add a view for the task queue in the metrics

index-scheduler/src/lib.rs

@@ -31,7 +31,7 @@ mod uuid_codec;
 pub type Result<T> = std::result::Result<T, Error>;
 pub type TaskId = u32;
 
-use std::collections::HashMap;
+use std::collections::{BTreeMap, HashMap};
 use std::ops::{Bound, RangeBounds};
 use std::path::{Path, PathBuf};
 use std::sync::atomic::AtomicBool;
@@ -737,6 +737,34 @@ impl IndexScheduler {
         Ok(tasks)
     }
 
+    pub fn get_stats(&self) -> Result<BTreeMap<String, BTreeMap<String, u64>>> {
+        let rtxn = self.read_txn()?;
+
+        let mut res = BTreeMap::new();
+
+        res.insert(
+            "statuses".to_string(),
+            enum_iterator::all::<Status>()
+                .map(|s| Ok((s.to_string(), self.get_status(&rtxn, s)?.len())))
+                .collect::<Result<BTreeMap<String, u64>>>()?,
+        );
+        res.insert(
+            "types".to_string(),
+            enum_iterator::all::<Kind>()
+                .map(|s| Ok((s.to_string(), self.get_kind(&rtxn, s)?.len())))
+                .collect::<Result<BTreeMap<String, u64>>>()?,
+        );
+        res.insert(
+            "indexes".to_string(),
+            self.index_tasks
+                .iter(&rtxn)?
+                .map(|res| Ok(res.map(|(name, bitmap)| (name.to_string(), bitmap.len()))?))
+                .collect::<Result<BTreeMap<String, u64>>>()?,
+        );
+
+        Ok(res)
+    }
+
     /// Return true iff there is at least one task associated with this index
     /// that is processing.
     pub fn is_index_processing(&self, index: &str) -> Result<bool> {

meilisearch/src/metrics.rs

@@ -40,4 +40,7 @@ lazy_static! {
         HTTP_RESPONSE_TIME_CUSTOM_BUCKETS.to_vec()
     )
     .expect("Can't create a metric");
+    pub static ref NB_TASKS: IntGaugeVec =
+        register_int_gauge_vec!(opts!("nb_tasks", "Number of tasks"), &["kind", "value"])
+            .expect("Can't create a metric");
 }

meilisearch/src/routes/metrics.rs

@@ -39,6 +39,12 @@ pub async fn get_metrics(
             .set(value.number_of_documents as i64);
     }
 
+    for (kind, value) in index_scheduler.get_stats()? {
+        for (value, count) in value {
+            crate::metrics::NB_TASKS.with_label_values(&[&kind, &value]).set(count as i64);
+        }
+    }
+
     let encoder = TextEncoder::new();
     let mut buffer = vec![];
     encoder.encode(&prometheus::gather(), &mut buffer).expect("Failed to encode metrics");