feat(crank): add beta describe command

Co-authored-by: jbasement <j.keller@celonis.com>
Co-authored-by: Philippe Scorsolini <p.scorsolini@gmail.com>
Signed-off-by: Philippe Scorsolini <p.scorsolini@gmail.com>

cmd/crank/beta/beta.go

@@ -20,12 +20,14 @@ limitations under the License.
 package beta
 
 import (
+	"github.com/crossplane/crossplane/cmd/crank/beta/describe"
 	"github.com/crossplane/crossplane/cmd/crank/beta/render"
 	"github.com/crossplane/crossplane/cmd/crank/beta/xpkg"
 )
 
 // Cmd contains beta commands.
 type Cmd struct {
-	XPKG   xpkg.Cmd   `cmd:"" help:"Manage packages."`
-	Render render.Cmd `cmd:"" help:"Render a claim or XR locally."`
+	XPKG     xpkg.Cmd     `cmd:"" help:"Manage packages."`
+	Render   render.Cmd   `cmd:"" help:"Render a claim or XR locally."`
+	Describe describe.Cmd `cmd:"" help:"Describe a Crossplane resource."`
 }

cmd/crank/beta/describe/describe.go

@@ -0,0 +1,127 @@
+/*
+Copyright 2023 The Crossplane 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 describe contains the describe command.
+package describe
+
+import (
+	"context"
+	"os"
+	"strings"
+
+	v1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/meta"
+	ctrl "sigs.k8s.io/controller-runtime"
+
+	"github.com/crossplane/crossplane-runtime/pkg/errors"
+	"github.com/crossplane/crossplane-runtime/pkg/logging"
+
+	"github.com/crossplane/crossplane/cmd/crank/beta/describe/internal/printer"
+	"github.com/crossplane/crossplane/cmd/crank/beta/describe/internal/resource"
+)
+
+const (
+	errGetResource            = "cannot get requested resource"
+	errCliOutput              = "cannot print output"
+	errKubeConfig             = "failed to get kubeconfig"
+	errCouldntInitKubeClient  = "cannot init kubeclient"
+	errCannotGetKindAndName   = "cannot get kind and name"
+	errCannotGetMapping       = "cannot get mapping for resource"
+	errCannotInitPrinter      = "cannot init new printer"
+	errFmtInvalidResourceName = "invalid combined kind and name format, should be in the form of 'resource.group.example.org/name', got: %q"
+)
+
+// Cmd describes a Crossplane resource.
+type Cmd struct {
+	Resource string `arg:"" required:"" help:"'TYPE[.VERSION][.GROUP][/NAME]' identifying the Crossplane resource."`
+	Name     string `arg:"" optional:"" help:"Name of the Crossplane resource. Ignored if already passed as part of the RESOURCE argument."`
+
+	// TODO(phisco): add support for all the usual kubectl flags; configFlags := genericclioptions.NewConfigFlags(true).AddFlags(...)
+	Namespace string `short:"n" name:"namespace" help:"Namespace of resource to describe." default:"default"`
+	Output    string `short:"o" name:"output" help:"Output format. One of: default, json." enum:"default,json" default:"default"`
+}
+
+// Run runs the describe command.
+func (c *Cmd) Run(logger logging.Logger) error {
+	logger = logger.WithValues("Resource", c.Resource)
+
+	kubeconfig, err := ctrl.GetConfig()
+	if err != nil {
+		logger.Debug(errKubeConfig, "error", err)
+		return errors.Wrap(err, errKubeConfig)
+	}
+	logger.Debug("Found kubeconfig")
+
+	// Get client for k8s package
+	client, err := resource.NewClient(kubeconfig)
+	if err != nil {
+		return errors.Wrap(err, errCouldntInitKubeClient)
+	}
+	logger.Debug("Built client")
+
+	kind, name, err := c.getKindAndName()
+	if err != nil {
+		return errors.Wrap(err, errCannotGetKindAndName)
+	}
+
+	mapping, err := client.MappingFor(kind)
+	if err != nil {
+		return errors.Wrap(err, errCannotGetMapping)
+	}
+
+	// Init new printer
+	p, err := printer.New(c.Output)
+	if err != nil {
+		return errors.Wrap(err, errCannotInitPrinter)
+	}
+	logger.Debug("Built printer", "output", c.Output)
+
+	// Get Resource object. Contains k8s resource and all its children, also as Resource.
+	rootRef := &v1.ObjectReference{
+		Kind:       mapping.GroupVersionKind.Kind,
+		APIVersion: mapping.GroupVersionKind.GroupVersion().String(),
+		Name:       name,
+	}
+	if mapping.Scope.Name() == meta.RESTScopeNameNamespace && c.Namespace != "" {
+		rootRef.Namespace = c.Namespace
+	}
+	logger.Debug("Getting resource tree", "rootRef", rootRef.String())
+	root, err := client.GetResourceTree(context.Background(), rootRef)
+	if err != nil {
+		logger.Debug(errGetResource, "error", err)
+		return errors.Wrap(err, errGetResource)
+	}
+	logger.Debug("Got resource tree", "root", root)
+
+	// Print resources
+	err = p.Print(os.Stdout, root)
+	if err != nil {
+		return errors.Wrap(err, errCliOutput)
+	}
+
+	return nil
+}
+
+func (c *Cmd) getKindAndName() (string, string, error) {
+	if c.Name != "" {
+		return c.Resource, c.Name, nil
+	}
+	kindAndName := strings.SplitN(c.Resource, "/", 2)
+	if len(kindAndName) != 2 {
+		return "", "", errors.Errorf(errFmtInvalidResourceName, c.Resource)
+	}
+	return kindAndName[0], kindAndName[1], nil
+}

cmd/crank/beta/describe/internal/printer/default.go

@@ -0,0 +1,136 @@
+/*
+Copyright 2023 The Crossplane 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 printer
+
+import (
+	"fmt"
+	"io"
+	"strings"
+
+	"k8s.io/cli-runtime/pkg/printers"
+
+	xpv1 "github.com/crossplane/crossplane-runtime/apis/common/v1"
+	"github.com/crossplane/crossplane-runtime/pkg/errors"
+
+	"github.com/crossplane/crossplane/cmd/crank/beta/describe/internal/resource"
+)
+
+const (
+	errFmtCannotWriteHeader    = "cannot write header: %s"
+	errFmtCannotWriteRow       = "cannot write row: %s"
+	errFmtCannotFlushTabWriter = "cannot flush tab writer: %s"
+)
+
+// DefaultPrinter defines the DefaultPrinter configuration
+type DefaultPrinter struct {
+	Indent string
+}
+
+var _ Printer = &DefaultPrinter{}
+
+type defaultPrinterRow struct {
+	namespace   string
+	apiVersion  string
+	name        string
+	ready       string
+	synced      string
+	latestEvent string
+}
+
+func (r *defaultPrinterRow) String() string {
+	return strings.Join([]string{
+		r.namespace,
+		r.apiVersion,
+		r.name,
+		r.ready,
+		r.synced,
+		r.latestEvent,
+	}, "\t") + "\t"
+}
+
+// Print implements the Printer interface by prints the resource tree in a
+// human-readable format.
+func (p *DefaultPrinter) Print(w io.Writer, root *resource.Resource) error {
+	tw := printers.GetNewTabWriter(w)
+
+	headers := defaultPrinterRow{
+		namespace:   "NAMESPACE",
+		apiVersion:  "APIVERSION",
+		name:        "NAME",
+		ready:       "READY",
+		synced:      "SYNCED",
+		latestEvent: "LATESTEVENT",
+	}
+	if _, err := fmt.Fprintln(tw, headers.String()); err != nil {
+		return errors.Errorf(errFmtCannotWriteHeader, err)
+	}
+
+	type queueItem struct {
+		resource *resource.Resource
+		depth    int
+		isLast   bool
+	}
+
+	// Initialize queue with root element
+	queue := make([]*queueItem, 0)
+	queue = append(queue, &queueItem{root, 0, false})
+
+	for len(queue) > 0 {
+		// Dequeue first element
+		item := queue[0]  //nolint:gosec // false positive, the queue length has been checked above
+		queue = queue[1:] //nolint:gosec // false positive, works even if the queue is a single element
+
+		// Choose the right prefix
+		name := strings.Builder{}
+		name.WriteString(strings.Repeat(p.Indent, item.depth))
+
+		if item.depth > 0 {
+			if item.isLast {
+				name.WriteString("└─ ")
+			} else {
+				name.WriteString("├─ ")
+			}
+		}
+
+		name.WriteString(fmt.Sprintf("%s/%s", item.resource.Unstructured.GetKind(), item.resource.Unstructured.GetName()))
+
+		row := defaultPrinterRow{
+			namespace:  item.resource.Unstructured.GetNamespace(),
+			apiVersion: item.resource.Unstructured.GetAPIVersion(),
+			name:       name.String(),
+			ready:      string(item.resource.GetCondition(xpv1.TypeReady).Status),
+			synced:     string(item.resource.GetCondition(xpv1.TypeSynced).Status),
+		}
+		if e := item.resource.LatestEvent; e != nil {
+			row.latestEvent = fmt.Sprintf("[%s] %s", e.Type, e.Message)
+		}
+		if _, err := fmt.Fprintln(tw, row.String()); err != nil {
+			return errors.Errorf(errFmtCannotWriteRow, err)
+		}
+
+		// Enqueue the children of the current node
+		for idx := range item.resource.Children {
+			isLast := idx == len(item.resource.Children)-1
+			queue = append(queue, &queueItem{item.resource.Children[idx], item.depth + 1, isLast})
+		}
+	}
+	if err := tw.Flush(); err != nil {
+		return errors.Errorf(errFmtCannotFlushTabWriter, err)
+	}
+
+	return nil
+}

cmd/crank/beta/describe/internal/printer/default_test.go

@@ -0,0 +1,115 @@
+/*
+Copyright 2023 The Crossplane 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 printer
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	v1 "k8s.io/api/core/v1"
+
+	"github.com/crossplane/crossplane-runtime/pkg/test"
+
+	"github.com/crossplane/crossplane/cmd/crank/beta/describe/internal/resource"
+)
+
+func TestDefaultPrinter(t *testing.T) {
+	type args struct {
+		resource *resource.Resource
+	}
+
+	type want struct {
+		output string
+		err    error
+	}
+
+	cases := map[string]struct {
+		reason string
+		args   args
+		want   want
+	}{
+		// Test valid resource
+		"ResourceWithChildren": {
+			reason: "Should print a complex Resource with children and events.",
+			args: args{
+				resource: &resource.Resource{
+					Unstructured: DummyManifest("ObjectStorage", "test-resource", "True", "True"),
+					LatestEvent: &v1.Event{
+						Type:    "Normal",
+						Message: "Successfully selected composition",
+					},
+					Children: []*resource.Resource{
+						{
+							Unstructured: DummyManifest("XObjectStorage", "test-resource-hash", "True", "True"),
+							LatestEvent:  nil,
+							Children: []*resource.Resource{
+								{
+									Unstructured: DummyManifest("Bucket", "test-resource-bucket-hash", "True", "True"),
+									LatestEvent: &v1.Event{
+										Type:    "Warning",
+										Message: "Error with bucket",
+									},
+								},
+								{
+									Unstructured: DummyManifest("User", "test-resource-user-hash", "True", "True"),
+									LatestEvent: &v1.Event{
+										Type:    "Normal",
+										Message: "User ready",
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+			want: want{
+				// Note: Use spaces instead of tabs for intendation
+				output: `
+NAMESPACE   APIVERSION            NAME                                    READY   SYNCED   LATESTEVENT                                  
+default     test.cloud/v1alpha1   ObjectStorage/test-resource             True    True     [Normal] Successfully selected composition   
+default     test.cloud/v1alpha1    └─ XObjectStorage/test-resource-hash   True    True                                                  
+default     test.cloud/v1alpha1     ├─ Bucket/test-resource-bucket-hash   True    True     [Warning] Error with bucket                  
+default     test.cloud/v1alpha1     └─ User/test-resource-user-hash       True    True     [Normal] User ready                          
+`,
+				err: nil,
+			},
+		},
+	}
+
+	for name, tc := range cases {
+		t.Run(name, func(t *testing.T) {
+			p := DefaultPrinter{
+				Indent: " ",
+			}
+			var buf bytes.Buffer
+			err := p.Print(&buf, tc.args.resource)
+			got := buf.String()
+
+			// Check error
+			if diff := cmp.Diff(tc.want.err, err, test.EquateErrors()); diff != "" {
+				t.Errorf("%s\nCliTableAddResource(): -want, +got:\n%s", tc.reason, diff)
+			}
+			// Check table
+			if diff := cmp.Diff(strings.TrimSpace(tc.want.output), strings.TrimSpace(got)); diff != "" {
+				t.Errorf("%s\nCliTableAddResource(): -want, +got:\n%s", tc.reason, diff)
+			}
+		})
+	}
+
+}