feat: add new inspect namespaces list command to skaffold

cmd/skaffold/app/cmd/inspect.go

@@ -43,7 +43,7 @@ func NewCmdInspect() *cobra.Command {
 		WithDescription("Helper commands for Cloud Code IDEs to interact with and modify skaffold configuration files.").
 		WithPersistentFlagAdder(cmdInspectFlags).
 		Hidden().
-		WithCommands(cmdModules(), cmdProfiles(), cmdBuildEnv(), cmdTests())
+		WithCommands(cmdModules(), cmdProfiles(), cmdBuildEnv(), cmdTests(), cmdNamespaces())
 }
 
 func cmdInspectFlags(f *pflag.FlagSet) {

cmd/skaffold/app/cmd/inspect_namespaces.go

@@ -0,0 +1,71 @@
+/*
+Copyright 2021 The Skaffold Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package cmd
+
+import (
+	"context"
+	"errors"
+	"io"
+
+	"github.com/spf13/cobra"
+	"github.com/spf13/pflag"
+
+	"github.com/GoogleContainerTools/skaffold/v2/pkg/skaffold/inspect"
+	namespaces "github.com/GoogleContainerTools/skaffold/v2/pkg/skaffold/inspect/namespaces"
+)
+
+func cmdNamespaces() *cobra.Command {
+	return NewCmd("namespaces").
+		WithDescription("View skaffold namespace information for resources it manages").
+		WithCommands(cmdNamespacesList())
+}
+
+func cmdNamespacesList() *cobra.Command {
+	return NewCmd("list").
+		WithExample("Get list of namespaces", "inspect namespaces list --format json").
+		WithExample("Get list of namespaces targeting a specific configuration", "inspect namespaces list --profile local --format json").
+		WithDescription("Print the list of namespaces that would be run for a given configuration (default skaffold configuration, specific module, specific profile, etc).").
+		WithFlagAdder(cmdNamespacesListFlags).
+		WithArgs(func(cmd *cobra.Command, args []string) error {
+			if len(args) != 1 {
+				return errors.New("`inspect namespaces list` requires exactly one manifest file path argument")
+			}
+			return nil
+		}, listNamespaces)
+}
+
+// NOTE:
+//   - currently kubecontext namespaces are not handled as they were not expected for the
+//     initial use cases involving this command
+//   - also this code currently does not account for the possibility of the -n flag passed
+//     additionally to a skaffold command (eg: skaffold apply -n foo)
+func listNamespaces(ctx context.Context, out io.Writer, args []string) error {
+	return namespaces.PrintNamespacesList(ctx, out, args[0], inspect.Options{
+		Filename:          inspectFlags.filename,
+		RepoCacheDir:      inspectFlags.repoCacheDir,
+		OutFormat:         inspectFlags.outFormat,
+		Modules:           inspectFlags.modules,
+		Profiles:          inspectFlags.profiles,
+		PropagateProfiles: inspectFlags.propagateProfiles,
+	})
+}
+
+func cmdNamespacesListFlags(f *pflag.FlagSet) {
+	f.StringSliceVarP(&inspectFlags.profiles, "profile", "p", nil, `Profile names to activate`)
+	f.BoolVar(&inspectFlags.propagateProfiles, "propagate-profiles", true, `Setting '--propagate-profiles=false' disables propagating profiles set by the '--profile' flag across config dependencies. This mean that only profiles defined directly in the target 'skaffold.yaml' file are activated.`)
+	f.StringSliceVarP(&inspectFlags.modules, "module", "m", nil, "Names of modules to filter target action by.")
+}

pkg/skaffold/inspect/namespaces/list.go

@@ -0,0 +1,150 @@
+/*
+Copyright 2021 The Skaffold Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package inspect
+
+import (
+	"context"
+	"io"
+	"io/ioutil"
+	"log"
+	"strings"
+
+	appsv1 "k8s.io/api/apps/v1"
+	"k8s.io/kubectl/pkg/scheme"
+
+	"github.com/GoogleContainerTools/skaffold/v2/pkg/skaffold/config"
+	"github.com/GoogleContainerTools/skaffold/v2/pkg/skaffold/inspect"
+	"github.com/GoogleContainerTools/skaffold/v2/pkg/webhook/constants"
+)
+
+type resourceToInfoContainer struct {
+	ResourceToInfoMap map[string][]resourceInfo `json:"resourceToInfoMap"`
+}
+
+type resourceInfo struct {
+	Name      string `json:"name"`
+	Namespace string `json:"namespace"`
+}
+
+func PrintNamespacesList(ctx context.Context, out io.Writer, manifestFile string, opts inspect.Options) error {
+	// do some additional processing here
+	b, err := ioutil.ReadFile(manifestFile)
+	if err != nil {
+		return err
+	}
+
+	// Create a runtime.Decoder from the Codecs field within
+	// k8s.io/client-go that's pre-loaded with the schemas for all
+	// the standard Kubernetes resource types.
+	decoder := scheme.Codecs.UniversalDeserializer()
+
+	resourceToInfoMap := map[string][]resourceInfo{}
+	for _, resourceYAML := range strings.Split(string(b), "---") {
+		// skip empty documents, `Decode` will fail on them
+		if len(resourceYAML) == 0 {
+			continue
+		}
+		// - obj is the API object (e.g., Deployment)
+		// - groupVersionKind is a generic object that allows
+		//   detecting the API type we are dealing with, for
+		//   accurate type casting later.
+		obj, groupVersionKind, err := decoder.Decode(
+			[]byte(resourceYAML),
+			nil,
+			nil)
+		if err != nil {
+			log.Print(err)
+			continue
+		}
+		// Only process Deployments for now
+		if groupVersionKind.Group == "apps" && groupVersionKind.Version == "v1" && groupVersionKind.Kind == "Deployment" {
+			deployment := obj.(*appsv1.Deployment)
+
+			if _, ok := resourceToInfoMap[groupVersionKind.String()]; !ok {
+				resourceToInfoMap[groupVersionKind.String()] = []resourceInfo{}
+			}
+			resourceToInfoMap[groupVersionKind.String()] = append(resourceToInfoMap[groupVersionKind.String()], resourceInfo{
+				Name:      deployment.ObjectMeta.Name,
+				Namespace: deployment.ObjectMeta.Namespace,
+			})
+		}
+	}
+
+	formatter := inspect.OutputFormatter(out, opts.OutFormat)
+	cfgs, err := inspect.GetConfigSet(ctx, config.SkaffoldOptions{
+		ConfigurationFile:   opts.Filename,
+		ConfigurationFilter: opts.Modules,
+		RepoCacheDir:        opts.RepoCacheDir,
+		Profiles:            opts.Profiles,
+		PropagateProfiles:   opts.PropagateProfiles,
+	})
+	if err != nil {
+		formatter.WriteErr(err)
+		return err
+	}
+
+	defaultNamespace := constants.Namespace
+	flagNamespace := ""
+	for _, c := range cfgs {
+		if c.Deploy.KubectlDeploy != nil {
+			if c.Deploy.KubectlDeploy.DefaultNamespace != nil && *c.Deploy.KubectlDeploy.DefaultNamespace != "" {
+				defaultNamespace = *c.Deploy.KubectlDeploy.DefaultNamespace
+			}
+			if namespaceVal := parseNamespaceFromFlags(c.Deploy.KubectlDeploy.Flags.Global); namespaceVal != "" {
+				flagNamespace = namespaceVal
+			}
+			if namespaceVal := parseNamespaceFromFlags(c.Deploy.KubectlDeploy.Flags.Apply); namespaceVal != "" {
+				flagNamespace = namespaceVal
+			}
+			// NOTE: Cloud Deploy uses `skaffold apply` which always uses kubectl deployer.  As such other
+			// namespace config should be ignored - eg: .Deploy.LegacyHelmDeploy.Releases[i].Namespace
+		}
+	}
+
+	for gvk, ris := range resourceToInfoMap {
+		for i := range ris {
+			if ris[i].Namespace == "" {
+				if flagNamespace != "" {
+					resourceToInfoMap[gvk][i].Namespace = flagNamespace
+					continue
+				}
+				resourceToInfoMap[gvk][i].Namespace = defaultNamespace
+			}
+		}
+	}
+	l := &resourceToInfoContainer{ResourceToInfoMap: resourceToInfoMap}
+
+	return formatter.Write(l)
+}
+
+func parseNamespaceFromFlags(flgs []string) string {
+	for i, s := range flgs {
+		if s == "-n" && i < len(flgs)-1 {
+			return flgs[i+1]
+		}
+		if strings.HasPrefix(s, "-n=") && len(strings.Split(s, "=")) == 2 {
+			return strings.Split(s, "=")[1]
+		}
+		if s == "--namespace" && i < len(flgs)-1 {
+			return flgs[i+1]
+		}
+		if strings.HasPrefix(s, "--namespace=") && len(strings.Split(s, "=")) == 2 {
+			return strings.Split(s, "=")[1]
+		}
+	}
+	return ""
+}