feat: add --config-patch parameter to talosctl gen config

Fixes: #3410

Same as in `talosctl cluster create`. Will apply RFC6902 json patch
during the config generation if specified.

Signed-off-by: Artem Chernyshev <artem.0xD2@gmail.com>

cmd/talosctl/cmd/mgmt/config.go

@@ -12,6 +12,7 @@ import (
 	"path/filepath"
 	"strings"
 
+	jsonpatch "github.com/evanphx/json-patch"
 	"github.com/spf13/cobra"
 	talosnet "github.com/talos-systems/net"
 	"gopkg.in/yaml.v3"
@@ -35,6 +36,7 @@ var genConfigCmdFlags struct {
 	installDisk       string
 	installImage      string
 	outputDir         string
+	configPatch       string
 	registryMirrors   []string
 	persistConfig     bool
 	withExamples      bool
@@ -143,7 +145,7 @@ func genV1Alpha1Config(args []string) error {
 		genOptions = append(genOptions, generate.WithVersionContract(versionContract))
 	}
 
-	configBundle, err := bundle.NewConfigBundle(
+	configBundleOpts := []bundle.Option{
 		bundle.WithInputOptions(
 			&bundle.InputOptions{
 				ClusterName: args[0],
@@ -158,7 +160,20 @@ func genV1Alpha1Config(args []string) error {
 				),
 			},
 		),
-	)
+	}
+
+	if genConfigCmdFlags.configPatch != "" {
+		var jsonPatch jsonpatch.Patch
+
+		jsonPatch, err = jsonpatch.DecodePatch([]byte(genConfigCmdFlags.configPatch))
+		if err != nil {
+			return fmt.Errorf("error parsing config JSON patch: %w", err)
+		}
+
+		configBundleOpts = append(configBundleOpts, bundle.WithJSONPatch(jsonPatch))
+	}
+
+	configBundle, err := bundle.NewConfigBundle(configBundleOpts...)
 	if err != nil {
 		return fmt.Errorf("failed to generate config bundle: %w", err)
 	}
@@ -205,6 +220,7 @@ func init() {
 	genConfigCmd.Flags().StringVar(&genConfigCmdFlags.talosVersion, "talos-version", "", "the desired Talos version to generate config for (backwards compatibility, e.g. v0.8)")
 	genConfigCmd.Flags().StringVar(&genConfigCmdFlags.kubernetesVersion, "kubernetes-version", "", "desired kubernetes version to run")
 	genConfigCmd.Flags().StringVarP(&genConfigCmdFlags.outputDir, "output-dir", "o", "", "destination to output generated files")
+	genConfigCmd.Flags().StringVar(&genConfigCmdFlags.configPatch, "config-patch", "", "patch generated machineconfigs")
 	genConfigCmd.Flags().StringSliceVar(&genConfigCmdFlags.registryMirrors, "registry-mirror", []string{}, "list of registry mirrors to use in format: <registry host>=<mirror URL>")
 	genConfigCmd.Flags().BoolVarP(&genConfigCmdFlags.persistConfig, "persist", "p", true, "the desired persist value for configs")
 	genConfigCmd.Flags().BoolVarP(&genConfigCmdFlags.withExamples, "with-examples", "", true, "renders all machine configs with the commented examples")

internal/integration/cli/gen.go

@@ -7,11 +7,13 @@
 package cli
 
 import (
+	"encoding/json"
 	"io/ioutil"
 	"os"
 	"regexp"
 
 	"github.com/talos-systems/talos/internal/integration/base"
+	"github.com/talos-systems/talos/pkg/machinery/config/configloader"
 )
 
 // GenSuite verifies dmesg command.
@@ -132,6 +134,26 @@ func (suite *GenSuite) TestGenConfigURLValidation() {
 		base.StderrShouldMatch(regexp.MustCompile(regexp.QuoteMeta(`try: "https://192.168.0.1:2000"`))))
 }
 
+// TestGenConfigPatch verify that gen config --config-patch works.
+func (suite *GenSuite) TestGenConfigPatch() {
+	patch, err := json.Marshal([]map[string]interface{}{
+		{
+			"op":    "replace",
+			"path":  "/cluster/clusterName",
+			"value": "bar",
+		},
+	})
+
+	suite.Assert().NoError(err)
+
+	suite.RunCLI([]string{"gen", "config", "foo", "https://192.168.0.1:6443", "--config-patch", string(patch)})
+
+	cfg, err := configloader.NewFromFile("controlplane.yaml")
+
+	suite.Assert().NoError(err)
+	suite.Assert().Equal("bar", cfg.Cluster().Name())
+}
+
 func init() {
 	allSuites = append(allSuites, new(GenSuite))
 }

website/content/docs/v0.10/Bare Metal Platforms/digital-rebar.md

@@ -37,6 +37,7 @@ created talosconfig
 > If you think this should be added to the docs, please [create a issue](https://github.com/talos-systems/talos/issues).
 
 At this point, you can modify the generated configs to your liking.
+Optionally, you can specify `--config-patch` with RFC6902 jsonpatch which will be applied during the config generation.
 
 #### Validate the Configuration Files
 

website/content/docs/v0.10/Bare Metal Platforms/equinix-metal.md

@@ -58,6 +58,7 @@ created talosconfig
 
 Now add the required shebang (e.g. `#!talos`) at the top of `init.yaml`, `controlplane.yaml`, and `join.yaml`
 At this point, you can modify the generated configs to your liking.
+Optionally, you can specify `--config-patch` with RFC6902 jsonpatch which will be applied during the config generation.
 
 #### Validate the Configuration Files
 

website/content/docs/v0.10/Bare Metal Platforms/matchbox.md

@@ -26,6 +26,7 @@ created talosconfig
 ```
 
 At this point, you can modify the generated configs to your liking.
+Optionally, you can specify `--config-patch` with RFC6902 jsonpatch which will be applied during the config generation.
 
 #### Validate the Configuration Files
 

website/content/docs/v0.10/Cloud Platforms/aws.md

@@ -149,6 +149,7 @@ created talosconfig
 ```
 
 At this point, you can modify the generated configs to your liking.
+Optionally, you can specify `--config-patch` with RFC6902 jsonpatch which will be applied during the config generation.
 
 #### Validate the Configuration Files
 

website/content/docs/v0.10/Cloud Platforms/digitalocean.md

@@ -63,6 +63,7 @@ created talosconfig
 ```
 
 At this point, you can modify the generated configs to your liking.
+Optionally, you can specify `--config-patch` with RFC6902 jsonpatch which will be applied during the config generation.
 
 #### Validate the Configuration Files
 

website/content/docs/v0.10/Cloud Platforms/gcp.md

@@ -119,6 +119,8 @@ LB_PUBLIC_IP=$(gcloud compute forwarding-rules describe talos-fwd-rule \
 talosctl gen config talos-k8s-gcp-tutorial https://${LB_PUBLIC_IP}:443
 ```
 
+Additionally, you can specify `--config-patch` with RFC6902 jsonpatch which will be applied during the config generation.
+
 ### Compute Creation
 
 We are now ready to create our GCP nodes.

website/content/docs/v0.10/Cloud Platforms/openstack.md

@@ -94,6 +94,8 @@ LB_PUBLIC_IP=$(openstack loadbalancer show talos-control-plane -f json | jq -r .
 talosctl gen config talos-k8s-openstack-tutorial https://${LB_PUBLIC_IP}:6443
 ```
 
+Additionally, you can specify `--config-patch` with RFC6902 jsonpatch which will be applied during the config generation.
+
 ### Compute Creation
 
 We are now ready to create our Openstack nodes.

website/content/docs/v0.10/Reference/cli.md

@@ -1016,6 +1016,7 @@ talosctl gen config <cluster name> <cluster endpoint> [flags]
 
 ```
       --additional-sans strings     additional Subject-Alt-Names for the APIServer certificate
+      --config-patch string         patch generated machineconfigs
       --dns-domain string           the dns domain to use for cluster (default "cluster.local")
   -h, --help                        help for config
       --install-disk string         the disk to install to (default "/dev/sda")

website/content/docs/v0.10/Virtualized Platforms/vmware.md

@@ -40,6 +40,7 @@ created talosconfig
 ```
 
 At this point, you can modify the generated configs to your liking.
+Optionally, you can specify `--config-patch` with RFC6902 jsonpatch which will be applied during the config generation.
 
 #### Validate the Configuration Files