Add container-diff summary

pkg/compiler/artifact.go

@@ -459,3 +459,38 @@ func ExtractArtifactFromDelta(src, dst string, layers []ArtifactLayer, concurren
 	}
 	return a, nil
 }
+
+func ComputeArtifactLayerSummary(diffs []ArtifactLayer) ArtifactLayersSummary {
+
+	ans := ArtifactLayersSummary{
+		Layers: make([]ArtifactLayerSummary, 0),
+	}
+
+	for _, layer := range diffs {
+		sum := ArtifactLayerSummary{
+			FromImage:   layer.FromImage,
+			ToImage:     layer.ToImage,
+			AddFiles:    0,
+			AddSizes:    0,
+			DelFiles:    0,
+			DelSizes:    0,
+			ChangeFiles: 0,
+			ChangeSizes: 0,
+		}
+		for _, a := range layer.Diffs.Additions {
+			sum.AddFiles++
+			sum.AddSizes += int64(a.Size)
+		}
+		for _, d := range layer.Diffs.Deletions {
+			sum.DelFiles++
+			sum.DelSizes += int64(d.Size)
+		}
+		for _, c := range layer.Diffs.Changes {
+			sum.ChangeFiles++
+			sum.ChangeSizes += int64(c.Size)
+		}
+		ans.Layers = append(ans.Layers, sum)
+	}
+
+	return ans
+}

pkg/compiler/backend/simpledocker.go

@@ -17,6 +17,7 @@ package backend
 
 import (
 	"encoding/json"
+	"fmt"
 	"io/ioutil"
 	"os"
 	"os/exec"
@@ -237,8 +238,6 @@ func (*SimpleDocker) Changes(fromImage, toImage string) ([]compiler.ArtifactLaye
 
 	if config.LuetCfg.GetGeneral().ShowBuildOutput {
 		Info(string(out))
-	} else {
-		Debug(string(out))
 	}
 
 	var diffs []compiler.ArtifactLayer
@@ -247,5 +246,17 @@ func (*SimpleDocker) Changes(fromImage, toImage string) ([]compiler.ArtifactLaye
 	if err != nil {
 		return []compiler.ArtifactLayer{}, errors.Wrap(err, "Failed unmarshalling json response: "+string(out))
 	}
+
+	if config.LuetCfg.GetLogging().Level == "debug" {
+		summary := compiler.ComputeArtifactLayerSummary(diffs)
+		for _, l := range summary.Layers {
+			Debug(fmt.Sprintf("Diff %s -> %s: add %d (%d bytes), del %d (%d bytes), change %d (%d bytes)",
+				l.FromImage, l.ToImage,
+				l.AddFiles, l.AddSizes,
+				l.DelFiles, l.DelSizes,
+				l.ChangeFiles, l.ChangeSizes))
+		}
+	}
+
 	return diffs, nil
 }

pkg/compiler/interface.go

@@ -106,6 +106,19 @@ type ArtifactLayer struct {
 	ToImage   string        `json:"Image2"`
 	Diffs     ArtifactDiffs `json:"Diff"`
 }
+type ArtifactLayerSummary struct {
+	FromImage   string `json:"image1"`
+	ToImage     string `json:"image2"`
+	AddFiles    int    `json:"add_files"`
+	AddSizes    int64  `json:"add_sizes"`
+	DelFiles    int    `json:"del_files"`
+	DelSizes    int64  `json:"del_sizes"`
+	ChangeFiles int    `json:"change_files"`
+	ChangeSizes int64  `json:"change_sizes"`
+}
+type ArtifactLayersSummary struct {
+	Layers []ArtifactLayerSummary `json:"summary"`
+}
 
 // CompilationSpec represent a compilation specification derived from a package
 type CompilationSpec interface {