Display the total number of tasks in the tasks route

index-scheduler/src/lib.rs

@@ -138,6 +138,12 @@ impl Query {
         index_vec.push(index_uid);
         Self { index_uids: Some(index_vec), ..self }
     }
+
+    // Removes the `from` and `limit` restrictions from the query.
+    // Useful to get the total number of tasks matching a filter.
+    pub fn without_limits(self) -> Self {
+        Query { limit: None, from: None, ..self }
+    }
 }
 
 #[derive(Debug, Clone)]
@@ -822,7 +828,8 @@ impl IndexScheduler {
         Ok(nbr_index_processing_tasks > 0)
     }
 
-    /// Return the task ids matching the query from the user's point of view.
+    /// Return the task ids matching the query along with the total number of tasks
+    /// by ignoring the from and limit parameters from the user's point of view.
     ///
     /// There are two differences between an internal query and a query executed by
     /// the user.
@@ -835,7 +842,13 @@ impl IndexScheduler {
         rtxn: &RoTxn,
         query: &Query,
         filters: &meilisearch_auth::AuthFilter,
-    ) -> Result<RoaringBitmap> {
+    ) -> Result<(RoaringBitmap, u64)> {
+        // compute all tasks matching the filter by ignoring the limits, to find the number of tasks matching
+        // the filter.
+        // As this causes us to compute the filter twice it is slightly inefficient, but doing it this way spares
+        // us from modifying the underlying implementation, and the performance remains sufficient.
+        // Should this change, we would modify `get_task_ids` to directly return the number of matching tasks.
+        let total_tasks = self.get_task_ids(rtxn, &query.clone().without_limits())?;
         let mut tasks = self.get_task_ids(rtxn, query)?;
 
         // If the query contains a list of index uid or there is a finite list of authorized indexes,
@@ -858,10 +871,11 @@ impl IndexScheduler {
             }
         }
 
-        Ok(tasks)
+        Ok((tasks, total_tasks.len()))
     }
 
-    /// Return the tasks matching the query from the user's point of view.
+    /// Return the tasks matching the query from the user's point of view along
+    /// with the total number of tasks matching the query, ignoring from and limit.
     ///
     /// There are two differences between an internal query and a query executed by
     /// the user.
@@ -873,11 +887,10 @@ impl IndexScheduler {
         &self,
         query: Query,
         filters: &meilisearch_auth::AuthFilter,
-    ) -> Result<Vec<Task>> {
+    ) -> Result<(Vec<Task>, u64)> {
         let rtxn = self.env.read_txn()?;
 
-        let tasks = self.get_task_ids_from_authorized_indexes(&rtxn, &query, filters)?;
-
+        let (tasks, total) = self.get_task_ids_from_authorized_indexes(&rtxn, &query, filters)?;
         let tasks = self.get_existing_tasks(
             &rtxn,
             tasks.into_iter().rev().take(query.limit.unwrap_or(u32::MAX) as usize),
@@ -888,16 +901,19 @@ impl IndexScheduler {
 
         let ret = tasks.into_iter();
         if processing.is_empty() {
-            Ok(ret.collect())
+            Ok((ret.collect(), total))
         } else {
-            Ok(ret
-                .map(|task| match processing.contains(task.uid) {
-                    true => {
+            Ok((
+                ret.map(|task| {
+                    if processing.contains(task.uid) {
                         Task { status: Status::Processing, started_at: Some(started_at), ..task }
+                    } else {
+                        task
                     }
-                    false => task,
                 })
-                .collect())
+                .collect(),
+                total,
+            ))
         }
     }
 

meilisearch/src/routes/tasks.rs

@@ -325,7 +325,7 @@ async fn cancel_tasks(
 
     let query = params.into_query();
 
-    let tasks = index_scheduler.get_task_ids_from_authorized_indexes(
+    let (tasks, _) = index_scheduler.get_task_ids_from_authorized_indexes(
         &index_scheduler.read_txn()?,
         &query,
         index_scheduler.filters(),
@@ -370,7 +370,7 @@ async fn delete_tasks(
     );
     let query = params.into_query();
 
-    let tasks = index_scheduler.get_task_ids_from_authorized_indexes(
+    let (tasks, _) = index_scheduler.get_task_ids_from_authorized_indexes(
         &index_scheduler.read_txn()?,
         &query,
         index_scheduler.filters(),
@@ -387,6 +387,7 @@ async fn delete_tasks(
 #[derive(Debug, Serialize)]
 pub struct AllTasks {
     results: Vec<TaskView>,
+    total: u64,
     limit: u32,
     from: Option<u32>,
     next: Option<u32>,
@@ -406,23 +407,17 @@ async fn get_tasks(
     let limit = params.limit.0;
     let query = params.into_query();
 
-    let mut tasks_results: Vec<TaskView> = index_scheduler
-        .get_tasks_from_authorized_indexes(query, index_scheduler.filters())?
-        .into_iter()
-        .map(|t| TaskView::from_task(&t))
-        .collect();
+    let filters = index_scheduler.filters();
+    let (tasks, total) = index_scheduler.get_tasks_from_authorized_indexes(query, filters)?;
+    let mut results: Vec<_> = tasks.iter().map(TaskView::from_task).collect();
 
     // If we were able to fetch the number +1 tasks we asked
     // it means that there is more to come.
-    let next = if tasks_results.len() == limit as usize {
-        tasks_results.pop().map(|t| t.uid)
-    } else {
-        None
-    };
+    let next = if results.len() == limit as usize { results.pop().map(|t| t.uid) } else { None };
 
-    let from = tasks_results.first().map(|t| t.uid);
+    let from = results.first().map(|t| t.uid);
+    let tasks = AllTasks { results, limit: limit.saturating_sub(1), total, from, next };
 
-    let tasks = AllTasks { results: tasks_results, limit: limit.saturating_sub(1), from, next };
     Ok(HttpResponse::Ok().json(tasks))
 }
 
@@ -444,10 +439,10 @@ async fn get_task(
     analytics.publish("Tasks Seen".to_string(), json!({ "per_task_uid": true }), Some(&req));
 
     let query = index_scheduler::Query { uids: Some(vec![task_uid]), ..Query::default() };
+    let filters = index_scheduler.filters();
+    let (tasks, _) = index_scheduler.get_tasks_from_authorized_indexes(query, filters)?;
 
-    if let Some(task) =
-        index_scheduler.get_tasks_from_authorized_indexes(query, index_scheduler.filters())?.first()
-    {
+    if let Some(task) = tasks.first() {
         let task_view = TaskView::from_task(task);
         Ok(HttpResponse::Ok().json(task_view))
     } else {