套接字：连接到cloudsql时不允许进行操作

When trying to connect with the following settings I get a socket:operation not permitted error on app engine, but not locally when using cloud-sql-proxy. The following code works locally but not with app engine:

connString = "user=USER_NAME password=PASSWORD host=/cloudsql/INSTANCE_NAME dbname=DB_NAME"
DBCon, err2 = sql.Open("postgres", connString)

Both the app engine and cloud sql are in the same project. Does anyone have any insight on what I am missing?

My App Engine projects use MySQL, but connections should theoretically be the same. Here is how I connect. Let me know if this doesn't work with Postgres

EDIT for 2nd gen instances

connString:= "@unix(/cloudsql/<your instance>)"
if appengine.IsDevAppServer() {
    connString = "@tcp(<instance ip>:port)"
}
sqlUser := "<your user>"
sqlPass := "<your pass>"
connString = sqlUser + ":" + sqlPass + connString

// connect main db
db, err := sqlx.Connect("mysql", connString)
if err != nil {
    return nil, err
}

Old string for 1st gen: connString := "@cloudsql(<your instance>)"

Unfortunately, Cloud SQL+postgres is not supported on AppEngine standard yet:

"Note: Connection from an App Engine standard environment application to a PostgreSQL instance is not supported"

https://cloud.google.com/sql/docs/postgres/connect-app-engine

NOTE: This is for mysql second version db

main.go

import (
    _ "github.com/go-sql-driver/mysql",
    "database/sql"
)

func InitDB() (err error, db *DB) {
    db, err = sql.Open("mysql", os.Getenv("SQL_STRING"))
}

SQL_STRING: 'username:password@cloudsql(project:region:instance_id)/db'

For more ref https://cloud.google.com/appengine/docs/standard/go/cloud-sql/reference