Instrument your Rust application with OpenTelemetry

This walkthrough shows how to add observability to your Rust application using the OpenTelemetry Rust libraries and tools.

Feature

Supported

Automatic instrumentation

Traces

Yes

Metrics

Yes

Logs

Yes

Prerequisites

Dynatrace version 1.222+
For tracing, W3C Trace Context is enabled
1. Go to Settings > Preferences > OneAgent features.
2. Turn on Send W3C Trace Context HTTP headers.

Get the Dynatrace access details

Determine the API base URL

For details on how to assemble the base OTLP endpoint URL, see Export with OTLP. The URL should end in /api/v2/otlp.

Get API access token

The access token for ingesting traces, logs, and metrics can be generated under Access Tokens.

Export with OTLP has more details on the format and the necessary access scopes.

Set up OpenTelemetry

Add the following crates to your Cargo.toml file.

opentelemetry = { version = "~0", features = ["trace", "metrics"] }
opentelemetry_sdk = { version = "~0" , features = ["rt-tokio"] }
opentelemetry-otlp = { version = "~0", features = ["http-proto", "reqwest-client", "reqwest-rustls"] }
opentelemetry-http = { version = "~0" }
opentelemetry-stdout = { version = "~0", features = ["trace"] }
opentelemetry-appender-log = { version = "~0" }
opentelemetry-semantic-conventions = { version = "~0" }

Add the following use declarations to your code.

use std::{env, convert::Infallible, net::SocketAddr, collections::HashMap, io::{BufRead, BufReader, Read}};
use opentelemetry_sdk::{logs::LoggerProvider, metrics::{PeriodicReader, SdkMeterProvider}, propagation::TraceContextPropagator, runtime, trace::{self as sdktrace, Config}, Resource};
use opentelemetry_otlp::{LogExporter, MetricExporter, Protocol, SpanExporter, WithExportConfig, WithHttpConfig};
use opentelemetry_semantic_conventions as semcov;
use opentelemetry_semantic_conventions::trace;
use opentelemetry_http::{Bytes, HeaderExtractor, HeaderInjector};
use opentelemetry_appender_log::OpenTelemetryLogBridge;
use opentelemetry::{global, trace::{FutureExt, Span, SpanKind, TraceContextExt, Tracer}, Context, KeyValue};

Add the following function to your startup file.

fn init_opentelemetry() {

    // Helper function to read potentially available OneAgent data
    fn read_dt_metadata() -> Resource {
        fn read_single(path: &str, metadata: &mut Vec<KeyValue>) -> std::io::Result<()> {
            let mut file = std::fs::File::open(path)?;
            if path.starts_with("dt_metadata") {
                let mut name = String::new();
                file.read_to_string(&mut name)?;
                file = std::fs::File::open(name)?;
            }
            for line in BufReader::new(file).lines() {
                if let Some((k, v)) = line?.split_once('=') {
                    metadata.push(KeyValue::new(k.to_string(), v.to_string()))
                }
            }
            Ok(())
        }
        let mut metadata = Vec::new();
        for name in [
            "dt_metadata_e617c525669e072eebe3d0f08212e8f2.properties",
            "/var/lib/dynatrace/enrichment/dt_metadata.properties",
            "/var/lib/dynatrace/enrichment/dt_host_metadata.properties"
        ] {
            let _ = read_single(name, &mut metadata);
        }
        Resource::new(metadata)
    }


    // ===== GENERAL SETUP =====
    let dt_api_token = env::var("DT_API_TOKEN").unwrap(); // TODO: change
    let dt_api_url = env::var("DT_API_URL").unwrap();
    
    let mut map = HashMap::new();
    map.insert("Authorization".to_string(), format!("Api-Token {}", dt_api_token));
    let mut resource = Resource::new([
    KeyValue::new(semcov::resource::SERVICE_NAME, "rust-manual-quickstart") //TODO Replace with the name of your application
    ]);
    resource = resource.merge(&read_dt_metadata());

    // ===== TRACING SETUP =====
    global::set_text_map_propagator(TraceContextPropagator::new());
    let tracer_exporter = SpanExporter::builder()
        .with_http()
        .with_headers(map.clone())
        .with_protocol(Protocol::HttpBinary)
        .with_endpoint(dt_api_url.clone() + "/v1/traces")
        .build()
        .unwrap();
    let tracer_provider = sdktrace::TracerProvider::builder()
        .with_config(Config::default().with_resource(resource.clone()))
        .with_batch_exporter(tracer_exporter, runtime::Tokio)
        .build();
    global::set_tracer_provider(tracer_provider);

    // ===== METRICS SETUP ======
    let metrics_exporter = MetricExporter::builder()
        .with_http()
        .with_headers(map.clone())
        .with_endpoint(dt_api_url.clone() + "/v1/metrics")
        .with_protocol(opentelemetry_otlp::Protocol::HttpBinary)
        .build()
        .unwrap();
    let meter_provider = SdkMeterProvider::builder()
        .with_reader(PeriodicReader::builder(metrics_exporter, runtime::Tokio).build())
        .with_resource(resource.clone())
        .build();
    global::set_meter_provider(meter_provider);

    // ===== LOGS SETUP ======
    let logger_exporter = LogExporter::builder()
        .with_http()
        .with_headers(map.clone())
        .with_endpoint(dt_api_url.clone() + "/v1/logs")
        .with_protocol(opentelemetry_otlp::Protocol::HttpBinary)
        .build()
        .unwrap();
    let logger_provider = LoggerProvider::builder()
        .with_batch_exporter(logger_exporter, runtime::Tokio)
        .with_resource(resource.clone())
        .build();      
    let otel_log_appender = OpenTelemetryLogBridge::new(&logger_provider);
    log::set_boxed_logger(Box::new(otel_log_appender)).unwrap();
    log::set_max_level(Level::Debug.to_level_filter());
}

Dynatrace data enrichment

The file read operations, parsing the dt_metadata files in the example code, attempt to read the OneAgent data files to enrich the OTLP request and ensure that all relevant topology information is available within Dynatrace.

Make sure the environment variables DT_API_URL and DT_API_TOKEN are properly configured for the Dynatrace URL and access token.
Call init_opentelemetry() as early as possible in your startup code.

Instrument your application

Add tracing

First, we need to get a tracer object.

let tracer = global::tracer("my-tracer");

With tracer, we can now start new spans.
```
let mut _span = tracer
    .span_builder("Call to /myendpoint")
    .with_kind(SpanKind::Internal)
    .start(&tracer);
_span.set_attribute(KeyValue::new("http.method", "GET"));
_span.set_attribute(KeyValue::new("net.protocol.version", "1.1"));

// TODO: Your code goes here

_span.end();
```
In the above code, we:
- Create a new span and name it "Call to /myendpoint"
- Add two attributes, following the semantic naming convention, specific to the action of this span: information on the HTTP method and version
- Add a TODO in place of the eventual business logic
- Call the span's end() method to complete the span

Collect metrics

First, we need to get a tracer object.

let meter = global::meter("request_counter");

With meter, we can now create individual instruments, such as a counter.

let updown_counter = meter.i64_up_down_counter("request_counter").build();

We can now invoke the add() method of updown_counter to record new values with the counter.
```
updown_counter.add(1,&[],);
```

Connect logs

In init_opentelemetry(), we earlier initialized the log crate with its OpenTelemetry log bridge and can now call any of its logging macros to log directly to Dynatrace.

error!("logging an error");
debug!("logging a debug message");

Maximum log level

Note the call to the log::set_max_level method in the initialization of OpenTelemetry earlier. This sets the maximum log level of the log crate to Level::Debug and is required for the logged messages at that level to be emitted in the first place and picked up by the OpenTelemetry log bridge. Adjust this if you use a different maximum log level.

Ensure context propagation optional

Context propagation is particularly important when network calls (for example, REST) are involved.

Extracting the context when receiving a request

To continue an existing trace from an HTTP request, we first need to extract the context. For this, we declare the function extract_context_from_request(), which takes the incoming request object, extracts the passed context using the propagator's extract() method, and returns the matching context object.

// Utility function to extract the context from the incoming request headers
fn extract_context_from_request(req: &Request<Incoming>) -> Context {
    global::get_text_map_propagator(|propagator| {
        propagator.extract(&HeaderExtractor(req.headers()))
    })
}

We can then use extract_context_from_request() in our request handler to obtain that context and pass it as parent to our own, new server span using start_with_context().

async fn router(req: Request<Incoming>) -> Result<Response<BoxBody<Bytes, hyper::Error>>, Infallible> {

    // Extract the context from the incoming request headers
    let parent_cx = extract_context_from_request(&req);

    let response = {
        // Create a span parenting the remote client span.
        let tracer = global::tracer("example/server");
        let mut span = tracer
            .span_builder("router")
            .with_kind(SpanKind::Server)
            .start_with_context(&tracer, &parent_cx);

        // Adding custom attributes
        span.set_attribute(KeyValue::new("my-server-key-1", "my-server-value-1"));
    };

    // TODO Handle the HTTP request
}

Injecting the context when sending requests

To propagate the current context to another HTTP service, we inject the context information into the HTTP request headers. The following example declares the function send_request(), which takes the URL of the request, the request content, and sends the request using hyper.

Once the hyper request object is initialized, we call get_text_map_propagator() to obtain the global propagator object and then use its inject_context() function to add the current context information to the request.

async fn send_request(url: &str, body_content: &str, span_name: &str) -> std::result::Result<(), Box<dyn std::error::Error + Send + Sync + 'static>> {
    let client = Client::builder(TokioExecutor::new()).build_http();
    let tracer = global::tracer("example/client");
    let span = tracer
        .span_builder(String::from(span_name))
        .with_kind(SpanKind::Client)
        .start(&tracer);
    let cx = Context::current_with_span(span);

    let mut req = hyper::Request::builder().uri(url);
    global::get_text_map_propagator(|propagator| {
        propagator.inject_context(&cx, &mut HeaderInjector(req.headers_mut().unwrap()))
    });
    let res = client
        .request(req.body(Full::new(Bytes::from(body_content.to_string())))?)
        .await?;

    cx.span().add_event(
        "Got response!",
        vec![KeyValue::new("status", res.status().to_string())],
    );

    Ok(())
}

Configure data capture to meet privacy requirements optional

While Dynatrace automatically captures all OpenTelemetry attributes, only attribute values specified in the allowlist are stored and displayed in the Dynatrace web UI. This prevents accidental storage of personal data, so you can meet your privacy requirements and control the amount of monitoring data stored.

To view your custom attributes, you need to allow them in the Dynatrace web UI first. To learn how to configure attribute storage and masking, see Attribute redaction.

Verify data ingestion into Dynatrace

Once you have finished the instrumentation of your application, perform a couple of test actions to create and send demo traces, metrics, and logs and verify that they were correctly ingested into Dynatrace.

To do that for traces, go to Distributed Traces or Distributed Traces Classic (latest Dynatrace) and select the Ingested traces tab. If you use OneAgent, select PurePaths instead.

For metrics and logs, go to Metrics or Logs or Logs & Events (latest Dynatrace).