feat(o11y): add metric macro

Author: ymgyt

crates/synd_o11y/src/opentelemetry/resource.rs

@@ -1,25 +1,28 @@
 use opentelemetry::KeyValue;
-use opentelemetry_sdk::Resource;
+use opentelemetry_sdk::{resource::EnvResourceDetector, Resource};
 use opentelemetry_semantic_conventions::{
-    resource::{DEPLOYMENT_ENVIRONMENT, SERVICE_NAME, SERVICE_NAMESPACE, SERVICE_VERSION},
+    resource::{SERVICE_NAME, SERVICE_NAMESPACE, SERVICE_VERSION},
     SCHEMA_URL,
 };
-use std::borrow::Cow;
+use std::{borrow::Cow, time::Duration};
 
 pub fn resource(
     service_name: impl Into<Cow<'static, str>>,
     service_version: impl Into<Cow<'static, str>>,
-    deployment_environment: impl Into<Cow<'static, str>>,
 ) -> Resource {
-    Resource::from_schema_url(
+    Resource::from_detectors(
+        Duration::from_millis(200),
+        // Detect "OTEL_RESOURCE_ATTRIBUTES" enviornment variables
+        vec![Box::new(EnvResourceDetector::new())],
+    )
+    .merge(&Resource::from_schema_url(
         [
             (SERVICE_NAME, service_name.into()),
             (SERVICE_VERSION, service_version.into()),
             (SERVICE_NAMESPACE, "syndicationd".into()),
-            (DEPLOYMENT_ENVIRONMENT, deployment_environment.into()),
         ]
         .into_iter()
         .map(|(key, value)| KeyValue::new(key, value)),
         SCHEMA_URL,
-    )
+    ))
 }

crates/synd_o11y/src/tracing_subscriber/otel_metrics/macros.rs

@@ -0,0 +1,8 @@
+#[macro_export]
+macro_rules! metric {
+    ($($tt:tt)* ) => { ::tracing::event!(
+        target: $crate::tracing_subscriber::otel_metrics::METRICS_EVENT_TARGET,
+        ::tracing::Level::INFO,
+        $($tt)*
+    );}
+}

crates/synd_o11y/src/tracing_subscriber/otel_metrics/mod.rs

@@ -1,9 +1,17 @@
 use std::time::Duration;
 
 use opentelemetry_sdk::{metrics::MeterProvider, runtime, Resource};
-use tracing::Subscriber;
+use tracing::{Metadata, Subscriber};
 use tracing_opentelemetry::MetricsLayer;
-use tracing_subscriber::{registry::LookupSpan, Layer};
+use tracing_subscriber::{filter::filter_fn, layer::Filter, registry::LookupSpan, Layer};
+
+pub mod macros;
+
+pub const METRICS_EVENT_TARGET: &str = "metrics";
+
+pub fn metrics_event_filter<S: Subscriber>() -> impl Filter<S> {
+    filter_fn(|metadata: &Metadata<'_>| metadata.target() != METRICS_EVENT_TARGET)
+}
 
 pub fn layer<S>(resource: Resource) -> impl Layer<S>
 where