Use strum_macros to automate generation of error reasons

Signed-off-by: Simon Beal <[email protected]>
awslabs · Dec 6, 2024 · 9766e08 · 9766e08
1 parent 3705db8
commit 9766e08
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Showing 4 changed files with 27 additions and 19 deletions.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/mountpoint-s3/Cargo.toml b/mountpoint-s3/Cargo.toml
@@ -47,6 +47,7 @@ tracing-subscriber = { version = "0.3.18", features = ["env-filter"] }
 async-stream = "0.3.6"
 humansize = "2.1.3"
 base64ct = "1.6.0"
+strum_macros = "0.26.4"
 
 [target.'cfg(target_os = "linux")'.dependencies]
 procfs = { version = "0.17.0", default-features = false }

diff --git a/mountpoint-s3/src/data_cache.rs b/mountpoint-s3/src/data_cache.rs
@@ -11,6 +11,7 @@ mod in_memory_data_cache;
 mod multilevel_cache;
 
 use async_trait::async_trait;
+use strum_macros::IntoStaticStr;
 use thiserror::Error;
 
 pub use crate::checksums::ChecksummedBytes;
@@ -26,7 +27,8 @@ use crate::object::ObjectId;
 pub type BlockIndex = u64;
 
 /// Errors returned by operations on a [DataCache]
-#[derive(Debug, Error)]
+#[derive(Debug, Error, IntoStaticStr)]
+#[strum(serialize_all = "snake_case")]
 pub enum DataCacheError {
     #[error("IO error when reading or writing from cache: {0}")]
     IoFailure(#[source] anyhow::Error),
@@ -44,14 +46,7 @@ pub enum DataCacheError {
 
 impl DataCacheError {
     fn get_reason(&self) -> &'static str {
-        match self {
-            DataCacheError::IoFailure(_) => "io_failure",
-            DataCacheError::InvalidBlockHeader(_) => "invalid_block_header",
-            DataCacheError::InvalidBlockChecksum => "invalid_block_checksum",
-            DataCacheError::InvalidBlockContent => "invalid_block_content",
-            DataCacheError::InvalidBlockOffset => "invalid_block_offset",
-            DataCacheError::EvictionFailure => "eviction_failure",
-        }
+        self.into()
     }
 }
 

diff --git a/mountpoint-s3/src/data_cache/express_data_cache.rs b/mountpoint-s3/src/data_cache/express_data_cache.rs
@@ -174,12 +174,10 @@ where
         let crc32c_b64 = checksum
             .checksum_crc32c
             .ok_or_else(|| DataCacheError::InvalidBlockChecksum)?;
-        let crc32c = crc32c_from_base64(&crc32c_b64)
-            .map_err(|_| DataCacheError::InvalidBlockChecksum)?;
+        let crc32c = crc32c_from_base64(&crc32c_b64).map_err(|_| DataCacheError::InvalidBlockChecksum)?;
 
         let block_metadata = BlockMetadata::new(block_idx, block_offset, cache_key, &self.bucket_name, crc32c);
-        block_metadata
-            .validate_object_metadata(&object_metadata)?;
+        block_metadata.validate_object_metadata(&object_metadata)?;
 
         Ok(Some(ChecksummedBytes::new_from_inner_data(buffer, crc32c)))
     }
@@ -203,9 +201,7 @@ where
 
         let object_key = get_s3_key(&self.prefix, &cache_key, block_idx);
 
-        let (data, checksum) = bytes
-            .into_inner()
-            .map_err(|_| DataCacheError::InvalidBlockContent)?;
+        let (data, checksum) = bytes.into_inner().map_err(|_| DataCacheError::InvalidBlockContent)?;
         let block_metadata = BlockMetadata::new(block_idx, block_offset, &cache_key, &self.bucket_name, checksum);
 
         self.client
@@ -248,7 +244,8 @@ where
             }
             Err(err) => {
                 metrics::counter!("express_data_cache.block_hit").increment(0);
-                metrics::counter!("express_data_cache.block_err", "reason" => err.get_reason(), "type" => "read").increment(1);
+                metrics::counter!("express_data_cache.block_err", "reason" => err.get_reason(), "type" => "read")
+                    .increment(1);
                 (Err(err), "error")
             }
         };
@@ -275,7 +272,8 @@ where
                 (Ok(()), "ok")
             }
             Err(err) => {
-                metrics::counter!("express_data_cache.block_err", "reason" => err.get_reason(), "type" => "write").increment(1);
+                metrics::counter!("express_data_cache.block_err", "reason" => err.get_reason(), "type" => "write")
+                    .increment(1);
                 (Err(err), "error")
             }
         };