feat(helm): Add a flag --dep-up that helm install will automatically execute helm dep up when charts are in requirements.yaml but not in charts

If checkdependencies returns an error, we can start download the
charts which are not in charts.

Closes #2879

cmd/helm/install.go

@@ -119,6 +119,7 @@ type installCmd struct {
 	wait         bool
 	repoURL      string
 	devel        bool
+	depUp        bool
 
 	certFile string
 	keyFile  string
@@ -194,6 +195,7 @@ func newInstallCmd(c helm.Interface, out io.Writer) *cobra.Command {
 	f.StringVar(&inst.keyFile, "key-file", "", "identify HTTPS client using this SSL key file")
 	f.StringVar(&inst.caFile, "ca-file", "", "verify certificates of HTTPS-enabled servers using this CA bundle")
 	f.BoolVar(&inst.devel, "devel", false, "use development versions, too. Equivalent to version '>0.0.0-0'. If --version is set, this is ignored.")
+	f.BoolVar(&inst.depUp, "dep-up", false, "run helm dependency update before installing the chart")
 
 	return cmd
 }
@@ -231,8 +233,23 @@ func (i *installCmd) run() error {
 		// As of Helm 2.4.0, this is treated as a stopping condition:
 		// https://github.com/kubernetes/helm/issues/2209
 		if err := checkDependencies(chartRequested, req); err != nil {
+			if i.depUp {
+				man := &downloader.Manager{
+					Out:        i.out,
+					ChartPath:  i.chartPath,
+					HelmHome:   settings.Home,
+					Keyring:    defaultKeyring(),
+					SkipUpdate: false,
+					Getters:    getter.All(settings),
+				}
+				if err := man.Update(); err != nil {
+					return prettyError(err)
+				}
+			} else {
 				return prettyError(err)
 			}
+
+		}
 	} else if err != chartutil.ErrRequirementsNotFound {
 		return fmt.Errorf("cannot load requirements: %v", err)
 	}

docs/helm/helm_install.md

@@ -70,6 +70,7 @@ helm install [CHART]
 ```
       --ca-file string         verify certificates of HTTPS-enabled servers using this CA bundle
       --cert-file string       identify HTTPS client using this SSL certificate file
+      --dep-up                 run helm dependency update before installing the chart
       --devel                  use development versions, too. Equivalent to version '>0.0.0-0'. If --version is set, this is ignored.
       --dry-run                simulate an install
       --key-file string        identify HTTPS client using this SSL key file

docs/man/man1/helm_install.1

@@ -122,6 +122,10 @@ charts in a repository, use 'helm search'.
 \fB\-\-cert\-file\fP=""
     identify HTTPS client using this SSL certificate file
 
+.PP
+\fB\-\-dep\-up\fP[=false]
+    run helm dependency update before installing the chart.
+
 .PP
 \fB\-\-devel\fP[=false]
     use development versions, too. Equivalent to version '>0.0.0\-a'. If \-\-version is set, this is ignored.
@@ -236,4 +240,4 @@ charts in a repository, use 'helm search'.
 
 .SH HISTORY
 .PP
-19\-May\-2017 Auto generated by spf13/cobra
+31\-Oct\-2017 Auto generated by spf13/cobra