Add augerctl get

Signed-off-by: Shiming Zhang <[email protected]>

augerctl/README.md

@@ -0,0 +1,136 @@
+# augerctl
+
+`augerctl` is a command line client for [Kubernetes][kubernetes] specific [etcd][etcd],
+and as close as possible to [kubectl][kubectl].
+It can be used in scripts or for administrators to explore an etcd cluster.
+
+## Getting augerctl
+
+The latest release is not yet available as a binary on [Github][github-release],
+the next release will be available.
+
+so that it can be built from source.
+
+``` bash
+git clone https://github.com/etcd-io/auger
+cd auger
+go install ./augerctl
+```
+
+or
+
+``` bash
+go install github.com/etcd-io/auger/augerctl@main
+```
+
+and the binary will be available in the path `$GOBIN` or `$GOPATH/bin`
+
+## Configuration
+
+### --endpoints
++ gRPC endpoints of etcd cluster
++ default: `"http://127.0.0.1:2379"`
+
+### --cert
++ path to the etcd client TLS cert file
++ default: none
+
+### --key
++ path to the etcd client TLS key file
++ default: none
+
+### --cacert
++ path to the etcd client TLS CA cert file
++ default: none
+
+### --user
++ username for authentication, provide username[:password]
++ default: none
+
+### --password
++ password for authentication, only available if --user has no password
++ default: none
+
+## Usage
+
+### Setting a resource
+
+TODO
+
+### Retrieving a resource
+
+List a single service with namespace `default` and name `kubernetes`
+
+``` bash
+augerctl get services -n default kubernetes
+
+# Nearly equivalent
+kubectl get services -n default kubernetes -o yaml
+```
+
+List a single resource of type `priorityclasses` and name `system-node-critical` without namespaced
+
+``` bash
+augerctl get priorityclasses system-node-critical
+
+# Nearly equivalent
+kubectl get priorityclasses system-node-critical -o yaml
+```
+
+List all leases with namespace `kube-system`
+
+``` bash
+augerctl get leases -n kube-system
+
+# Nearly equivalent
+kubectl get leases -n kube-system -o yaml
+```
+
+List a single resource of type `apiservices.apiregistration.k8s.io` and name `v1.apps`
+
+``` bash
+augerctl get apiservices.apiregistration.k8s.io v1.apps
+
+# Nearly equivalent
+kubectl get apiservices.apiregistration.k8s.io v1.apps -o yaml
+```
+
+List all resources
+
+``` bash
+augerctl get
+
+# Nearly equivalent
+kubectl get $(kubectl api-resources --verbs=list --output=name | paste -s -d, - ) -A -o yaml
+```
+
+### Deleting a resource
+
+TODO
+
+### Watching for changes
+
+TODO
+
+## Endpoint
+
+If the etcd cluster isn't available on `http://127.0.0.1:2379`, specify a `--endpoints` flag.
+
+## Project Details
+
+### Versioning
+
+augerctl uses [semantic versioning][semver].
+Releases will follow with the [Kubernetes][kubernetes] release cycle as possible (need API updates),
+but the version numbers will be not.
+
+### License
+
+augerctl is under the Apache 2.0 license. See the [LICENSE][license] file for details.
+
+[kubernetes]: https://kubernetes.io/
+[kubectl]: https://kubectl.sigs.k8s.io/
+[etcd]: https://github.com/etcd-io/etcd
+[github-release]: https://github.com/etcd-io/auger/releases/
+[license]: ../LICENSE
+[semver]: http://semver.org/

augerctl/command/ctl.go

@@ -0,0 +1,59 @@
+/*
+Copyright 2024 The Kubernetes 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 command is a simple command line client for directly accessing data objects stored in etcd by Kubernetes.
+package command
+
+import (
+	"github.com/spf13/cobra"
+
+	"go.etcd.io/etcd/client/pkg/v3/transport"
+)
+
+type flagpole struct {
+	Endpoints []string
+
+	InsecureSkipVerify bool
+	InsecureDiscovery  bool
+	TLS                transport.TLSInfo
+
+	User     string
+	Password string
+}
+
+// NewCtlCommand returns a new cobra.Command for use ctl
+func NewCtlCommand() *cobra.Command {
+	flags := &flagpole{}
+
+	cmd := &cobra.Command{
+		Use:   "augerctl",
+		Short: "A simple command line client for directly accessing data objects stored in etcd by Kubernetes.",
+	}
+	cmd.PersistentFlags().StringSliceVar(&flags.Endpoints, "endpoints", []string{"127.0.0.1:2379"}, "gRPC endpoints of etcd cluster")
+
+	cmd.PersistentFlags().BoolVar(&flags.InsecureDiscovery, "insecure-discovery", true, "accept insecure SRV records describing cluster endpoints")
+	cmd.PersistentFlags().BoolVar(&flags.InsecureSkipVerify, "insecure-skip-tls-verify", false, "skip server certificate verification")
+	cmd.PersistentFlags().StringVar(&flags.TLS.CertFile, "cert", "", "path to the etcd client TLS cert file")
+	cmd.PersistentFlags().StringVar(&flags.TLS.KeyFile, "key", "", "path to the etcd client TLS key file")
+	cmd.PersistentFlags().StringVar(&flags.TLS.TrustedCAFile, "cacert", "", "path to the etcd client TLS CA cert file")
+	cmd.PersistentFlags().StringVar(&flags.User, "user", "", "username for authentication, provide username[:password]")
+	cmd.PersistentFlags().StringVar(&flags.Password, "password", "", "password for authentication, only available if --user has no password")
+
+	cmd.AddCommand(
+		newCtlGetCommand(flags),
+	)
+	return cmd
+}

augerctl/command/get_command.go

@@ -0,0 +1,137 @@
+/*
+Copyright 2024 The Kubernetes 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 command
+
+import (
+	"context"
+	"fmt"
+	"os"
+
+	"github.com/etcd-io/auger/pkg/client"
+	"github.com/spf13/cobra"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+)
+
+type getFlagpole struct {
+	Namespace string
+	Output    string
+	ChunkSize int64
+	Prefix    string
+}
+
+var (
+	getExample = `
+  # List a single service with namespace "default" and name "kubernetes"
+  augerctl get services -n default kubernetes
+  # Nearly equivalent
+  kubectl get services -n default kubernetes -o yaml
+
+  # List a single resource of type "priorityclasses" and name "system-node-critical" without namespaced
+  augerctl get priorityclasses system-node-critical
+  # Nearly equivalent
+  kubectl get priorityclasses system-node-critical -A -o yaml
+
+  # List all leases with namespace "kube-system"
+  augerctl get leases -n kube-system
+  # Nearly equivalent
+  kubectl get leases -n kube-system -o yaml
+
+  # List a single resource of type "apiservices.apiregistration.k8s.io" and name "v1.apps"
+  augerctl get apiservices.apiregistration.k8s.io v1.apps
+  # Nearly equivalent
+  kubectl get apiservices.apiregistration.k8s.io v1.apps -o yaml
+
+  # List all resources
+  augerctl get
+  # Nearly equivalent
+  kubectl get $(kubectl api-resources --verbs=list --output=name | paste -s -d, - ) -A -o yaml
+`
+)
+
+func newCtlGetCommand(f *flagpole) *cobra.Command {
+	flags := &getFlagpole{}
+
+	cmd := &cobra.Command{
+		Args:    cobra.RangeArgs(0, 2),
+		Use:     "get [resource] [name]",
+		Short:   "Gets the resource of Kubernetes in etcd",
+		Example: getExample,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			etcdclient, err := clientFromCmd(f)
+			if err != nil {
+				return err
+			}
+			err = getCommand(cmd.Context(), etcdclient, flags, args)
+
+			if err != nil {
+				return fmt.Errorf("%v: %w", args, err)
+			}
+			return nil
+		},
+	}
+
+	cmd.Flags().StringVarP(&flags.Output, "output", "o", "yaml", "output format. One of: (yaml).")
+	cmd.Flags().StringVarP(&flags.Namespace, "namespace", "n", "", "namespace of resource")
+	cmd.Flags().Int64Var(&flags.ChunkSize, "chunk-size", 500, "chunk size of the list pager")
+	cmd.Flags().StringVar(&flags.Prefix, "prefix", "/registry", "prefix to prepend to the resource")
+
+	return cmd
+}
+
+func getCommand(ctx context.Context, etcdclient client.Client, flags *getFlagpole, args []string) error {
+	var targetGr schema.GroupResource
+	var targetName string
+	var targetNamespace string
+	if len(args) != 0 {
+		// TODO: Support get information from CRD and scheme.Codecs
+		//       Support short name
+		//       Check for namespaced
+
+		gr := schema.ParseGroupResource(args[0])
+		if gr.Empty() {
+			return fmt.Errorf("invalid resource %q", args[0])
+		}
+		targetGr = gr
+		targetNamespace = flags.Namespace
+		if len(args) >= 2 {
+			targetName = args[1]
+		}
+	}
+
+	printer := NewPrinter(os.Stdout, flags.Output)
+	if printer == nil {
+		return fmt.Errorf("invalid output format: %q", flags.Output)
+	}
+
+	opOpts := []client.OpOption{
+		client.WithName(targetName, targetNamespace),
+		client.WithGroupResource(targetGr),
+		client.WithChunkSize(flags.ChunkSize),
+		client.WithResponse(printer.Print),
+	}
+
+	// TODO: Support watch
+
+	_, err := etcdclient.Get(ctx, flags.Prefix,
+		opOpts...,
+	)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}