使用Go在App Engine上进行GORM Cloud SQL连接

Question

I'm trying to connect to a Cloud SQL database using GORM in golang.

db, _ = gorm.Open("mysql", "user:pass@cloudsql(connection:name:example)/")
if err != nil {
        log.Println(err)
        //panic(err)
    }

When I attempt to serve the app

goapp serve appengine/

I get a runtime error

ERROR    2017-02-19 20:48:05,436 http_runtime.py:396] bad runtime process port ['
']

Which I found was related to the database migration

db.AutoMigrate(&models.Event{})

If I remove the AutoMigrate, the runtime process port error goes away. However whenever I access a route (ie /events) that does a database query, the connection gets dropped, a 404 page is thrown, and an error message is logged sql: database is closed

When I run the app locally by building the package go build && ./appname and using a local MySQL server, it works fine.

Can someone please tell me how to connect to a Cloud SQL database using Go's GORM framework and App Engine?

Answer 1

This is due to the call to log.New in this file: https://github.com/jinzhu/gorm/blob/master/logger.go#L15

This anwser explain why dev_appserver.py gets it: https://stackoverflow.com/a/24112953/4266494

To disable this, you can either disable all GORM logging:

db.LogMode(false)

Or use an adapter the logger output: https://github.com/benguild/GAEBridge/blob/master/log/debugLevel.go

db.SetLogger(NewDebugLogger(nil)) // on application scope
db.SetLogger(NewDebugLogger(appengine.NewContext(req))) // on request scope

I'm setting a new logger with the real context This is the only workaround I found to avoid crashes while keeping some logs, it could be awesome if one of you had a real one.