Go 中来自 Kubernetes 的云 SQL 连接 - 错误 403:权限不足

我需要使用 Go 从 Kubernetes pod 连接到 Google Cloud SQL。

我一直虔诚地遵循以下指南： https://cloud.google.com/sql/docs/mysql/connect-kubernetes-engine https://cloud.google.com/sql/docs/mysql/connect-external-app#go

这是我的 Kubernetes 部署 yaml 文件：

---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: my-service
  labels:
    app: my-service
spec:
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 10%
      maxSurge: 10%
  replicas: 1
  template:
    metadata:
      labels:
        app: my-service
    spec:
      imagePullSecrets:
      - name: regsecret
      containers:
      - name: my-service
        image: my-image
        imagePullPolicy: IfNotPresent
        env:
          - name: DB_INSTANCE
            value: "my-project-id:europe-west1:uk"
          - name: DB_USERNAME
            valueFrom:
              secretKeyRef:
                name: cloudsql-db-credentials
                key: username
          - name: DB_PASSWORD
            valueFrom:
              secretKeyRef:
                name: cloudsql-db-credentials
                key: password
      - name: cloudsql-proxy
        image: gcr.io/cloudsql-docker/gce-proxy:1.11
        command: ["/cloud_sql_proxy",
                  "-instances=my-project-id:europe-west1:uk=tcp:3306",
                  "-credential_file=/secrets/cloudsql/credentials.json"]
        volumeMounts:
          - name: cloudsql-instance-credentials
            mountPath: /secrets/cloudsql
            readOnly: true
      volumes:
        - name: cloudsql-instance-credentials
          secret:
            secretName: cloudsql-instance-credentials

这是我尝试使用 Go 进行连接的尝试：

import (
    "github.com/GoogleCloudPlatform/cloudsql-proxy/proxy/dialers/mysql"
    "github.com/spf13/viper"
    "log"
)
func Connect() {
    cfg := mysql.Cfg(
        viper.GetString("DB_INSTANCE"),
        viper.GetString("DB_USERNAME"),
        viper.GetString("DB_PASSWORD"))
    cfg.DBName = "my-db-name"
    db, err := mysql.DialCfg(cfg)
    if err != nil {
        log.Fatalf("Failed to create the Cloud SQL client: %v", err)
    }
}

遗憾的是，运行此代码会导致：

2018/08/08 15:19:45 Failed to create the Cloud SQL client: ensure that the Cloud SQL API is enabled for your project (https://console.cloud.google.com/flows/enableapi?apiid=sqladmin). Error during createEphemeral for my-project-id:europe-west1:uk: googleapi: Error 403: Insufficient Permission, insufficientPermissions

我可以确认该数据库显然存在于 Cloud SQL 中，Cloud SQL API 确实已启用，并且我用于生成凭据的服务帐户(如上述链接中所述(确实附加了 Cloud SQL 客户端角色(我也尝试过使用 Cloud SQL 管理员甚至项目所有者，但没有成功(。

我错过了什么？

编辑：

通过将我的 Go 代码更新为：

dsn := fmt.Sprintf("%s:%s@tcp(%s)/%s",
    viper.GetString("DB_USERNAME"),
    viper.GetString("DB_PASSWORD"),
    "127.0.0.1:3306",
    "my-db-name")
db, err := sql.Open("mysql", dsn)
if err != nil {
    log.Fatalf("Failed to create the Cloud SQL client: %v", err)
}

感谢@DazWilkin提示。