feat: Add declarative configuration initial version.

Author: andborja

Cargo.toml

@@ -4,6 +4,7 @@ members = [
     "opentelemetry-*",
     "opentelemetry-*/examples/*",
     "opentelemetry-otlp/tests/*",
+    "opentelemetry-declarative-config",
     "examples/*",
     "stress",
 ]
@@ -81,7 +82,6 @@ schemars = "0.8"
 sysinfo = "0.32"
 tempfile = "3.3.0"
 tracing-log = "0.2"
-tracing-opentelemetry = "0.32"
 typed-builder = "0.20"
 uuid = "1.3"
 pprof = { version = "0.14", features = ["flamegraph", "criterion"] }

opentelemetry-appender-tracing/CHANGELOG.md

@@ -2,6 +2,16 @@
 
 ## vNext
 
+- Remove the `experimental_use_tracing_span_context` since
+  `tracing-opentelemetry` now supports [activating][31901]  the OpenTelemetry
+  context for the current tracing span.
+  
+  This fixes [3190][3190] the circular dependency introduced by depending on
+  `tracing-opentelemetry` that depends on `opentelemetry`.
+
+[3190]: https://github.com/open-telemetry/opentelemetry-rust/issues/3190
+[31901]: https://github.com/tokio-rs/tracing-opentelemetry/blob/884b00cf438557733bd9cef9456281bea8c4bea1/src/layer.rs#L842
+
 ## 0.31.1
 
 Released 2025-Oct-1

opentelemetry-appender-tracing/Cargo.toml

@@ -18,7 +18,6 @@ tracing = { workspace = true, features = ["std"]}
 tracing-core = { workspace = true }
 tracing-log = { workspace = true, optional = true }
 tracing-subscriber = { workspace = true, features = ["registry", "std"] }
-tracing-opentelemetry = { workspace = true, optional = true }
 
 [dev-dependencies]
 log = { workspace = true }
@@ -28,7 +27,6 @@ tracing = { workspace = true, features = ["std"]}
 tracing-subscriber = { workspace = true, features = ["env-filter","registry", "std", "fmt"] }
 tracing-log = { workspace = true }
 criterion = { workspace = true }
-#tokio = { workspace = true, features = ["full"]}
 
 [target.'cfg(not(target_os = "windows"))'.dev-dependencies]
 pprof = { workspace = true }
@@ -37,10 +35,8 @@ pprof = { workspace = true }
 default = []
 experimental_metadata_attributes = ["dep:tracing-log"]
 spec_unstable_logs_enabled = ["opentelemetry/spec_unstable_logs_enabled"]
-experimental_use_tracing_span_context = ["tracing-opentelemetry"]
 bench_profiling = []
 
-
 [[bench]]
 name = "logs"
 harness = false

opentelemetry-appender-tracing/src/layer.rs

@@ -244,29 +244,6 @@ where
         // Visit fields.
         event.record(&mut visitor);
 
-        #[cfg(feature = "experimental_use_tracing_span_context")]
-        if let Some(span) = _ctx.event_span(event) {
-            use tracing_opentelemetry::OtelData;
-            if let Some(otd) = span.extensions().get::<OtelData>() {
-                if let Some(span_id) = otd.span_id() {
-                    // Try the trace_id of the current span first;
-                    // If it is not already established (still in the Builder state), try finding the root span.
-                    let opt_trace_id = otd.trace_id().or_else(|| {
-                        span.scope().last().and_then(|root_span| {
-                            root_span
-                                .extensions()
-                                .get::<OtelData>()
-                                .and_then(|root_otd| root_otd.trace_id())
-                        })
-                    });
-                    if let Some(trace_id) = opt_trace_id {
-                        // Unable to reliably obtain TraceFlags (old implementation also passed None)
-                        log_record.set_trace_context(trace_id, span_id, None);
-                    }
-                }
-            }
-        }
-
         //emit record
         self.logger.emit(log_record);
     }
@@ -611,121 +588,6 @@ mod tests {
         }
     }
 
-    #[cfg(feature = "experimental_use_tracing_span_context")]
-    #[test]
-    fn tracing_appender_inside_tracing_crate_context() {
-        use opentelemetry::{trace::SpanContext, Context, SpanId, TraceId};
-        use opentelemetry_sdk::trace::InMemorySpanExporterBuilder;
-        use tracing_opentelemetry::OpenTelemetrySpanExt;
-
-        // Arrange
-        let exporter: InMemoryLogExporter = InMemoryLogExporter::default();
-        let logger_provider = SdkLoggerProvider::builder()
-            .with_simple_exporter(exporter.clone())
-            .build();
-
-        // setup tracing layer to compare trace/span IDs against
-        let span_exporter = InMemorySpanExporterBuilder::new().build();
-        let tracer_provider = SdkTracerProvider::builder()
-            .with_simple_exporter(span_exporter.clone())
-            .build();
-        let tracer = tracer_provider.tracer("test-tracer");
-
-        let level_filter = tracing_subscriber::filter::LevelFilter::ERROR;
-        let log_layer =
-            layer::OpenTelemetryTracingBridge::new(&logger_provider).with_filter(level_filter);
-
-        let subscriber = tracing_subscriber::registry()
-            .with(log_layer)
-            .with(tracing_opentelemetry::layer().with_tracer(tracer));
-
-        // Avoiding global subscriber.init() as that does not play well with unit tests.
-        let _guard = tracing::subscriber::set_default(subscriber);
-
-        // Act
-        tracing::error_span!("outer-span").in_scope(|| {
-            error!("first-event");
-
-            tracing::error_span!("inner-span").in_scope(|| {
-                error!("second-event");
-            });
-        });
-
-        assert!(logger_provider.force_flush().is_ok());
-
-        let logs = exporter.get_emitted_logs().expect("No emitted logs");
-        assert_eq!(logs.len(), 2, "Expected 2 logs, got: {logs:?}");
-
-        let spans = span_exporter.get_finished_spans().unwrap();
-        assert_eq!(spans.len(), 2);
-
-        let trace_id = spans[0].span_context.trace_id();
-        assert_eq!(trace_id, spans[1].span_context.trace_id());
-        let inner_span_id = spans[0].span_context.span_id();
-        let outer_span_id = spans[1].span_context.span_id();
-        assert_eq!(outer_span_id, spans[0].parent_span_id);
-
-        let trace_ctx0 = logs[0].record.trace_context().unwrap();
-        let trace_ctx1 = logs[1].record.trace_context().unwrap();
-
-        assert_eq!(trace_ctx0.trace_id, trace_id);
-        assert_eq!(trace_ctx1.trace_id, trace_id);
-        assert_eq!(trace_ctx0.span_id, outer_span_id);
-        assert_eq!(trace_ctx1.span_id, inner_span_id);
-
-        // Set context from remote.
-        let remote_trace_id = TraceId::from(233);
-        let remote_span_id = SpanId::from(2333);
-        let remote_span_context = SpanContext::new(
-            remote_trace_id,
-            remote_span_id,
-            TraceFlags::SAMPLED,
-            true,
-            Default::default(),
-        );
-
-        // Act again.
-        {
-            let parent_context = Context::current().with_remote_span_context(remote_span_context);
-            let outer_span = tracing::error_span!("outer-span");
-            let _ = outer_span.set_parent(parent_context);
-
-            outer_span.in_scope(|| {
-                error!("first-event");
-
-                let inner_span = tracing::error_span!("inner-span");
-                inner_span.in_scope(|| {
-                    error!("second-event");
-                });
-            });
-        }
-
-        assert!(logger_provider.force_flush().is_ok());
-
-        let logs = exporter.get_emitted_logs().expect("No emitted logs");
-        assert_eq!(logs.len(), 4, "Expected 4 logs, got: {logs:?}");
-        let logs = &logs[2..];
-
-        let spans = span_exporter.get_finished_spans().unwrap();
-        assert_eq!(spans.len(), 4);
-        let spans = &spans[2..];
-
-        let trace_id = spans[0].span_context.trace_id();
-        assert_eq!(trace_id, remote_trace_id);
-        assert_eq!(trace_id, spans[1].span_context.trace_id());
-        let inner_span_id = spans[0].span_context.span_id();
-        let outer_span_id = spans[1].span_context.span_id();
-        assert_eq!(outer_span_id, spans[0].parent_span_id);
-
-        let trace_ctx0 = logs[0].record.trace_context().unwrap();
-        let trace_ctx1 = logs[1].record.trace_context().unwrap();
-
-        assert_eq!(trace_ctx0.trace_id, trace_id);
-        assert_eq!(trace_ctx1.trace_id, trace_id);
-        assert_eq!(trace_ctx0.span_id, outer_span_id);
-        assert_eq!(trace_ctx1.span_id, inner_span_id);
-    }
-
     #[test]
     fn tracing_appender_standalone_with_tracing_log() {
         // Arrange

opentelemetry-declarative-config/CHANGELOG.md

@@ -0,0 +1,9 @@
+# Changelog
+
+## vNext
+
+## v0.1.0
+
+### Added
+
+- Initial declarative configuration

opentelemetry-declarative-config/Cargo.toml

@@ -0,0 +1,41 @@
+[package]
+name = "opentelemetry-declarative-config"
+version = "0.29.1"
+description = "Declarative configuration for OpenTelemetry SDK"
+homepage = "https://github.com/open-telemetry/opentelemetry-rust/tree/main/opentelemetry-declarative-config"
+repository = "https://github.com/open-telemetry/opentelemetry-rust/tree/main/opentelemetry-declarative-config"
+readme = "README.md"
+categories = [
+    "development-tools::debugging",
+    "development-tools::profiling",
+]
+keywords = ["opentelemetry", "declarative", "metrics", "configuration"]
+license = "Apache-2.0"
+edition = "2021"
+rust-version = "1.75.0"
+
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]
+
+[dependencies]
+opentelemetry = { version = "0.31.0" }
+opentelemetry_sdk = { version = "0.31.0", features = ["experimental_metrics_custom_reader"] }
+opentelemetry-stdout = { version = "0.31.0" }
+opentelemetry-otlp = { version = "0.31.0" }
+opentelemetry-http = { workspace = true, optional = true, default-features = false }
+serde = { workspace = true, features = ["derive"] }
+reqwest = { workspace = true, optional = true }
+serde_yaml = "0.9.34"
+
+[dev-dependencies]
+tokio = { workspace = true, features = ["macros", "rt-multi-thread"] }
+
+[features]
+tonic-client = ["opentelemetry-otlp/grpc-tonic", "opentelemetry-otlp/trace", "opentelemetry-otlp/logs", "opentelemetry-otlp/metrics"]
+hyper-client = ["opentelemetry-http/hyper"]
+reqwest-client = ["reqwest", "opentelemetry-http/reqwest"]
+reqwest-blocking-client = ["reqwest/blocking", "opentelemetry-http/reqwest-blocking"]
+
+# Keep tonic as the default client
+default = ["tonic-client"]

opentelemetry-declarative-config/README.md

@@ -0,0 +1,30 @@
+# OpenTelemetry Declarative Configuration
+
+![OpenTelemetry — An observability framework for cloud-native software.][splash]
+
+[splash]: https://raw.githubusercontent.com/open-telemetry/opentelemetry-rust/main/assets/logo-text.png
+
+Declarative configuration for applications instrumented with [`OpenTelemetry`]. 
+
+## OpenTelemetry Overview
+
+OpenTelemetry is an Observability framework and toolkit designed to create and
+manage telemetry data such as traces, metrics, and logs. OpenTelemetry is
+vendor- and tool-agnostic, meaning that it can be used with a broad variety of
+Observability backends, including open source tools like [Jaeger] and
+[Prometheus], as well as commercial offerings.
+
+OpenTelemetry is *not* an observability backend like Jaeger, Prometheus, or other
+commercial vendors. OpenTelemetry is focused on the generation, collection,
+management, and export of telemetry. A major goal of OpenTelemetry is that you
+can easily instrument your applications or systems, no matter their language,
+infrastructure, or runtime environment. Crucially, the storage and visualization
+of telemetry is intentionally left to other tools.
+
+[`Prometheus`]: https://prometheus.io
+[`OpenTelemetry`]: https://crates.io/crates/opentelemetry
+[`Jaeger`]: https://www.jaegertracing.io
+
+## Release Notes
+
+You can find the release notes (changelog) [here](https://github.com/open-telemetry/opentelemetry-rust/blob/main/opentelemetry-declarative-config/CHANGELOG.md).

opentelemetry-declarative-config/examples/declarative_basic.rs

@@ -0,0 +1,44 @@
+use opentelemetry_declarative_config::Configurator;
+
+/// Example of configuring OpenTelemetry telemetry using declarative YAML configuration.
+
+#[tokio::main]
+pub async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let configurator = Configurator::new();
+    let config_yaml = r#"
+        metrics:
+            readers:
+                - periodic:
+                    exporter:
+                        otlp:
+                            protocol: http/protobuf
+                            endpoint: https://backend:4318
+                        stdout:
+                            temporality: cumulative
+        logs:
+            processors:
+                - batch:
+                    exporter:
+                        stdout:
+                        otlp:
+                            protocol: http/protobuf
+                            endpoint: https://backend:4318
+        resource:
+            service.name: sample-service
+            service.version: "1.0.0"
+    "#;
+    let result = configurator.configure_telemetry_from_yaml(config_yaml.into());
+    if let Err(ref e) = result {
+        panic!("Failed to configure telemetry from YAML string: {}", e);
+    }
+    assert!(result.is_ok());
+    let telemetry_providers = result.unwrap();
+    assert!(telemetry_providers.meter_provider().is_some());
+    assert!(telemetry_providers.logs_provider().is_some());
+    assert!(telemetry_providers.traces_provider().is_none());
+
+    println!("All the expected telemetry providers were configured successfully. Shutting down...");
+
+    telemetry_providers.shutdown()?;
+    Ok(())
+}