add metrics for caches

proxy/src/cache/common.rs

@@ -2,8 +2,12 @@ use std::ops::{Deref, DerefMut};
 use std::time::{Duration, Instant};
 
 use moka::Expiry;
+use moka::notification::RemovalCause;
 
 use crate::control_plane::messages::ControlPlaneErrorMessage;
+use crate::metrics::{
+    CacheEviction, CacheKind, CacheOutcome, CacheOutcomeGroup, CacheRemovalCause, Metrics,
+};
 
 /// Default TTL used when caching errors from control plane.
 pub const DEFAULT_ERROR_TTL: Duration = Duration::from_secs(30);
@@ -130,3 +134,35 @@ impl<K, V> Expiry<K, ControlPlaneResult<V>> for CplaneExpiry {
         self.expire_early(value, updated_at)
     }
 }
+
+pub fn eviction_listener(kind: CacheKind, cause: RemovalCause) {
+    let cause = match cause {
+        RemovalCause::Expired => CacheRemovalCause::Expired,
+        RemovalCause::Explicit => CacheRemovalCause::Explicit,
+        RemovalCause::Replaced => CacheRemovalCause::Replaced,
+        RemovalCause::Size => CacheRemovalCause::Size,
+    };
+    Metrics::get()
+        .cache
+        .evicted_total
+        .inc(CacheEviction { cache: kind, cause });
+}
+
+#[inline]
+pub fn count_cache_outcome<T>(kind: CacheKind, cache_result: Option<T>) -> Option<T> {
+    let outcome = if cache_result.is_some() {
+        CacheOutcome::Hit
+    } else {
+        CacheOutcome::Miss
+    };
+    Metrics::get().cache.request_total.inc(CacheOutcomeGroup {
+        cache: kind,
+        outcome,
+    });
+    cache_result
+}
+
+#[inline]
+pub fn count_cache_insert(kind: CacheKind) {
+    Metrics::get().cache.inserted_total.inc(kind);
+}

proxy/src/cache/node_info.rs

@@ -1,7 +1,8 @@
-use crate::cache::common::Cache;
+use crate::cache::common::{Cache, count_cache_insert, count_cache_outcome, eviction_listener};
 use crate::cache::{Cached, ControlPlaneResult, CplaneExpiry};
 use crate::config::CacheOptions;
 use crate::control_plane::NodeInfo;
+use crate::metrics::{CacheKind, Metrics};
 use crate::types::EndpointCacheKey;
 
 pub(crate) struct NodeInfoCache(moka::sync::Cache<EndpointCacheKey, ControlPlaneResult<NodeInfo>>);
@@ -22,15 +23,27 @@ impl NodeInfoCache {
             .name("node_info_cache")
             .expire_after(CplaneExpiry::default());
         let builder = config.moka(builder);
+
+        if let Some(size) = config.size {
+            Metrics::get()
+                .cache
+                .capacity
+                .set(CacheKind::NodeInfo, size as i64);
+        }
+
+        let builder = builder
+            .eviction_listener(|_k, _v, cause| eviction_listener(CacheKind::NodeInfo, cause));
+
         Self(builder.build())
     }
 
     pub fn insert(&self, key: EndpointCacheKey, value: ControlPlaneResult<NodeInfo>) {
+        count_cache_insert(CacheKind::NodeInfo);
         self.0.insert(key, value);
     }
 
-    pub fn get(&'static self, key: &EndpointCacheKey) -> Option<ControlPlaneResult<NodeInfo>> {
-        self.0.get(key)
+    pub fn get(&self, key: &EndpointCacheKey) -> Option<ControlPlaneResult<NodeInfo>> {
+        count_cache_outcome(CacheKind::NodeInfo, self.0.get(key))
     }
 
     pub fn get_entry(

proxy/src/cache/project_info.rs

@@ -5,11 +5,14 @@ use clashmap::ClashMap;
 use moka::sync::Cache;
 use tracing::{debug, info};
 
-use crate::cache::common::{ControlPlaneResult, CplaneExpiry};
+use crate::cache::common::{
+    ControlPlaneResult, CplaneExpiry, count_cache_insert, count_cache_outcome, eviction_listener,
+};
 use crate::config::ProjectInfoCacheOptions;
 use crate::control_plane::messages::{ControlPlaneErrorMessage, Reason};
 use crate::control_plane::{EndpointAccessControl, RoleAccessControl};
 use crate::intern::{AccountIdInt, EndpointIdInt, ProjectIdInt, RoleNameInt};
+use crate::metrics::{CacheKind, Metrics};
 use crate::types::{EndpointId, RoleName};
 
 /// Cache for project info.
@@ -82,17 +85,32 @@ impl ProjectInfoCache {
 
 impl ProjectInfoCache {
     pub(crate) fn new(config: ProjectInfoCacheOptions) -> Self {
+        Metrics::get().cache.capacity.set(
+            CacheKind::ProjectInfoRoles,
+            (config.size * config.max_roles) as i64,
+        );
+        Metrics::get()
+            .cache
+            .capacity
+            .set(CacheKind::ProjectInfoEndpoints, config.size as i64);
+
         // we cache errors for 30 seconds, unless retry_at is set.
         let expiry = CplaneExpiry::default();
         Self {
             role_controls: Cache::builder()
                 .name("role_access_controls")
+                .eviction_listener(|_k, _v, cause| {
+                    eviction_listener(CacheKind::ProjectInfoRoles, cause);
+                })
                 .max_capacity(config.size * config.max_roles)
                 .time_to_live(config.ttl)
                 .expire_after(expiry)
                 .build(),
             ep_controls: Cache::builder()
                 .name("endpoint_access_controls")
+                .eviction_listener(|_k, _v, cause| {
+                    eviction_listener(CacheKind::ProjectInfoEndpoints, cause);
+                })
                 .max_capacity(config.size)
                 .time_to_live(config.ttl)
                 .expire_after(expiry)
@@ -111,7 +129,10 @@ impl ProjectInfoCache {
         let endpoint_id = EndpointIdInt::get(endpoint_id)?;
         let role_name = RoleNameInt::get(role_name)?;
 
-        self.role_controls.get(&(endpoint_id, role_name))
+        count_cache_outcome(
+            CacheKind::ProjectInfoRoles,
+            self.role_controls.get(&(endpoint_id, role_name)),
+        )
     }
 
     pub(crate) fn get_endpoint_access(
@@ -120,7 +141,10 @@ impl ProjectInfoCache {
     ) -> Option<ControlPlaneResult<EndpointAccessControl>> {
         let endpoint_id = EndpointIdInt::get(endpoint_id)?;
 
-        self.ep_controls.get(&endpoint_id)
+        count_cache_outcome(
+            CacheKind::ProjectInfoEndpoints,
+            self.ep_controls.get(&endpoint_id),
+        )
     }
 
     pub(crate) fn insert_endpoint_access(
@@ -144,6 +168,9 @@ impl ProjectInfoCache {
             "created a cache entry for endpoint access"
         );
 
+        count_cache_insert(CacheKind::ProjectInfoEndpoints);
+        count_cache_insert(CacheKind::ProjectInfoRoles);
+
         self.ep_controls.insert(endpoint_id, Ok(controls));
         self.role_controls
             .insert((endpoint_id, role_name), Ok(role_controls));
@@ -172,10 +199,14 @@ impl ProjectInfoCache {
                     // leave the entry alone if it's already Ok
                     Some(entry) if entry.value().is_ok() => moka::ops::compute::Op::Nop,
                     // replace the entry
-                    _ => moka::ops::compute::Op::Put(Err(msg.clone())),
+                    _ => {
+                        count_cache_insert(CacheKind::ProjectInfoEndpoints);
+                        moka::ops::compute::Op::Put(Err(msg.clone()))
+                    }
                 });
         }
 
+        count_cache_insert(CacheKind::ProjectInfoRoles);
         self.role_controls
             .insert((endpoint_id, role_name), Err(msg));
     }