Merge #5048

5048: Reverse the order of the task queue r=Kerollmops a=irevoire

# Pull Request

## Related issue
Fixes https://github.com/meilisearch/meilisearch/issues/5047

## What does this PR do?
- Provide a new parameter to reverse the order of the task queue
- Add tests
- Remove some unrelated tests that were duplicated in tests/tasks/mod.rs and tests/tasks/error.rs


Co-authored-by: Tamo <tamo@meilisearch.com>

crates/index-scheduler/src/lib.rs

@@ -84,6 +84,8 @@ pub struct Query {
     pub limit: Option<u32>,
     /// The minimum [task id](`meilisearch_types::tasks::Task::uid`) to be matched
     pub from: Option<u32>,
+    /// The order used to return the tasks. By default the newest tasks are returned first and the boolean is `false`.
+    pub reverse: Option<bool>,
     /// The allowed [statuses](`meilisearch_types::tasks::Task::status`) of the matched tasls
     pub statuses: Option<Vec<Status>>,
     /// The allowed [kinds](meilisearch_types::tasks::Kind) of the matched tasks.
@@ -126,6 +128,7 @@ impl Query {
             Query {
                 limit: None,
                 from: None,
+                reverse: None,
                 statuses: None,
                 types: None,
                 index_uids: None,
@@ -706,7 +709,12 @@ impl IndexScheduler {
         let mut tasks = self.all_task_ids(rtxn)?;
 
         if let Some(from) = &query.from {
-            tasks.remove_range(from.saturating_add(1)..);
+            let range = if query.reverse.unwrap_or_default() {
+                u32::MIN..*from
+            } else {
+                from.saturating_add(1)..u32::MAX
+            };
+            tasks.remove_range(range);
         }
 
         if let Some(status) = &query.statuses {
@@ -826,7 +834,11 @@ impl IndexScheduler {
         )?;
 
         if let Some(limit) = query.limit {
-            tasks = tasks.into_iter().rev().take(limit as usize).collect();
+            tasks = if query.reverse.unwrap_or_default() {
+                tasks.into_iter().take(limit as usize).collect()
+            } else {
+                tasks.into_iter().rev().take(limit as usize).collect()
+            };
         }
 
         Ok(tasks)
@@ -951,10 +963,13 @@ impl IndexScheduler {
         let rtxn = self.env.read_txn()?;
 
         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),
-        )?;
+        let tasks = if query.reverse.unwrap_or_default() {
+            Box::new(tasks.into_iter()) as Box<dyn Iterator<Item = u32>>
+        } else {
+            Box::new(tasks.into_iter().rev()) as Box<dyn Iterator<Item = u32>>
+        };
+        let tasks =
+            self.get_existing_tasks(&rtxn, tasks.take(query.limit.unwrap_or(u32::MAX) as usize))?;
 
         let ProcessingTasks { started_at, processing, .. } =
             self.processing_tasks.read().map_err(|_| Error::CorruptedTaskQueue)?.clone();

crates/meilisearch-types/src/error.rs

@@ -318,6 +318,7 @@ InvalidTaskBeforeStartedAt            , InvalidRequest       , BAD_REQUEST ;
 InvalidTaskCanceledBy                 , InvalidRequest       , BAD_REQUEST ;
 InvalidTaskFrom                       , InvalidRequest       , BAD_REQUEST ;
 InvalidTaskLimit                      , InvalidRequest       , BAD_REQUEST ;
+InvalidTaskReverse                    , InvalidRequest       , BAD_REQUEST ;
 InvalidTaskStatuses                   , InvalidRequest       , BAD_REQUEST ;
 InvalidTaskTypes                      , InvalidRequest       , BAD_REQUEST ;
 InvalidTaskUids                       , InvalidRequest       , BAD_REQUEST  ;

crates/meilisearch/src/routes/tasks.rs

@@ -42,6 +42,8 @@ pub struct TasksFilterQuery {
     pub limit: Param<u32>,
     #[deserr(default, error = DeserrQueryParamError<InvalidTaskFrom>)]
     pub from: Option<Param<TaskId>>,
+    #[deserr(default, error = DeserrQueryParamError<InvalidTaskReverse>)]
+    pub reverse: Option<Param<bool>>,
 
     #[deserr(default, error = DeserrQueryParamError<InvalidTaskUids>)]
     pub uids: OptionStarOrList<u32>,
@@ -73,6 +75,7 @@ impl TasksFilterQuery {
         Query {
             limit: Some(self.limit.0),
             from: self.from.as_deref().copied(),
+            reverse: self.reverse.as_deref().copied(),
             statuses: self.statuses.merge_star_and_none(),
             types: self.types.merge_star_and_none(),
             index_uids: self.index_uids.map(|x| x.to_string()).merge_star_and_none(),
@@ -142,6 +145,7 @@ impl TaskDeletionOrCancelationQuery {
         Query {
             limit: None,
             from: None,
+            reverse: None,
             statuses: self.statuses.merge_star_and_none(),
             types: self.types.merge_star_and_none(),
             index_uids: self.index_uids.map(|x| x.to_string()).merge_star_and_none(),
@@ -701,14 +705,14 @@ mod tests {
         {
             let params = "from=12&limit=15&indexUids=toto,tata-78&statuses=succeeded,enqueued&afterEnqueuedAt=2012-04-23&uids=1,2,3";
             let query = deserr_query_params::<TasksFilterQuery>(params).unwrap();
-            snapshot!(format!("{:?}", query), @r###"TasksFilterQuery { limit: Param(15), from: Some(Param(12)), uids: List([1, 2, 3]), canceled_by: None, types: None, statuses: List([Succeeded, Enqueued]), index_uids: List([IndexUid("toto"), IndexUid("tata-78")]), after_enqueued_at: Other(2012-04-24 0:00:00.0 +00:00:00), before_enqueued_at: None, after_started_at: None, before_started_at: None, after_finished_at: None, before_finished_at: None }"###);
+            snapshot!(format!("{:?}", query), @r###"TasksFilterQuery { limit: Param(15), from: Some(Param(12)), reverse: None, uids: List([1, 2, 3]), canceled_by: None, types: None, statuses: List([Succeeded, Enqueued]), index_uids: List([IndexUid("toto"), IndexUid("tata-78")]), after_enqueued_at: Other(2012-04-24 0:00:00.0 +00:00:00), before_enqueued_at: None, after_started_at: None, before_started_at: None, after_finished_at: None, before_finished_at: None }"###);
         }
         {
             // Stars should translate to `None` in the query
             // Verify value of the default limit
             let params = "indexUids=*&statuses=succeeded,*&afterEnqueuedAt=2012-04-23&uids=1,2,3";
             let query = deserr_query_params::<TasksFilterQuery>(params).unwrap();
-            snapshot!(format!("{:?}", query), @"TasksFilterQuery { limit: Param(20), from: None, uids: List([1, 2, 3]), canceled_by: None, types: None, statuses: Star, index_uids: Star, after_enqueued_at: Other(2012-04-24 0:00:00.0 +00:00:00), before_enqueued_at: None, after_started_at: None, before_started_at: None, after_finished_at: None, before_finished_at: None }");
+            snapshot!(format!("{:?}", query), @"TasksFilterQuery { limit: Param(20), from: None, reverse: None, uids: List([1, 2, 3]), canceled_by: None, types: None, statuses: Star, index_uids: Star, after_enqueued_at: Other(2012-04-24 0:00:00.0 +00:00:00), before_enqueued_at: None, after_started_at: None, before_started_at: None, after_finished_at: None, before_finished_at: None }");
         }
         {
             // Stars should also translate to `None` in task deletion/cancelation queries

crates/meilisearch/tests/tasks/errors.rs

@@ -279,6 +279,55 @@ async fn task_bad_from() {
     "###);
 }
 
+#[actix_rt::test]
+async fn task_bad_reverse() {
+    let server = Server::new_shared();
+
+    let (response, code) = server.tasks_filter("reverse=doggo").await;
+    snapshot!(code, @"400 Bad Request");
+    snapshot!(response, @r###"
+    {
+      "message": "Invalid value in parameter `reverse`: could not parse `doggo` as a boolean, expected either `true` or `false`",
+      "code": "invalid_task_reverse",
+      "type": "invalid_request",
+      "link": "https://docs.meilisearch.com/errors#invalid_task_reverse"
+    }
+    "###);
+
+    let (response, code) = server.tasks_filter("reverse=*").await;
+    snapshot!(code, @"400 Bad Request");
+    snapshot!(response, @r###"
+    {
+      "message": "Invalid value in parameter `reverse`: could not parse `*` as a boolean, expected either `true` or `false`",
+      "code": "invalid_task_reverse",
+      "type": "invalid_request",
+      "link": "https://docs.meilisearch.com/errors#invalid_task_reverse"
+    }
+    "###);
+
+    let (response, code) = server.cancel_tasks("reverse=doggo").await;
+    snapshot!(code, @"400 Bad Request");
+    snapshot!(response, @r###"
+    {
+      "message": "Unknown parameter `reverse`: expected one of `uids`, `canceledBy`, `types`, `statuses`, `indexUids`, `afterEnqueuedAt`, `beforeEnqueuedAt`, `afterStartedAt`, `beforeStartedAt`, `afterFinishedAt`, `beforeFinishedAt`",
+      "code": "bad_request",
+      "type": "invalid_request",
+      "link": "https://docs.meilisearch.com/errors#bad_request"
+    }
+    "###);
+
+    let (response, code) = server.delete_tasks("reverse=doggo").await;
+    snapshot!(code, @"400 Bad Request");
+    snapshot!(response, @r###"
+    {
+      "message": "Unknown parameter `reverse`: expected one of `uids`, `canceledBy`, `types`, `statuses`, `indexUids`, `afterEnqueuedAt`, `beforeEnqueuedAt`, `afterStartedAt`, `beforeStartedAt`, `afterFinishedAt`, `beforeFinishedAt`",
+      "code": "bad_request",
+      "type": "invalid_request",
+      "link": "https://docs.meilisearch.com/errors#bad_request"
+    }
+    "###);
+}
+
 #[actix_rt::test]
 async fn task_bad_after_enqueued_at() {
     let server = Server::new_shared();

crates/meilisearch/tests/tasks/mod.rs

@@ -62,6 +62,44 @@ async fn list_tasks() {
     assert_eq!(response["results"].as_array().unwrap().len(), 2);
 }
 
+#[actix_rt::test]
+async fn list_tasks_pagination_and_reverse() {
+    let server = Server::new().await;
+    // First of all we want to create a lot of tasks very quickly. The fastest way is to delete a lot of unexisting indexes
+    let mut last_task = None;
+    for i in 0..10 {
+        let index = server.index(format!("test-{i}"));
+        last_task = Some(index.create(None).await.0.uid());
+    }
+    server.wait_task(last_task.unwrap()).await;
+
+    let (response, code) = server.tasks_filter("limit=3").await;
+    assert_eq!(code, 200);
+    let results = response["results"].as_array().unwrap();
+    let task_ids: Vec<_> = results.iter().map(|ret| ret["uid"].as_u64().unwrap()).collect();
+    snapshot!(format!("{task_ids:?}"), @"[9, 8, 7]");
+
+    let (response, code) = server.tasks_filter("limit=3&from=1").await;
+    assert_eq!(code, 200);
+    let results = response["results"].as_array().unwrap();
+    let task_ids: Vec<_> = results.iter().map(|ret| ret["uid"].as_u64().unwrap()).collect();
+    snapshot!(format!("{task_ids:?}"), @"[1, 0]");
+
+    // In reversed order
+
+    let (response, code) = server.tasks_filter("limit=3&reverse=true").await;
+    assert_eq!(code, 200);
+    let results = response["results"].as_array().unwrap();
+    let task_ids: Vec<_> = results.iter().map(|ret| ret["uid"].as_u64().unwrap()).collect();
+    snapshot!(format!("{task_ids:?}"), @"[0, 1, 2]");
+
+    let (response, code) = server.tasks_filter("limit=3&from=8&reverse=true").await;
+    assert_eq!(code, 200);
+    let results = response["results"].as_array().unwrap();
+    let task_ids: Vec<_> = results.iter().map(|ret| ret["uid"].as_u64().unwrap()).collect();
+    snapshot!(format!("{task_ids:?}"), @"[8, 9]");
+}
+
 #[actix_rt::test]
 async fn list_tasks_with_star_filters() {
     let server = Server::new().await;
@@ -193,131 +231,6 @@ async fn list_tasks_status_and_type_filtered() {
     assert_eq!(response["results"].as_array().unwrap().len(), 2);
 }
 
-#[actix_rt::test]
-async fn get_task_filter_error() {
-    let server = Server::new().await;
-
-    let (response, code) = server.tasks_filter("lol=pied").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Unknown parameter `lol`: expected one of `limit`, `from`, `uids`, `canceledBy`, `types`, `statuses`, `indexUids`, `afterEnqueuedAt`, `beforeEnqueuedAt`, `afterStartedAt`, `beforeStartedAt`, `afterFinishedAt`, `beforeFinishedAt`",
-      "code": "bad_request",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#bad_request"
-    }
-    "###);
-
-    let (response, code) = server.tasks_filter("uids=pied").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Invalid value in parameter `uids`: could not parse `pied` as a positive integer",
-      "code": "invalid_task_uids",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#invalid_task_uids"
-    }
-    "###);
-
-    let (response, code) = server.tasks_filter("from=pied").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Invalid value in parameter `from`: could not parse `pied` as a positive integer",
-      "code": "invalid_task_from",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#invalid_task_from"
-    }
-    "###);
-
-    let (response, code) = server.tasks_filter("beforeStartedAt=pied").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Invalid value in parameter `beforeStartedAt`: `pied` is an invalid date-time. It should follow the YYYY-MM-DD or RFC 3339 date-time format.",
-      "code": "invalid_task_before_started_at",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#invalid_task_before_started_at"
-    }
-    "###);
-}
-
-#[actix_rt::test]
-async fn delete_task_filter_error() {
-    let server = Server::new().await;
-
-    let (response, code) = server.delete_tasks("").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Query parameters to filter the tasks to delete are missing. Available query parameters are: `uids`, `indexUids`, `statuses`, `types`, `canceledBy`, `beforeEnqueuedAt`, `afterEnqueuedAt`, `beforeStartedAt`, `afterStartedAt`, `beforeFinishedAt`, `afterFinishedAt`.",
-      "code": "missing_task_filters",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#missing_task_filters"
-    }
-    "###);
-
-    let (response, code) = server.delete_tasks("lol=pied").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Unknown parameter `lol`: expected one of `uids`, `canceledBy`, `types`, `statuses`, `indexUids`, `afterEnqueuedAt`, `beforeEnqueuedAt`, `afterStartedAt`, `beforeStartedAt`, `afterFinishedAt`, `beforeFinishedAt`",
-      "code": "bad_request",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#bad_request"
-    }
-    "###);
-
-    let (response, code) = server.delete_tasks("uids=pied").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Invalid value in parameter `uids`: could not parse `pied` as a positive integer",
-      "code": "invalid_task_uids",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#invalid_task_uids"
-    }
-    "###);
-}
-
-#[actix_rt::test]
-async fn cancel_task_filter_error() {
-    let server = Server::new().await;
-
-    let (response, code) = server.cancel_tasks("").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Query parameters to filter the tasks to cancel are missing. Available query parameters are: `uids`, `indexUids`, `statuses`, `types`, `canceledBy`, `beforeEnqueuedAt`, `afterEnqueuedAt`, `beforeStartedAt`, `afterStartedAt`, `beforeFinishedAt`, `afterFinishedAt`.",
-      "code": "missing_task_filters",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#missing_task_filters"
-    }
-    "###);
-
-    let (response, code) = server.cancel_tasks("lol=pied").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Unknown parameter `lol`: expected one of `uids`, `canceledBy`, `types`, `statuses`, `indexUids`, `afterEnqueuedAt`, `beforeEnqueuedAt`, `afterStartedAt`, `beforeStartedAt`, `afterFinishedAt`, `beforeFinishedAt`",
-      "code": "bad_request",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#bad_request"
-    }
-    "###);
-
-    let (response, code) = server.cancel_tasks("uids=pied").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Invalid value in parameter `uids`: could not parse `pied` as a positive integer",
-      "code": "invalid_task_uids",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#invalid_task_uids"
-    }
-    "###);
-}
-
 macro_rules! assert_valid_summarized_task {
     ($response:expr, $task_type:literal, $index:literal) => {{
         assert_eq!($response.as_object().unwrap().len(), 5);