Implementing in memory response cache

src/utils/lazylock.rs

@@ -1,7 +1,11 @@
 use dashmap::DashMap;
 use moka::sync::Cache;
+use pingora_cache::eviction::simple_lru::Manager;
+use pingora_cache::lock::CacheLock;
+use pingora_cache::MemCache;
 use pingora_limits::rate::Rate;
 use std::net::IpAddr;
+use std::sync::OnceLock;
 use std::sync::{Arc, LazyLock};
 use std::time::Duration;
 
@@ -9,3 +13,7 @@ pub static REVERSE_STORE: LazyLock<DashMap<String, String>> = LazyLock::new(Dash
 pub static RATE_LIMITER: LazyLock<Rate> = LazyLock::new(|| Rate::new(Duration::from_secs(1)));
 pub static REQUESTS_4XX: LazyLock<Cache<IpAddr, u32>> = LazyLock::new(|| Cache::builder().time_to_live(Duration::from_secs(1)).build());
 pub static LOCALHOST: LazyLock<Arc<str>> = LazyLock::new(|| Arc::from("localhost"));
+pub static MEM_CACHE: LazyLock<MemCache> = LazyLock::new(MemCache::new);
+pub static CACHE_LOCK: LazyLock<CacheLock> = LazyLock::new(|| CacheLock::new(Duration::from_secs(30)));
+pub static EVICTION: OnceLock<Manager> = OnceLock::new();
+pub static CACHE_TTL: OnceLock<u64> = OnceLock::new();

src/utils/metrics.rs

@@ -1,3 +1,5 @@
+use crate::utils::lazylock::EVICTION;
+use pingora_cache::eviction::EvictionManager;
 use pingora_http::Method;
 use pingora_http::StatusCode;
 use pingora_http::Version;
@@ -20,6 +22,11 @@ pub static MEMORY_USAGE: LazyLock<IntGauge> = LazyLock::new(|| register_int_gaug
 pub static ACTIVE_SESSIONS: LazyLock<IntGauge> = LazyLock::new(|| register_int_gauge!("aralez_active_sessions", "Current number of active sessions").unwrap());
 pub static REQUEST_COUNT: LazyLock<IntCounter> = LazyLock::new(|| register_int_counter!("aralez_requests_total", "Total number of requests handled by Aralez").unwrap());
 
+pub static CACHE_SIZE_BYTES: LazyLock<IntGauge> = LazyLock::new(|| register_int_gauge!("aralez_cache_size_bytes", "Current cache size in bytes").unwrap());
+pub static CACHE_ITEMS: LazyLock<IntGauge> = LazyLock::new(|| register_int_gauge!("aralez_cache_items", "Current number of cached objects").unwrap());
+pub static CACHE_EVICTED_BYTES: LazyLock<IntGauge> = LazyLock::new(|| register_int_gauge!("aralez_cache_evicted_bytes_total", "Total bytes evicted from cache").unwrap());
+
+pub static CACHE_EVICTED_ITEMS: LazyLock<IntGauge> = LazyLock::new(|| register_int_gauge!("aralez_cache_evicted_items_total", "Total cache items evicted").unwrap());
 pub static RESPONSE_CODES: LazyLock<IntCounterVec> =
     LazyLock::new(|| register_int_counter_vec!("aralez_responses_total", "Responses grouped by status code", &["status"]).unwrap());
 
@@ -55,6 +62,13 @@ pub fn calc_metrics(metric_types: &MetricTypes) {
     REQUESTS_BY_METHOD.with_label_values(&[metric_types.method.as_str()]).inc();
     REQUESTS_BY_UPSTREAM.with_label_values(&[metric_types.upstream.as_ref()]).inc();
     RESPONSE_LATENCY.observe(metric_types.latency.as_secs_f64());
+
+    if let Some(eviction) = EVICTION.get() {
+        CACHE_SIZE_BYTES.set(eviction.total_size() as i64);
+        CACHE_ITEMS.set(eviction.total_items() as i64);
+        CACHE_EVICTED_BYTES.set(eviction.evicted_size() as i64);
+        CACHE_EVICTED_ITEMS.set(eviction.evicted_items() as i64);
+    }
 }
 
 pub(crate) fn get_memory_usage() -> usize {

src/utils/structs.rs

@@ -110,6 +110,8 @@ pub struct AppConfig {
     pub hc_method: String,
     pub upstreams_conf: String,
     pub log_level: String,
+    pub cache_size_mb: Option<usize>,
+    pub cache_ttl: Option<u64>,
     pub access_log: Option<String>,
     pub pid_file: Option<String>,
     pub master_key: Option<String>,