Fix metrics and tracing providers not being set globally

This is relied on by other parts of spin-telemetry

Signed-off-by: Caleb Schoepp <[email protected]>

Author: calebschoepp

crates/telemetry/src/metrics.rs

@@ -1,6 +1,7 @@
 use std::time::Duration;
 
 use anyhow::{bail, Result};
+use opentelemetry::global;
 use opentelemetry_otlp::MetricsExporterBuilder;
 use opentelemetry_sdk::{
     metrics::{
@@ -57,6 +58,8 @@ pub(crate) fn otel_metrics_layer<S: Subscriber + for<'span> LookupSpan<'span>>(
         .with_resource(resource)
         .build();
 
+    global::set_meter_provider(meter_provider.clone());
+
     Ok(MetricsLayer::new(meter_provider))
 }
 

crates/telemetry/src/traces.rs

@@ -1,7 +1,7 @@
 use std::time::Duration;
 
 use anyhow::bail;
-use opentelemetry::trace::TracerProvider;
+use opentelemetry::{global, trace::TracerProvider};
 use opentelemetry_otlp::SpanExporterBuilder;
 use opentelemetry_sdk::{
     resource::{EnvResourceDetector, TelemetryResourceDetector},
@@ -35,18 +35,20 @@ pub(crate) fn otel_tracing_layer<S: Subscriber + for<'span> LookupSpan<'span>>(
     );
 
     // This will configure the exporter based on the OTEL_EXPORTER_* environment variables.
-    let exporter: SpanExporterBuilder = match OtlpProtocol::traces_protocol_from_env() {
+    let exporter_builder: SpanExporterBuilder = match OtlpProtocol::traces_protocol_from_env() {
         OtlpProtocol::Grpc => opentelemetry_otlp::new_exporter().tonic().into(),
         OtlpProtocol::HttpProtobuf => opentelemetry_otlp::new_exporter().http().into(),
         OtlpProtocol::HttpJson => bail!("http/json OTLP protocol is not supported"),
     };
 
     let tracer_provider = opentelemetry_otlp::new_pipeline()
         .tracing()
-        .with_exporter(exporter)
+        .with_exporter(exporter_builder)
         .with_trace_config(opentelemetry_sdk::trace::Config::default().with_resource(resource))
         .install_batch(opentelemetry_sdk::runtime::Tokio)?;
 
+    global::set_tracer_provider(tracer_provider.clone());
+
     let env_filter = match EnvFilter::try_from_env("SPIN_OTEL_TRACING_LEVEL") {
         Ok(filter) => filter,
         // If it isn't set or it fails to parse default to info