Add basic support for notifications package

PROVIDER.md

@@ -137,7 +137,18 @@ func init() {
 	i2gw.ProviderConstructorByName[Name] = NewProvider
 }
 ```
-6. Import the new package at `cmd/print`.
+6. [optional] In order to use notification mechanism, create a `notify` function in a file named `notification.go`. This method is used to reduce the function signature for creating notifications during the conversion process.
+```go
+package examplegateway
+
+import "github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw/notifications"
+
+func notify(mType notifications.MessageType, message string) {
+	newNotification := notifications.Notification{Type: mType, Message: message}
+    notifications.CommonNotification.DispatchNotication(newNotification, string(ProviderName))
+}
+```
+7. Import the new package at `cmd/print`.
 ```go
 package cmd
 

cmd/print.go

@@ -36,6 +36,9 @@ import (
 	_ "github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw/providers/istio"
 	_ "github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw/providers/kong"
 	_ "github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw/providers/openapi3"
+
+	// Call init for notifications
+	_ "github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw/notifications"
 )
 
 type PrintRunner struct {
@@ -82,11 +85,15 @@ func (pr *PrintRunner) PrintGatewayAPIObjects(cmd *cobra.Command, _ []string) er
 		return fmt.Errorf("failed to initialize namespace filter: %w", err)
 	}
 
-	gatewayResources, err := i2gw.ToGatewayAPIResources(cmd.Context(), pr.namespaceFilter, pr.inputFile, pr.providers, pr.getProviderSpecificFlags())
+	gatewayResources, notificationTablesMap, err := i2gw.ToGatewayAPIResources(cmd.Context(), pr.namespaceFilter, pr.inputFile, pr.providers, pr.getProviderSpecificFlags())
 	if err != nil {
 		return err
 	}
 
+	for _, table := range notificationTablesMap {
+		fmt.Println(table)
+	}
+
 	pr.outputResult(gatewayResources)
 
 	return nil

go.mod

@@ -6,6 +6,7 @@ require (
 	github.com/getkin/kin-openapi v0.124.0
 	github.com/google/go-cmp v0.6.0
 	github.com/kong/kubernetes-ingress-controller/v2 v2.12.3
+	github.com/olekukonko/tablewriter v0.0.5
 	github.com/samber/lo v1.39.0
 	github.com/spf13/cobra v1.8.0
 	github.com/stretchr/testify v1.9.0
@@ -14,18 +15,19 @@ require (
 	k8s.io/apimachinery v0.28.4
 	k8s.io/cli-runtime v0.28.4
 	k8s.io/client-go v0.28.4
-	k8s.io/klog v0.2.0
 	k8s.io/utils v0.0.0-20231121161247-cf03d44ff3cf
 	sigs.k8s.io/controller-runtime v0.16.3
 	sigs.k8s.io/gateway-api v1.0.0
 )
 
 require (
 	github.com/invopop/yaml v0.2.0 // indirect
+	github.com/mattn/go-runewidth v0.0.15 // indirect
 	github.com/matttproud/golang_protobuf_extensions/v2 v2.0.0 // indirect
 	github.com/mohae/deepcopy v0.0.0-20170929034955-c48cc78d4826 // indirect
 	github.com/perimeterx/marshmallow v1.1.5 // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
+	github.com/rivo/uniseg v0.2.0 // indirect
 	golang.org/x/exp v0.0.0-20231006140011-7918f672742d // indirect
 )
 
@@ -45,7 +47,7 @@ require (
 	github.com/google/gnostic-models v0.6.9-0.20230804172637-c7be7c783f49 // indirect
 	github.com/google/gofuzz v1.2.0 // indirect
 	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 // indirect
-	github.com/google/uuid v1.4.0 // indirect
+	github.com/google/uuid v1.6.0 // indirect
 	github.com/gregjones/httpcache v0.0.0-20190611155906-901d90724c79 // indirect
 	github.com/imdario/mergo v0.3.16 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
@@ -65,8 +67,8 @@ require (
 	golang.org/x/net v0.18.0 // indirect
 	golang.org/x/oauth2 v0.14.0 // indirect
 	golang.org/x/sync v0.5.0 // indirect
-	golang.org/x/sys v0.14.0 // indirect
-	golang.org/x/term v0.14.0 // indirect
+	golang.org/x/sys v0.17.0 // indirect
+	golang.org/x/term v0.17.0 // indirect
 	golang.org/x/text v0.14.0 // indirect
 	golang.org/x/time v0.4.0 // indirect
 	google.golang.org/appengine v1.6.8 // indirect

go.sum

@@ -53,12 +53,14 @@ github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeN
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/gofuzz v1.2.0 h1:xRy4A+RhZaiKjJ1bPfwQ8sedCA+YS2YcCHW6ec7JMi0=
 github.com/google/gofuzz v1.2.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
+github.com/google/pprof v0.0.0-20210720184732-4bb14d4b1be1 h1:K6RDEckDVWvDI9JAJYCmNdQXq6neHJOYx3V6jnqNEec=
+github.com/google/pprof v0.0.0-20210720184732-4bb14d4b1be1/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
 github.com/google/pprof v0.0.0-20211214055906-6f57359322fd h1:1FjCyPC+syAzJ5/2S8fqdZK1R22vvA0J7JZKcuOIQ7Y=
 github.com/google/pprof v0.0.0-20211214055906-6f57359322fd/go.mod h1:KgnwoLYCZ8IQu3XUZ8Nc/bM9CCZFOyjUNOSygVozoDg=
 github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 h1:El6M4kTTCOh6aBiKaUGG7oYTSPP8MxqL4YI3kZKwcP4=
 github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510/go.mod h1:pupxD2MaaD3pAXIBCelhxNneeOaAeabZDe5s4K6zSpQ=
-github.com/google/uuid v1.4.0 h1:MtMxsa51/r9yyhkyLsVeVt0B+BGQZzpQiTQ4eHZ8bc4=
-github.com/google/uuid v1.4.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/gregjones/httpcache v0.0.0-20190611155906-901d90724c79 h1:+ngKgrYPPJrOjhax5N+uePQ0Fh1Z7PheYoUI/0nzkPA=
 github.com/gregjones/httpcache v0.0.0-20190611155906-901d90724c79/go.mod h1:FecbI9+v66THATjSRHfNgh1IVFe/9kFxbXtjV0ctIMA=
 github.com/imdario/mergo v0.3.16 h1:wwQJbIsHYGMUyLSPrEq1CT16AhnhNJQ51+4fdHUnCl4=
@@ -86,6 +88,9 @@ github.com/liggitt/tabwriter v0.0.0-20181228230101-89fcab3d43de h1:9TO3cAIGXtEhn
 github.com/liggitt/tabwriter v0.0.0-20181228230101-89fcab3d43de/go.mod h1:zAbeS9B/r2mtpb6U+EI2rYA5OAXxsYw6wTamcNW+zcE=
 github.com/mailru/easyjson v0.7.7 h1:UGYAvKxe3sBsEDzO8ZeWOSlIQfWFlxbzLZe7hwFURr0=
 github.com/mailru/easyjson v0.7.7/go.mod h1:xzfreul335JAWq5oZzymOObrkdz5UnU4kGfJJLY9Nlc=
+github.com/mattn/go-runewidth v0.0.9/go.mod h1:H031xJmbD/WCDINGzjvQ9THkh0rPKHF+m2gUSrubnMI=
+github.com/mattn/go-runewidth v0.0.15 h1:UNAjwbU9l54TA3KzvqLGxwWjHmMgBUVhBiTjelZgg3U=
+github.com/mattn/go-runewidth v0.0.15/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
 github.com/matttproud/golang_protobuf_extensions/v2 v2.0.0 h1:jWpvCLoY8Z/e3VKvlsiIGKtc+UG6U5vzxaoagmhXfyg=
 github.com/matttproud/golang_protobuf_extensions/v2 v2.0.0/go.mod h1:QUyp042oQthUoa9bqDv0ER0wrtXnBruoNd7aNjkbP+k=
 github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
@@ -99,6 +104,8 @@ github.com/monochromegane/go-gitignore v0.0.0-20200626010858-205db1a8cc00 h1:n6/
 github.com/monochromegane/go-gitignore v0.0.0-20200626010858-205db1a8cc00/go.mod h1:Pm3mSP3c5uWn86xMLZ5Sa7JB9GsEZySvHYXCTK4E9q4=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
+github.com/olekukonko/tablewriter v0.0.5 h1:P2Ga83D34wi1o9J6Wh1mRuqd4mF/x/lgBS7N7AbDhec=
+github.com/olekukonko/tablewriter v0.0.5/go.mod h1:hPp6KlRPjbx+hW8ykQs1w3UBbZlj6HuIJcUGPhkA7kY=
 github.com/onsi/ginkgo v1.16.4 h1:29JGrr5oVBm5ulCWet69zQkzWipVXIol6ygQUe/EzNc=
 github.com/onsi/ginkgo/v2 v2.11.0 h1:WgqUCUt/lT6yXoQ8Wef0fsNn5cAuMK7+KT9UFRz2tcU=
 github.com/onsi/ginkgo/v2 v2.11.0/go.mod h1:ZhrRA5XmEE3x3rhlzamx/JJvujdZoJ2uvgI7kR0iZvM=
@@ -121,6 +128,8 @@ github.com/prometheus/common v0.45.0 h1:2BGz0eBc2hdMDLnO/8n0jeB3oPrt2D08CekT0lne
 github.com/prometheus/common v0.45.0/go.mod h1:YJmSTw9BoKxJplESWWxlbyttQR4uaEcGyv9MZjVOJsY=
 github.com/prometheus/procfs v0.12.0 h1:jluTpSng7V9hY0O2R9DzzJHYb2xULk9VTR1V1R/k6Bo=
 github.com/prometheus/procfs v0.12.0/go.mod h1:pcuDEFsWDnvcgNzo4EEweacyhjeA9Zk3cnaOZAZEfOo=
+github.com/rivo/uniseg v0.2.0 h1:S1pD9weZBuJdFmowNwbpi7BJ8TNftyUImj/0WQi72jY=
+github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
 github.com/rogpeppe/go-internal v1.12.0 h1:exVL4IDcn6na9z1rAb56Vxr+CgyK3nn3O+epU5NdKM8=
 github.com/rogpeppe/go-internal v1.12.0/go.mod h1:E+RYuTGaKKdloAfM02xzb0FW3Paa99yedzYV+kq4uf4=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
@@ -189,12 +198,12 @@ golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.14.0 h1:Vz7Qs629MkJkGyHxUlRHizWJRG2j8fbQKjELVSNhy7Q=
-golang.org/x/sys v0.14.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.17.0 h1:25cE3gD+tdBA7lp7QfhuV+rJiE9YXTcS3VG1SqssI/Y=
+golang.org/x/sys v0.17.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
-golang.org/x/term v0.14.0 h1:LGK9IlZ8T9jvdy6cTdfKUCltatMFOehAQo9SRC46UQ8=
-golang.org/x/term v0.14.0/go.mod h1:TySc+nGkYR6qt8km8wUhuFRTVSMIX3XPR58y2lC8vww=
+golang.org/x/term v0.17.0 h1:mkTF7LCd6WGJNL3K1Ad7kwxNfYAW6a8a8QqtMblp/4U=
+golang.org/x/term v0.17.0/go.mod h1:lLRBjIVuehSbZlaOtGMbcMncT+aqLLLmKrsjNrUguwk=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
@@ -254,8 +263,6 @@ k8s.io/cli-runtime v0.28.4 h1:IW3aqSNFXiGDllJF4KVYM90YX4cXPGxuCxCVqCD8X+Q=
 k8s.io/cli-runtime v0.28.4/go.mod h1:MLGRB7LWTIYyYR3d/DOgtUC8ihsAPA3P8K8FDNIqJ0k=
 k8s.io/client-go v0.28.4 h1:Np5ocjlZcTrkyRJ3+T3PkXDpe4UpatQxj85+xjaD2wY=
 k8s.io/client-go v0.28.4/go.mod h1:0VDZFpgoZfelyP5Wqu0/r/TRYcLYuJ2U1KEeoaPa1N4=
-k8s.io/klog v0.2.0 h1:0ElL0OHzF3N+OhoJTL0uca20SxtYt4X4+bzHeqrB83c=
-k8s.io/klog v0.2.0/go.mod h1:Gq+BEi5rUBO/HRz0bTSXDUcqjScdoY3a9IHpCEIOOfk=
 k8s.io/klog/v2 v2.110.1 h1:U/Af64HJf7FcwMcXyKm2RPM22WZzyR7OSpYj5tg3cL0=
 k8s.io/klog/v2 v2.110.1/go.mod h1:YGtd1984u+GgbuZ7e08/yBuAfKLSO0+uR1Fhi6ExXjo=
 k8s.io/kube-openapi v0.0.0-20231113174909-778a5567bc1e h1:snPmy96t93RredGRjKfMFt+gvxuVAncqSAyBveJtr4Q=

pkg/i2gw/ingress2gateway.go

@@ -21,6 +21,7 @@ import (
 	"fmt"
 	"maps"
 
+	"github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw/notifications"
 	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/apimachinery/pkg/util/validation/field"
 	"sigs.k8s.io/controller-runtime/pkg/client"
@@ -30,18 +31,18 @@ import (
 	gatewayv1beta1 "sigs.k8s.io/gateway-api/apis/v1beta1"
 )
 
-func ToGatewayAPIResources(ctx context.Context, namespace string, inputFile string, providers []string, providerSpecificFlags map[string]map[string]string) ([]GatewayResources, error) {
+func ToGatewayAPIResources(ctx context.Context, namespace string, inputFile string, providers []string, providerSpecificFlags map[string]map[string]string) ([]GatewayResources, map[string]string, error) {
 	var clusterClient client.Client
 
 	if inputFile == "" {
 		conf, err := config.GetConfig()
 		if err != nil {
-			return nil, fmt.Errorf("failed to get client config: %w", err)
+			return nil, nil, fmt.Errorf("failed to get client config: %w", err)
 		}
 
 		cl, err := client.New(conf, client.Options{})
 		if err != nil {
-			return nil, fmt.Errorf("failed to create client: %w", err)
+			return nil, nil, fmt.Errorf("failed to create client: %w", err)
 		}
 		clusterClient = client.NewNamespacedClient(cl, namespace)
 	}
@@ -52,16 +53,16 @@ func ToGatewayAPIResources(ctx context.Context, namespace string, inputFile stri
 		ProviderSpecificFlags: providerSpecificFlags,
 	}, providers)
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 
 	if inputFile != "" {
 		if err = readProviderResourcesFromFile(ctx, providerByName, inputFile); err != nil {
-			return nil, err
+			return nil, nil, err
 		}
 	} else {
 		if err = readProviderResourcesFromCluster(ctx, providerByName); err != nil {
-			return nil, err
+			return nil, nil, err
 		}
 	}
 
@@ -74,11 +75,12 @@ func ToGatewayAPIResources(ctx context.Context, namespace string, inputFile stri
 		errs = append(errs, conversionErrs...)
 		gatewayResources = append(gatewayResources, providerGatewayResources)
 	}
+	notificationTablesMap := notifications.NotificationAggr.CreateNotificationTables()
 	if len(errs) > 0 {
-		return nil, aggregatedErrs(errs)
+		return nil, notificationTablesMap, aggregatedErrs(errs)
 	}
 
-	return gatewayResources, nil
+	return gatewayResources, notificationTablesMap, nil
 }
 
 func readProviderResourcesFromFile(ctx context.Context, providerByName map[ProviderName]Provider, inputFile string) error {

pkg/i2gw/notifications/notifications.go

@@ -0,0 +1,99 @@
+/*
+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 notifications
+
+import (
+	"fmt"
+	"strings"
+	"sync"
+
+	"sigs.k8s.io/controller-runtime/pkg/client"
+
+	"github.com/olekukonko/tablewriter"
+)
+
+func init() {
+	NotificationAggr = NotificationAggregator{Notifications: map[string][]Notification{}}
+}
+
+const (
+	InfoNotification    MessageType = "INFO"
+	WarningNotification MessageType = "WARNING"
+	ErrorNotification   MessageType = "ERROR"
+)
+
+type MessageType string
+
+type Notification struct {
+	Type           MessageType
+	Message        string
+	CallingObjects []client.Object
+}
+
+type NotificationAggregator struct {
+	mutex         sync.Mutex
+	Notifications map[string][]Notification
+}
+
+var NotificationAggr NotificationAggregator
+
+// DispatchNotification is used to send a notification to the NotificationAggregator
+func (na *NotificationAggregator) DispatchNotification(notification Notification, ProviderName string) {
+	na.mutex.Lock()
+	na.Notifications[ProviderName] = append(na.Notifications[ProviderName], notification)
+	na.mutex.Unlock()
+}
+
+// CreateNotificationTables takes all generated notifications and returns a map[string]string
+// that displays the notifications in a tabular format based on provider
+func (na *NotificationAggregator) CreateNotificationTables() map[string]string {
+	notificationTablesMap := make(map[string]string)
+
+	for provider, msgs := range na.Notifications {
+		providerTable := strings.Builder{}
+
+		t := tablewriter.NewWriter(&providerTable)
+		t.SetHeader([]string{"Message Type", "Notification", "Calling Object"})
+		t.SetColWidth(200)
+		t.SetRowLine(true)
+
+		for _, n := range msgs {
+			row := []string{string(n.Type), n.Message, convertObjectsToStr(n.CallingObjects)}
+			t.Append(row)
+		}
+
+		providerTable.WriteString(fmt.Sprintf("Notifications from %v:\n", strings.ToUpper(provider)))
+		t.Render()
+		notificationTablesMap[provider] = providerTable.String()
+	}
+
+	return notificationTablesMap
+}
+
+func convertObjectsToStr(ob []client.Object) string {
+	var sb strings.Builder
+
+	for i, o := range ob {
+		if i > 0 {
+			sb.WriteString(", ")
+		}
+		object := o.GetObjectKind().GroupVersionKind().Kind + ": " + client.ObjectKeyFromObject(o).String()
+		sb.WriteString(object)
+	}
+
+	return sb.String()
+}