pkg/asset/installconfig/platform: Remove libvirt image prompt

Keep the environment variable (with a warning about using it), but
drop the interactive prompt.  The default is solid, and users
manipulating it are more likely to break something (e.g. by continuing
to use the old v1 pipeline), while the installer can update its
default to track the RHCOS folks (e.g. like 1117821, rhcos: implement
image discovery for new pipeline, 2018-10-26, #554).

docs/user/environment-variables.md

@@ -47,5 +47,7 @@ The installer accepts a number of environment variable that allow the interactiv
     This must be accessible from the running cluster.
 * `OPENSHIFT_INSTALL_LIBVIRT_IMAGE`:
     The URI for the OS image.
-    For example it might be url like `http://aos-ostree.rhev-ci-vms.eng.rdu2.redhat.com/rhcos/images/cloud/latest/rhcos-qemu.qcow2.gz` or
-    a local file like `file:///tmp/openshift-install-853528428`.
+    For example it might be a URI like `https://example.com/rhcos-qemu.qcow2` or a local file like `file:///tmp/redhat-coreos-maipo-47.78-qemu.qcow2`.
+
+    **Warning**: you should only set this if you're testing RHCOS releases.
+    Most users should allow the installer to choose the OS image.

pkg/asset/installconfig/platform.go

@@ -289,40 +289,26 @@ func (a *platform) libvirtPlatform() (*types.LibvirtPlatform, error) {
 		return nil, err
 	}
 
-	// TODO: Ideally, this would live inside of a closure which is passed to
-	//       asset.GenerateUserProvidedAsset and only called if the environment
-	//       variable isn't present. As this exists, it ruins the abstraction.
-	var qcowImage string
-	if _, ok := os.LookupEnv("OPENSHIFT_INSTALL_LIBVIRT_IMAGE"); !ok {
+	qcowImage, ok :=os.LookupEnv("OPENSHIFT_INSTALL_LIBVIRT_IMAGE")
+	if ok {
+		err = validURI(qcowImage)
+		if err != nil {
+			return nil, errors.Wrap(err, "resolve OPENSHIFT_INSTALL_LIBVIRT_IMAGE")
+		}
+	} else {
 		qcowImage, err = rhcos.QEMU(context.TODO(), rhcos.DefaultChannel)
 		if err != nil {
 			return nil, errors.Wrap(err, "failed to fetch QEMU image URL")
 		}
 	}
 
-	image, err := asset.GenerateUserProvidedAsset(
-		"Libvirt Image",
-		&survey.Question{
-			Prompt: &survey.Input{
-				Message: "Image",
-				Help:    "URI of the OS image.",
-				Default: qcowImage,
-			},
-			Validate: survey.ComposeValidators(survey.Required, uriValidator),
-		},
-		"OPENSHIFT_INSTALL_LIBVIRT_IMAGE",
-	)
-	if err != nil {
-		return nil, errors.Wrapf(err, "failed to Marshal %s platform", LibvirtPlatformType)
-	}
-
 	return &types.LibvirtPlatform{
 		Network: types.LibvirtNetwork{
 			IfName:  defaultLibvirtNetworkIfName,
 			IPRange: defaultLibvirtNetworkIPRange,
 		},
 		DefaultMachinePlatform: &types.LibvirtMachinePoolPlatform{
-			Image: image,
+			Image: qcowImage,
 		},
 		URI: uri,
 	}, nil
@@ -331,13 +317,17 @@ func (a *platform) libvirtPlatform() (*types.LibvirtPlatform, error) {
 // uriValidator validates if the answer provided in prompt is a valid
 // url and has non-empty scheme.
 func uriValidator(ans interface{}) error {
-	value := ans.(string)
-	uri, err := url.Parse(value)
+	return validURI(ans.(string))
+}
+
+// validURI validates if the URI is a valid URI with a non-empty scheme.
+func validURI(uri string) error {
+	parsed, err := url.Parse(uri)
 	if err != nil {
 		return err
 	}
-	if uri.Scheme == "" {
-		return fmt.Errorf("invalid URI %q (no scheme)", value)
+	if parsed.Scheme == "" {
+		return fmt.Errorf("invalid URI %q (no scheme)", uri)
 	}
 	return nil
 }