api: add get_active_operations endpoint

Signed-off-by: Hannes Laimer <h.laimer@proxmox.com>

pbs-datastore/src/task_tracking.rs

@@ -1,6 +1,7 @@
 use anyhow::Error;
 use libc::pid_t;
 use nix::unistd::Pid;
+use std::iter::Sum;
 use std::path::PathBuf;
 
 use pbs_api_types::Operation;
@@ -8,12 +9,46 @@ use proxmox_sys::fs::{file_read_optional_string, open_file_locked, replace_file,
 use proxmox_sys::linux::procfs;
 use serde::{Deserialize, Serialize};
 
+#[derive(Deserialize, Serialize, Clone, Copy, Default)]
+pub struct ActiveOperationStats {
+    pub read: i64,
+    pub write: i64,
+}
+
+impl Sum<Self> for ActiveOperationStats {
+    fn sum<I>(iter: I) -> Self
+    where
+        I: Iterator<Item = Self>,
+    {
+        iter.fold(Self::default(), |a, b| Self {
+            read: a.read + b.read,
+            write: a.write + b.write,
+        })
+    }
+}
+
 #[derive(Deserialize, Serialize, Clone)]
 struct TaskOperations {
     pid: u32,
     starttime: u64,
-    reading_operations: i64,
-    writing_operations: i64,
+    active_operations: ActiveOperationStats,
+}
+
+pub fn get_active_operations(name: &str) -> Result<ActiveOperationStats, Error> {
+    let path = PathBuf::from(format!("{}/{}", crate::ACTIVE_OPERATIONS_DIR, name));
+
+    Ok(match file_read_optional_string(&path)? {
+        Some(data) => serde_json::from_str::<Vec<TaskOperations>>(&data)?
+            .iter()
+            .filter_map(
+                |task| match procfs::check_process_running(task.pid as pid_t) {
+                    Some(stat) if task.starttime == stat.starttime => Some(task.active_operations),
+                    _ => None,
+                },
+            )
+            .sum(),
+        None => ActiveOperationStats::default(),
+    })
 }
 
 pub fn update_active_operations(name: &str, operation: Operation, count: i64) -> Result<(), Error> {
@@ -43,8 +78,8 @@ pub fn update_active_operations(name: &str, operation: Operation, count: i64) ->
                         if pid == task.pid {
                             updated = true;
                             match operation {
-                                Operation::Read => task.reading_operations += count,
-                                Operation::Write => task.writing_operations += count,
+                                Operation::Read => task.active_operations.read += count,
+                                Operation::Write => task.active_operations.write += count,
                             };
                         }
                         Some(task.clone())
@@ -57,18 +92,12 @@ pub fn update_active_operations(name: &str, operation: Operation, count: i64) ->
     };
 
     if !updated {
-        updated_tasks.push(match operation {
-            Operation::Read => TaskOperations {
-                pid,
-                starttime,
-                reading_operations: 1,
-                writing_operations: 0,
-            },
-            Operation::Write => TaskOperations {
-                pid,
-                starttime,
-                reading_operations: 0,
-                writing_operations: 1,
+        updated_tasks.push(TaskOperations {
+            pid,
+            starttime,
+            active_operations: match operation {
+                Operation::Read => ActiveOperationStats { read: 1, write: 0 },
+                Operation::Write => ActiveOperationStats { read: 0, write: 1 },
             },
         })
     }