add defualt tag suffix

cmd/drone-docker/main.go

@@ -131,6 +131,11 @@ func main() {
 			Usage:  "default build tags",
 			EnvVar: "PLUGIN_DEFAULT_TAGS,PLUGIN_AUTO_TAG",
 		},
+		cli.StringFlag{
+			Name:   "tags.suffix",
+			Usage:  "default build tags with suffix",
+			EnvVar: "PLUGIN_DEFAULT_SUFFIX,PLUGIN_AUTO_TAG_SUFFIX",
+		},
 		cli.StringSliceFlag{
 			Name:   "args",
 			Usage:  "build args",
@@ -235,8 +240,9 @@ func run(c *cli.Context) error {
 	}
 
 	if c.Bool("tags.auto") {
-		plugin.Build.Tags = docker.DefaultTags(
+		plugin.Build.Tags = docker.DefaultTagSuffix(
 			c.String("commit.ref"),
+			c.String("tags.suffix"),
 		)
 	}
 

tags.go

@@ -7,7 +7,24 @@ import (
 	"github.com/coreos/go-semver/semver"
 )
 
-// Default tags returns a set of default suggested tags based on
+// DefaultTagSuffix returns a set of default suggested tags
+// based on the commit ref with an attached suffix.
+func DefaultTagSuffix(ref, suffix string) []string {
+	tags := DefaultTags(ref)
+	if len(suffix) == 0 {
+		return tags
+	}
+	for i, tag := range tags {
+		if tag == "latest" {
+			tags[i] = suffix
+		} else {
+			tags[i] = fmt.Sprintf("%s-%s", tag, suffix)
+		}
+	}
+	return tags
+}
+
+// DefaultTags returns a set of default suggested tags based on
 // the commit ref.
 func DefaultTags(ref string) []string {
 	if !strings.HasPrefix(ref, "refs/tags/") {

tags_test.go

@@ -23,7 +23,7 @@ func Test_stripTagPrefix(t *testing.T) {
 	}
 }
 
-func Test_defaultTags(t *testing.T) {
+func TestDefaultTags(t *testing.T) {
 	var tests = []struct {
 		Before string
 		After  []string
@@ -47,3 +47,58 @@ func Test_defaultTags(t *testing.T) {
 		}
 	}
 }
+
+func TestDefaultTagSuffix(t *testing.T) {
+	var tests = []struct {
+		Before string
+		Suffix string
+		After  []string
+	}{
+		// without suffix
+		{
+			After: []string{"latest"},
+		},
+		{
+			Before: "refs/tags/v1.0.0",
+			After: []string{
+				"1",
+				"1.0",
+				"1.0.0",
+			},
+		},
+		// with suffix
+		{
+			Suffix: "linux-amd64",
+			After:  []string{"linux-amd64"},
+		},
+		{
+			Before: "refs/tags/v1.0.0",
+			Suffix: "linux-amd64",
+			After: []string{
+				"1-linux-amd64",
+				"1.0-linux-amd64",
+				"1.0.0-linux-amd64",
+			},
+		},
+		{
+			Suffix: "nanoserver",
+			After:  []string{"nanoserver"},
+		},
+		{
+			Before: "refs/tags/v1.9.2",
+			Suffix: "nanoserver",
+			After: []string{
+				"1-nanoserver",
+				"1.9-nanoserver",
+				"1.9.2-nanoserver",
+			},
+		},
+	}
+
+	for _, test := range tests {
+		got, want := DefaultTagSuffix(test.Before, test.Suffix), test.After
+		if !reflect.DeepEqual(got, want) {
+			t.Errorf("Got tag %v, want %v", got, want)
+		}
+	}
+}