英文:
Finding endpoint (server) address when sending gRPC requests
问题
在客户端发送gRPC请求时,有没有办法获取端点(服务器)地址?我有一个客户端部署,通过gRPC与Kubernetes集群中的服务器部署进行通信。服务器部署位于一个clusterIP后面。我使用clusterIP的名称和端口来建立客户端和服务器之间的连接。如果我使用多个服务器(将副本数设置为大于1),在客户端发送gRPC请求时,有没有办法获取目标服务器地址?我想选择一个特定的服务器,并且我需要它的IP地址。如何在客户端找到它?
我认为grpc/xds可以自动完成这个操作。然而,似乎这样的信息是隐藏的,并且没有API可以访问它。
我正在使用golang。
英文:
Is there anyway to get the endpoint (server) address when sending gRPC requests in client? I have a client deployment talking to a server deployment in a kubernetes cluster through gRPC. Server deployment sits behind a clusterIP. I use clusterIP's name and port to establish a connection between my client and server. If I use more than one server (setting replicas to more than 1), is there any way to get targeted server address when sending gRPC requests at the client side? I want to chose an specific server, and I need its IP address. How can I find it at client side?
I think grpc/xds somehow does this by itself. However, It seems such information is hidden and there is no API to access it.
I am using golang.
答案1
得分: 1
导入 (
"context"
"fmt"
"google.golang.org/grpc"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/rest"
"k8s.io/client-go/tools/clientcmd"
"k8s.io/client-go/util/retry"
"k8s.io/apimachinery/pkg/api/errors"
"k8s.io/apimachinery/pkg/api/resource"
"k8s.io/apimachinery/pkg/apis/meta/v1"
)
var kubeClient kubernetes.Interface
var kubeConfig *rest.Config
func init() {
var err error
kubeConfig, err = clientcmd.BuildConfigFromFlags("", "/path/to/kubeconfig")
if err != nil {
// 处理错误
}
kubeClient, err = kubernetes.NewForConfig(kubeConfig)
if err != nil {
// 处理错误
}
}
func main() {
r := manual.NewBuilderWithScheme("grpc")
// 获取 gRPC 服务的 Pod 的 IP 和端口
address, port, err := GetPodIPAndPort("grpc-service")
if err != nil {
// 处理错误
}
// 将服务器地址添加到解析器
r.InitialState(resolver.State{Addresses: []resolver.Address{
{Addr: fmt.Sprintf("%s:%d", address, port)},
}})
dialer := grpc.WithResolver(r).DialContext
// 使用拨号器创建与服务器的连接
conn, err := grpc.DialContext(ctx, "grpc://service-name", dialer)
if err != nil {
// 处理错误
}
// 进行 gRPC 操作
}
func GetPodIPAndPort(serviceName string) (string, int32, error) {
// 获取服务的端点
endpoints, err := kubeClient.CoreV1().Endpoints("default").Get(context.TODO(), serviceName, v1.GetOptions{})
if err != nil {
if errors.IsNotFound(err) {
return "", 0, fmt.Errorf("未找到服务:%s", serviceName)
} else {
return "", 0, err
}
}
// 获取端点列表中第一个 Pod 的 IP 和端口
if len(endpoints.Subsets) == 0 {
return "", 0, fmt.Errorf("未找到服务的 Pod:%s", serviceName)
}
address := endpoints.Subsets[0].Addresses[0].IP
port := endpoints.Subsets[0].Ports[0].Port
return address, port, nil
}
要获取特定 Pod 的详细信息,我们需要使用 Kubernetes API。
英文:
import (
"context"
"fmt"
"google.golang.org/grpc"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/rest"
"k8s.io/client-go/tools/clientcmd"
"k8s.io/client-go/util/retry"
"k8s.io/apimachinery/pkg/api/errors"
"k8s.io/apimachinery/pkg/api/resource"
"k8s.io/apimachinery/pkg/apis/meta/v1"
)
var kubeClient kubernetes.Interface
var kubeConfig *rest.Config
func init() {
var err error
kubeConfig, err = clientcmd.BuildConfigFromFlags("", "/path/to/kubeconfig")
if err != nil {
// handle error
}
kubeClient, err = kubernetes.NewForConfig(kubeConfig)
if err != nil {
// handle error
}
}
func main() {
r := manual.NewBuilderWithScheme("grpc")
// get the IP and port of the pod for the gRPC service
address, port, err := GetPodIPAndPort("grpc-service")
if err != nil {
// handle error
}
// add the server address to the resolver
r.InitialState(resolver.State{Addresses: []resolver.Address{
{Addr: fmt.Sprintf("%s:%d", address, port)},
}})
dialer := grpc.WithResolver(r).DialContext
// use the dialer to create a connection to the server
conn, err := grpc.DialContext(ctx, "grpc://service-name", dialer)
if err != nil {
// handle error
}
// do gRPC
}
func GetPodIPAndPort(serviceName string) (string, int32, error) {
// get the endpoints for the service
endpoints, err := kubeClient.CoreV1().Endpoints("default").Get(context.TODO(), serviceName, v1.GetOptions{})
if err != nil {
if errors.IsNotFound(err) {
return "", 0, fmt.Errorf("service not found: %s", serviceName)
} else {
return "", 0, err
}
}
// get the IP and port of the first pod in the endpoints list
if len(endpoints.Subsets) == 0 {
return "", 0, fmt.Errorf("no pods found for service: %s", serviceName)
}
address := endpoints.Subsets[0].Addresses[0].IP
port := endpoints.Subsets[0].Ports[0].Port
return address, port, nil
}
For getting specific pod details we need to use kubernetes apis.
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