From 6ea5cde02e980eade9c17f99932b894d432bdf56 Mon Sep 17 00:00:00 2001
From: Yuchen Wu <yuchen@cloudflare.com>
Date: Thu, 20 Jun 2024 15:32:37 -0700
Subject: [PATCH] Report evction/invalidtion types

This helps the storage to log/track different type of cache deletions.
---
 .bleep                       |  2 +-
 pingora-cache/src/lib.rs     | 12 +++++++++---
 pingora-cache/src/memory.rs  | 15 ++++++++++++---
 pingora-cache/src/put.rs     |  2 +-
 pingora-cache/src/storage.rs | 16 +++++++++++++++-
 5 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/.bleep b/.bleep
index 990b361..123ae30 100644
--- a/.bleep
+++ b/.bleep
@@ -1 +1 @@
-b8ac54b482f643f04533dcc04061b1575482c92d
\ No newline at end of file
+27bf4df19b465281ddc2d348ed6f3f0402fa60cc
\ No newline at end of file
diff --git a/pingora-cache/src/lib.rs b/pingora-cache/src/lib.rs
index 563727c..6ba057e 100644
--- a/pingora-cache/src/lib.rs
+++ b/pingora-cache/src/lib.rs
@@ -44,7 +44,7 @@ pub use key::CacheKey;
 use lock::{CacheLock, LockStatus, Locked};
 pub use memory::MemCache;
 pub use meta::{CacheMeta, CacheMetaDefaults};
-pub use storage::{HitHandler, MissHandler, Storage};
+pub use storage::{HitHandler, MissHandler, PurgeType, Storage};
 pub use variance::VarianceBuilder;
 
 pub mod prelude {}
@@ -658,7 +658,10 @@ impl HttpCache {
                     let handle = span.handle();
                     for item in evicted {
                         // TODO: warn/log the error
-                        let _ = inner.storage.purge(&item, &handle).await;
+                        let _ = inner
+                            .storage
+                            .purge(&item, PurgeType::Eviction, &handle)
+                            .await;
                     }
                 }
                 inner.traces.finish_miss_span();
@@ -1063,7 +1066,10 @@ impl HttpCache {
                 let inner = self.inner_mut();
                 let mut span = inner.traces.child("purge");
                 let key = inner.key.as_ref().unwrap().to_compact();
-                let result = inner.storage.purge(&key, &span.handle()).await;
+                let result = inner
+                    .storage
+                    .purge(&key, PurgeType::Invalidation, &span.handle())
+                    .await;
                 // FIXME: also need to remove from eviction manager
                 span.set_tag(|| trace::Tag::new("purged", matches!(result, Ok(true))));
                 result
diff --git a/pingora-cache/src/memory.rs b/pingora-cache/src/memory.rs
index 3863b2b..dec8f1a 100644
--- a/pingora-cache/src/memory.rs
+++ b/pingora-cache/src/memory.rs
@@ -306,7 +306,12 @@ impl Storage for MemCache {
         Ok(Box::new(miss_handler))
     }
 
-    async fn purge(&'static self, key: &CompactCacheKey, _trace: &SpanHandle) -> Result<bool> {
+    async fn purge(
+        &'static self,
+        key: &CompactCacheKey,
+        _type: PurgeType,
+        _trace: &SpanHandle,
+    ) -> Result<bool> {
         // This usually purges the primary key because, without a lookup, the variance key is usually
         // empty
         let hash = key.combined();
@@ -525,7 +530,9 @@ mod test {
 
         assert!(cache.temp.read().contains_key(&hash));
 
-        let result = cache.purge(&key, &Span::inactive().handle()).await;
+        let result = cache
+            .purge(&key, PurgeType::Invalidation, &Span::inactive().handle())
+            .await;
         assert!(result.is_ok());
 
         assert!(!cache.temp.read().contains_key(&hash));
@@ -551,7 +558,9 @@ mod test {
 
         assert!(cache.cached.read().contains_key(&hash));
 
-        let result = cache.purge(&key, &Span::inactive().handle()).await;
+        let result = cache
+            .purge(&key, PurgeType::Invalidation, &Span::inactive().handle())
+            .await;
         assert!(result.is_ok());
 
         assert!(!cache.cached.read().contains_key(&hash));
diff --git a/pingora-cache/src/put.rs b/pingora-cache/src/put.rs
index e29cfad..e1041e0 100644
--- a/pingora-cache/src/put.rs
+++ b/pingora-cache/src/put.rs
@@ -119,7 +119,7 @@ impl<C: CachePut> CachePutCtx<C> {
                 .handle();
             for item in evicted {
                 // TODO: warn/log the error
-                let _ = self.storage.purge(&item, &trace).await;
+                let _ = self.storage.purge(&item, PurgeType::Eviction, &trace).await;
             }
         }
 
diff --git a/pingora-cache/src/storage.rs b/pingora-cache/src/storage.rs
index c6365c7..0d4e104 100644
--- a/pingora-cache/src/storage.rs
+++ b/pingora-cache/src/storage.rs
@@ -22,6 +22,15 @@ use async_trait::async_trait;
 use pingora_error::Result;
 use std::any::Any;
 
+/// The reason a purge() is called
+#[derive(Debug, Clone, Copy)]
+pub enum PurgeType {
+    // For eviction because the cache storage is full
+    Eviction,
+    // For cache invalidation
+    Invalidation,
+}
+
 /// Cache storage interface
 #[async_trait]
 pub trait Storage {
@@ -45,7 +54,12 @@ pub trait Storage {
     /// Delete the cached asset for the given key
     ///
     /// [CompactCacheKey] is used here because it is how eviction managers store the keys
-    async fn purge(&'static self, key: &CompactCacheKey, trace: &SpanHandle) -> Result<bool>;
+    async fn purge(
+        &'static self,
+        key: &CompactCacheKey,
+        purge_type: PurgeType,
+        trace: &SpanHandle,
+    ) -> Result<bool>;
 
     /// Update cache header and metadata for the already stored asset.
     async fn update_meta(