--- a/pkg/controllers/diff.go	Sat Aug 21 15:01:52 2021 +0200
+++ b/pkg/controllers/diff.go	Mon Sep 20 17:45:39 2021 +0200
@@ -18,13 +18,13 @@
 	"database/sql"
 	"errors"
 	"fmt"
-	"log"
 	"net/http"
 	"runtime"
 	"time"
 
 	"gemma.intevation.de/gemma/pkg/auth"
 	"gemma.intevation.de/gemma/pkg/common"
+	"gemma.intevation.de/gemma/pkg/log"
 	"gemma.intevation.de/gemma/pkg/mesh"
 	"gemma.intevation.de/gemma/pkg/models"
 
@@ -166,7 +166,7 @@
 		ctx, conn,
 		dci.Bottleneck, dci.Minuend.Time)
 
-	log.Printf("info: loading minuend mesh took %s\n", time.Since(start))
+	log.Infof("loading minuend mesh took %s\n", time.Since(start))
 	if err != nil {
 		return 0, err
 	}
@@ -199,13 +199,13 @@
 		return 0, errors.New("intersection is empty")
 	}
 
-	log.Printf("info: bbox of intersection: (%.2f, %.2f) - (%.2f, %.2f)\n",
+	log.Infof("bbox of intersection: (%.2f, %.2f) - (%.2f, %.2f)\n",
 		box.X1, box.Y1, box.X2, box.Y2)
 
 	start = time.Now()
 	raster := mesh.NewRaster(box, isoCellSize)
 	raster.Rasterize(minuendTree.Value)
-	log.Printf("info: rasterizing minuend took %v\n", time.Since(start))
+	log.Infof("rasterizing minuend took %v\n", time.Since(start))
 
 	minuendTree = nil
 
@@ -215,7 +215,7 @@
 		ctx, conn,
 		dci.Bottleneck, dci.Subtrahend.Time)
 
-	log.Printf("info: loading subtrahend mesh took %s\n", time.Since(start))
+	log.Infof("loading subtrahend mesh took %s\n", time.Since(start))
 	if err != nil {
 		return 0, err
 	}
@@ -234,7 +234,7 @@
 
 	start = time.Now()
 	raster.Diff(subtrahendTree.Value)
-	log.Printf("info: A - B took %v\n", time.Since(start))
+	log.Infof("A - B took %v\n", time.Since(start))
 	subtrahendTree = nil
 
 	// XXX: Maybe we should start this transaction earlier!?
@@ -249,7 +249,7 @@
 		return 0, errors.New("scans do not have common points")
 	}
 
-	log.Printf("info: z range: %.3f - %.3f\n", zMin, zMax)
+	log.Infof("z range: %.3f - %.3f\n", zMin, zMax)
 
 	var heights mesh.ClassBreaks
 
@@ -257,7 +257,7 @@
 		ctx, tx,
 		"morphology_classbreaks_compare")
 	if err != nil {
-		log.Printf("warn: Loading class breaks failed: %v\n", err)
+		log.Warnf("Loading class breaks failed: %v\n", err)
 		err = nil
 		heights = mesh.SampleDiffHeights(zMin, zMax, contourStep)
 	} else {
@@ -266,7 +266,7 @@
 
 	heights = common.DedupFloat64s(heights)
 
-	log.Printf("info: num heights: %d\n", len(heights))
+	log.Infof("num heights: %d\n", len(heights))
 
 	var isoStmt *sql.Stmt
 	if isoStmt, err = tx.PrepareContext(ctx, insertDiffIsoAreasQL); err != nil {
@@ -308,18 +308,18 @@
 		}
 	}
 
-	log.Printf("info: Transferred WKB size: %.2fMB.\n",
+	log.Infof("Transferred WKB size: %.2fMB.\n",
 		float64(size)/(1024*1024))
 
-	log.Printf("info: calculating and storing iso areas took %v\n",
+	log.Infof("calculating and storing iso areas took %v\n",
 		time.Since(start))
 
 	if err = tx.Commit(); err != nil {
-		log.Printf("info: difference calculation failed after %v\n",
+		log.Infof("difference calculation failed after %v\n",
 			time.Since(begin))
 		return 0, err
 	}
-	log.Printf("info: difference calculation succeed after %v\n",
+	log.Infof("difference calculation succeed after %v\n",
 		time.Since(begin))
 
 	return id, nil
@@ -443,7 +443,7 @@
 			}
 		}
 	case <-ctx.Done():
-		log.Println("request canceled")
+		log.Infoln("request canceled")
 	}
 
 	return