feat(health): Health check for Decision engine (#8243)

Co-authored-by: hyperswitch-bot[bot] <148525504+hyperswitch-bot[bot]@users.noreply.github.com>

crates/api_models/src/health_check.rs

@@ -12,6 +12,8 @@ pub struct RouterHealthCheckResponse {
     pub outgoing_request: bool,
     #[cfg(feature = "dynamic_routing")]
     pub grpc_health_check: HealthCheckMap,
+    #[cfg(feature = "dynamic_routing")]
+    pub decision_engine: bool,
 }
 
 impl common_utils::events::ApiEventMetric for RouterHealthCheckResponse {}

crates/router/src/core/health_check.rs

@@ -35,6 +35,11 @@ pub trait HealthCheckInterface {
     async fn health_check_grpc(
         &self,
     ) -> CustomResult<HealthCheckMap, errors::HealthCheckGRPCServiceError>;
+
+    #[cfg(feature = "dynamic_routing")]
+    async fn health_check_decision_engine(
+        &self,
+    ) -> CustomResult<HealthState, errors::HealthCheckDecisionEngineError>;
 }
 
 #[async_trait::async_trait]
@@ -184,4 +189,25 @@ impl HealthCheckInterface for app::SessionState {
         logger::debug!("Health check successful");
         Ok(health_check_map)
     }
+
+    #[cfg(feature = "dynamic_routing")]
+    async fn health_check_decision_engine(
+        &self,
+    ) -> CustomResult<HealthState, errors::HealthCheckDecisionEngineError> {
+        if self.conf.open_router.enabled {
+            let url = format!("{}/{}", &self.conf.open_router.url, "health");
+            let request = services::Request::new(services::Method::Get, &url);
+            let _ = services::call_connector_api(self, request, "health_check_for_decision_engine")
+                .await
+                .change_context(
+                    errors::HealthCheckDecisionEngineError::FailedToCallDecisionEngineService,
+                )?;
+
+            logger::debug!("Decision engine health check successful");
+            Ok(HealthState::Running)
+        } else {
+            logger::debug!("Decision engine health check not applicable");
+            Ok(HealthState::NotApplicable)
+        }
+    }
 }

crates/router/src/routes/health.rs

@@ -108,6 +108,23 @@ async fn deep_health_check_func(
 
     logger::debug!("gRPC health check end");
 
+    logger::debug!("Decision Engine health check begin");
+
+    #[cfg(feature = "dynamic_routing")]
+    let decision_engine_health_check =
+        state
+            .health_check_decision_engine()
+            .await
+            .map_err(|error| {
+                let message = error.to_string();
+                error.change_context(errors::ApiErrorResponse::HealthCheckError {
+                    component: "Decision Engine service",
+                    message,
+                })
+            })?;
+
+    logger::debug!("Decision Engine health check end");
+
     logger::debug!("Opensearch health check begin");
 
     #[cfg(feature = "olap")]
@@ -144,6 +161,8 @@ async fn deep_health_check_func(
         outgoing_request: outgoing_check.into(),
         #[cfg(feature = "dynamic_routing")]
         grpc_health_check,
+        #[cfg(feature = "dynamic_routing")]
+        decision_engine: decision_engine_health_check.into(),
     };
 
     Ok(api::ApplicationResponse::Json(response))

crates/storage_impl/src/errors.rs

@@ -280,3 +280,9 @@ pub enum RecoveryError {
     #[error("Failed to fetch billing connector account id")]
     BillingMerchantConnectorAccountIdNotFound,
 }
+
+#[derive(Debug, Clone, thiserror::Error)]
+pub enum HealthCheckDecisionEngineError {
+    #[error("Failed to establish Decision Engine connection")]
+    FailedToCallDecisionEngineService,
+}