WIP: - Parse Host, Port, Image and Tag with regular expressions

docker/docker.go

@@ -104,67 +104,38 @@ func NewImage(qname, user, password string, insecureTLS, insecureRegistry bool)
 	}
 	registry := dockerHub
 	tag := "latest"
-	var nameParts, tagParts []string
-	var name, port string
-	state := stateInitial
-	start := 0
-	for i, c := range qname {
-		if c == ':' || c == '/' || c == '@' || i == len(qname)-1 {
-			if i == len(qname)-1 {
-				// ignore a separator, include the last symbol
-				i += 1
-			}
-			part := qname[start:i]
-			start = i + 1
-
-			switch state {
-			case stateInitial:
-				if part == "localhost" || strings.Contains(part, ".") || (string(qname[i]) == ":" && strings.Contains(qname, "/")) {
+	var name string
 
-					// it's registry, let's check what's next =port of image name
-					registry = part
-					if c == ':' {
-						state = statePort
-					} else {
-						state = stateName
-					}
-				} else {
-					// it's an image name, if separator is /
-					// next part is also part of the name
-					// othrewise it's an offcial image
-					if c == '/' {
-						// we got just a part of name, till next time
-						start = 0
-						state = stateName
-					} else {
-						state = stateTag
-						name = fmt.Sprintf("library/%s", part)
-					}
-				}
-			case stateTag:
-				tag = ""
-				tagParts = append(tagParts, part)
-			case statePort:
-				state = stateName
-				port = part
-			case stateName:
-				if c == ':' || c == '@' {
-					state = stateTag
-				}
-				nameParts = append(nameParts, part)
+	if !utils.ImageOnlyRegexp.MatchString(string(qname)) || strings.HasPrefix(qname, "localhost/") {
+		registry = utils.DomainRegexp.FindString(string(qname))
+		imageAndTag := utils.ImageRegexp.FindStringSubmatch(string(qname))
+		result := make(map[string]string)
+		for i, name := range utils.ImageRegexp.SubexpNames() {
+			if i != 0 {
+				result[name] = imageAndTag[i]
+			}
+		}
+		name = result["name"]
+		if len(result["tag"]) > 0 {
+			tag = result["tag"]
+		}
+	} else {
+		imageAndTag := utils.ImageNoRegistryRegexp.FindStringSubmatch(string(qname))
+		result := make(map[string]string)
+		for i, name := range utils.ImageRegexp.SubexpNames() {
+			if i != 0 {
+				result[name] = imageAndTag[i]
 			}
 		}
+		name = result["name"]
+		if !strings.Contains(name, "/") {
+			name = "library/" + name
+		}
+		if len(result["tag"]) > 0 {
+			tag = result["tag"]
+		}
 	}
 
-	if port != "" {
-		registry = fmt.Sprintf("%s:%s", registry, port)
-	}
-	if name == "" {
-		name = strings.Join(nameParts, "/")
-	}
-	if tag == "" {
-		tag = strings.Join(tagParts, ":")
-	}
 	if insecureRegistry {
 		registry = fmt.Sprintf("http://%s/v2", registry)
 	} else {

docker/docker_test.go

@@ -58,6 +58,12 @@ func TestNewImage(t *testing.T) {
 			name:     "skynetservices/skydns",
 			tag:      "2.3",
 		},
+        "no_registry_no_tag": {
+			image:    "skynetservices/skydns",
+			registry: "https://registry-1.docker.io/v2",
+			name:     "skynetservices/skydns",
+			tag:      "latest",
+		},
 		"no_registry_root": {
 			image:    "postgres:9.5.1",
 			registry: "https://registry-1.docker.io/v2",
@@ -70,6 +76,18 @@ func TestNewImage(t *testing.T) {
 			name:     "library/postgres",
 			tag:      "sha256:f6a2b81d981ace74aeafb2ed2982d52984d82958bfe836b82cbe4bf1ba440999",
 		},
+        "digest_with_registry": {
+			image:    "registry:8000/postgres@sha256:f6a2b81d981ace74aeafb2ed2982d52984d82958bfe836b82cbe4bf1ba440999",
+			registry: "https://registry:8000/v2",
+			name:     "postgres",
+			tag:      "sha256:f6a2b81d981ace74aeafb2ed2982d52984d82958bfe836b82cbe4bf1ba440999",
+		},
+        "digest_with_localhost_registry": {
+			image:    "localhost/postgres@sha256:f6a2b81d981ace74aeafb2ed2982d52984d82958bfe836b82cbe4bf1ba440999",
+			registry: "https://localhost/v2",
+			name:     "postgres",
+			tag:      "sha256:f6a2b81d981ace74aeafb2ed2982d52984d82958bfe836b82cbe4bf1ba440999",
+		},
 		"localhost_no_tag": {
 			image:    "localhost/nginx",
 			registry: "https://localhost/v2",

utils/regex.go

@@ -0,0 +1,71 @@
+package utils
+
+import "regexp"
+
+var (
+	domainComponentRegexp = match(`[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9]`)
+
+	DomainRegexp = expression(
+		domainComponentRegexp,
+		optional(repeated(literal(`.`), domainComponentRegexp)),
+		optional(literal(`:`), match(`[0-9]+`)))
+
+	ImageRegexp = match(`(?:[/])(?P<name>[a-zA-Z0-9/]*)[:@]?(?P<tag>.*)?`)
+
+	ImageNoRegistryRegexp = match(`(?P<name>[a-zA-Z0-9/]*)[:@]?(?P<tag>.*)?`)
+
+	ImageOnlyRegexp = match(`^([a-zA-Z0-9]*)([/@][^/].*$|[:][a-zA-Z0-9\.]*$)`)
+)
+
+// match compiles the string to a regular expression.
+var match = regexp.MustCompile
+
+// literal compiles s into a literal regular expression, escaping any regexp
+// reserved characters.
+func literal(s string) *regexp.Regexp {
+	re := match(regexp.QuoteMeta(s))
+
+	if _, complete := re.LiteralPrefix(); !complete {
+		panic("must be a literal")
+	}
+
+	return re
+}
+
+// expression defines a full expression, where each regular expression must
+// follow the previous.
+func expression(res ...*regexp.Regexp) *regexp.Regexp {
+	var s string
+	for _, re := range res {
+		s += re.String()
+	}
+
+	return match(s)
+}
+
+// optional wraps the expression in a non-capturing group and makes the
+// production optional.
+func optional(res ...*regexp.Regexp) *regexp.Regexp {
+	return match(group(expression(res...)).String() + `?`)
+}
+
+// repeated wraps the regexp in a non-capturing group to get one or more
+// matches.
+func repeated(res ...*regexp.Regexp) *regexp.Regexp {
+	return match(group(expression(res...)).String() + `+`)
+}
+
+// group wraps the regexp in a non-capturing group.
+func group(res ...*regexp.Regexp) *regexp.Regexp {
+	return match(`(?:` + expression(res...).String() + `)`)
+}
+
+// capture wraps the expression in a capturing group.
+func capture(res ...*regexp.Regexp) *regexp.Regexp {
+	return match(`(` + expression(res...).String() + `)`)
+}
+
+// anchored anchors the regular expression by adding start and end delimiters.
+func anchored(res ...*regexp.Regexp) *regexp.Regexp {
+	return match(`^` + expression(res...).String() + `$`)
+}