Add Retry to OTLP Exporter

opentelemetry-otlp/src/exporter/http/mod.rs

@@ -322,7 +322,7 @@ impl OtlpHttpClient {
         logs: LogBatch<'_>,
     ) -> opentelemetry_sdk::logs::LogResult<(Vec<u8>, &'static str)> {
         use opentelemetry_proto::tonic::collector::logs::v1::ExportLogsServiceRequest;
-        let resource_logs = group_logs_by_resource_and_scope(logs, &self.resource);
+        let resource_logs = group_logs_by_resource_and_scope(&logs, &self.resource);
         let req = ExportLogsServiceRequest { resource_logs };
 
         match self.protocol {

opentelemetry-otlp/src/exporter/tonic/logs.rs

@@ -12,6 +12,8 @@ use opentelemetry_proto::transform::logs::tonic::group_logs_by_resource_and_scop
 
 use super::BoxInterceptor;
 
+use super::retry::{retry_with_exponential_backoff, RetryPolicy};
+
 pub(crate) struct TonicLogsClient {
     inner: Mutex<Option<ClientInner>>,
     #[allow(dead_code)]
@@ -69,19 +71,56 @@ impl LogExporter for TonicLogsClient {
             None => return Err(OTelSdkError::AlreadyShutdown),
         };
 
-        let resource_logs = group_logs_by_resource_and_scope(batch, &self.resource);
+        let resource_logs = group_logs_by_resource_and_scope(&batch, &self.resource);
 
         otel_debug!(name: "TonicsLogsClient.CallingExport");
 
-        client
+        // First attempt without retry
+        let result = client
             .export(Request::from_parts(
-                metadata,
-                extensions,
-                ExportLogsServiceRequest { resource_logs },
+                metadata.clone(),
+                extensions.clone(),
+                ExportLogsServiceRequest { 
+                    resource_logs: resource_logs.clone() 
+                },
             ))
-            .await
-            .map_err(|e| OTelSdkError::InternalFailure(format!("export error: {:?}", e)))?;
-        Ok(())
+            .await;
+
+        // If the first attempt succeeds, return success
+        if result.is_ok() {
+            return Ok(());
+        }
+
+        // If the first attempt fails, try with retry
+        otel_debug!(name: "TonicsLogsClient.FirstAttemptFailed.Retrying");
+
+        let policy = RetryPolicy {
+            max_retries: 10,
+            initial_delay_ms: 100,
+            max_delay_ms: 1600,
+            jitter_ms: 100,
+        };
+
+        // Now use retry_with_exponential_backoff for subsequent attempts
+        retry_with_exponential_backoff(
+            policy,
+            "TonicsLogsClient.export",
+            || async {
+                client
+                    .clone()
+                    .export(Request::from_parts(
+                        metadata.clone(),
+                        extensions.clone(),
+                        ExportLogsServiceRequest { 
+                            resource_logs: resource_logs.clone() 
+                        },
+                    ))
+                    .await
+                    .map_err(|e| OTelSdkError::InternalFailure(format!("export error: {:?}", e)))
+            }
+        )
+        .await
+        .map(|_| ()) // Convert successful response to () as required by OTelSdkResult
     }
 
     fn shutdown(&self) -> OTelSdkResult {

opentelemetry-otlp/src/exporter/tonic/mod.rs

@@ -28,6 +28,11 @@ pub(crate) mod metrics;
 #[cfg(feature = "trace")]
 pub(crate) mod trace;
 
+// For now, we are not exposing the retry policy. Only work with grpc-tonic since retry takes a hard dependency on tokio
+// while we sort out an abstraction for the async runtime which can be used by all exporters.
+#[cfg(feature = "grpc-tonic")]
+mod retry;
+
 /// Configuration for [tonic]
 ///
 /// [tonic]: https://github.com/hyperium/tonic
@@ -498,9 +503,6 @@ mod tests {
     #[test]
     #[cfg(feature = "gzip-tonic")]
     fn test_with_gzip_compression() {
-        // metadata should merge with the current one with priority instead of just replacing it
-        let mut metadata = MetadataMap::new();
-        metadata.insert("foo", "bar".parse().unwrap());
         let builder = TonicExporterBuilder::default().with_compression(Compression::Gzip);
         assert_eq!(builder.tonic_config.compression.unwrap(), Compression::Gzip);
     }

opentelemetry-otlp/src/exporter/tonic/retry.rs

@@ -0,0 +1,229 @@
+//! This module provides functionality for retrying operations with exponential backoff and jitter.
+//!
+//! The `RetryPolicy` struct defines the configuration for the retry behavior, including the maximum
+//! number of retries, initial delay, maximum delay, and jitter.
+//!
+//! The `Sleep` trait abstracts the sleep functionality, allowing different implementations for
+//! various async runtimes such as Tokio and async-std, as well as a synchronous implementation.
+//!
+//! The `retry_with_exponential_backoff` function retries the given operation according to the
+//! specified retry policy, using exponential backoff and jitter to determine the delay between
+//! retries. The function logs errors and retries the operation until it succeeds or the maximum
+//! number of retries is reached.
+
+use std::future::Future;
+use std::time::{Duration, SystemTime};
+use opentelemetry::otel_warn;
+
+/// Configuration for retry policy.
+#[derive(Debug)]
+pub(super) struct RetryPolicy {
+    /// Maximum number of retry attempts.
+    pub max_retries: usize,
+    /// Initial delay in milliseconds before the first retry.
+    pub initial_delay_ms: u64,
+    /// Maximum delay in milliseconds between retries.
+    pub max_delay_ms: u64,
+    /// Maximum jitter in milliseconds to add to the delay.
+    pub jitter_ms: u64,
+}
+
+// Generates a random jitter value up to max_jitter
+fn generate_jitter(max_jitter: u64) -> u64 {
+    let now = SystemTime::now();
+    let nanos = now.duration_since(SystemTime::UNIX_EPOCH).unwrap().subsec_nanos();
+    nanos as u64 % (max_jitter + 1)
+}
+
+// /// Trait to abstract the sleep functionality.
+// pub trait Sleep {
+//     /// The future returned by the sleep function.
+//     type SleepFuture: Future<Output = ()>;
+
+//     /// Sleeps for the specified duration.
+//     fn sleep(duration: Duration) -> Self::SleepFuture;
+// }
+
+// /// Implementation of the Sleep trait for tokio::time::Sleep
+// #[cfg(feature = "rt-tokio")]
+// impl Sleep for tokio::time::Sleep {
+//     type SleepFuture = tokio::time::Sleep;
+
+//     fn sleep(duration: Duration) -> Self::SleepFuture {
+//     }
+// }
+
+// #[cfg(feature = "rt-async-std")]
+// /// There is no direct equivalent to `tokio::time::Sleep` in `async-std`.
+// /// Instead, we create a new struct `AsyncStdSleep` and implement the `Sleep`
+// /// trait for it, boxing the future returned by `async_std::task::sleep` to fit
+// /// the trait's associated type requirements.
+// #[derive(Debug)]
+// pub struct AsyncStdSleep;
+
+// /// Implementation of the Sleep trait for async-std
+// #[cfg(feature = "rt-async-std")]
+// impl Sleep for AsyncStdSleep {
+//     type SleepFuture = Pin<Box<dyn Future<Output = ()> + Send>>;
+
+//     fn sleep(duration: Duration) -> Self::SleepFuture {
+//         Box::pin(async_std::task::sleep(duration))
+//     }
+// }
+
+// /// Implement the Sleep trait for synchronous sleep
+// #[derive(Debug)]
+// pub struct StdSleep;
+
+// impl Sleep for StdSleep {
+//     type SleepFuture = std::future::Ready<()>;
+
+//     fn sleep(duration: Duration) -> Self::SleepFuture {
+//         std::thread::sleep(duration);
+//         std::future::ready(())
+//     }
+// }
+
+/// Retries the given operation with exponential backoff and jitter.
+///
+/// # Arguments
+///
+/// * `policy` - The retry policy configuration.
+/// * `operation_name` - The name of the operation being retried.
+/// * `operation` - The operation to be retried.
+///
+/// # Returns
+///
+/// A `Result` containing the operation's result or an error if the maximum retries are reached.
+pub(super) async fn retry_with_exponential_backoff<F, Fut, T, E>(
+    policy: RetryPolicy,
+    operation_name: &str,
+    mut operation: F,
+) -> Result<T, E>
+where
+    F: FnMut() -> Fut,
+    E: std::fmt::Debug,
+    Fut: Future<Output = Result<T, E>>,
+{
+    let mut attempt = 0;
+    let mut delay = policy.initial_delay_ms;
+
+    loop {
+        match operation().await {
+            Ok(result) => return Ok(result), // Return the result if the operation succeeds
+            Err(err) if attempt < policy.max_retries => {
+                attempt += 1;
+                // Log the error and retry after a delay with jitter
+                otel_warn!(name: "OtlpRetry", message = format!("Retrying operation {:?} due to error: {:?}", operation_name, err));
+                let jitter = generate_jitter(policy.jitter_ms);
+                let delay_with_jitter = std::cmp::min(delay + jitter, policy.max_delay_ms);
+
+                // Retry currently only supports tokio::time::sleep (for use with gRPC/tonic). This
+                // should be replaced with a more generic sleep function that works with async-std
+                // and a synchronous runtime in the future.
+                tokio::time::sleep(Duration::from_millis(delay_with_jitter)).await;
+
+                delay = std::cmp::min(delay * 2, policy.max_delay_ms); // Exponential backoff
+            }
+            Err(err) => return Err(err), // Return the error if max retries are reached
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use tokio::time::timeout;
+    use std::sync::atomic::{AtomicUsize, Ordering};
+    use std::time::Duration;
+
+    // Test to ensure generate_jitter returns a value within the expected range
+    #[tokio::test]
+    async fn test_generate_jitter() {
+        let max_jitter = 100;
+        let jitter = generate_jitter(max_jitter);
+        assert!(jitter <= max_jitter);
+    }
+
+    // Test to ensure retry_with_exponential_backoff succeeds on the first attempt
+    #[tokio::test]
+    async fn test_retry_with_exponential_backoff_success() {
+        let policy = RetryPolicy {
+            max_retries: 3,
+            initial_delay_ms: 100,
+            max_delay_ms: 1600,
+            jitter_ms: 100,
+        };
+
+        let result = retry_with_exponential_backoff(policy, "test_operation", || {
+            Box::pin(async { Ok::<_, ()>("success") })
+        }).await;
+
+        assert_eq!(result, Ok("success"));
+    }
+
+    // Test to ensure retry_with_exponential_backoff retries the operation and eventually succeeds
+    #[tokio::test]
+    async fn test_retry_with_exponential_backoff_retries() {
+        let policy = RetryPolicy {
+            max_retries: 3,
+            initial_delay_ms: 100,
+            max_delay_ms: 1600,
+            jitter_ms: 100,
+        };
+
+        let attempts = AtomicUsize::new(0);
+
+        let result = retry_with_exponential_backoff(policy, "test_operation", || {
+            let attempt = attempts.fetch_add(1, Ordering::SeqCst);
+            Box::pin(async move {
+                if attempt < 2 {
+                    Err::<&str, &str>("error") // Fail the first two attempts
+                } else {
+                    Ok::<&str, &str>("success") // Succeed on the third attempt
+                }
+            })
+        }).await;
+
+        assert_eq!(result, Ok("success"));
+        assert_eq!(attempts.load(Ordering::SeqCst), 3); // Ensure there were 3 attempts
+    }
+
+    // Test to ensure retry_with_exponential_backoff fails after max retries
+    #[tokio::test]
+    async fn test_retry_with_exponential_backoff_failure() {
+        let policy = RetryPolicy {
+            max_retries: 3,
+            initial_delay_ms: 100,
+            max_delay_ms: 1600,
+            jitter_ms: 100,
+        };
+
+        let attempts = AtomicUsize::new(0);
+
+        let result = retry_with_exponential_backoff(policy, "test_operation", || {
+            attempts.fetch_add(1, Ordering::SeqCst);
+            Box::pin(async { Err::<(), _>("error") }) // Always fail
+        }).await;
+
+        assert_eq!(result, Err("error"));
+        assert_eq!(attempts.load(Ordering::SeqCst), 4); // Ensure there were 4 attempts (initial + 3 retries)
+    }
+
+    // Test to ensure retry_with_exponential_backoff respects the timeout
+    #[tokio::test]
+    async fn test_retry_with_exponential_backoff_timeout() {
+        let policy = RetryPolicy {
+            max_retries: 12, // Increase the number of retries
+            initial_delay_ms: 100,
+            max_delay_ms: 1600,
+            jitter_ms: 100,
+        };
+
+        let result = timeout(Duration::from_secs(1), retry_with_exponential_backoff(policy, "test_operation", || {
+            Box::pin(async { Err::<(), _>("error") }) // Always fail
+        })).await;
+
+        assert!(result.is_err()); // Ensure the operation times out
+    }
+}

opentelemetry-otlp/tests/integration_test/src/logs_asserter.rs

@@ -1,8 +1,5 @@
 use anyhow::Result;
-use opentelemetry_proto::tonic::{
-    common::v1::KeyValue,
-    logs::v1::{LogRecord, LogsData, ResourceLogs},
-};
+use opentelemetry_proto::tonic::logs::v1::{LogRecord, LogsData, ResourceLogs};
 use std::fs::File;
 
 // Given two ResourceLogs, assert that they are equal except for the timestamps

opentelemetry-otlp/tests/integration_test/src/test_utils.rs

@@ -13,7 +13,7 @@
 //! Only a single test suite can run at once, as each container has statically mapped ports, but
 //! this works nicely with the way cargo executes the suite.
 //!
-//! To skip integration tests with cargo, you can run `cargo test --mod`, which will run unit tests
+//! To skip integration tests with cargo, you can run `cargo test --lib`, which will run unit tests
 //! only.
 //!
 #![cfg(unix)]

opentelemetry-proto/src/transform/logs.rs

@@ -164,8 +164,8 @@ pub mod tonic {
         }
     }
 
-    pub fn group_logs_by_resource_and_scope(
-        logs: LogBatch<'_>,
+    pub fn group_logs_by_resource_and_scope<'a>(
+        logs: &'a LogBatch<'a>,
         resource: &ResourceAttributesWithSchema,
     ) -> Vec<ResourceLogs> {
         // Group logs by target or instrumentation name
@@ -273,7 +273,7 @@ mod tests {
         let resource: ResourceAttributesWithSchema = (&resource).into(); // Convert Resource to ResourceAttributesWithSchema
 
         let grouped_logs =
-            crate::transform::logs::tonic::group_logs_by_resource_and_scope(log_batch, &resource);
+            crate::transform::logs::tonic::group_logs_by_resource_and_scope(&log_batch, &resource);
 
         assert_eq!(grouped_logs.len(), 1);
         let resource_logs = &grouped_logs[0];
@@ -293,7 +293,7 @@ mod tests {
         let log_batch = LogBatch::new(&logs);
         let resource: ResourceAttributesWithSchema = (&resource).into(); // Convert Resource to ResourceAttributesWithSchema
         let grouped_logs =
-            crate::transform::logs::tonic::group_logs_by_resource_and_scope(log_batch, &resource);
+            crate::transform::logs::tonic::group_logs_by_resource_and_scope(&log_batch, &resource);
 
         assert_eq!(grouped_logs.len(), 1);
         let resource_logs = &grouped_logs[0];