Styjun

For a project i'm trying to connection a cloud function to a cloud sql database setup as described in this quickstart guide.

The function is configured in the same region, the service account has the Role Cloud SQL-Client. I called the function through my computer like this:

gcloud functions call <function-name> --region=<region> --data '"recipient":"hello","requester":"hello","message":"test"'

The connection to the function is working, it seems like just the authentication to the database doesn't work but i don't get where i failed.

I checked the password, user and connection name multiple times, reset the password and it still doesn't work.
I found the issue here related to connecting cloud functions to cloud sql.

I tried surrounding the password in the dsn-string with single-quotes just to be sure escaping of characters in the password isn't a problem.

I also checked the environment variables coming in and they are the ones i entered in the configuration.

The function just pings the database for test purposes:

package receiver

import (
 "database/sql"
 "fmt"
 "net/http"
 "os"

 // Import Postgres SQL driver
 _ "github.com/lib/pq"
)

// Receives a message and stores it
func Receive(w http.ResponseWriter, r *http.Request) 
 connectionName := os.Getenv("POSTGRES_INSTANCE_CONNECTION_NAME")
 dbUser := os.Getenv("POSTGRES_USER")
 dbPassword := os.Getenv("POSTGRES_PASSWORD")
 dsn := fmt.Sprintf("user=%s password='%s' host=/cloudsql/%s dbname=messages", dbUser, dbPassword, connectionName)

 var err error
 db, err := sql.Open("postgres", dsn)
 if err != nil 
 fmt.Fprintf(w, "Could not open db: %v n", err)
 

 // Only allow 1 connection to the database to avoid overloading
 db.SetMaxIdleConns(1)
 db.SetMaxOpenConns(1)
 defer db.Close()

 if pingerror := db.Ping(); pingerror != nil 
 fmt.Fprintf(w, "Failed to ping database: %s n", pingerror)
 return
 

The variable POSTGRES_INSTANCE_CONNECTION_NAME is formatted as described here as ProjectID:Region:InstanceID.

Expected is a success message or no error and i'm actually getting this message:

pq: password authentication failed for user "postgres" 

Note: I also created a function containing the demo code from here with my sql database settings and the error is the same. It seems like i missed some step while setting up the user or sql instance. But i can't find out which.

Feels strange to answer my own question but here it is: For some reason connecting with the postgres user doesn't work. Finally i created a new database user for the function and a password containing only alphanumeric characters.

The unix socket at /cloudsql/connectionName is only provided in the GCF runtime. When running locally, you either need change your connection string or use the Cloud SQL proxy to simulate a unix socket at the same path.