fix: Ensure that the container info of each process is up to date

Before this change, we were storing a map of namespaces and
corresponding container info, but that didn't work - namespaces
used by one container might be reused by a next container later.

This change drops that solution and fetches the container info
always.

crates/pulsar-core/src/pdk/process_tracker.rs

@@ -140,8 +140,6 @@ struct ProcessTracker {
     rx: mpsc::UnboundedReceiver<TrackerRequest>,
     /// current processes
     processes: HashMap<Pid, ProcessData>,
-    /// current containers
-    containers: HashMap<Namespaces, ContainerInfo>,
     /// scheduled removal of exited processes
     next_cleanup: Timestamp,
     /// pending info requests arrived before the process was created
@@ -162,6 +160,7 @@ struct ProcessData {
     >,
     argv: Vec<String>,
     namespaces: Namespaces,
+    container: Option<ContainerInfo>,
 }
 
 /// Cleanup timeout in nanoseconds. This is how long an exited process
@@ -186,12 +185,12 @@ impl ProcessTracker {
                 exec_changes: BTreeMap::new(),
                 argv: Vec::new(),
                 namespaces: Namespaces::default(),
+                container: None,
             },
         );
         Self {
             rx,
             processes,
-            containers: HashMap::new(),
             next_cleanup: Timestamp::now() + CLEANUP_TIMEOUT,
             pending_requests: Vec::new(),
             pending_updates: HashMap::new(),
@@ -263,25 +262,24 @@ impl ProcessTracker {
         }
     }
 
-    fn handle_container_info(
+    fn get_container_info(
         &mut self,
         pid: Pid,
-        namespaces: Namespaces,
         is_new_container: bool,
-    ) -> Result<(), ContainerError> {
+    ) -> Result<Option<ContainerInfo>, ContainerError> {
         let container_id = procfs::get_process_container_id(pid)?;
-        if let Some(id) = container_id {
-            let container_info = ContainerInfo::from_container_id(id.clone())?;
-            self.containers.entry(namespaces).or_insert_with(|| {
+        match container_id {
+            Some(id) => {
+                let container_info = ContainerInfo::from_container_id(id.clone())?;
                 if is_new_container {
                     log::debug!("Detected a new container {id}");
                 } else {
                     log::debug!("Detected an already existing container {id}");
                 }
-                container_info
-            });
+                Ok(Some(container_info))
+            }
+            None => Ok(None),
         }
-        Ok(())
     }
 
     fn handle_update(&mut self, mut update: TrackerUpdate) {
@@ -293,8 +291,13 @@ impl ProcessTracker {
                 namespaces,
                 is_new_container,
             } => {
-                self.handle_container_info(pid, namespaces, is_new_container)
-                    .unwrap_or_else(|err| log::error!("{err}"));
+                let container = match self.get_container_info(pid, is_new_container) {
+                    Ok(container) => container,
+                    Err(err) => {
+                        log::error!("{err}");
+                        None
+                    }
+                };
                 self.processes.insert(
                     pid,
                     ProcessData {
@@ -309,6 +312,7 @@ impl ProcessTracker {
                             .map(|parent| parent.argv.clone())
                             .unwrap_or_default(),
                         namespaces,
+                        container,
                     },
                 );
                 if let Some(pending_updates) = self.pending_updates.remove(&pid) {
@@ -325,11 +329,18 @@ impl ProcessTracker {
                 namespaces,
                 is_new_container,
             } => {
-                self.handle_container_info(pid, namespaces, is_new_container)
-                    .unwrap_or_else(|err| log::error!("{err}"));
+                let container = match self.get_container_info(pid, is_new_container) {
+                    Ok(container) => container,
+                    Err(err) => {
+                        log::error!("{err}");
+                        None
+                    }
+                };
                 if let Some(p) = self.processes.get_mut(&pid) {
                     p.exec_changes.insert(timestamp, std::mem::take(image));
-                    p.argv = std::mem::take(argv)
+                    p.argv = std::mem::take(argv);
+                    p.namespaces = namespaces;
+                    p.container = container;
                 } else {
                     // if exec arrived before the fork, we save the event as pending
                     log::debug!("(exec) Process {pid} not found in process tree, saving for later");
@@ -360,7 +371,6 @@ impl ProcessTracker {
             .processes
             .get(&pid)
             .ok_or(TrackerError::ProcessNotFound)?;
-        let container: Option<ContainerInfo> = self.containers.get(&process.namespaces).cloned();
         if ts < process.fork_time {
             log::warn!(
                 "{} not forked yet {} < {} ({}ms)",
@@ -383,7 +393,7 @@ impl ProcessTracker {
             fork_time: process.fork_time,
             argv: process.argv.clone(),
             namespaces: process.namespaces,
-            container,
+            container: process.container.clone(),
         })
     }