From 7bfcd766281da06fe4fce3ed16623249f7f23ff6 Mon Sep 17 00:00:00 2001
From: Nicolas Lamirault <nicolas.lamirault@gmail.com>
Date: Tue, 3 Sep 2024 10:12:08 +0200
Subject: [PATCH] feat(prometheus): add build_info metric

Signed-off-by: Nicolas Lamirault <nicolas.lamirault@gmail.com>
---
 meilisearch/src/metrics.rs        | 7 +++++++
 meilisearch/src/routes/metrics.rs | 6 ++++++
 2 files changed, 13 insertions(+)

diff --git a/meilisearch/src/metrics.rs b/meilisearch/src/metrics.rs
index d380e9b96..e349fdc83 100644
--- a/meilisearch/src/metrics.rs
+++ b/meilisearch/src/metrics.rs
@@ -5,6 +5,13 @@ use prometheus::{
 };
 
 lazy_static! {
+    pub static ref MEILISEARCH_BUILD_INFO: IntGaugeVec = register_int_gauge_vec!(
+          opts!(
+            "meilisearch_build_info",
+            "A metric with a constant '1' value labelled by version from which meilisearch was built"),
+          & ["revision", "version"]
+    )
+    .expect("Can't create a metric");
     pub static ref MEILISEARCH_HTTP_REQUESTS_TOTAL: IntCounterVec = register_int_counter_vec!(
         opts!("meilisearch_http_requests_total", "Meilisearch HTTP requests total"),
         &["method", "path", "status"]
diff --git a/meilisearch/src/routes/metrics.rs b/meilisearch/src/routes/metrics.rs
index 7a13a758f..fd866b64f 100644
--- a/meilisearch/src/routes/metrics.rs
+++ b/meilisearch/src/routes/metrics.rs
@@ -1,6 +1,7 @@
 use actix_web::http::header;
 use actix_web::web::{self, Data};
 use actix_web::HttpResponse;
+use build_info;
 use index_scheduler::IndexScheduler;
 use meilisearch_auth::AuthController;
 use meilisearch_types::error::ResponseError;
@@ -54,6 +55,11 @@ pub async fn get_metrics(
     }
     crate::metrics::MEILISEARCH_IS_INDEXING.set(index_scheduler.is_task_processing()? as i64);
 
+    let build_info = build_info::BuildInfo::from_build();
+    let commit_sha = build_info.commit_sha1.unwrap_or("unknown").to_string();
+    let pkg_version = env!("CARGO_PKG_VERSION").to_string();
+    crate::metrics::MEILISEARCH_BUILD_INFO.with_label_values(&[&commit_sha, &pkg_version]).set(1);
+
     let encoder = TextEncoder::new();
     let mut buffer = vec![];
     encoder.encode(&prometheus::gather(), &mut buffer).expect("Failed to encode metrics");