OpenTelemetry Tracing

Enable distributed tracing for end-to-end visibility across your system.

Setting Up Tracing

use grpc_graphql_gateway::{Gateway, TracingConfig, init_tracer, shutdown_tracer};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Initialize the tracer
    let config = TracingConfig::new()
        .with_service_name("my-gateway")
        .with_sample_ratio(1.0);  // Sample all requests

    let _provider = init_tracer(&config);

    let gateway = Gateway::builder()
        .with_descriptor_set_bytes(DESCRIPTORS)
        .enable_tracing()
        .build()?;

    gateway.serve("0.0.0.0:8888").await?;

    // Shutdown on exit
    shutdown_tracer();
    Ok(())
}

Spans Created

Span	Kind	Description
`graphql.query`	Server	GraphQL query operation
`graphql.mutation`	Server	GraphQL mutation operation
`grpc.call`	Client	gRPC backend call

Span Attributes

GraphQL Spans

Attribute	Description
`graphql.operation.name`	The operation name if provided
`graphql.operation.type`	query, mutation, or subscription
`graphql.document`	The GraphQL query (truncated)

gRPC Spans

Attribute	Description
`rpc.service`	gRPC service name
`rpc.method`	gRPC method name
`rpc.grpc.status_code`	gRPC status code

OTLP Export

Enable OTLP export by adding the feature:

[dependencies]
grpc_graphql_gateway = { version = "0.2", features = ["otlp"] }

Then configure the exporter:

use grpc_graphql_gateway::TracingConfig;

let config = TracingConfig::new()
    .with_service_name("my-gateway")
    .with_otlp_endpoint("http://jaeger:4317");

Jaeger Integration

Run Jaeger locally:

docker run -d --name jaeger \
  -p 4317:4317 \
  -p 16686:16686 \
  jaegertracing/jaeger:1.47

View traces at: http://localhost:16686

Sampling Configuration

Sample Ratio	Description
`1.0`	Sample all requests (dev)
`0.1`	Sample 10% (staging)
`0.01`	Sample 1% (production)

TracingConfig::new()
    .with_sample_ratio(0.1)  // 10% sampling

Context Propagation

The gateway automatically propagates trace context:

Incoming HTTP headers (traceparent, tracestate)
Outgoing gRPC metadata

Enable Header Propagation for distributed tracing headers.

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