fix: metrics prometheus format

src/data.rs

@@ -1733,3 +1733,32 @@ impl BrainData {
         self.app_contracts.write().unwrap().push(app_contracts);
     }
 }
+
+impl BrainData {
+    pub fn metrics(&self) -> Result<String, Error> {
+        let app_nodes_read = self.app_nodes.read().unwrap();
+        let app_node_no = app_nodes_read.len();
+        drop(app_nodes_read);
+        let vm_nodes_read = self.vm_nodes.read().unwrap();
+        let vm_node_no = vm_nodes_read.len();
+        drop(vm_nodes_read);
+        let app_contract_no = self.list_all_app_contracts().len();
+        let vm_contract_no = self.list_all_contracts().len();
+        let account_no = self.list_accounts().len();
+        let operator_no = self.list_operators().len();
+        let locations = String::from("wip");
+
+        let metrics = vec![
+            format!("app_nodes {app_node_no}"),
+            format!("vm_nodes {vm_node_no}"),
+            format!("app_contracts {app_contract_no}"),
+            format!("vm_contracts {vm_contract_no}"),
+            format!("operators {operator_no}"),
+            format!("accounts {account_no}"),
+            format!("locations {locations}"),
+        ]
+        .join("\n");
+
+        Ok(metrics)
+    }
+}

src/http_server.rs

@@ -20,11 +20,7 @@ pub async fn http_metrics_server(listen_address: SocketAddr, state: Arc<BrainDat
 
 #[get("/metrics")]
 async fn homepage(data: web::Data<Arc<BrainData>>) -> impl Responder {
-    let vm_contracts = data.get_ref().list_all_contracts();
-    let app_contracts = data.get_ref().list_all_app_contracts();
-    let text = format!(
-        "App contracts: {:#?}\n\nVM contracts: {:#?}",
-        app_contracts, vm_contracts
-    );
-    HttpResponse::Ok().body(text)
+    let metrics_data = data.get_ref().metrics().unwrap_or_default();
+
+    HttpResponse::Ok().body(metrics_data)
 }