fix(spooler): Proactively move on-disk spool to memory when it fits (#…

…2949)

To make sure that we switch to in-memory spool faster we can proactively
check if the size of the on-disk data fits into memory and move the
spooled envelopes in one go to memory.

- this will ensure that we eventually switch to in-memory spool, even
though there are still some envelopes left unspooled
- this PR also makes sure to use better estimate of the used disk size
for the spooled envelopes
- the test is updated to account for the change mentioned above

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+**Internal**:
+
+- Proactively move on-disk spool to memory. ([#2949](https://github.com/getsentry/relay/pull/2949))
+
 **Bug Fixes**:
 
 - Add automatic PII scrubbing to `logentry.params`. ([#2956](https://github.com/getsentry/relay/pull/2956))

relay-server/src/actors/project_cache.rs

@@ -1148,6 +1148,8 @@ mod tests {
 
  #[tokio::test]
  async fn always_spools() {
+ relay_log::init_test!();
+
  let num_permits = 5;
  let buffer_guard: Arc<_> = BufferGuard::new(num_permits).into();
  let services = mocked_services();
@@ -1194,7 +1196,7 @@ mod tests {
  ));
  tokio::time::sleep(Duration::from_millis(100)).await;
 
- // We should be able to unspool once since we have 1 permit.
+ // We should be able to unspool 5 envelopes since we have 5 permits.
  let mut envelopes = vec![];
  while let Ok(envelope) = rx.try_recv() {
  envelopes.push(envelope)