From 9e3f418121ea729eaa26bd803a797df7db140f3b Mon Sep 17 00:00:00 2001
From: Hubert Bugaj <lesny.rumcajs+github@gmail.com>
Date: Wed, 14 Aug 2024 12:59:00 +0200
Subject: [PATCH 1/2] Reapply "feat(metric): add forest version to prometheus
 (#4535)" (#4594)

This reverts commit 7502528e42c4bca9c56ae6447fb8ffa3e47f1fc2.
---
 src/metrics/mod.rs       |  4 +++-
 src/utils/version/mod.rs | 30 ++++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/metrics/mod.rs b/src/metrics/mod.rs
index f2d1239c2ad7..6b355a5518b4 100644
--- a/src/metrics/mod.rs
+++ b/src/metrics/mod.rs
@@ -80,7 +80,9 @@ where
         warn!("Failed to register process metrics: {err}");
     }
 
-    // Add the DBCollector to the registry
+    DEFAULT_REGISTRY.write().register_collector(Box::new(
+        crate::utils::version::ForestVersionCollector::new(),
+    ));
     DEFAULT_REGISTRY
         .write()
         .register_collector(Box::new(crate::metrics::db::DBCollector::new(db_directory)));
diff --git a/src/utils/version/mod.rs b/src/utils/version/mod.rs
index 792525298f32..bb1de6fc4838 100644
--- a/src/utils/version/mod.rs
+++ b/src/utils/version/mod.rs
@@ -3,6 +3,11 @@
 
 use git_version::git_version;
 use once_cell::sync::Lazy;
+use prometheus_client::{
+    collector::Collector,
+    encoding::{DescriptorEncoder, EncodeMetric},
+    metrics::info::Info,
+};
 
 /// Current git commit hash of the Forest repository.
 pub const GIT_HASH: &str =
@@ -15,3 +20,28 @@ pub static FOREST_VERSION_STRING: Lazy<String> =
 
 pub static FOREST_VERSION: Lazy<semver::Version> =
     Lazy::new(|| semver::Version::parse(env!("CARGO_PKG_VERSION")).expect("Invalid version"));
+
+#[derive(Debug)]
+pub struct ForestVersionCollector {
+    version: Info<Vec<(&'static str, &'static str)>>,
+}
+
+impl ForestVersionCollector {
+    pub fn new() -> Self {
+        let version = Info::new(vec![("version", FOREST_VERSION_STRING.as_str())]);
+        Self { version }
+    }
+}
+
+impl Collector for ForestVersionCollector {
+    fn encode(&self, mut encoder: DescriptorEncoder) -> Result<(), std::fmt::Error> {
+        let metric_encoder = encoder.encode_descriptor(
+            "forest_version",
+            "semantic version of the forest binary",
+            None,
+            self.version.metric_type(),
+        )?;
+        self.version.encode(metric_encoder)?;
+        Ok(())
+    }
+}

From fc2e8b24111c77fb76229cca573155bb51a7864f Mon Sep 17 00:00:00 2001
From: Hubert Bugaj <lesny.rumcajs+github@gmail.com>
Date: Wed, 14 Aug 2024 14:00:33 +0200
Subject: [PATCH 2/2] fix: use gauge instead of non-standard info

---
 CHANGELOG.md             |  3 +++
 src/utils/version/mod.rs | 27 +++++++++++++++++++++------
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 28dfa85496d0..012db05ddcc2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -50,6 +50,9 @@
   snapshots instead of moving or copying them. This can be invoked with
   `--import-snapshot <path> --import-mode=symlink`.
 
+- [#4533](https://github.com/ChainSafe/forest/pull/4641) Added `build_info`
+  metric to Prometheus metrics, which include the current build's version.
+
 ### Changed
 
 - [#4583](https://github.com/ChainSafe/forest/pull/4583) Removed the expiration
diff --git a/src/utils/version/mod.rs b/src/utils/version/mod.rs
index bb1de6fc4838..779a73e20fae 100644
--- a/src/utils/version/mod.rs
+++ b/src/utils/version/mod.rs
@@ -5,8 +5,8 @@ use git_version::git_version;
 use once_cell::sync::Lazy;
 use prometheus_client::{
     collector::Collector,
-    encoding::{DescriptorEncoder, EncodeMetric},
-    metrics::info::Info,
+    encoding::{DescriptorEncoder, EncodeLabelSet, EncodeMetric},
+    metrics::{family::Family, gauge::Gauge},
 };
 
 /// Current git commit hash of the Forest repository.
@@ -21,26 +21,41 @@ pub static FOREST_VERSION_STRING: Lazy<String> =
 pub static FOREST_VERSION: Lazy<semver::Version> =
     Lazy::new(|| semver::Version::parse(env!("CARGO_PKG_VERSION")).expect("Invalid version"));
 
+#[derive(Clone, Debug, Hash, PartialEq, Eq, EncodeLabelSet)]
+pub struct VersionLabel {
+    version: &'static str,
+}
+
+impl VersionLabel {
+    pub const fn new(version: &'static str) -> Self {
+        Self { version }
+    }
+}
+
 #[derive(Debug)]
 pub struct ForestVersionCollector {
-    version: Info<Vec<(&'static str, &'static str)>>,
+    version: Family<VersionLabel, Gauge>,
 }
 
 impl ForestVersionCollector {
     pub fn new() -> Self {
-        let version = Info::new(vec![("version", FOREST_VERSION_STRING.as_str())]);
-        Self { version }
+        Self {
+            version: Family::default(),
+        }
     }
 }
 
 impl Collector for ForestVersionCollector {
     fn encode(&self, mut encoder: DescriptorEncoder) -> Result<(), std::fmt::Error> {
         let metric_encoder = encoder.encode_descriptor(
-            "forest_version",
+            "build_info",
             "semantic version of the forest binary",
             None,
             self.version.metric_type(),
         )?;
+        self.version
+            .get_or_create(&VersionLabel::new(FOREST_VERSION_STRING.as_str()))
+            .set(1);
         self.version.encode(metric_encoder)?;
         Ok(())
     }