✨ clusterctl: Suppress "finalizer name" API warnings in "move" command (#11173)

* ✨ util: Warning handler that discards a default set of messages

* ✨ clusterctl: Suppress API warnings in "move" command

* fixup! ✨ util: Warning handler that discards a default set of messages

Move all handlers to one file, expressions to another

* fixup! ✨ clusterctl: Suppress API warnings in "move" command

Allow user to choose which warnings to hide

* fixup! fixup! ✨ util: Warning handler that discards a default set of messages

Make return value easier to consume

* fixup! fixup! ✨ clusterctl: Suppress API warnings in "move" command

Add LogAllHandler for consistent prefix, and DiscardAllHandler for convenience

Author: dlipovetsky

cmd/clusterctl/cmd/move.go

@@ -18,11 +18,17 @@ package cmd
 
 import (
 	"context"
+	"fmt"
 
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
+	"k8s.io/client-go/rest"
 
 	"sigs.k8s.io/cluster-api/cmd/clusterctl/client"
+	"sigs.k8s.io/cluster-api/cmd/clusterctl/client/cluster"
+	"sigs.k8s.io/cluster-api/cmd/clusterctl/client/config"
+	logf "sigs.k8s.io/cluster-api/cmd/clusterctl/log"
+	"sigs.k8s.io/cluster-api/util/apiwarnings"
 )
 
 type moveOptions struct {
@@ -34,6 +40,7 @@ type moveOptions struct {
 	fromDirectory         string
 	toDirectory           string
 	dryRun                bool
+	hideAPIWarnings       string
 }
 
 var mo = &moveOptions{}
@@ -80,6 +87,8 @@ func init() {
 		"Write Cluster API objects and all dependencies from a management cluster to directory.")
 	moveCmd.Flags().StringVar(&mo.fromDirectory, "from-directory", "",
 		"Read Cluster API objects and all dependencies from a directory into a management cluster.")
+	moveCmd.Flags().StringVar(&mo.hideAPIWarnings, "hide-api-warnings", "default",
+		"Set of API server warnings to hide. Valid sets are \"default\" (includes metadata.finalizer warnings), \"all\" , and \"none\".")
 
 	moveCmd.MarkFlagsMutuallyExclusive("to-directory", "to-kubeconfig")
 	moveCmd.MarkFlagsMutuallyExclusive("from-directory", "to-directory")
@@ -98,7 +107,55 @@ func runMove() error {
 		return errors.New("please specify a target cluster using the --to-kubeconfig flag when not using --dry-run, --to-directory or --from-directory")
 	}
 
-	c, err := client.New(ctx, cfgFile)
+	configClient, err := config.New(ctx, cfgFile)
+	if err != nil {
+		return err
+	}
+
+	clientOptions := []client.Option{}
+
+	var warningHandler rest.WarningHandler
+	switch mo.hideAPIWarnings {
+	case "all":
+		// Hide all warnings.
+		warningHandler = apiwarnings.DiscardAllHandler
+	case "default":
+		// Hide only the default set of warnings.
+		warningHandler = apiwarnings.DefaultHandler(logf.Log.WithName("API Server Warning"))
+	case "none":
+		// Hide no warnings.
+		warningHandler = apiwarnings.LogAllHandler(logf.Log.WithName("API Server Warning"))
+	default:
+		return fmt.Errorf(
+			"set of API warnings %q is unknown; choose \"default\", \"all\", or \"none\"",
+			mo.hideAPIWarnings,
+		)
+	}
+
+	if warningHandler != nil {
+		clientOptions = append(clientOptions,
+			client.InjectClusterClientFactory(
+				func(input client.ClusterClientFactoryInput) (cluster.Client, error) {
+					return cluster.New(
+						cluster.Kubeconfig(input.Kubeconfig),
+						configClient,
+						cluster.InjectYamlProcessor(input.Processor),
+						cluster.InjectProxy(
+							cluster.NewProxy(
+								cluster.Kubeconfig(input.Kubeconfig),
+								cluster.InjectWarningHandler(
+									warningHandler,
+								),
+							)),
+					), nil
+				},
+			),
+			// Ensure that the same configClient used by both the client constructor, and the cluster client factory.
+			client.InjectConfig(configClient),
+		)
+	}
+
+	c, err := client.New(ctx, cfgFile, clientOptions...)
 	if err != nil {
 		return err
 	}

util/apiwarnings/expressions.go

@@ -0,0 +1,30 @@
+/*
+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 apiwarnings
+
+import (
+	"fmt"
+	"regexp"
+)
+
+// DomainQualifiedFinalizerWarning is a regular expression that matches a
+// warning that the API server returns when a finalizer is not domain-qualified.
+func DomainQualifiedFinalizerWarning(domain string) regexp.Regexp {
+	return *regexp.MustCompile(
+		fmt.Sprintf("^metadata.finalizers:.*%s.*prefer a domain-qualified finalizer name to avoid accidental conflicts with other finalizer writers$", domain),
+	)
+}

util/apiwarnings/handler.go

@@ -20,6 +20,9 @@ import (
 	"regexp"
 
 	"github.com/go-logr/logr"
+	"k8s.io/client-go/rest"
+
+	clusterv1 "sigs.k8s.io/cluster-api/api/v1beta1"
 )
 
 // DiscardMatchingHandler is a handler that discards API server warnings
@@ -49,3 +52,23 @@ func (h *DiscardMatchingHandler) HandleWarningHeader(code int, _, message string
 
 	h.Logger.Info(message)
 }
+
+// DefaultHandler is a handler that discards warnings that are the result of
+// decisions made by the Cluster API project, but cannot be immediately
+// addressed, and are therefore not helpful to the user.
+func DefaultHandler(l logr.Logger) *DiscardMatchingHandler {
+	return &DiscardMatchingHandler{
+		Logger: l,
+		Expressions: []regexp.Regexp{
+			DomainQualifiedFinalizerWarning(clusterv1.GroupVersion.Group),
+		},
+	}
+}
+
+// DiscardAllHandler is a handler that discards all warnings.
+var DiscardAllHandler = rest.NoWarnings{}
+
+// LogAllHandler is a handler that logs all warnings.
+func LogAllHandler(l logr.Logger) rest.WarningHandler {
+	return &DiscardMatchingHandler{Logger: l}
+}

util/apiwarnings/handler_test.go

@@ -95,3 +95,83 @@ func TestDiscardMatchingHandler_uninitialized(t *testing.T) {
 		h.HandleWarningHeader(299, "", "example")
 	}).ToNot(Panic())
 }
+
+func TestDefaultHandler(t *testing.T) {
+	tests := []struct {
+		name       string
+		code       int
+		message    string
+		wantLogged bool
+	}{
+		{
+			name:       "log, if warning does not match any expression",
+			code:       299,
+			message:    `metadata.finalizers: "foo.example.com": prefer a domain-qualified finalizer name to avoid accidental conflicts with other finalizer writers`,
+			wantLogged: true,
+		},
+		{
+			name:       "do not log, if warning matches at least one expression",
+			code:       299,
+			message:    `metadata.finalizers: "dockermachine.infrastructure.cluster.x-k8s.io": prefer a domain-qualified finalizer name to avoid accidental conflicts with other finalizer writers`,
+			wantLogged: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			g := NewWithT(t)
+			logged := false
+			h := DefaultHandler(
+				funcr.New(func(_, _ string) {
+					logged = true
+				},
+					funcr.Options{},
+				),
+			)
+			h.HandleWarningHeader(tt.code, "", tt.message)
+			g.Expect(logged).To(Equal(tt.wantLogged))
+		})
+	}
+}
+
+func TestLogAllHandler(t *testing.T) {
+	tests := []struct {
+		name       string
+		code       int
+		message    string
+		wantLogged bool
+	}{
+		{
+			name:       "log, if code is 299, and message is not empty",
+			code:       299,
+			message:    "warning",
+			wantLogged: true,
+		},
+		{
+			name:       "do not log, if code is not 299",
+			code:       0,
+			message:    "warning",
+			wantLogged: false,
+		},
+		{
+			name:       "do not log, if message is empty",
+			code:       299,
+			message:    "",
+			wantLogged: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			g := NewWithT(t)
+			logged := false
+			h := LogAllHandler(
+				funcr.New(func(_, _ string) {
+					logged = true
+				},
+					funcr.Options{},
+				),
+			)
+			h.HandleWarningHeader(tt.code, "", tt.message)
+			g.Expect(logged).To(Equal(tt.wantLogged))
+		})
+	}
+}