feat: added some info logs and prometheus health check on startup

Author: milindsrivastava1997

asap-query-engine/src/drivers/query/servers/http.rs

@@ -217,6 +217,12 @@ async fn process_query_request(
                 total_duration.as_secs_f64() * 1000.0
             );
             debug!("=== RETURNING SUCCESS RESPONSE ===");
+            info!(
+                "query='{}' destination=asap asap_latency_ms={:.2} total_latency_ms={:.2}",
+                parsed_request.query,
+                query_duration.as_secs_f64() * 1000.0,
+                total_duration.as_secs_f64() * 1000.0
+            );
 
             match state
                 .adapter
@@ -238,6 +244,11 @@ async fn process_query_request(
             // Step 4: Handle unsupported query using fallback client
             if let Some(fallback) = &state.fallback {
                 debug!("Query not supported locally, forwarding to fallback");
+                info!(
+                    "query='{}' destination=prometheus total_latency_ms={:.2}",
+                    parsed_request.query,
+                    total_duration.as_secs_f64() * 1000.0
+                );
                 // Fallback client handles the HTTP call and returns formatted response
                 match fallback
                     .execute_query_with_headers(parsed_request, headers)
@@ -248,6 +259,11 @@ async fn process_query_request(
                 }
             } else {
                 debug!("Query not supported and forwarding disabled, returning error");
+                info!(
+                    "query='{}' destination=none_unsupported total_latency_ms={:.2}",
+                    parsed_request.query,
+                    total_duration.as_secs_f64() * 1000.0
+                );
                 // Adapter formats the unsupported query error for its protocol
                 match state.adapter.format_unsupported_query_response().await {
                     Ok(json) => json.into_response(),

asap-query-engine/src/main.rs

@@ -403,6 +403,40 @@ async fn main() -> Result<()> {
         adapter_config,
     };
 
+    // Verify Prometheus is reachable before starting
+    {
+        let client = reqwest::Client::new();
+        let health_url = format!(
+            "{}/api/v1/status/runtimeinfo",
+            args.prometheus_server.trim_end_matches('/')
+        );
+        match client
+            .get(&health_url)
+            .timeout(std::time::Duration::from_secs(5))
+            .send()
+            .await
+        {
+            Ok(resp) if resp.status().is_success() => {
+                info!("Prometheus reachable at {}", args.prometheus_server);
+            }
+            Ok(resp) => {
+                error!(
+                    "Prometheus at {} returned HTTP {} — cannot start",
+                    args.prometheus_server,
+                    resp.status()
+                );
+                std::process::exit(1);
+            }
+            Err(e) => {
+                error!(
+                    "Cannot reach Prometheus at {}: {}",
+                    args.prometheus_server, e
+                );
+                std::process::exit(1);
+            }
+        }
+    }
+
     let query_tracker = if args.enable_query_tracker {
         use query_engine_rust::planner_client::{LocalPlannerClient, PlannerResult};
         use query_engine_rust::QueryTrackerConfig;