feat(clean): log removed/untagged images (#1466)

internal/util/rand_sha256.go

@@ -0,0 +1,24 @@
+package util
+
+import (
+	"bytes"
+	"fmt"
+	"math/rand"
+)
+
+// GenerateRandomSHA256 generates a random 64 character SHA 256 hash string
+func GenerateRandomSHA256() string {
+	return GenerateRandomPrefixedSHA256()[7:]
+}
+
+// GenerateRandomPrefixedSHA256 generates a random 64 character SHA 256 hash string, prefixed with `sha256:`
+func GenerateRandomPrefixedSHA256() string {
+	hash := make([]byte, 32)
+	_, _ = rand.Read(hash)
+	sb := bytes.NewBufferString("sha256:")
+	sb.Grow(64)
+	for _, h := range hash {
+		_, _ = fmt.Fprintf(sb, "%02x", h)
+	}
+	return sb.String()
+}

internal/util/util_test.go

@@ -1,8 +1,10 @@
 package util
 
 import (
-	"github.com/stretchr/testify/assert"
+	"regexp"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
 func TestSliceEqual_True(t *testing.T) {
@@ -62,3 +64,15 @@ func TestStructMapSubtract(t *testing.T) {
 	assert.Equal(t, map[string]struct{}{"a": x, "b": x, "c": x}, m1)
 	assert.Equal(t, map[string]struct{}{"a": x, "c": x}, m2)
 }
+
+// GenerateRandomSHA256 generates a random 64 character SHA 256 hash string
+func TestGenerateRandomSHA256(t *testing.T) {
+	res := GenerateRandomSHA256()
+	assert.Len(t, res, 64)
+	assert.NotContains(t, res, "sha256:")
+}
+
+func TestGenerateRandomPrefixedSHA256(t *testing.T) {
+	res := GenerateRandomPrefixedSHA256()
+	assert.Regexp(t, regexp.MustCompile("sha256:[0-9|a-f]{64}"), res)
+}

pkg/container/client.go

@@ -39,9 +39,9 @@ type Client interface {
 // NewClient returns a new Client instance which can be used to interact with
 // the Docker API.
 // The client reads its configuration from the following environment variables:
-//  * DOCKER_HOST			the docker-engine host to send api requests to
+//   - DOCKER_HOST			the docker-engine host to send api requests to
-//  * DOCKER_TLS_VERIFY		whether to verify tls certificates
+//   - DOCKER_TLS_VERIFY		whether to verify tls certificates
-//  * DOCKER_API_VERSION	the minimum docker api version to work with
+//   - DOCKER_API_VERSION	the minimum docker api version to work with
 func NewClient(opts ClientOptions) Client {
 	cli, err := sdkClient.NewClientWithOpts(sdkClient.FromEnv)
 
@@ -369,13 +369,34 @@ func (client dockerClient) PullImage(ctx context.Context, container t.Container)
 func (client dockerClient) RemoveImageByID(id t.ImageID) error {
 	log.Infof("Removing image %s", id.ShortID())
 
-	_, err := client.api.ImageRemove(
+	items, err := client.api.ImageRemove(
 		context.Background(),
 		string(id),
 		types.ImageRemoveOptions{
 			Force: true,
 		})
 
+	if log.IsLevelEnabled(log.DebugLevel) {
+		deleted := strings.Builder{}
+		untagged := strings.Builder{}
+		for _, item := range items {
+			if item.Deleted != "" {
+				if deleted.Len() > 0 {
+					deleted.WriteString(`, `)
+				}
+				deleted.WriteString(t.ImageID(item.Deleted).ShortID())
+			}
+			if item.Untagged != "" {
+				if untagged.Len() > 0 {
+					untagged.WriteString(`, `)
+				}
+				untagged.WriteString(t.ImageID(item.Untagged).ShortID())
+			}
+		}
+		fields := log.Fields{`deleted`: deleted.String(), `untagged`: untagged.String()}
+		log.WithFields(fields).Debug("Image removal completed")
+	}
+
 	return err
 }
 

pkg/container/client_test.go

@@ -3,6 +3,7 @@ package container
 import (
 	"time"
 
+	"github.com/containrrr/watchtower/internal/util"
 	"github.com/containrrr/watchtower/pkg/container/mocks"
 	"github.com/containrrr/watchtower/pkg/filters"
 	t "github.com/containrrr/watchtower/pkg/types"
@@ -10,6 +11,7 @@ import (
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/api/types/backend"
 	cli "github.com/docker/docker/client"
+	"github.com/docker/docker/errdefs"
 	"github.com/onsi/gomega/gbytes"
 	"github.com/onsi/gomega/ghttp"
 	"github.com/sirupsen/logrus"
@@ -103,6 +105,37 @@ var _ = Describe("the client", func() {
 			})
 		})
 	})
+	When("removing a image", func() {
+		When("debug logging is enabled", func() {
+			It("should log removed and untagged images", func() {
+				imageA := util.GenerateRandomSHA256()
+				imageAParent := util.GenerateRandomSHA256()
+				images := map[string][]string{imageA: {imageAParent}}
+				mockServer.AppendHandlers(mocks.RemoveImageHandler(images))
+				c := dockerClient{api: docker}
+
+				resetLogrus, logbuf := captureLogrus(logrus.DebugLevel)
+				defer resetLogrus()
+
+				Expect(c.RemoveImageByID(t.ImageID(imageA))).To(Succeed())
+
+				shortA := t.ImageID(imageA).ShortID()
+				shortAParent := t.ImageID(imageAParent).ShortID()
+
+				Eventually(logbuf).Should(gbytes.Say(`deleted="%v, %v" untagged="?%v"?`, shortA, shortAParent, shortA))
+			})
+		})
+		When("image is not found", func() {
+			It("should return an error", func() {
+				image := util.GenerateRandomSHA256()
+				mockServer.AppendHandlers(mocks.RemoveImageHandler(nil))
+				c := dockerClient{api: docker}
+
+				err := c.RemoveImageByID(t.ImageID(image))
+				Expect(errdefs.IsNotFound(err)).To(BeTrue())
+			})
+		})
+	})
 	When("listing containers", func() {
 		When("no filter is provided", func() {
 			It("should return all available containers", func() {
@@ -193,10 +226,8 @@ var _ = Describe("the client", func() {
 				}
 
 				// Capture logrus output in buffer
-				logbuf := gbytes.NewBuffer()
+				resetLogrus, logbuf := captureLogrus(logrus.DebugLevel)
-				origOut := logrus.StandardLogger().Out
+				defer resetLogrus()
-				defer logrus.SetOutput(origOut)
-				logrus.SetOutput(logbuf)
 
 				user := ""
 				containerID := t.ContainerID("ex-cont-id")
@@ -255,6 +286,23 @@ var _ = Describe("the client", func() {
 	})
 })
 
+// Capture logrus output in buffer
+func captureLogrus(level logrus.Level) (func(), *gbytes.Buffer) {
+
+	logbuf := gbytes.NewBuffer()
+
+	origOut := logrus.StandardLogger().Out
+	logrus.SetOutput(logbuf)
+
+	origLev := logrus.StandardLogger().Level
+	logrus.SetLevel(level)
+
+	return func() {
+		logrus.SetOutput(origOut)
+		logrus.SetLevel(origLev)
+	}, logbuf
+}
+
 // Gomega matcher helpers
 
 func withContainerImageName(matcher gt.GomegaMatcher) gt.GomegaMatcher {

pkg/container/mocks/ApiServer.go

@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"net/url"
 	"path/filepath"
+	"strings"
 
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/api/types/filters"
@@ -190,3 +191,29 @@ const (
 	Found   FoundStatus = true
 	Missing FoundStatus = false
 )
+
+// RemoveImageHandler mocks the DELETE images/ID endpoint, simulating removal of the given imagesWithParents
+func RemoveImageHandler(imagesWithParents map[string][]string) http.HandlerFunc {
+	return ghttp.CombineHandlers(
+		ghttp.VerifyRequest("DELETE", O.MatchRegexp("/images/.*")),
+		func(w http.ResponseWriter, r *http.Request) {
+			parts := strings.Split(r.URL.Path, `/`)
+			image := parts[len(parts)-1]
+
+			if parents, found := imagesWithParents[image]; found {
+				items := []types.ImageDeleteResponseItem{
+					{Untagged: image},
+					{Deleted: image},
+				}
+				for _, parent := range parents {
+					items = append(items, types.ImageDeleteResponseItem{Deleted: parent})
+				}
+				ghttp.RespondWithJSONEncoded(http.StatusOK, items)(w, r)
+			} else {
+				ghttp.RespondWithJSONEncoded(http.StatusNotFound, struct{ message string }{
+					message: "Something went wrong.",
+				})(w, r)
+			}
+		},
+	)
+}