Set the size of the global http_client cache in bytes (#40974)

GitOrigin-RevId: 5e2a7196955aa8532c183819bb8f3050c54ef19f

Author: goffrie

Cargo.lock

@@ -1415,3 +1415,8 @@ pub static SUBSCRIPTION_ADVANCE_LOG_TRACING_THRESHOLD: LazyLock<u64> =
 /// How many concurrent index backfill threads to run concurrently.
 pub static INDEX_BACKFILL_CONCURRENCY: LazyLock<usize> =
     LazyLock::new(|| env_config("INDEX_BACKFILL_CONCURRENCY", 8));
+
+/// The max size of the global HTTP cache, in bytes. This is only used for
+/// getting auth metadata right now.
+pub static HTTP_CACHE_SIZE: LazyLock<u64> =
+    LazyLock::new(|| env_config("HTTP_CACHE_SIZE", 16 * 1024 * 1024));

crates/common/src/knobs.rs

@@ -12,6 +12,7 @@ doctest = false
 [dependencies]
 anyhow = { workspace = true }
 bytes = { workspace = true }
+common = { workspace = true }
 futures = { workspace = true }
 http-body-util = { workspace = true }
 http-cache = { workspace = true }
@@ -24,6 +25,7 @@ strum = { workspace = true }
 thiserror = { workspace = true }
 
 [dev-dependencies]
+common = { workspace = true, features = ["testing"] }
 metrics = { workspace = true, features = ["testing"] }
 tokio = { workspace = true }
 

crates/http_client/Cargo.toml

@@ -1,12 +1,19 @@
 #![feature(try_blocks)]
 #![feature(impl_trait_in_fn_trait_return)]
 
-use std::sync::LazyLock;
+use std::sync::{
+    Arc,
+    LazyLock,
+};
 
 use bytes::BufMut;
+use common::knobs::HTTP_CACHE_SIZE;
 use futures::Future;
 use http_body_util::BodyExt;
-use http_cache::XCACHE;
+use http_cache::{
+    MokaCache,
+    XCACHE,
+};
 use http_cache_reqwest::{
     Cache,
     CacheMode,
@@ -29,7 +36,16 @@ mod metrics;
 #[error(transparent)]
 pub struct AsStdError(#[from] anyhow::Error);
 
-static CACHE: LazyLock<MokaManager> = LazyLock::new(MokaManager::default);
+static CACHE: LazyLock<MokaManager> = LazyLock::new(|| {
+    MokaManager::new(
+        MokaCache::builder()
+            .max_capacity(*HTTP_CACHE_SIZE)
+            .weigher(|k: &String, v: &Arc<Vec<u8>>| {
+                u32::try_from(k.len() + v.len()).unwrap_or(u32::MAX)
+            })
+            .build(),
+    )
+});
 static HTTP_CLIENT: LazyLock<reqwest_middleware::ClientWithMiddleware> = LazyLock::new(|| {
     ClientBuilder::new(Client::new())
         .with(Cache(HttpCache {