Make the experimental route /metrics activable via HTTP

index-scheduler/src/features.rs

@@ -10,19 +10,17 @@ const EXPERIMENTAL_FEATURES: &str = "experimental-features";
 #[derive(Clone)]
 pub(crate) struct FeatureData {
     runtime: Database<Str, SerdeJson<RuntimeTogglableFeatures>>,
-    instance: InstanceTogglableFeatures,
 }
 
 #[derive(Debug, Clone, Copy)]
 pub struct RoFeatures {
     runtime: RuntimeTogglableFeatures,
-    instance: InstanceTogglableFeatures,
 }
 
 impl RoFeatures {
     fn new(txn: RoTxn<'_>, data: &FeatureData) -> Result<Self> {
         let runtime = data.runtime_features(txn)?;
-        Ok(Self { runtime, instance: data.instance })
+        Ok(Self { runtime })
     }
 
     pub fn runtime_features(&self) -> RuntimeTogglableFeatures {
@@ -43,7 +41,7 @@ impl RoFeatures {
     }
 
     pub fn check_metrics(&self) -> Result<()> {
-        if self.instance.metrics {
+        if self.runtime.metrics {
             Ok(())
         } else {
             Err(FeatureNotEnabledError {
@@ -73,9 +71,12 @@ impl FeatureData {
     pub fn new(env: &Env, instance_features: InstanceTogglableFeatures) -> Result<Self> {
         let mut wtxn = env.write_txn()?;
         let runtime_features = env.create_database(&mut wtxn, Some(EXPERIMENTAL_FEATURES))?;
+        let default_features =
+            RuntimeTogglableFeatures { metrics: instance_features.metrics, ..Default::default() };
+        runtime_features.put(&mut wtxn, EXPERIMENTAL_FEATURES, &default_features)?;
         wtxn.commit()?;
 
-        Ok(Self { runtime: runtime_features, instance: instance_features })
+        Ok(Self { runtime: runtime_features })
     }
 
     pub fn put_runtime_features(

meilisearch-types/src/features.rs

@@ -5,6 +5,7 @@ use serde::{Deserialize, Serialize};
 pub struct RuntimeTogglableFeatures {
     pub score_details: bool,
     pub vector_store: bool,
+    pub metrics: bool,
 }
 
 #[derive(Default, Debug, Clone, Copy)]

meilisearch/src/routes/features.rs

@@ -44,6 +44,8 @@ pub struct RuntimeTogglableFeatures {
     pub score_details: Option<bool>,
     #[deserr(default)]
     pub vector_store: Option<bool>,
+    #[deserr(default)]
+    pub metrics: Option<bool>,
 }
 
 async fn patch_features(
@@ -62,19 +64,24 @@ async fn patch_features(
     let new_features = meilisearch_types::features::RuntimeTogglableFeatures {
         score_details: new_features.0.score_details.unwrap_or(old_features.score_details),
         vector_store: new_features.0.vector_store.unwrap_or(old_features.vector_store),
+        metrics: new_features.0.metrics.unwrap_or(old_features.metrics),
     };
 
     // explicitly destructure for analytics rather than using the `Serialize` implementation, because
     // the it renames to camelCase, which we don't want for analytics.
     // **Do not** ignore fields with `..` or `_` here, because we want to add them in the future.
-    let meilisearch_types::features::RuntimeTogglableFeatures { score_details, vector_store } =
-        new_features;
+    let meilisearch_types::features::RuntimeTogglableFeatures {
+        score_details,
+        vector_store,
+        metrics,
+    } = new_features;
 
     analytics.publish(
         "Experimental features Updated".to_string(),
         json!({
             "score_details": score_details,
             "vector_store": vector_store,
+            "metrics": metrics,
         }),
         Some(&req),
     );

meilisearch/tests/auth/authorization.rs

@@ -2,10 +2,12 @@ use std::collections::{HashMap, HashSet};
 
 use ::time::format_description::well_known::Rfc3339;
 use maplit::{hashmap, hashset};
+use meilisearch::Opt;
 use once_cell::sync::Lazy;
+use tempfile::TempDir;
 use time::{Duration, OffsetDateTime};
 
-use crate::common::{Server, Value};
+use crate::common::{default_settings, Server, Value};
 use crate::json;
 
 pub static AUTHORIZATIONS: Lazy<HashMap<(&'static str, &'static str), HashSet<&'static str>>> =
@@ -195,7 +197,9 @@ async fn access_authorized_master_key() {
 
 #[actix_rt::test]
 async fn access_authorized_restricted_index() {
-    let mut server = Server::new_auth().await;
+    let dir = TempDir::new().unwrap();
+    let enable_metrics = Opt { experimental_enable_metrics: true, ..default_settings(dir.path()) };
+    let mut server = Server::new_auth_with_options(enable_metrics, dir).await;
     for ((method, route), actions) in AUTHORIZATIONS.iter() {
         for action in actions {
             // create a new API key letting only the needed action.

meilisearch/tests/common/server.rs

@@ -202,6 +202,10 @@ impl Server {
     pub async fn set_features(&self, value: Value) -> (Value, StatusCode) {
         self.service.patch("/experimental-features", value).await
     }
+
+    pub async fn get_metrics(&self) -> (Value, StatusCode) {
+        self.service.get("/metrics").await
+    }
 }
 
 pub fn default_settings(dir: impl AsRef<Path>) -> Opt {
@@ -221,7 +225,7 @@ pub fn default_settings(dir: impl AsRef<Path>) -> Opt {
             skip_index_budget: true,
             ..Parser::parse_from(None as Option<&str>)
         },
-        experimental_enable_metrics: true,
+        experimental_enable_metrics: false,
         ..Parser::parse_from(None as Option<&str>)
     }
 }

meilisearch/tests/features/mod.rs

@@ -1,4 +1,7 @@
-use crate::common::Server;
+use meilisearch::Opt;
+use tempfile::TempDir;
+
+use crate::common::{default_settings, Server};
 use crate::json;
 
 /// Feature name to test against.
@@ -16,7 +19,8 @@ async fn experimental_features() {
     meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
     {
       "scoreDetails": false,
-      "vectorStore": false
+      "vectorStore": false,
+      "metrics": false
     }
     "###);
 
@@ -26,7 +30,8 @@ async fn experimental_features() {
     meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
     {
       "scoreDetails": false,
-      "vectorStore": true
+      "vectorStore": true,
+      "metrics": false
     }
     "###);
 
@@ -36,7 +41,8 @@ async fn experimental_features() {
     meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
     {
       "scoreDetails": false,
-      "vectorStore": true
+      "vectorStore": true,
+      "metrics": false
     }
     "###);
 
@@ -47,7 +53,8 @@ async fn experimental_features() {
     meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
     {
       "scoreDetails": false,
-      "vectorStore": true
+      "vectorStore": true,
+      "metrics": false
     }
     "###);
 
@@ -58,11 +65,63 @@ async fn experimental_features() {
     meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
     {
       "scoreDetails": false,
-      "vectorStore": true
+      "vectorStore": true,
+      "metrics": false
     }
     "###);
 }
 
+#[actix_rt::test]
+async fn experimental_feature_metrics() {
+    // instance flag for metrics enables metrics at startup
+    let dir = TempDir::new().unwrap();
+    let enable_metrics = Opt { experimental_enable_metrics: true, ..default_settings(dir.path()) };
+    let server = Server::new_with_options(enable_metrics).await.unwrap();
+
+    let (response, code) = server.get_features().await;
+
+    meili_snap::snapshot!(code, @"200 OK");
+    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
+    {
+      "scoreDetails": false,
+      "vectorStore": false,
+      "metrics": true
+    }
+    "###);
+
+    let (response, code) = server.get_metrics().await;
+    meili_snap::snapshot!(code, @"200 OK");
+
+    // metrics are not returned in json format
+    // so the test server will return null
+    meili_snap::snapshot!(response, @"null");
+
+    // disabling metrics results in invalid request
+    let (response, code) = server.set_features(json!({"metrics": false})).await;
+    meili_snap::snapshot!(code, @"200 OK");
+    meili_snap::snapshot!(response["metrics"], @"false");
+
+    let (response, code) = server.get_metrics().await;
+    meili_snap::snapshot!(code, @"400 Bad Request");
+    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
+    {
+      "message": "Getting metrics requires enabling the `metrics` experimental feature. See https://github.com/meilisearch/meilisearch/discussions/3518",
+      "code": "feature_not_enabled",
+      "type": "invalid_request",
+      "link": "https://docs.meilisearch.com/errors#feature_not_enabled"
+    }
+    "###);
+
+    // enabling metrics via HTTP results in valid request
+    let (response, code) = server.set_features(json!({"metrics": true})).await;
+    meili_snap::snapshot!(code, @"200 OK");
+    meili_snap::snapshot!(response["metrics"], @"true");
+
+    let (response, code) = server.get_metrics().await;
+    meili_snap::snapshot!(code, @"200 OK");
+    meili_snap::snapshot!(response, @"null");
+}
+
 #[actix_rt::test]
 async fn errors() {
     let server = Server::new().await;
@@ -73,7 +132,7 @@ async fn errors() {
     meili_snap::snapshot!(code, @"400 Bad Request");
     meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
     {
-      "message": "Unknown field `NotAFeature`: expected one of `scoreDetails`, `vectorStore`",
+      "message": "Unknown field `NotAFeature`: expected one of `scoreDetails`, `vectorStore`, `metrics`",
       "code": "bad_request",
       "type": "invalid_request",
       "link": "https://docs.meilisearch.com/errors#bad_request"