From 9773022e50fa2fa0bf9abffe858f9c2c7bed8970 Mon Sep 17 00:00:00 2001
From: Aliaksandr Valialkin <valyala@gmail.com>
Date: Wed, 22 Jan 2020 17:32:11 +0200
Subject: [PATCH] app/vmselect: mention the original query and time range in
 error messages

This should simplify debugging invalid or heavy queries.
---
 app/vmselect/main.go                  |  2 +-
 app/vmselect/prometheus/prometheus.go | 12 ++++++------
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/app/vmselect/main.go b/app/vmselect/main.go
index 7c73a0ba0d..e33e1a641b 100644
--- a/app/vmselect/main.go
+++ b/app/vmselect/main.go
@@ -216,7 +216,7 @@ func RequestHandler(w http.ResponseWriter, r *http.Request) bool {
 }
 
 func sendPrometheusError(w http.ResponseWriter, r *http.Request, err error) {
-	logger.Errorf("error in %q: %s", r.URL.Path, err)
+	logger.Errorf("error in %q: %s", r.RequestURI, err)
 
 	w.Header().Set("Content-Type", "application/json")
 	statusCode := http.StatusUnprocessableEntity
diff --git a/app/vmselect/prometheus/prometheus.go b/app/vmselect/prometheus/prometheus.go
index e5068f3d23..efdc0b9c18 100644
--- a/app/vmselect/prometheus/prometheus.go
+++ b/app/vmselect/prometheus/prometheus.go
@@ -136,7 +136,7 @@ func ExportHandler(w http.ResponseWriter, r *http.Request) error {
 		end = start + defaultStep
 	}
 	if err := exportHandler(w, matches, start, end, format, deadline); err != nil {
-		return err
+		return fmt.Errorf("error when exporting data for queries=%q on the time range (start=%d, end=%d): %s", matches, start, end, err)
 	}
 	exportDuration.UpdateDuration(startTime)
 	return nil
@@ -580,7 +580,7 @@ func QueryHandler(w http.ResponseWriter, r *http.Request) error {
 		end := start
 		start = end - window
 		if err := exportHandler(w, []string{childQuery}, start, end, "promapi", deadline); err != nil {
-			return err
+			return fmt.Errorf("error when exporting data for query=%q on the time range (start=%d, end=%d): %s", childQuery, start, end, err)
 		}
 		queryDuration.UpdateDuration(startTime)
 		return nil
@@ -605,7 +605,7 @@ func QueryHandler(w http.ResponseWriter, r *http.Request) error {
 		end := start
 		start = end - window
 		if err := queryRangeHandler(w, childQuery, start, end, step, r, ct); err != nil {
-			return err
+			return fmt.Errorf("error when executing query=%q on the time range (start=%d, end=%d, step=%d): %s", childQuery, start, end, step, err)
 		}
 		queryDuration.UpdateDuration(startTime)
 		return nil
@@ -620,7 +620,7 @@ func QueryHandler(w http.ResponseWriter, r *http.Request) error {
 	}
 	result, err := promql.Exec(&ec, query, true)
 	if err != nil {
-		return fmt.Errorf("cannot execute %q: %s", query, err)
+		return fmt.Errorf("error when executing query=%q for (time=%d, step=%d): %s", query, start, step, err)
 	}
 
 	w.Header().Set("Content-Type", "application/json")
@@ -669,7 +669,7 @@ func QueryRangeHandler(w http.ResponseWriter, r *http.Request) error {
 		return err
 	}
 	if err := queryRangeHandler(w, query, start, end, step, r, ct); err != nil {
-		return err
+		return fmt.Errorf("error when executing query=%q on the time range (start=%d, end=%d, step=%d): %s", query, start, end, step, err)
 	}
 	queryRangeDuration.UpdateDuration(startTime)
 	return nil
@@ -707,7 +707,7 @@ func queryRangeHandler(w http.ResponseWriter, query string, start, end, step int
 	}
 	result, err := promql.Exec(&ec, query, false)
 	if err != nil {
-		return fmt.Errorf("cannot execute %q: %s", query, err)
+		return fmt.Errorf("cannot execute query: %s", err)
 	}
 	queryOffset := getLatencyOffsetMilliseconds()
 	if ct-end < queryOffset {