feat: allow to specif a service.instance.id; fix service.name usage

Signed-off-by: jeluard <jeluard@users.noreply.github.com>

Author: jeluard

Cargo.toml

@@ -47,7 +47,7 @@ opentelemetry-otlp = { version = "0.31.0", features = [
   "http-proto",
   "reqwest-blocking-client",
 ] }
-opentelemetry-semantic-conventions = "0.31.0"
+opentelemetry-semantic-conventions = { version = "0.31.0", features = ["semconv_experimental"] }
 opentelemetry_sdk = "0.31.0"
 pallas-addresses = "0.34.0"
 pallas-codec = "0.34.0" # When updating, double check that minicbor doesn't need to be updated too (see https://github.com/txpipe/pallas/blob/v0.32.0/pallas-codec/Cargo.toml#L22)

crates/amaru/src/observability.rs

@@ -13,7 +13,7 @@
 // limitations under the License.
 
 use std::{
-    env::VarError,
+    env::{VarError, var},
     error::Error,
     fmt,
     io::{self, IsTerminal},
@@ -25,7 +25,7 @@ use std::{
 use opentelemetry::trace::TracerProvider;
 use opentelemetry_otlp::WithExportConfig;
 use opentelemetry_sdk::{metrics::SdkMeterProvider, trace::SdkTracerProvider};
-use opentelemetry_semantic_conventions::resource::SERVICE_NAME;
+use opentelemetry_semantic_conventions::resource::{SERVICE_INSTANCE_ID, SERVICE_NAME};
 use tracing::{Metadata, Subscriber, info, level_filters::LevelFilter, span, subscriber::Interest, warn};
 use tracing_subscriber::{
     EnvFilter, Registry,
@@ -267,17 +267,21 @@ impl Default for OpenTelemetryHandle {
     }
 }
 
-pub const DEFAULT_OTLP_SERVICE_NAME: &str = "amaru";
-
-pub const DEFAULT_OTLP_METRIC_URL: &str = "http://localhost:4318/v1/metrics";
+const DEFAULT_OTLP_SERVICE_NAME: &str = "amaru";
+const DEFAULT_OTLP_METRIC_URL: &str = "http://localhost:4318/v1/metrics";
 
 #[expect(clippy::panic)]
 pub fn setup_open_telemetry(subscriber: &mut TracingSubscriber<Registry>) -> (OpenTelemetryHandle, DelayedWarning) {
     use opentelemetry::KeyValue;
     use opentelemetry_sdk::{Resource, metrics::Temporality};
 
-    let service_name = std::env::var("OTEL_SERVICE_NAME").unwrap_or_else(|_| DEFAULT_OTLP_SERVICE_NAME.to_string());
-    let resource = Resource::builder().with_attribute(KeyValue::new(SERVICE_NAME, service_name)).build();
+    let service_name = var("OTEL_SERVICE_NAME").unwrap_or_else(|_| DEFAULT_OTLP_SERVICE_NAME.to_string());
+    let service_instance_id = var("OTEL_SERVICE_INSTANCE_ID").ok();
+    let mut attributes = vec![KeyValue::new(SERVICE_NAME, service_name.clone())];
+    if let Some(id) = service_instance_id {
+        attributes.push(KeyValue::new(SERVICE_INSTANCE_ID, id));
+    }
+    let resource = Resource::builder().with_attributes(attributes).build();
 
     // Traces & span
     let opentelemetry_provider = SdkTracerProvider::builder()
@@ -313,7 +317,7 @@ pub fn setup_open_telemetry(subscriber: &mut TracingSubscriber<Registry>) -> (Op
     opentelemetry::global::set_meter_provider(metrics_provider.clone());
 
     // Subscriber
-    let opentelemetry_tracer = opentelemetry_provider.tracer(DEFAULT_OTLP_SERVICE_NAME);
+    let opentelemetry_tracer = opentelemetry_provider.tracer(service_name);
     let (default_filter, warning) = new_default_filter(AMARU_TRACE_VAR, DEFAULT_AMARU_TRACE_FILTER);
 
     let opentelemetry_layer =

monitoring/README.md

@@ -91,7 +91,8 @@ Coming soon.
 
 Amaru recognizes standard OpenTelemetry env variable for its configuration:
 
-- `OTEL_SERVICE_NAME`: Sets the `service.name` key used to identify metrics and traces. This is useful when a single OTLP service stack collects telemetry from several Amaru instances
+- `OTEL_SERVICE_NAME`: Sets the [service.name](https://opentelemetry.io/docs/specs/semconv/registry/attributes/service/#service-name) key used to identify metrics and traces. Defaults to `amaru`.
+- `OTEL_SERVICE_INSTANCE_ID`: Sets the [service.instance.id](https://opentelemetry.io/docs/specs/semconv/registry/attributes/service/#service-instance-id) key used to identify this specific amaru instance
 - `OTEL_EXPORTER_OTLP_ENDPOINT`: Sets the endpoint used to send spans, defaults to `http://localhost:4317`
 - `OTEL_EXPORTER_OTLP_METRICS_ENDPOINT`: Sets the endpoint used to send metrics, defaults to `http://localhost:4318/v1/metrics`