Minor update to stdout exporter example to show log correlation (#2459)

Author: cijothomas

opentelemetry-stdout/examples/basic.rs

@@ -4,7 +4,7 @@ use once_cell::sync::Lazy;
 use opentelemetry::{global, KeyValue};
 
 #[cfg(feature = "trace")]
-use opentelemetry::trace::{Span, Tracer};
+use opentelemetry::trace::Tracer;
 
 #[cfg(feature = "metrics")]
 use opentelemetry_sdk::metrics::{PeriodicReader, SdkMeterProvider};
@@ -60,52 +60,23 @@ fn init_logs() -> opentelemetry_sdk::logs::LoggerProvider {
 
 #[cfg(feature = "trace")]
 fn emit_span() {
-    use opentelemetry::{
-        trace::{SpanContext, SpanId, TraceFlags, TraceId, TraceState},
-        InstrumentationScope,
-    };
+    use opentelemetry::{trace::TraceContextExt, InstrumentationScope};
 
     let scope = InstrumentationScope::builder("stdout-example")
         .with_version("v1")
         .with_attributes([KeyValue::new("scope_key", "scope_value")])
         .build();
 
     let tracer = global::tracer_with_scope(scope);
-    let mut span = tracer.start("example-span");
-    span.set_attribute(KeyValue::new("attribute_key1", "attribute_value1"));
-    span.set_attribute(KeyValue::new("attribute_key2", "attribute_value2"));
-    span.add_event(
-        "example-event-name",
-        vec![KeyValue::new("event_attribute1", "event_value1")],
-    );
-    span.add_link(
-        SpanContext::new(
-            TraceId::from_hex("58406520a006649127e371903a2de979").expect("invalid"),
-            SpanId::from_hex("b6d7d7f6d7d6d7f6").expect("invalid"),
-            TraceFlags::default(),
-            false,
-            TraceState::NONE,
-        ),
-        vec![
-            KeyValue::new("link_attribute1", "link_value1"),
-            KeyValue::new("link_attribute2", "link_value2"),
-        ],
-    );
-
-    span.add_link(
-        SpanContext::new(
-            TraceId::from_hex("23401120a001249127e371903f2de971").expect("invalid"),
-            SpanId::from_hex("cd37d765d743d7f6").expect("invalid"),
-            TraceFlags::default(),
-            false,
-            TraceState::NONE,
-        ),
-        vec![
-            KeyValue::new("link_attribute1", "link_value1"),
-            KeyValue::new("link_attribute2", "link_value2"),
-        ],
-    );
-    span.end();
+    tracer.in_span("example-span", |cx| {
+        let span = cx.span();
+        span.set_attribute(KeyValue::new("my-attribute", "my-value"));
+        span.add_event(
+            "example-event-name",
+            vec![KeyValue::new("event_attribute1", "event_value1")],
+        );
+        emit_log();
+    })
 }
 
 #[cfg(feature = "metrics")]

opentelemetry-stdout/src/logs/exporter.rs

@@ -82,6 +82,9 @@ fn print_logs(batch: LogBatch<'_>) {
         if let Some(trace_context) = record.trace_context() {
             println!("\t TraceId: {:?}", trace_context.trace_id);
             println!("\t SpanId: {:?}", trace_context.span_id);
+            if let Some(trace_flags) = trace_context.trace_flags {
+                println!("\t TraceFlags: {:?}", trace_flags);
+            }
         }
         if let Some(timestamp) = record.timestamp() {
             let datetime: DateTime<Utc> = timestamp.into();

opentelemetry-stdout/src/trace/exporter.rs

@@ -96,6 +96,7 @@ fn print_spans(batch: Vec<export::trace::SpanData>) {
         println!("\tName        : {}", &span.name);
         println!("\tTraceId     : {}", &span.span_context.trace_id());
         println!("\tSpanId      : {}", &span.span_context.span_id());
+        println!("\tTraceFlags  : {:?}", &span.span_context.trace_flags());
         println!("\tParentSpanId: {}", &span.parent_span_id);
         println!("\tKind        : {:?}", &span.span_kind);