From a17e45c38d802aa518f344bb2b92b1b2c6951259 Mon Sep 17 00:00:00 2001
From: Paul Masurel <paul@quickwit.io>
Date: Mon, 11 Mar 2024 18:04:13 +0900
Subject: [PATCH] Added a metric for number of indexes

---
 quickwit/quickwit-control-plane/src/metrics.rs   | 4 +++-
 quickwit/quickwit-control-plane/src/model/mod.rs | 8 ++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/quickwit/quickwit-control-plane/src/metrics.rs b/quickwit/quickwit-control-plane/src/metrics.rs
index 69a1caa5c51..54d05e0a9ff 100644
--- a/quickwit/quickwit-control-plane/src/metrics.rs
+++ b/quickwit/quickwit-control-plane/src/metrics.rs
@@ -18,9 +18,10 @@
 // along with this program. If not, see <http://www.gnu.org/licenses/>.
 
 use once_cell::sync::Lazy;
-use quickwit_common::metrics::{new_counter, new_gauge_vec, IntCounter, IntGaugeVec};
+use quickwit_common::metrics::{new_counter, new_gauge, new_gauge_vec, IntCounter, IntGaugeVec};
 
 pub struct ControlPlaneMetrics {
+    pub indexes_total: IntGauge,
     pub restart_total: IntCounter,
     pub schedule_total: IntCounter,
     pub metastore_error_aborted: IntCounter,
@@ -31,6 +32,7 @@ pub struct ControlPlaneMetrics {
 impl Default for ControlPlaneMetrics {
     fn default() -> Self {
         ControlPlaneMetrics {
+            indexes_total: new_gauge("indexes_total", "Number of indexes.", "control_plane", &[]),
             restart_total: new_counter(
                 "restart_total",
                 "Number of control plane restart.",
diff --git a/quickwit/quickwit-control-plane/src/model/mod.rs b/quickwit/quickwit-control-plane/src/model/mod.rs
index 9602cb814b6..86dbf578198 100644
--- a/quickwit/quickwit-control-plane/src/model/mod.rs
+++ b/quickwit/quickwit-control-plane/src/model/mod.rs
@@ -152,6 +152,12 @@ impl ControlPlaneModel {
         self.index_uid_table.get(index_id).cloned()
     }
 
+    fn update_metrics(&self) {
+        crate::metrics::CONTROL_PLANE_METRICS
+            .indexes_total
+            .set(self.index_table.len() as i64);
+    }
+
     pub(crate) fn source_configs(&self) -> impl Iterator<Item = (SourceUid, &SourceConfig)> + '_ {
         self.index_table.values().flat_map(|index_metadata| {
             index_metadata
@@ -181,12 +187,14 @@ impl ControlPlaneModel {
             }
         }
         self.index_table.insert(index_uid, index_metadata);
+        self.update_metrics();
     }
 
     pub(crate) fn delete_index(&mut self, index_uid: &IndexUid) {
         self.index_table.remove(index_uid);
         self.index_uid_table.remove(&index_uid.index_id);
         self.shard_table.delete_index(&index_uid.index_id);
+        self.update_metrics();
     }
 
     /// Adds a source to a given index. Returns an error if the source already