Add parsing of image sha

Not yet using it in comparison

main.go

@@ -24,7 +24,7 @@ var (
 	maxPages = 10
 
 	// Regexp used to extract tag information
-	tagRegexp = regexp.MustCompile(`(.*):[vV]{0,1}([0-9.]+)(-(.*)){0,1}`)
+	tagRegexp = regexp.MustCompile(`(.*):[vV]{0,1}([0-9.]+)(-([a-zA-Z0-9_-]*)){0,1}(@([:0-9a-z]+)){0,1}`)
 	// version of tag checker
 	version = "dev"
 )
@@ -35,6 +35,7 @@ type ImageTag struct {
 	Registry     string
 	Image        string
 	TagDesc      string
+	TagSha       string
 	Version      string
 	VersionParts []int
 }
@@ -109,6 +110,7 @@ func ParseImageTag(imageTag string) (ImageTag, error) {
 		Version:      version,
 		VersionParts: versionParts,
 		TagDesc:      results[4],
+		TagSha:       results[6],
 	}, nil
 }
 

main_test.go

@@ -0,0 +1,110 @@
+package main
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestTagParsing(t *testing.T) {
+	cases := []struct {
+		tag          string
+		expected     ImageTag
+		expectsError bool
+	}{
+		{
+			"image",
+			ImageTag{},
+			true,
+		},
+		{
+			"image:latest",
+			ImageTag{},
+			true,
+		},
+		{
+			"image:v1",
+			ImageTag{
+				ImageTag:     "image:v1",
+				Image:        "library/image",
+				Version:      "1",
+				VersionParts: []int{1},
+			},
+			false,
+		},
+		{
+			"image:v1.0",
+			ImageTag{
+				ImageTag:     "image:v1.0",
+				Image:        "library/image",
+				Version:      "1.0",
+				VersionParts: []int{1, 0},
+			},
+			false,
+		},
+		{
+			"image:v1.0.0",
+			ImageTag{
+				ImageTag:     "image:v1.0.0",
+				Image:        "library/image",
+				Version:      "1.0.0",
+				VersionParts: []int{1, 0, 0},
+			},
+			false,
+		},
+		{
+			"image:v1.0.0-desc",
+			ImageTag{
+				ImageTag:     "image:v1.0.0-desc",
+				Image:        "library/image",
+				TagDesc:      "desc",
+				Version:      "1.0.0",
+				VersionParts: []int{1, 0, 0},
+			},
+			false,
+		},
+		{
+			"image:v1.0.0-desc@sha256:abc",
+			ImageTag{
+				ImageTag:     "image:v1.0.0-desc@sha256:abc",
+				Image:        "library/image",
+				TagDesc:      "desc",
+				TagSha:       "sha256:abc",
+				Version:      "1.0.0",
+				VersionParts: []int{1, 0, 0},
+			},
+			false,
+		},
+		{
+			"image:v1.0.0@sha256:abc",
+			ImageTag{
+				ImageTag:     "image:v1.0.0@sha256:abc",
+				Image:        "library/image",
+				TagSha:       "sha256:abc",
+				Version:      "1.0.0",
+				VersionParts: []int{1, 0, 0},
+			},
+			false,
+		},
+	}
+
+	for _, c := range cases {
+		result, err := ParseImageTag(c.tag)
+		if c.expectsError {
+			if err == nil {
+				t.Errorf("ParseImageTag(%s): expected erro but didn't get one", c.tag)
+			}
+			continue
+		}
+		if err != nil {
+			t.Errorf("ParseImageTag(%s): unexpected error: %v", c.tag, err)
+		}
+		if !reflect.DeepEqual(result, c.expected) {
+			t.Errorf(
+				"ParseImageTag(%s): unexpected result. Actual: %+v Expected: %+v",
+				c.tag,
+				result,
+				c.expected,
+			)
+		}
+	}
+}