Golang SSH tunneling connection to a remote postgres DB - postgresql

Question

I have looked at various resources. I'm not sure how to accomplish this task. I can connect locally no problem, but I cannot connect to the remote easily. I need to pass on an RSA .pem key, and I'm not quite sure how to do this w/o forcing a connection unsecured
package main
import (
"database/sql"
"fmt"
"os"
_ "github.com/lib/pq"
)
var (
dbUser = os.Getenv("DB_USER")
dbPass = os.Getenv("DB_PASS")
dbName = os.Getenv("DB_NAME")
dbHost = os.Getenv("DB_HOST")
dbPort = os.Getenv("DB_PORT")
sslMode = os.Getenv("SSLMODE")
)
// ConnectDb is a short cut function that takes parameters through
// CLI that returns a pointer to a sql.DB connection.
// It takes no arguments.
func ConnectDb() (*sql.DB, error) {
db, err := sql.Open("postgres", getDbInfo())
CheckErr(err, "Unable to connecto tthe DB")
if err := db.Ping(); err != nil {
return nil, err
}
return db, nil
}
func getDbInfo() string {
var dbInfo string
if dbName != "" {
dbInfo += fmt.Sprintf("dbname=%s ", dbName)
} else {
dbInfo += fmt.Sprintf("dbname=%s ", "development")
}
// checks for nil value
if dbUser != "" {
dbInfo += fmt.Sprintf("dbuser=%s ", "user")
}
// checks for nil value
if dbPass != "" {
dbInfo += fmt.Sprintf("dbpass=%s ", dbPass)
}
if sslMode != "" {
dbInfo += fmt.Sprintf("sslmode=%s", sslMode)
} else {
dbInfo += fmt.Sprintf("sslmode=disable")
}
return dbInfo
}

Answer 1

It is my understanding that you need to open connection to postgre database. I don't know if a native postgre ssh tunneling support exists. So, this answer about SSH tunneling to DB machine.
I have not tested postgre this way, but I have had this model used in some proprietary server connections.
The process goes like that:
open ssh connection to db machine
establish tunnel from local port to remote db port
open db connection on local port
You can accomplish #1 and #2 with ssh client like OpenSSH or putty. You should probably do that 1st. If external client works, then you can attempt to put it all into go language code without external SSH client.
In go you would use
"golang.org/x/crypto/ssh"
package.
There are tutorials out there how to use GO ssh tunneling. Below is not a tested sample without error checking:
var buffer []byte
var err error
buffer, err = ioutil.ReadFile(sshKeyFile)
var key ssh.Signer
key, err = ssh.ParsePrivateKey(buffer)
var authMethod ssh.AuthMethod
authMethod = ssh.PublicKeys(key)
sshConfig = &ssh.ClientConfig{
User: "user_id",
Auth: []ssh.AuthMethod{authMethod},
}
conn, err := ssh.Dial("tcp", endpoint, sshConfig)
// open connection on postgre:
dbConn, err = conn.Dial("tcp", dbEndpoint)
The last line above is not exactly tunneling, but an TCP connection open to DB server. You might be able to pass that connection into db library. If not, you would have to setup a tunnel.