--- a/pkg/controllers/gauges.go	Wed Jul 21 15:14:40 2021 +0200
+++ b/pkg/controllers/gauges.go	Tue Feb 08 10:20:26 2022 +0100
@@ -18,7 +18,6 @@
 	"database/sql"
 	"encoding/csv"
 	"fmt"
-	"log"
 	"math"
 	"net/http"
 	"sort"
@@ -31,6 +30,7 @@
 	"gonum.org/v1/gonum/stat"
 
 	"gemma.intevation.de/gemma/pkg/common"
+	"gemma.intevation.de/gemma/pkg/log"
 	"gemma.intevation.de/gemma/pkg/models"
 
 	mw "gemma.intevation.de/gemma/pkg/middleware"
@@ -193,8 +193,8 @@
 	begin := time.Date(year, time.January, 1, 0, 0, 0, 0, time.UTC)
 	end := time.Date(year+1, time.January, 1, 0, 0, 0, 0, time.UTC).Add(-time.Microsecond)
 
-	log.Printf("info: begin %s\n", begin)
-	log.Printf("info: end   %s\n", end)
+	log.Infof("begin %s\n", begin)
+	log.Infof("end   %s\n", end)
 
 	rows, err := conn.QueryContext(
 		ctx,
@@ -235,7 +235,7 @@
 		var when time.Time
 		var value float64
 		if err := rows.Scan(&when, &value); err != nil {
-			log.Printf("error: %v", err)
+			log.Errorf("%v", err)
 			// Too late for an HTTP error code.
 			return
 		}
@@ -243,7 +243,7 @@
 		day, month := when.Day(), int(when.Month())
 		if day != lastDay || month != lastMonth {
 			if err := write(); err != nil {
-				log.Printf("error: %v", err)
+				log.Errorf("%v", err)
 				// Too late for an HTTP error code.
 				return
 			}
@@ -253,13 +253,13 @@
 	}
 
 	if err := rows.Err(); err != nil {
-		log.Printf("error: %v", err)
+		log.Errorf("%v", err)
 		// Too late for an HTTP error code.
 		return
 	}
 
 	if err := write(); err != nil {
-		log.Printf("error: %v", err)
+		log.Errorf("%v", err)
 		// Too late for an HTTP error code.
 	}
 }
@@ -364,9 +364,9 @@
 		return
 	}
 
-	log.Printf("info: loading entries took %s\n", time.Since(start))
+	log.Infof("loading entries took %s\n", time.Since(start))
 
-	log.Printf("info: days found: %d\n", len(results))
+	log.Infof("days found: %d\n", len(results))
 
 	sort.Slice(results, func(i, j int) bool {
 		if d := results[i].month - results[j].month; d != 0 {
@@ -392,7 +392,7 @@
 	}
 
 	if err := out.Write(record); err != nil {
-		log.Printf("error: %v\n", err)
+		log.Errorf("%v\n", err)
 		// Too late for an HTTP error code.
 		return
 	}
@@ -408,7 +408,7 @@
 	}
 
 	if err := out.Write(record); err != nil {
-		log.Printf("error: %v\n", err)
+		log.Errorf("%v\n", err)
 		// Too late for an HTTP error code.
 		return
 	}
@@ -423,7 +423,7 @@
 		record[5] = float64format(r.q25)
 		record[6] = float64format(r.q75)
 		if err := out.Write(record); err != nil {
-			log.Printf("error: %v\n", err)
+			log.Errorf("%v\n", err)
 			// Too late for an HTTP error code.
 			return
 		}
@@ -431,7 +431,7 @@
 
 	out.Flush()
 	if err := out.Error(); err != nil {
-		log.Printf("error: %v", err)
+		log.Errorf("%v", err)
 		// Too late for an HTTP error code.
 		return
 	}
@@ -557,10 +557,10 @@
 	}
 
 	// for i := range values {
-	// 	log.Printf("%v %f %d\n", values[i].when, values[i].observed, len(values[i].predicted))
+	// 	log.Debugf("%v %f %d\n", values[i].when, values[i].observed, len(values[i].predicted))
 	// 	if len(values[i].predicted) > 0 {
 	// 		for j := range values[i].predicted {
-	// 			log.Printf("\t%v %f\n", values[i].predicted[j].When, values[i].predicted[j].Value)
+	// 			log.Debugf("\t%v %f\n", values[i].predicted[j].When, values[i].predicted[j].Value)
 	// 		}
 	// 	}
 	// }
@@ -599,7 +599,7 @@
 		return
 	}
 
-	log.Printf("info: found %d value(s) for Nash Sutcliffe.\n", len(values))
+	log.Infof("found %d value(s) for Nash Sutcliffe.\n", len(values))
 
 	type coeff struct {
 		Value   float64 `json:"value"`
@@ -746,7 +746,7 @@
 	}
 
 	if err := out.Write(record); err != nil {
-		log.Printf("error: %v", err)
+		log.Errorf("%v", err)
 		// Too late for an HTTP error code.
 		return
 	}
@@ -766,7 +766,7 @@
 			&valueMax,
 			&predicted,
 		); err != nil {
-			log.Printf("error: %v\n", err)
+			log.Errorf("%v\n", err)
 			// Too late for an HTTP error code.
 			return
 		}
@@ -777,21 +777,21 @@
 		record[4] = boolFormat(predicted)
 
 		if err := out.Write(record); err != nil {
-			log.Printf("error: %v", err)
+			log.Errorf("%v", err)
 			// Too late for an HTTP error code.
 			return
 		}
 	}
 
 	if err := rows.Err(); err != nil {
-		log.Printf("error: %v", err)
+		log.Errorf("%v", err)
 		// Too late for an HTTP error code.
 		return
 	}
 
 	out.Flush()
 	if err := out.Error(); err != nil {
-		log.Printf("error: %v", err)
+		log.Errorf("%v", err)
 		// Too late for an HTTP error code.
 		return
 	}