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//! # OpenTelemetry Datadog Exporter //! //! An OpenTelemetry datadog exporter implementation //! //! See the [Datadog Docs](https://docs.datadoghq.com/agent/) for information on how to run the datadog-agent //! //! ## Quirks //! //! There are currently some incompatibilities between Datadog and OpenTelemetry, and this manifests //! as minor quirks to this exporter. //! //! Firstly Datadog uses operation_name to describe what OpenTracing would call a component. //! Or to put it another way, in OpenTracing the operation / span name's are relatively //! granular and might be used to identify a specific endpoint. In datadog, however, they //! are less granular - it is expected in Datadog that a service will have single //! primary span name that is the root of all traces within that service, with an additional piece of //! metadata called resource_name providing granularity. See [here](https://docs.datadoghq.com/tracing/guide/configuring-primary-operation/) //! //! The Datadog Golang API takes the approach of using a `resource.name` OpenTelemetry attribute to set the //! resource_name. See [here](https://github.com/DataDog/dd-trace-go/blob/ecb0b805ef25b00888a2fb62d465a5aa95e7301e/ddtrace/opentracer/tracer.go#L10) //! //! Unfortunately, this breaks compatibility with other OpenTelemetry exporters which expect //! a more granular operation name - as per the OpenTracing specification. //! //! This exporter therefore takes a different approach of naming the span with the name of the //! tracing provider, and using the span name to set the resource_name. This should in most cases //! lead to the behaviour that users expect. //! //! Datadog additionally has a span_type string that alters the rendering of the spans in the web UI. //! This can be set as the `span.type` OpenTelemetry span attribute. //! //! For standard values see [here](https://github.com/DataDog/dd-trace-go/blob/ecb0b805ef25b00888a2fb62d465a5aa95e7301e/ddtrace/ext/app_types.go#L31) //! //! ## Performance //! //! For optimal performance, a batch exporter is recommended as the simple exporter will export //! each span synchronously on drop. You can enable the [`rt-tokio`], [`rt-tokio-current-thread`] //! or [`rt-async-std`] features and specify a runtime on the pipeline to have a batch exporter //! configured for you automatically. //! //! ```toml //! [dependencies] //! opentelemetry = { version = "*", features = ["rt-tokio"] } //! opentelemetry-datadog = "*" //! ``` //! //! ```no_run //! # fn main() -> Result<(), opentelemetry::trace::TraceError> { //! let tracer = opentelemetry_datadog::new_pipeline() //! .install_batch(opentelemetry::runtime::Tokio)?; //! # Ok(()) //! # } //! ``` //! //! [`rt-tokio`]: https://tokio.rs //! [`rt-tokio-current-thread`]: https://tokio.rs //! [`rt-async-std`]: https://async.rs //! //! ## Bring your own http client //! //! Users can choose appropriate http clients to align with their runtime. //! //! Based on the feature enabled. The default http client will be different. If user doesn't specific //! features or enabled `reqwest-blocking-client` feature. The blocking reqwest http client will be used as //! default client. If `reqwest-client` feature is enabled. The async reqwest http client will be used. If //! `surf-client` feature is enabled. The surf http client will be used. //! //! Note that async http clients may need specific runtime otherwise it will panic. User should make //! sure the http client is running in appropriate runime. //! //! Users can always use their own http clients by implementing `HttpClient` trait. //! //! ## Kitchen Sink Full Configuration //! //! Example showing how to override all configuration options. See the //! [`DatadogPipelineBuilder`] docs for details of each option. //! //! [`DatadogPipelineBuilder`]: struct.DatadogPipelineBuilder.html //! //! ```no_run //! use opentelemetry::{KeyValue, trace::Tracer}; //! use opentelemetry::sdk::{trace::{self, IdGenerator, Sampler}, Resource}; //! use opentelemetry::sdk::export::trace::ExportResult; //! use opentelemetry::global::shutdown_tracer_provider; //! use opentelemetry_datadog::{new_pipeline, ApiVersion, Error}; //! use opentelemetry_http::{HttpClient, HttpError}; //! use async_trait::async_trait; //! use bytes::Bytes; //! use futures_util::io::AsyncReadExt as _; //! use http::{Request, Response}; //! use std::convert::TryInto as _; //! //! // `reqwest` and `surf` are supported through features, if you prefer an //! // alternate http client you can add support by implementing `HttpClient` as //! // shown here. //! #[derive(Debug)] //! struct IsahcClient(isahc::HttpClient); //! //! async fn body_to_bytes(mut body: isahc::Body) -> Result<Bytes, HttpError> { //! let mut bytes = Vec::with_capacity(body.len().unwrap_or(0).try_into()?); //! let _ = body.read_to_end(&mut bytes).await?; //! Ok(bytes.into()) //! } //! //! #[async_trait] //! impl HttpClient for IsahcClient { //! async fn send(&self, request: Request<Vec<u8>>) -> Result<Response<Bytes>, HttpError> { //! let response = self.0.send_async(request).await?; //! Ok(Response::builder() //! .status(response.status()) //! .body(body_to_bytes(response.into_body()).await?)?) //! } //! } //! //! fn main() -> Result<(), opentelemetry::trace::TraceError> { //! let tracer = new_pipeline() //! .with_service_name("my_app") //! .with_version(ApiVersion::Version05) //! .with_agent_endpoint("http://localhost:8126") //! .with_trace_config( //! trace::config() //! .with_sampler(Sampler::AlwaysOn) //! .with_id_generator(IdGenerator::default()) //! ) //! .install_batch(opentelemetry::runtime::Tokio)?; //! //! tracer.in_span("doing_work", |cx| { //! // Traced app logic here... //! }); //! //! shutdown_tracer_provider(); // sending remaining spans before exit //! //! Ok(()) //! } //! ``` mod exporter; mod propagator { use opentelemetry::{ propagation::{text_map_propagator::FieldIter, Extractor, Injector, TextMapPropagator}, trace::{ SpanContext, SpanId, TraceContextExt, TraceId, TraceState, TRACE_FLAG_DEFERRED, TRACE_FLAG_NOT_SAMPLED, TRACE_FLAG_SAMPLED, }, Context, }; const DATADOG_TRACE_ID_HEADER: &str = "x-datadog-trace-id"; const DATADOG_PARENT_ID_HEADER: &str = "x-datadog-parent-id"; const DATADOG_SAMPLING_PRIORITY_HEADER: &str = "x-datadog-sampling-priority"; lazy_static::lazy_static! { static ref DATADOG_HEADER_FIELDS: [String; 3] = [ DATADOG_TRACE_ID_HEADER.to_string(), DATADOG_PARENT_ID_HEADER.to_string(), DATADOG_SAMPLING_PRIORITY_HEADER.to_string(), ]; } enum SamplingPriority { UserReject = -1, AutoReject = 0, AutoKeep = 1, UserKeep = 2, } #[derive(Debug)] enum ExtractError { TraceId, SpanId, SamplingPriority, } /// Extracts and injects `SpanContext`s into `Extractor`s or `Injector`s using Datadog's header format. /// /// The Datadog header format does not have an explicit spec, but can be divined from the client libraries, /// such as [dd-trace-go] /// /// ## Example /// /// ``` /// use opentelemetry::global; /// use opentelemetry_datadog::DatadogPropagator; /// /// global::set_text_map_propagator(DatadogPropagator::default()); /// ``` /// /// [dd-trace-go]: https://github.com/DataDog/dd-trace-go/blob/v1.28.0/ddtrace/tracer/textmap.go#L293 #[derive(Clone, Debug, Default)] pub struct DatadogPropagator { _private: (), } impl DatadogPropagator { /// Creates a new `DatadogPropagator`. pub fn new() -> Self { DatadogPropagator::default() } fn extract_trace_id(&self, trace_id: &str) -> Result<TraceId, ExtractError> { trace_id .parse::<u64>() .map(|id| TraceId::from_u128(id as u128)) .map_err(|_| ExtractError::TraceId) } fn extract_span_id(&self, span_id: &str) -> Result<SpanId, ExtractError> { span_id .parse::<u64>() .map(SpanId::from_u64) .map_err(|_| ExtractError::SpanId) } fn extract_sampling_priority( &self, sampling_priority: &str, ) -> Result<SamplingPriority, ExtractError> { let i = sampling_priority .parse::<i32>() .map_err(|_| ExtractError::SamplingPriority)?; match i { -1 => Ok(SamplingPriority::UserReject), 0 => Ok(SamplingPriority::AutoReject), 1 => Ok(SamplingPriority::AutoKeep), 2 => Ok(SamplingPriority::UserKeep), _ => Err(ExtractError::SamplingPriority), } } fn extract_span_context( &self, extractor: &dyn Extractor, ) -> Result<SpanContext, ExtractError> { let trace_id = self.extract_trace_id(extractor.get(DATADOG_TRACE_ID_HEADER).unwrap_or(""))?; // If we have a trace_id but can't get the parent span, we default it to invalid instead of completely erroring // out so that the rest of the spans aren't completely lost let span_id = self .extract_span_id(extractor.get(DATADOG_PARENT_ID_HEADER).unwrap_or("")) .unwrap_or_else(|_| SpanId::invalid()); let sampling_priority = self.extract_sampling_priority( extractor .get(DATADOG_SAMPLING_PRIORITY_HEADER) .unwrap_or(""), ); let sampled = match sampling_priority { Ok(SamplingPriority::UserReject) | Ok(SamplingPriority::AutoReject) => { TRACE_FLAG_NOT_SAMPLED } Ok(SamplingPriority::UserKeep) | Ok(SamplingPriority::AutoKeep) => { TRACE_FLAG_SAMPLED } // Treat the sampling as DEFERRED instead of erroring on extracting the span context Err(_) => TRACE_FLAG_DEFERRED, }; let trace_state = TraceState::default(); Ok(SpanContext::new( trace_id, span_id, sampled, true, trace_state, )) } } impl TextMapPropagator for DatadogPropagator { fn inject_context(&self, cx: &Context, injector: &mut dyn Injector) { let span = cx.span(); let span_context = span.span_context(); if span_context.is_valid() { injector.set( DATADOG_TRACE_ID_HEADER, (span_context.trace_id().to_u128() as u64).to_string(), ); injector.set( DATADOG_PARENT_ID_HEADER, span_context.span_id().to_u64().to_string(), ); if !span_context.is_deferred() { let sampling_priority = if span_context.is_sampled() { SamplingPriority::AutoKeep } else { SamplingPriority::AutoReject }; injector.set( DATADOG_SAMPLING_PRIORITY_HEADER, (sampling_priority as i32).to_string(), ); } } } fn extract_with_context(&self, cx: &Context, extractor: &dyn Extractor) -> Context { let extracted = self .extract_span_context(extractor) .unwrap_or_else(|_| SpanContext::empty_context()); cx.with_remote_span_context(extracted) } fn fields(&self) -> FieldIter<'_> { FieldIter::new(DATADOG_HEADER_FIELDS.as_ref()) } } #[cfg(test)] mod tests { use super::*; use opentelemetry::testing::trace::TestSpan; use opentelemetry::trace::TraceState; use std::collections::HashMap; #[rustfmt::skip] fn extract_test_data() -> Vec<(Vec<(&'static str, &'static str)>, SpanContext)> { vec![ (vec![], SpanContext::empty_context()), (vec![(DATADOG_SAMPLING_PRIORITY_HEADER, "0")], SpanContext::empty_context()), (vec![(DATADOG_TRACE_ID_HEADER, "garbage")], SpanContext::empty_context()), (vec![(DATADOG_TRACE_ID_HEADER, "1234"), (DATADOG_PARENT_ID_HEADER, "garbage")], SpanContext::new(TraceId::from_u128(1234), SpanId::invalid(), TRACE_FLAG_DEFERRED, true, TraceState::default())), (vec![(DATADOG_TRACE_ID_HEADER, "1234"), (DATADOG_PARENT_ID_HEADER, "12")], SpanContext::new(TraceId::from_u128(1234), SpanId::from_u64(12), TRACE_FLAG_DEFERRED, true, TraceState::default())), (vec![(DATADOG_TRACE_ID_HEADER, "1234"), (DATADOG_PARENT_ID_HEADER, "12"), (DATADOG_SAMPLING_PRIORITY_HEADER, "0")], SpanContext::new(TraceId::from_u128(1234), SpanId::from_u64(12), TRACE_FLAG_NOT_SAMPLED, true, TraceState::default())), (vec![(DATADOG_TRACE_ID_HEADER, "1234"), (DATADOG_PARENT_ID_HEADER, "12"), (DATADOG_SAMPLING_PRIORITY_HEADER, "1")], SpanContext::new(TraceId::from_u128(1234), SpanId::from_u64(12), TRACE_FLAG_SAMPLED, true, TraceState::default())), ] } #[rustfmt::skip] fn inject_test_data() -> Vec<(Vec<(&'static str, &'static str)>, SpanContext)> { vec![ (vec![], SpanContext::empty_context()), (vec![], SpanContext::new(TraceId::from_hex("garbage"), SpanId::invalid(), TRACE_FLAG_DEFERRED, true, TraceState::default())), (vec![], SpanContext::new(TraceId::from_hex("1234"), SpanId::invalid(), TRACE_FLAG_DEFERRED, true, TraceState::default())), (vec![], SpanContext::new(TraceId::from_hex("1234"), SpanId::invalid(), TRACE_FLAG_SAMPLED, true, TraceState::default())), (vec![(DATADOG_TRACE_ID_HEADER, "1234"), (DATADOG_PARENT_ID_HEADER, "12")], SpanContext::new(TraceId::from_u128(1234), SpanId::from_u64(12), TRACE_FLAG_DEFERRED, true, TraceState::default())), (vec![(DATADOG_TRACE_ID_HEADER, "1234"), (DATADOG_PARENT_ID_HEADER, "12"), (DATADOG_SAMPLING_PRIORITY_HEADER, "0")], SpanContext::new(TraceId::from_u128(1234), SpanId::from_u64(12), TRACE_FLAG_NOT_SAMPLED, true, TraceState::default())), (vec![(DATADOG_TRACE_ID_HEADER, "1234"), (DATADOG_PARENT_ID_HEADER, "12"), (DATADOG_SAMPLING_PRIORITY_HEADER, "1")], SpanContext::new(TraceId::from_u128(1234), SpanId::from_u64(12), TRACE_FLAG_SAMPLED, true, TraceState::default())), ] } #[test] fn test_extract() { for (header_list, expected) in extract_test_data() { let map: HashMap<String, String> = header_list .into_iter() .map(|(k, v)| (k.to_string(), v.to_string())) .collect(); let propagator = DatadogPropagator::default(); let context = propagator.extract(&map); assert_eq!(context.span().span_context(), &expected); } } #[test] fn test_extract_empty() { let map: HashMap<String, String> = HashMap::new(); let propagator = DatadogPropagator::default(); let context = propagator.extract(&map); assert_eq!(context.span().span_context(), &SpanContext::empty_context()) } #[test] fn test_inject() { let propagator = DatadogPropagator::default(); for (header_values, span_context) in inject_test_data() { let mut injector: HashMap<String, String> = HashMap::new(); propagator.inject_context( &Context::current_with_span(TestSpan(span_context)), &mut injector, ); if header_values.is_empty() { assert!(injector.is_empty()); } else { for (k, v) in header_values.into_iter() { let injected_value: Option<&String> = injector.get(k); assert_eq!(injected_value, Some(&v.to_string())); injector.remove(k); } assert!(injector.is_empty()); } } } } } pub use exporter::{new_pipeline, ApiVersion, DatadogExporter, DatadogPipelineBuilder, Error}; pub use propagator::DatadogPropagator;