[PATCH datacenter-manager v2 2/2] server: cache: short-circuit on special max age value 0

[Shannon Sterz <s.sterz@proxmox.com>]

a max age of 0 means that the cached information is always considered
outdated. instead of reading from the cache first and then checking
the max age parameter, simply return early.

Signed-off-by: Shannon Sterz <s.sterz@proxmox.com>
---

Notes:
    note, currently the cache only reads from the tmpfs /run. so the
    speed-up is likely minimal for now. however, once we persist the cache
    further this should help a bit.

 server/src/namespaced_cache.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/server/src/namespaced_cache.rs b/server/src/namespaced_cache.rs
index 2f96df41..ccdec92f 100644
--- a/server/src/namespaced_cache.rs
+++ b/server/src/namespaced_cache.rs
@@ -554,6 +554,10 @@ fn get_impl<T: Serialize + DeserializeOwned>(
     // Namespace should already be verified at this point, no point in checking it again.
     ensure_valid_key(key)?;
 
+    if max_age == Some(0) {
+        return Ok(None);
+    }
+
     let path = get_path(base, namespace, key);
 
     Ok(get_from_path(&path, max_age)?.map(|a| a.value))
-- 
2.47.3