Implement default tags logic drone-plugins#150

Gopkg.toml

@@ -36,4 +36,8 @@
 [[constraint]]
   branch = "master"
   name = "github.com/urfave/cli"
-  source = "https://github.com/bradrydzewski/cli.git"
+  source = "https://github.com/bradrydzewski/cli.git"
+
+[[constraint]]
+  name = "github.com/coreos/go-semver"
+  version = "v0.2.0"

cmd/drone-docker/main.go

@@ -41,6 +41,11 @@ func main() {
 			EnvVar: "DRONE_COMMIT_SHA",
 			Value:  "00000000",
 		},
+		cli.StringFlag{
+			Name:   "commit.ref",
+			Usage:  "git commit ref",
+			EnvVar: "DRONE_COMMIT_REF",
+		},
 		cli.StringFlag{
 			Name:   "daemon.mirror",
 			Usage:  "docker daemon registry mirror",
@@ -121,6 +126,11 @@ func main() {
 			EnvVar:   "PLUGIN_TAG,PLUGIN_TAGS",
 			FilePath: ".tags",
 		},
+		cli.BoolFlag{
+			Name:   "tags.auto",
+			Usage:  "default build tags",
+			EnvVar: "PLUGIN_DEFAULT_TAGS,PLUGIN_AUTO_TAG",
+		},
 		cli.StringSliceFlag{
 			Name:   "args",
 			Usage:  "build args",
@@ -224,5 +234,11 @@ func run(c *cli.Context) error {
 		},
 	}
 
+	if c.Bool("tags.auto") {
+		plugin.Build.Tags = docker.DefaultTags(
+			c.String("commit.ref"),
+		)
+	}
+
 	return plugin.Exec()
 }

tags.go

@@ -0,0 +1,43 @@
+package docker
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/coreos/go-semver/semver"
+)
+
+// Default tags returns a set of default suggested tags based on
+// the commit ref.
+func DefaultTags(ref string) []string {
+	if !strings.HasPrefix(ref, "refs/tags/") {
+		return []string{"latest"}
+	}
+	v := stripTagPrefix(ref)
+	version, err := semver.NewVersion(v)
+	if err != nil {
+		return []string{"latest"}
+	}
+	if version.PreRelease != "" || version.Metadata != "" {
+		return []string{
+			version.String(),
+		}
+	}
+	if version.Major == 0 {
+		return []string{
+			fmt.Sprintf("%d.%d", version.Major, version.Minor),
+			fmt.Sprintf("%d.%d.%d", version.Major, version.Minor, version.Patch),
+		}
+	}
+	return []string{
+		fmt.Sprint(version.Major),
+		fmt.Sprintf("%d.%d", version.Major, version.Minor),
+		fmt.Sprintf("%d.%d.%d", version.Major, version.Minor, version.Patch),
+	}
+}
+
+func stripTagPrefix(ref string) string {
+	ref = strings.TrimPrefix(ref, "refs/tags/")
+	ref = strings.TrimPrefix(ref, "v")
+	return ref
+}

tags_test.go

@@ -0,0 +1,49 @@
+package docker
+
+import (
+	"reflect"
+	"testing"
+)
+
+func Test_stripTagPrefix(t *testing.T) {
+	var tests = []struct {
+		Before string
+		After  string
+	}{
+		{"refs/tags/1.0.0", "1.0.0"},
+		{"refs/tags/v1.0.0", "1.0.0"},
+		{"v1.0.0", "1.0.0"},
+	}
+
+	for _, test := range tests {
+		got, want := stripTagPrefix(test.Before), test.After
+		if got != want {
+			t.Errorf("Got tag %s, want %s", got, want)
+		}
+	}
+}
+
+func Test_defaultTags(t *testing.T) {
+	var tests = []struct {
+		Before string
+		After  []string
+	}{
+		{"", []string{"latest"}},
+		{"refs/heads/master", []string{"latest"}},
+		{"refs/tags/0.9.0", []string{"0.9", "0.9.0"}},
+		{"refs/tags/1.0.0", []string{"1", "1.0", "1.0.0"}},
+		{"refs/tags/v1.0.0", []string{"1", "1.0", "1.0.0"}},
+		{"refs/tags/v1.0.0-alpha.1", []string{"1.0.0-alpha.1"}},
+
+		// malformed or errors
+		{"refs/tags/x1.0.0", []string{"latest"}},
+		{"v1.0.0", []string{"latest"}},
+	}
+
+	for _, test := range tests {
+		got, want := DefaultTags(test.Before), test.After
+		if !reflect.DeepEqual(got, want) {
+			t.Errorf("Got tag %v, want %v", got, want)
+		}
+	}
+}