fix: LogProcessor.SetResource to require mutable self (open-telemetry#2801)

Author: cijothomas

opentelemetry-sdk/CHANGELOG.md

@@ -64,6 +64,9 @@
  `LogExporter` trait no longer requires a mutable ref to `self`. If the exporter
  needs to mutate state, it should rely on interior mutability.
  [2764](https://github.com/open-telemetry/opentelemetry-rust/pull/2764)
+- **Breaking** for custom `LogProcessor` authors: Changed `set_resource`
+  to require mutable ref.
+  `fn set_resource(&mut self, _resource: &Resource) {}`
 
 ## 0.28.0
 

opentelemetry-sdk/src/logs/batch_log_processor.rs

@@ -319,7 +319,7 @@ impl LogProcessor for BatchLogProcessor {
         }
     }
 
-    fn set_resource(&self, resource: &Resource) {
+    fn set_resource(&mut self, resource: &Resource) {
         let resource = Arc::new(resource.clone());
         let _ = self
             .message_sender

opentelemetry-sdk/src/logs/concurrent_log_processor.rs

@@ -1,6 +1,6 @@
 use opentelemetry::{otel_info, InstrumentationScope};
 
-use crate::error::OTelSdkResult;
+use crate::{error::OTelSdkResult, Resource};
 
 use super::{LogBatch, LogExporter, LogProcessor, SdkLogRecord};
 
@@ -56,4 +56,8 @@ impl<T: LogExporter> LogProcessor for SimpleConcurrentLogProcessor<T> {
     ) -> bool {
         self.exporter.event_enabled(level, target, name)
     }
+
+    fn set_resource(&mut self, resource: &Resource) {
+        self.exporter.set_resource(resource);
+    }
 }

opentelemetry-sdk/src/logs/log_processor.rs

@@ -65,7 +65,7 @@ pub trait LogProcessor: Send + Sync + Debug {
     }
 
     /// Set the resource for the log processor.
-    fn set_resource(&self, _resource: &Resource) {}
+    fn set_resource(&mut self, _resource: &Resource) {}
 }
 
 #[cfg(all(test, feature = "testing", feature = "logs"))]

opentelemetry-sdk/src/logs/log_processor_with_async_runtime.rs

@@ -108,7 +108,7 @@ impl<R: RuntimeChannel> LogProcessor for BatchLogProcessor<R> {
             .and_then(std::convert::identity)
     }
 
-    fn set_resource(&self, resource: &Resource) {
+    fn set_resource(&mut self, resource: &Resource) {
         let resource = Arc::new(resource.clone());
         let _ = self
             .message_sender