发送 gRPC 请求时查找端点（服务器）地址

huangapple
go评论122阅读模式
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

  1. kubeConfig, err = clientcmd.BuildConfigFromFlags("", "/path/to/kubeconfig")
  2. if err != nil {
  3.     // 处理错误
  4. }
  6. kubeClient, err = kubernetes.NewForConfig(kubeConfig)
  7. if err != nil {
  8.     // 处理错误
  9. }

}

func main() {
r := manual.NewBuilderWithScheme("grpc")

  1. // 获取 gRPC 服务的 Pod 的 IP 和端口
  2. address, port, err := GetPodIPAndPort("grpc-service")
  3. if err != nil {
  4.     // 处理错误
  5. }
  7. // 将服务器地址添加到解析器
  8. r.InitialState(resolver.State{Addresses: []resolver.Address{
  9.     {Addr: fmt.Sprintf("%s:%d", address, port)},
  10. }})
  12. dialer := grpc.WithResolver(r).DialContext
  14. // 使用拨号器创建与服务器的连接
  15. conn, err := grpc.DialContext(ctx, "grpc://service-name", dialer)
  16. if err != nil {
  17.     // 处理错误
  18. }
  20. // 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
}
}

  1. // 获取端点列表中第一个 Pod 的 IP 和端口
  2. if len(endpoints.Subsets) == 0 {
  3.     return "", 0, fmt.Errorf("未找到服务的 Pod：%s", serviceName)
  4. }
  5. address := endpoints.Subsets[0].Addresses[0].IP
  6. port := endpoints.Subsets[0].Ports[0].Port
  8. 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: 
  1.     import (
  2.     "context"
  3.     "fmt"
  4.     "google.golang.org/grpc"
  5.     "k8s.io/client-go/kubernetes"
  6.     "k8s.io/client-go/rest"
  7.     "k8s.io/client-go/tools/clientcmd"
  8.     "k8s.io/client-go/util/retry"
  9.     "k8s.io/apimachinery/pkg/api/errors"
  10.     "k8s.io/apimachinery/pkg/api/resource"
  11.     "k8s.io/apimachinery/pkg/apis/meta/v1"
  12. )
  14. var kubeClient kubernetes.Interface
  15. var kubeConfig *rest.Config
  17. func init() {
  18.     var err error
  20.     kubeConfig, err = clientcmd.BuildConfigFromFlags("", "/path/to/kubeconfig")
  21.     if err != nil {
  22.         // handle error
  23.     }
  25.     kubeClient, err = kubernetes.NewForConfig(kubeConfig)
  26.     if err != nil {
  27.         // handle error
  28.     }
  29. }
  31. func main() {
  32.     r := manual.NewBuilderWithScheme("grpc")
  34.     // get the IP and port of the pod for the gRPC service
  35.     address, port, err := GetPodIPAndPort("grpc-service")
  36.     if err != nil {
  37.         // handle error
  38.     }
  40.     // add the server address to the resolver
  41.     r.InitialState(resolver.State{Addresses: []resolver.Address{
  42.         {Addr: fmt.Sprintf("%s:%d", address, port)},
  43.     }})
  45.     dialer := grpc.WithResolver(r).DialContext
  47.     // use the dialer to create a connection to the server
  48.     conn, err := grpc.DialContext(ctx, "grpc://service-name", dialer)
  49.     if err != nil {
  50.         // handle error
  51.     }
  53.     // do gRPC 
  54. }
  56. func GetPodIPAndPort(serviceName string) (string, int32, error) {
  57.     // get the endpoints for the service
  58.     endpoints, err := kubeClient.CoreV1().Endpoints("default").Get(context.TODO(), serviceName, v1.GetOptions{})
  59.     if err != nil {
  60.         if errors.IsNotFound(err) {
  61.             return "", 0, fmt.Errorf("service not found: %s", serviceName)
  62.         } else {
  63.             return "", 0, err
  64.         }
  65.     }
  67.     // get the IP and port of the first pod in the endpoints list
  68.     if len(endpoints.Subsets) == 0 {
  69.         return "", 0, fmt.Errorf("no pods found for service: %s", serviceName)
  70.     }
  71.     address := endpoints.Subsets[0].Addresses[0].IP
  72.     port := endpoints.Subsets[0].Ports[0].Port
  74.     return address, port, nil
  75. }

For getting specific pod details we need to use kubernetes apis.

huangapple
  • 本文由 发表于 2023年3月30日 12:30:35
  • 转载请务必保留本文链接：https://go.coder-hub.com/75884146.html
  • go
  • grpc
  • grpc-go
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