
                .setEndpoint("http://localhost:4317") // adjust as needed
                .setTimeout(Duration.ofSeconds(2));
        OtlpGrpcSpanExporter otlpExporter = null;
        if (apiKey != null && !apiKey.isEmpty()) {
            otlpExporter = otlpExporterBuilder
                    .setHeaders(() -> Map.of("Authorization", String.format("Bearer %s", apiKey)))
                    .build();
        } else {
            logger.log(Level.WARNING, "Please set PHOENIX_API_KEY environment variable if auth is enabled.");
            otlpExporter = otlpExporterBuilder.build();
        }

        // Create tracer provider with both OTLP (for Phoenix) and console exporters
        tracerProvider = SdkTracerProvider.builder()
                .addSpanProcessor(BatchSpanProcessor.builder(otlpExporter)
                        .setScheduleDelay(Duration.ofSeconds(1))
                        .build())
                .addSpanProcessor(SimpleSpanProcessor.create(LoggingSpanExporter.create()))
                .setResource(resource)
                .build();

        // Build OpenTelemetry SDK
        OpenTelemetrySdk.builder()
                .setTracerProvider(tracerProvider)
                .setPropagators(ContextPropagators.create(W3CTraceContextPropagator.getInstance()))
                .buildAndRegisterGlobal();

        System.out.println("OpenTelemetry initialized. Traces will be sent to Phoenix at http://localhost:6006");
    }
}

import io.openinference.instrumentation.langchain4j.LangChain4jInstrumentor;
import dev.langchain4j.model.openai.OpenAiChatModel;

initializeOpenTelemetry();

// Auto-instrument LangChain4j
LangChain4jInstrumentor.instrument();

// Use LangChain4j as normal - traces will be automatically created
OpenAiChatModel model = OpenAiChatModel.builder()
    .apiKey("your-openai-api-key")
    .modelName("gpt-4")
    .build();

String response = model.generate("What is the capital of France?");