Stdout example to default to all features (#1734)

Author: cijothomas

opentelemetry-stdout/Cargo.toml

@@ -16,6 +16,7 @@ edition = "2021"
 rust-version = "1.65"
 
 [features]
+default = ["trace", "metrics", "logs"]
 trace = ["opentelemetry/trace", "opentelemetry_sdk/trace", "futures-util"]
 metrics = ["async-trait", "opentelemetry/metrics", "opentelemetry_sdk/metrics"]
 logs = ["opentelemetry/logs", "opentelemetry_sdk/logs", "async-trait", "thiserror"]

opentelemetry-stdout/examples/basic.rs

@@ -1,56 +1,74 @@
-//! run with `$ cargo run --example basic --all-features
-
-#[cfg(all(feature = "metrics", feature = "trace"))]
-use opentelemetry::{
-    global,
-    trace::{Span, Tracer, TracerProvider as _},
-    KeyValue,
-};
-#[cfg(all(feature = "metrics", feature = "trace"))]
-use opentelemetry_sdk::{
-    metrics::{PeriodicReader, SdkMeterProvider},
-    runtime,
-    trace::TracerProvider,
-};
-
-#[cfg(all(feature = "metrics", feature = "trace"))]
-fn init_trace() -> TracerProvider {
+//! run with `$ cargo run --example basic
+
+use opentelemetry::{global, KeyValue};
+
+#[cfg(feature = "trace")]
+use opentelemetry::trace::{Span, Tracer};
+
+#[cfg(feature = "metrics")]
+use opentelemetry_sdk::runtime;
+
+#[cfg(feature = "metrics")]
+use opentelemetry_sdk::metrics::{PeriodicReader, SdkMeterProvider};
+
+#[cfg(feature = "trace")]
+use opentelemetry_sdk::trace::TracerProvider;
+
+#[cfg(feature = "trace")]
+fn init_trace() {
     let exporter = opentelemetry_stdout::SpanExporter::default();
-    TracerProvider::builder()
+    let provider = TracerProvider::builder()
         .with_simple_exporter(exporter)
-        .build()
+        .build();
+    global::set_tracer_provider(provider);
 }
 
-#[cfg(all(feature = "metrics", feature = "trace"))]
+#[cfg(feature = "metrics")]
 fn init_metrics() {
     let exporter = opentelemetry_stdout::MetricsExporter::default();
     let reader = PeriodicReader::builder(exporter, runtime::Tokio).build();
     let provider = SdkMeterProvider::builder().with_reader(reader).build();
     global::set_meter_provider(provider);
 }
 
-#[tokio::main]
-#[cfg(all(feature = "metrics", feature = "trace"))]
-async fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let tracer_provider = init_trace();
-    init_metrics();
-
-    let tracer = tracer_provider.tracer("stdout-test");
+#[cfg(feature = "trace")]
+fn emit_span() {
+    let tracer = global::tracer("stdout-test");
     let mut span = tracer.start("test_span");
     span.set_attribute(KeyValue::new("test_key", "test_value"));
     span.add_event(
         "test_event",
         vec![KeyValue::new("test_event_key", "test_event_value")],
     );
     span.end();
+}
 
+#[cfg(feature = "metrics")]
+fn emit_metrics() {
     let meter = global::meter("stdout-test");
-    let c = meter.u64_counter("test_events").init();
+    let c = meter.u64_counter("test_counter").init();
     c.add(1, &[KeyValue::new("test_key", "test_value")]);
+}
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    #[cfg(feature = "trace")]
+    init_trace();
+
+    #[cfg(feature = "metrics")]
+    init_metrics();
+
+    #[cfg(feature = "trace")]
+    emit_span();
+
+    #[cfg(feature = "metrics")]
+    emit_metrics();
+
+    #[cfg(feature = "trace")]
+    global::shutdown_tracer_provider();
 
+    #[cfg(feature = "metrics")]
     global::shutdown_meter_provider();
 
     Ok(())
 }
-#[cfg(not(all(feature = "metrics", feature = "trace")))]
-fn main() {}