zstd compression for tonic exporter

opentelemetry-otlp/Cargo.toml

@@ -65,6 +65,7 @@ default = ["grpc-tonic", "trace", "metrics", "logs"]
 # grpc using tonic
 grpc-tonic = ["tonic", "prost", "http", "tokio", "opentelemetry-proto/gen-tonic"]
 gzip-tonic = ["tonic/gzip"]
+zstd-tonic = ["tonic/zstd"]
 tls = ["tonic/tls"]
 tls-roots = ["tls", "tonic/tls-roots"]
 tls-webpki-roots = ["tls", "tonic/tls-webpki-roots"]

opentelemetry-otlp/src/exporter/mod.rs

@@ -98,12 +98,15 @@
 pub enum Compression {
     /// Compresses data using gzip.
     Gzip,
+    /// Compresses data using zstd.
+    Zstd,
 }
 
 impl Display for Compression {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         match self {
             Compression::Gzip => write!(f, "gzip"),
+            Compression::Zstd => write!(f, "zstd"),
         }
     }
 }
@@ -114,6 +117,7 @@
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         match s {
             "gzip" => Ok(Compression::Gzip),
+            "zstd" => Ok(Compression::Zstd),
             _ => Err(Error::UnsupportedCompressionAlgorithm(s.to_string())),
         }
     }

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

@@ -52,8 +52,16 @@ impl TryFrom<Compression> for tonic::codec::CompressionEncoding {
             #[cfg(feature = "gzip-tonic")]
             Compression::Gzip => Ok(tonic::codec::CompressionEncoding::Gzip),
             #[cfg(not(feature = "gzip-tonic"))]
-            Compression::Gzip => Err(crate::Error::UnsupportedCompressionAlgorithm(
-                value.to_string(),
+            Compression::Gzip => Err(crate::Error::FeatureRequiredForCompressionAlgorithm(
+                "gzip-tonic",
+                Compression::Gzip,
+            )),
+            #[cfg(feature = "zstd-tonic")]
+            Compression::Zstd => Ok(tonic::codec::CompressionEncoding::Zstd),
+            #[cfg(not(feature = "zstd-tonic"))]
+            Compression::Zstd => Err(crate::Error::FeatureRequiredForCompressionAlgorithm(
+                "zstd-tonic",
+                Compression::Zstd,
             )),
         }
     }
@@ -399,7 +407,7 @@ fn parse_headers_from_env(signal_headers_var: &str) -> HeaderMap {
 #[cfg(test)]
 mod tests {
     use crate::exporter::tests::run_env_test;
-    #[cfg(feature = "gzip-tonic")]
+    #[cfg(feature = "grpc-tonic")]
     use crate::exporter::Compression;
     use crate::TonicExporterBuilder;
     use crate::{OTEL_EXPORTER_OTLP_HEADERS, OTEL_EXPORTER_OTLP_TRACES_HEADERS};
@@ -438,14 +446,34 @@ mod tests {
 
     #[test]
     #[cfg(feature = "gzip-tonic")]
-    fn test_with_compression() {
+    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);
     }
 
+    #[test]
+    #[cfg(feature = "zstd-tonic")]
+    fn test_with_zstd_compression() {
+        let builder = TonicExporterBuilder::default().with_compression(Compression::Zstd);
+        assert_eq!(builder.tonic_config.compression.unwrap(), Compression::Zstd);
+    }
+
+    #[test]
+    #[cfg(feature = "grpc-tonic")]
+    fn test_convert_compression() {
+        #[cfg(feature = "gzip-tonic")]
+        assert!(tonic::codec::CompressionEncoding::try_from(Compression::Gzip).is_ok());
+        #[cfg(not(feature = "gzip-tonic"))]
+        assert!(tonic::codec::CompressionEncoding::try_from(Compression::Gzip).is_err());
+        #[cfg(feature = "zstd-tonic")]
+        assert!(tonic::codec::CompressionEncoding::try_from(Compression::Zstd).is_ok());
+        #[cfg(not(feature = "zstd-tonic"))]
+        assert!(tonic::codec::CompressionEncoding::try_from(Compression::Zstd).is_err());
+    }
+
     #[test]
     fn test_parse_headers_from_env() {
         run_env_test(

opentelemetry-otlp/src/lib.rs

@@ -97,6 +97,7 @@
 //! For users uses `tonic` as grpc layer:
 //! * `grpc-tonic`: Use `tonic` as grpc layer. This is enabled by default.
 //! * `gzip-tonic`: Use gzip compression for `tonic` grpc layer.
+//! * `zstd-tonic`: Use zstd compression for `tonic` grpc layer.
 //! * `tls-tonic`: Enable TLS.
 //! * `tls-roots`: Adds system trust roots to rustls-based gRPC clients using the rustls-native-certs crate
 //! * `tls-webkpi-roots`: Embeds Mozilla's trust roots to rustls-based gRPC clients using the webkpi-roots crate
@@ -372,6 +373,11 @@ pub enum Error {
     /// Unsupported compression algorithm.
     #[error("unsupported compression algorithm '{0}'")]
     UnsupportedCompressionAlgorithm(String),
+
+    /// Feature required to use the specified compression algorithm.
+    #[cfg(any(not(feature = "gzip-tonic"), not(feature = "zstd-tonic")))]
+    #[error("feature '{0}' is required to use the compression algorithm '{1}'")]
+    FeatureRequiredForCompressionAlgorithm(&'static str, Compression),
 }
 
 #[cfg(feature = "grpc-tonic")]