Add createpod element

go.mod

@@ -16,6 +16,7 @@ require (
 	golang.org/x/tools v0.0.0-20200812195022-5ae4c3c160a0 // indirect
 	google.golang.org/grpc v1.35.0
 	google.golang.org/protobuf v1.25.0
+	k8s.io/api v0.20.1
 	k8s.io/apimachinery v0.20.1
 	k8s.io/client-go v0.20.1
 	k8s.io/kubelet v0.20.1

pkg/networkservice/common/createpod/option.go

@@ -0,0 +1,45 @@
+// Copyright (c) 2021 Doc.ai and/or its affiliates.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// 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 createpod
+
+// Option is an option for the createpod server
+type Option func(t *createPodServer)
+
+// WithNamespace sets namespace in which new pods will be created. Default value is "default".
+func WithNamespace(namespace string) Option {
+	return func(t *createPodServer) {
+		t.namespace = namespace
+	}
+}
+
+// WithLabelsKey sets labels key value. Default value is "NSM_LABELS".
+//
+// Environment variable with specified labels key is set on pod creation,
+// to notify the pod about the node it is being create on.
+func WithLabelsKey(labelsKey string) Option {
+	return func(t *createPodServer) {
+		t.labelsKey = labelsKey
+	}
+}
+
+// WithNameGenerator sets function to be used for pod name generation.
+// Default behavior is to append "-nodeName=<nodeName>" to the template name.
+func WithNameGenerator(nameGenerator func(templateName, nodeName string) string) Option {
+	return func(t *createPodServer) {
+		t.nameGenerator = nameGenerator
+	}
+}

pkg/networkservice/common/createpod/server.go

@@ -0,0 +1,92 @@
+// Copyright (c) 2021 Doc.ai and/or its affiliates.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// 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 createpod provides server chain element that creates pods with specified parameters on demand
+package createpod
+
+import (
+	"context"
+
+	"github.com/golang/protobuf/ptypes/empty"
+	"github.com/networkservicemesh/api/pkg/api/networkservice"
+	"github.com/networkservicemesh/sdk/pkg/networkservice/core/next"
+	"github.com/pkg/errors"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/kubernetes"
+)
+
+const (
+	nodeNameKey = "NodeNameKey"
+)
+
+type createPodServer struct {
+	client        kubernetes.Interface
+	podTemplate   *corev1.Pod
+	namespace     string
+	labelsKey     string
+	nameGenerator func(templateName, nodeName string) string
+}
+
+// NewServer - returns a new server chain element that creates new pods using provided template.
+//
+// Pods are created on the node with a name specified by key "NodeNameKey" in request labels
+// (this label is expected to be filled by clientinfo client).
+func NewServer(client kubernetes.Interface, podTemplate *corev1.Pod, options ...Option) networkservice.NetworkServiceServer {
+	s := &createPodServer{
+		podTemplate: podTemplate.DeepCopy(),
+		client:      client,
+		namespace:   "default",
+		labelsKey:   "NSM_LABELS",
+		nameGenerator: func(templateName, nodeName string) string {
+			return templateName + "-nodeName=" + nodeName
+		},
+	}
+
+	for _, opt := range options {
+		opt(s)
+	}
+
+	return s
+}
+
+func (s *createPodServer) Request(ctx context.Context, request *networkservice.NetworkServiceRequest) (*networkservice.Connection, error) {
+	nodeName := request.GetConnection().GetLabels()[nodeNameKey]
+	if nodeName == "" {
+		return nil, errors.New("NodeNameKey not set")
+	}
+
+	podTemplate := s.podTemplate.DeepCopy()
+	podTemplate.ObjectMeta.Name = s.nameGenerator(podTemplate.ObjectMeta.Name, nodeName)
+	podTemplate.Spec.NodeName = nodeName
+	for i := range podTemplate.Spec.Containers {
+		podTemplate.Spec.Containers[i].Env = append(podTemplate.Spec.Containers[i].Env, corev1.EnvVar{
+			Name:  s.labelsKey,
+			Value: "nodeName: " + nodeName,
+		})
+	}
+
+	_, err := s.client.CoreV1().Pods(s.namespace).Create(ctx, podTemplate, metav1.CreateOptions{})
+	if err != nil {
+		return nil, errors.WithStack(err)
+	}
+
+	return nil, errors.New("cannot provide required networkservice")
+}
+
+func (s *createPodServer) Close(ctx context.Context, conn *networkservice.Connection) (*empty.Empty, error) {
+	return next.Server(ctx).Close(ctx, conn)
+}

pkg/networkservice/common/createpod/server_test.go

@@ -0,0 +1,151 @@
+// Copyright (c) 2021 Doc.ai and/or its affiliates.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// 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 createpod_test
+
+import (
+	"context"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/networkservicemesh/api/pkg/api/networkservice"
+	"github.com/networkservicemesh/sdk/pkg/networkservice/common/clientinfo"
+	"github.com/networkservicemesh/sdk/pkg/networkservice/core/adapters"
+	"github.com/networkservicemesh/sdk/pkg/networkservice/core/next"
+	"github.com/stretchr/testify/require"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/kubernetes/fake"
+
+	"github.com/networkservicemesh/sdk-k8s/pkg/networkservice/common/createpod"
+)
+
+const (
+	testNamespace = "pod-ns-name"
+	nodeName1     = "node1"
+	nodeName2     = "node2"
+)
+
+func TestCreatePod_RepeatedRequest(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+
+	clientSet := fake.NewSimpleClientset()
+
+	podTemplate := defaultPodTemplate()
+
+	server := next.NewNetworkServiceServer(
+		adapters.NewClientToServer(clientinfo.NewClient()),
+		createpod.NewServer(clientSet, podTemplate, createpod.WithNamespace(testNamespace)),
+	)
+
+	err := os.Setenv("NODE_NAME", nodeName1)
+	require.NoError(t, err)
+
+	// first request: should succeed
+	_, err = server.Request(ctx, &networkservice.NetworkServiceRequest{
+		Connection: &networkservice.Connection{},
+	})
+	require.Error(t, err)
+	require.Equal(t, "cannot provide required networkservice", err.Error())
+
+	// second request: should fail
+	_, err = server.Request(ctx, &networkservice.NetworkServiceRequest{
+		Connection: &networkservice.Connection{},
+	})
+	require.Error(t, err)
+	require.Equal(t, "pods \""+podTemplate.ObjectMeta.Name+"-nodeName="+nodeName1+"\" already exists", err.Error())
+
+	podList, err := clientSet.CoreV1().Pods(testNamespace).List(ctx, metav1.ListOptions{})
+	require.NoError(t, err)
+	require.Equal(t, 1, len(podList.Items))
+	pod := podList.Items[0]
+
+	want := podTemplate.DeepCopy()
+	want.Spec.NodeName = nodeName1
+	want.Spec.Containers[0].Env = []corev1.EnvVar{{Name: "NSM_LABELS", Value: "nodeName: " + nodeName1}}
+	want.Spec.Containers[1].Env = []corev1.EnvVar{{Name: "NSM_LABELS", Value: "nodeName: " + nodeName1}}
+	require.Equal(t, pod.Spec, want.Spec)
+
+	err = clientSet.CoreV1().Pods(testNamespace).Delete(ctx, pod.ObjectMeta.Name, metav1.DeleteOptions{})
+	require.NoError(t, err)
+
+	// third request: should succeed because the pod has died
+	_, err = server.Request(ctx, &networkservice.NetworkServiceRequest{
+		Connection: &networkservice.Connection{},
+	})
+	require.Error(t, err)
+	require.Equal(t, "cannot provide required networkservice", err.Error())
+}
+
+func TestCreatePod_TwoNodes(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+
+	clientSet := fake.NewSimpleClientset()
+
+	podTemplate := defaultPodTemplate()
+
+	server := next.NewNetworkServiceServer(
+		adapters.NewClientToServer(clientinfo.NewClient()),
+		createpod.NewServer(clientSet, podTemplate, createpod.WithNamespace(testNamespace)),
+	)
+
+	err := os.Setenv("NODE_NAME", nodeName1)
+	require.NoError(t, err)
+
+	_, err = server.Request(ctx, &networkservice.NetworkServiceRequest{
+		Connection: &networkservice.Connection{},
+	})
+	require.Error(t, err)
+	require.Equal(t, "cannot provide required networkservice", err.Error())
+
+	err = os.Setenv("NODE_NAME", nodeName2)
+	require.NoError(t, err)
+
+	_, err = server.Request(ctx, &networkservice.NetworkServiceRequest{
+		Connection: &networkservice.Connection{},
+	})
+	require.Error(t, err)
+	require.Equal(t, "cannot provide required networkservice", err.Error())
+
+	podList, err := clientSet.CoreV1().Pods(testNamespace).List(ctx, metav1.ListOptions{})
+	require.NoError(t, err)
+	require.Equal(t, 2, len(podList.Items))
+	require.Equal(t, nodeName1, podList.Items[0].Spec.NodeName)
+	require.Equal(t, nodeName2, podList.Items[1].Spec.NodeName)
+}
+
+func defaultPodTemplate() *corev1.Pod {
+	return &corev1.Pod{
+		ObjectMeta: metav1.ObjectMeta{
+			Name: "PodName",
+		},
+		Spec: corev1.PodSpec{
+			Containers: []corev1.Container{
+				{
+					Name:  "my-container-1",
+					Image: "my-image-1",
+				},
+				{
+					Name:  "my-container-2",
+					Image: "my-image-2",
+				},
+			},
+		},
+	}
+}