Move shutdown checks to MeterProvider (#2433)

Author: cijothomas

opentelemetry-sdk/src/metrics/meter_provider.rs

@@ -38,7 +38,7 @@ pub struct SdkMeterProvider {
 struct SdkMeterProviderInner {
     pipes: Arc<Pipelines>,
     meters: Mutex<HashMap<InstrumentationScope, Arc<SdkMeter>>>,
-    is_shutdown: AtomicBool,
+    shutdown_invoked: AtomicBool,
 }
 
 impl Default for SdkMeterProvider {
@@ -119,20 +119,29 @@ impl SdkMeterProvider {
 
 impl SdkMeterProviderInner {
     fn force_flush(&self) -> MetricResult<()> {
-        self.pipes.force_flush()
+        if self
+            .shutdown_invoked
+            .load(std::sync::atomic::Ordering::Relaxed)
+        {
+            Err(MetricError::Other(
+                "Cannot perform flush as MeterProvider shutdown already invoked.".into(),
+            ))
+        } else {
+            self.pipes.force_flush()
+        }
     }
 
     fn shutdown(&self) -> MetricResult<()> {
         if self
-            .is_shutdown
-            .compare_exchange(false, true, Ordering::SeqCst, Ordering::SeqCst)
-            .is_ok()
+            .shutdown_invoked
+            .swap(true, std::sync::atomic::Ordering::SeqCst)
         {
-            self.pipes.shutdown()
-        } else {
+            // If the previous value was true, shutdown was already invoked.
             Err(MetricError::Other(
-                "metrics provider already shut down".into(),
+                "MeterProvider shutdown already invoked.".into(),
             ))
+        } else {
+            self.pipes.shutdown()
         }
     }
 }
@@ -141,7 +150,7 @@ impl Drop for SdkMeterProviderInner {
     fn drop(&mut self) {
         // If user has already shutdown the provider manually by calling
         // shutdown(), then we don't need to call shutdown again.
-        if self.is_shutdown.load(Ordering::Relaxed) {
+        if self.shutdown_invoked.load(Ordering::Relaxed) {
             otel_debug!(
                 name: "MeterProvider.Drop.AlreadyShutdown",
                 message = "MeterProvider was already shut down; drop will not attempt shutdown again."
@@ -173,7 +182,7 @@ impl MeterProvider for SdkMeterProvider {
     }
 
     fn meter_with_scope(&self, scope: InstrumentationScope) -> Meter {
-        if self.inner.is_shutdown.load(Ordering::Relaxed) {
+        if self.inner.shutdown_invoked.load(Ordering::Relaxed) {
             otel_debug!(
                 name: "MeterProvider.NoOpMeterReturned",
                 meter_name = scope.name(),
@@ -270,7 +279,7 @@ impl MeterProviderBuilder {
                     self.views,
                 )),
                 meters: Default::default(),
-                is_shutdown: AtomicBool::new(false),
+                shutdown_invoked: AtomicBool::new(false),
             }),
         };
 

opentelemetry-sdk/src/metrics/periodic_reader.rs

@@ -1,7 +1,6 @@
 use std::{
     env, fmt,
     sync::{
-        atomic::AtomicBool,
         mpsc::{self, Receiver, Sender},
         Arc, Mutex, Weak,
     },
@@ -158,7 +157,6 @@ impl PeriodicReader {
         let reader = PeriodicReader {
             inner: Arc::new(PeriodicReaderInner {
                 message_sender: Arc::new(message_sender),
-                shutdown_invoked: AtomicBool::new(false),
                 producer: Mutex::new(None),
                 exporter: Arc::new(exporter),
             }),
@@ -300,7 +298,6 @@ struct PeriodicReaderInner {
     exporter: Arc<dyn PushMetricExporter>,
     message_sender: Arc<mpsc::Sender<Message>>,
     producer: Mutex<Option<Weak<dyn SdkProducer>>>,
-    shutdown_invoked: AtomicBool,
 }
 
 impl PeriodicReaderInner {
@@ -374,15 +371,6 @@ impl PeriodicReaderInner {
     }
 
     fn force_flush(&self) -> MetricResult<()> {
-        if self
-            .shutdown_invoked
-            .load(std::sync::atomic::Ordering::Relaxed)
-        {
-            return Err(MetricError::Other(
-                "Cannot perform flush as PeriodicReader shutdown already invoked.".into(),
-            ));
-        }
-
         // TODO: Better message for this scenario.
         // Flush and Shutdown called from 2 threads Flush check shutdown
         // flag before shutdown thread sets it. Both threads attempt to send
@@ -414,15 +402,6 @@ impl PeriodicReaderInner {
     }
 
     fn shutdown(&self) -> MetricResult<()> {
-        if self
-            .shutdown_invoked
-            .swap(true, std::sync::atomic::Ordering::Relaxed)
-        {
-            return Err(MetricError::Other(
-                "PeriodicReader shutdown already invoked.".into(),
-            ));
-        }
-
         // TODO: See if this is better to be created upfront.
         let (response_tx, response_rx) = mpsc::channel();
         self.message_sender