Added some minimal documentation.

apollo-router-core/src/layers/instrument.rs

@@ -1,3 +1,20 @@
+//! Instrumentation layer that allows services to be wrapped in a span.
+//!
+//! See [`Layer`] and [`Service`] for more details.
+//!
+//! Using ServiceBuilderExt:
+//! ```rust
+//! use tower::ServiceBuilder;
+//! use tracing::info_span;
+//! use apollo_router_core::ServiceBuilderExt;
+//!
+//! let instrumented = ServiceBuilder::new()
+//!             .instrument(|_request| info_span!("query_planning"))
+//!             .service(service);
+//! ```
+//! Now calls to the wrapped service will be wrapped in a span. You can attach attributes to the span from the request.
+//!
+
 use futures::future::BoxFuture;
 use futures::FutureExt;
 use std::marker::PhantomData;
@@ -6,6 +23,7 @@ use tower::Layer;
 use tower_service::Service;
 use tracing::Instrument;
 
+/// [`Layer`] for instrumentation.
 pub struct InstrumentLayer<F, Request>
 where
     F: Fn(&Request) -> tracing::Span,
@@ -42,6 +60,7 @@ where
     }
 }
 
+/// [`Service`] for instrumentation.
 pub struct InstrumentService<F, S, Request>
 where
     S: Service<Request>,

apollo-router-core/src/query_cache.rs

@@ -1,3 +1,4 @@
+//! A cache for queries.
 use crate::prelude::graphql::*;
 use crate::CacheResolver;
 use std::sync::Arc;

apollo-router/src/axum_http_server_factory.rs

@@ -1,3 +1,4 @@
+//! Axum http server factory. Axum provides routing capability on top of Hyper HTTP.
 use crate::configuration::{Configuration, Cors, ListenAddr};
 use crate::http_server_factory::{HttpServerFactory, HttpServerHandle, Listener, NetworkStream};
 use crate::FederatedServerError;
@@ -34,7 +35,7 @@ use tower_http::trace::{DefaultMakeSpan, MakeSpan, TraceLayer};
 use tower_service::Service;
 use tracing::{Level, Span};
 
-/// A basic http server using warp.
+/// A basic http server using Axum.
 /// Uses streaming as primary method of response.
 /// Redirects to studio for GET requests.
 #[derive(Debug)]

apollo-router/src/plugins/telemetry/apollo.rs

@@ -1,3 +1,4 @@
+//! Configuration for apollo telemetry.
 use crate::graphql::serde_utils::deserialize_header_name;
 use http::header::HeaderName;
 use schemars::JsonSchema;

apollo-router/src/plugins/telemetry/config.rs

@@ -1,3 +1,4 @@
+//! Configuration for the telemetry plugin.
 use super::*;
 use crate::plugins::telemetry::metrics;
 use opentelemetry::sdk::Resource;

apollo-router/src/plugins/telemetry/otlp.rs

@@ -1,3 +1,4 @@
+//! Shared configuration for Otlp tracing and metrics.
 use crate::configuration::ConfigurationError;
 use crate::plugins::telemetry::config::GenericWith;
 use opentelemetry_otlp::{HttpExporterBuilder, TonicExporterBuilder, WithExportConfig};

apollo-router/src/plugins/telemetry/tracing/apollo.rs

@@ -1,3 +1,4 @@
+//! Tracing configuration for apollo telemetry.
 use crate::plugins::telemetry::apollo::Config;
 use crate::plugins::telemetry::config::Trace;
 use crate::plugins::telemetry::tracing::apollo_telemetry::{SpaceportConfig, StudioGraph};

apollo-router/src/plugins/telemetry/tracing/datadog.rs

@@ -1,3 +1,4 @@
+//! Configuration for datadog tracing.
 use crate::plugins::telemetry::config::{GenericWith, Trace};
 use crate::plugins::telemetry::tracing::TracingConfigurator;
 use opentelemetry::sdk::trace::Builder;

apollo-router/src/plugins/telemetry/tracing/jaeger.rs

@@ -1,3 +1,4 @@
+//! Configuration for jaeger tracing.
 use crate::plugins::telemetry::config::{GenericWith, Trace};
 use crate::plugins::telemetry::tracing::TracingConfigurator;
 use opentelemetry::sdk::trace::{BatchSpanProcessor, Builder};

apollo-router/src/plugins/telemetry/tracing/otlp.rs

@@ -1,3 +1,4 @@
+//! Configuration for Otlp tracing.
 use crate::plugins::telemetry::config::Trace;
 use crate::plugins::telemetry::tracing::TracingConfigurator;
 use opentelemetry::sdk::trace::Builder;

apollo-router/src/plugins/telemetry/tracing/zipkin.rs

@@ -1,3 +1,4 @@
+//! Configuration for zipkin tracing.
 use crate::plugins::telemetry::config::{GenericWith, Trace};
 use crate::plugins::telemetry::tracing::TracingConfigurator;
 use opentelemetry::sdk::trace::Builder;