[pdm-devel] [PATCH proxmox-datacenter-manager v2 18/28] metric collection: periodically clean removed remotes from statefile

[Lukas Wagner]

Adding and removing remotes can leave leftover data in the statefile,
hence it makes sense to clean it up periodically.

Signed-off-by: Lukas Wagner <l.wagner at proxmox.com>
---
 .../src/metric_collection/collection_task.rs  |  6 ++++
 server/src/metric_collection/state.rs         | 32 +++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/server/src/metric_collection/collection_task.rs b/server/src/metric_collection/collection_task.rs
index 60c62c87..2ea735c5 100644
--- a/server/src/metric_collection/collection_task.rs
+++ b/server/src/metric_collection/collection_task.rs
@@ -98,6 +98,8 @@ impl MetricCollectionTask {
                     ).await;
 
                     if let Some(remotes) = Self::load_remote_config() {
+                        self.cleanup_removed_remotes_from_state(&remotes);
+
                         let now = Instant::now();
                         let to_fetch = remotes.order.as_slice();
                         self.fetch_remotes(&remotes, to_fetch).await;
@@ -177,6 +179,10 @@ impl MetricCollectionTask {
         tokio::time::sleep(Duration::from_millis(jitter)).await;
     }
 
+    fn cleanup_removed_remotes_from_state(&mut self, remotes: &SectionConfigData<Remote>) {
+        self.state.retain(|remote| remotes.get(remote).is_some());
+    }
+
     fn get_settings_or_default() -> CollectionSettings {
         // We want to fall back to defaults if
         //   - the config file does not exist (no error should be logged)
diff --git a/server/src/metric_collection/state.rs b/server/src/metric_collection/state.rs
index 86375a65..a8d49e5d 100644
--- a/server/src/metric_collection/state.rs
+++ b/server/src/metric_collection/state.rs
@@ -74,6 +74,11 @@ impl MetricCollectionState {
         Ok(())
     }
 
+    /// Retain all remotes for which the predicate holds.
+    pub fn retain(&mut self, check: impl Fn(&str) -> bool) {
+        self.state.remote_status.retain(|remote, _| check(remote));
+    }
+
     fn load_or_default(path: &Path) -> Result<State, Error> {
         let content = proxmox_sys::fs::file_read_optional_string(path)?;
 
@@ -115,4 +120,31 @@ mod tests {
 
         Ok(())
     }
+
+    #[test]
+    fn test_retain() -> Result<(), Error> {
+        let file = NamedTempFile::new(get_create_options())?;
+        let options = get_create_options();
+        let mut state = MetricCollectionState::new(file.path().into(), options.clone());
+
+        state.set_status(
+            "remote-1".into(),
+            RemoteStatus {
+                ..Default::default()
+            },
+        );
+        state.set_status(
+            "remote-2".into(),
+            RemoteStatus {
+                ..Default::default()
+            },
+        );
+
+        state.retain(|remote| remote == "remote-1");
+
+        assert!(state.get_status("remote-1").is_some());
+        assert!(state.get_status("remote-2").is_none());
+
+        Ok(())
+    }
 }
-- 
2.39.5