support default manifest path and application name like cf push does

autopilot.go

@@ -10,6 +10,9 @@ import (
 	"strings"
 
 	"code.cloudfoundry.org/cli/plugin"
+	"code.cloudfoundry.org/cli/cf/manifest"
+	"code.cloudfoundry.org/cli/cf/models"
+	cfFlag "code.cloudfoundry.org/cli/command/flag"
 	"github.com/contraband/autopilot/rewind"
 )
 
@@ -127,21 +130,59 @@ func ParseArgs(args []string) (string, string, string, error) {
 	manifestPath := flags.String("f", "", "path to an application manifest")
 	appPath := flags.String("p", "", "path to application files")
 
-	err := flags.Parse(args[2:])
+	var appName string
+	var err error
+
+	if args[1][0] == '-' {
+		err = flags.Parse(args[1:])
+		appName, err = GetAppNameFromManifest(*manifestPath)
+	} else {
+		err = flags.Parse(args[2:])
+		appName = args[1]
+	}
+
 	if err != nil {
 		return "", "", "", err
 	}
 
-	appName := args[1]
-
-	if *manifestPath == "" {
-		return "", "", "", ErrNoManifest
+	if appName == "" {
+		return "", "", "", ErrNoAppName
 	}
 
 	return appName, *manifestPath, *appPath, nil
 }
 
-var ErrNoManifest = errors.New("a manifest is required to push this application")
+func GetAppNameFromManifest(manifestPath string) (string, error) {
+	var err error
+
+	var path = cfFlag.PathWithExistenceCheck(manifestPath)
+	err = path.UnmarshalFlag(manifestPath)
+	if err != nil {
+		return "", err
+	}
+
+	var m *manifest.Manifest
+	var dr = manifest.NewDiskRepository()
+	m, err = dr.ReadManifest(manifestPath)
+	if err != nil {
+		return "", err
+	}
+
+	var apps []models.AppParams
+	apps, err = m.Applications()
+	if err != nil {
+		return "", err
+	}
+
+	var name = apps[0].Name
+	if name == nil {
+		return "", ErrNoAppName
+	}
+
+	return *name, nil
+}
+
+var ErrNoAppName = errors.New("a name is required to push this application")
 
 type ApplicationRepo struct {
 	conn plugin.CliConnection

autopilot_test.go

@@ -25,26 +25,84 @@ var _ = Describe("Flag Parsing", func() {
 			[]string{
 				"zero-downtime-push",
 				"appname",
-				"-f", "manifest-path",
+				"-f", "./fixtures/manifests/manifest.yml",
 				"-p", "app-path",
 			},
 		)
 		Expect(err).ToNot(HaveOccurred())
 
 		Expect(appName).To(Equal("appname"))
-		Expect(manifestPath).To(Equal("manifest-path"))
+		Expect(manifestPath).To(Equal("./fixtures/manifests/manifest.yml"))
 		Expect(appPath).To(Equal("app-path"))
 	})
 
-	It("requires a manifest", func() {
-		_, _, _, err := ParseArgs(
+	It("does not require path or manifest flag", func() {
+		appName, _, _, err := ParseArgs(
 			[]string{
 				"zero-downtime-push",
 				"appname",
-				"-p", "app-path",
 			},
 		)
-		Expect(err).To(MatchError(ErrNoManifest))
+		Expect(err).ToNot(HaveOccurred())
+
+		Expect(appName).To(Equal("appname"))
+	})
+
+	It("does not require app name if provided in the manifest", func() {
+		appName, manifestPath, _, err := ParseArgs(
+			[]string{
+				"zero-downtime-push",
+				"-f", "./fixtures/manifests/manifest.yml",
+			},
+		)
+		Expect(err).ToNot(HaveOccurred())
+
+		Expect(appName).To(Equal("appname-from-manifest"))
+		Expect(manifestPath).To(Equal("./fixtures/manifests/manifest.yml"))
+	})
+
+	It("errors if no app name is provided (as either a flag or in the manifest)", func() {
+		_, _, _, err := ParseArgs(
+			[]string{
+				"zero-downtime-push",
+				"-f", "./fixtures/manifests/manifest-without-appname.yml",
+			},
+		)
+		Expect(err).To(MatchError(ErrNoAppName))
+	})
+
+	It("the provided app flag takes precedence over an app name in the manifest", func() {
+		appName, manifestPath, _, err := ParseArgs(
+			[]string{
+				"zero-downtime-push",
+				"appname-from-flag",
+				"-f", "./fixtures/manifests/manifest.yml",
+			},
+		)
+		Expect(err).ToNot(HaveOccurred())
+
+		Expect(appName).To(Equal("appname-from-flag"))
+		Expect(manifestPath).To(Equal("./fixtures/manifests/manifest.yml"))
+	})
+
+	It("defaults to finding the name from the first app in the manifest", func() {
+		appName, _, _, _ := ParseArgs(
+			[]string{
+				"zero-downtime-push",
+				"-f", "./fixtures/manifests/manifest-with-multiple-apps.yml",
+			},
+		)
+		Expect(appName).To(Equal("first-appname"))
+	})
+
+	It("errors if manifest path is bad", func() {
+		_, _, _, err := ParseArgs(
+			[]string{
+				"zero-downtime-push",
+				"-f", "./fixtures/manifests/nonexistent-manifest.yml",
+			},
+		)
+		Expect(err).To(HaveOccurred())
 	})
 })
 

fixtures/manifests/manifest-with-multiple-apps.yml

@@ -0,0 +1,4 @@
+---
+applications:
+- name: first-appname
+- name: second-appname

fixtures/manifests/manifest-without-appname.yml

@@ -0,0 +1,3 @@
+---
+applications:
+- memory: 256M

fixtures/manifests/manifest.yml

@@ -0,0 +1,3 @@
+---
+applications:
+- name: appname-from-manifest