images --format compatible with docker

This patch lets valid values of --format be compatible with docker. Replace CreatedTime with CreatedAt, Created with CreatedSince.
Keep CreatedTime and Created are valid as hidden options.

Signed-off-by: Qi Wang <qiwan@redhat.com>

cmd/podman/images.go

@@ -26,8 +26,8 @@ type imagesTemplateParams struct {
 	ID           string
 	Digest       digest.Digest
 	Digests      []digest.Digest
-	Created     string
+	CreatedAt    time.Time
-	CreatedTime time.Time
+	CreatedSince string
 	Size         string
 	ReadOnly     bool
 	History      string
@@ -65,7 +65,7 @@ func (a imagesSorted) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
 type imagesSortedCreated struct{ imagesSorted }
 
 func (a imagesSortedCreated) Less(i, j int) bool {
-	return a.imagesSorted[i].CreatedTime.After(a.imagesSorted[j].CreatedTime)
+	return a.imagesSorted[i].CreatedAt.After(a.imagesSorted[j].CreatedAt)
 }
 
 type imagesSortedID struct{ imagesSorted }
@@ -185,7 +185,17 @@ func imagesCmd(c *cliconfig.ImagesValues) error {
 		history:   c.History,
 	}
 
-	opts.outputformat = opts.setOutputFormat()
+	outputformat := opts.setOutputFormat()
+	// These fields were renamed, so we need to provide backward compat for
+	// the old names.
+	if strings.Contains(outputformat, "{{.Created}}") {
+		outputformat = strings.Replace(outputformat, "{{.Created}}", "{{.CreatedSince}}", -1)
+	}
+	if strings.Contains(outputformat, "{{.CreatedTime}}") {
+		outputformat = strings.Replace(outputformat, "{{.CreatedTime}}", "{{.CreatedAt}}", -1)
+	}
+	opts.outputformat = outputformat
+
 	filteredImages, err := runtime.GetFilteredImages(filters, false)
 	if err != nil {
 		return errors.Wrapf(err, "unable to get images")
@@ -216,7 +226,7 @@ func (i imagesOptions) setOutputFormat() string {
 	if i.digests {
 		format += "{{.Digest}}\t"
 	}
-	format += "{{.ID}}\t{{.Created}}\t{{.Size}}\t"
+	format += "{{.ID}}\t{{.CreatedSince}}\t{{.Size}}\t"
 	if i.history {
 		format += "{{if .History}}{{.History}}{{else}}<none>{{end}}\t"
 	}
@@ -306,8 +316,8 @@ func getImagesTemplateOutput(ctx context.Context, images []*adapter.ContainerIma
 					ID:           imageID,
 					Digest:       imageDigest,
 					Digests:      img.Digests(),
-					CreatedTime: createdTime,
+					CreatedAt:    createdTime,
-					Created:     units.HumanDuration(time.Since(createdTime)) + " ago",
+					CreatedSince: units.HumanDuration(time.Since(createdTime)) + " ago",
 					Size:         sizeStr,
 					ReadOnly:     img.IsReadOnly(),
 					History:      strings.Join(img.NamesHistory(), ", "),
@@ -384,6 +394,9 @@ func GenImageOutputMap() map[string]string {
 			values[key] = "R/O"
 			continue
 		}
+		if value == "CreatedSince" {
+			value = "created"
+		}
 		values[key] = strings.ToUpper(splitCamelCase(value))
 	}
 	return values

docs/source/markdown/podman-images.1.md

@@ -51,6 +51,18 @@ Filter output based on conditions provided
 
 Change the default output format.  This can be of a supported type like 'json'
 or a Go template.
+Valid placeholders for the Go template are listed below:
+
+| **Placeholder** | **Description**                                                               |
+| --------------- | ----------------------------------------------------------------------------- |
+| .ID             | Image ID                                                                      |
+| .Repository     | Image repository                                                              |
+| .Tag            | Image tag                                                                     |
+| .Digest         | Image digest                                                                  |
+| .CreatedSince   | Elapsed time since the image was created			     					  |
+| .CreatedAt      | Time when the image was created                                               |
+| .Size           | Size of layer on disk                                                         |
+| .History        | History of the image layer                                                    |
 
 **--history**
 

test/e2e/images_test.go

@@ -116,7 +116,8 @@ var _ = Describe("Podman images", func() {
 	})
 
 	It("podman images in GO template format", func() {
-		session := podmanTest.Podman([]string{"images", "--format={{.ID}}"})
+		formatStr := "{{.ID}}\t{{.Created}}\t{{.CreatedAt}}\t{{.CreatedSince}}\t{{.CreatedTime}}"
+		session := podmanTest.Podman([]string{"images", fmt.Sprintf("--format=%s", formatStr)})
 		session.WaitWithDefaultTimeout()
 		Expect(session.ExitCode()).To(Equal(0))
 	})
@@ -280,7 +281,7 @@ RUN apk update && apk add man
 			return session.OutputToStringArray()
 		}
 
-		sortedArr := sortValueTest("created", 0, "CreatedTime")
+		sortedArr := sortValueTest("created", 0, "CreatedAt")
 		Expect(sort.SliceIsSorted(sortedArr, func(i, j int) bool { return sortedArr[i] > sortedArr[j] })).To(BeTrue())
 
 		sortedArr = sortValueTest("id", 0, "ID")