use Compression enum instead of static src

Author: harscoet

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

@@ -54,14 +54,14 @@ impl TryFrom<Compression> for tonic::codec::CompressionEncoding {
             #[cfg(not(feature = "gzip-tonic"))]
             Compression::Gzip => Err(crate::Error::FeatureRequiredForCompressionAlgorithm(
                 "gzip-tonic",
-                "gzip",
+                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",
-                "zstd",
+                Compression::Zstd,
             )),
         }
     }

opentelemetry-otlp/src/lib.rs

@@ -377,7 +377,7 @@ pub enum Error {
     /// 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, &'static str),
+    FeatureRequiredForCompressionAlgorithm(&'static str, Compression),
 }
 
 #[cfg(feature = "grpc-tonic")]