Railway•17mo ago

Mysql + Golang App

So I've deployed a mysql database, and then deployed a golang api from github... I added a reference to the MYSQL_URL in the variables for my golang app. But my app cant connect to it. Its able to connect to a local db just fine. But i get these logs that the default addr for the mysql app is unknown then my app crashes.

36 Replies

Brody•17mo ago

can you show a screenshot of your service variables

ByronOP•17mo ago

ByronOP•17mo ago

Tht DB_CONNECTION one isn't being used. I just added it to test

Brody•17mo ago

show me the code that connects to the database please

ByronOP•17mo ago

ByronOP•17mo ago

I have MYSQL_URL set to a local MySQL db connection string in a local .env file. And it connects to that just fine

Brody•17mo ago

everything looks fine, i will do some tests and get back to you

ByronOP•17mo ago

Okay thanks

Brody•17mo ago

package main

import (
    "fmt"
    "os"

    "github.com/xo/dburl"
    "gorm.io/driver/mysql"
    "gorm.io/gorm"
)

func main() {
    mysqlURL, ok := os.LookupEnv("MYSQL_URL")
    if ok == false {
        fmt.Println("MYSQL_URL not found")
        return
    }

    u, err := dburl.Parse(mysqlURL + "?charset=utf8&parseTime=True&loc=Local")
    if err != nil {
        fmt.Println(err)
        return
    }

    _, err = gorm.Open(mysql.Open(u.DSN), &gorm.Config{})
    if err != nil {
        fmt.Println(err)
        return
    }

    fmt.Println("connected to database successfully")
}

package main

import (
    "fmt"
    "os"

    "github.com/xo/dburl"
    "gorm.io/driver/mysql"
    "gorm.io/gorm"
)

func main() {
    mysqlURL, ok := os.LookupEnv("MYSQL_URL")
    if ok == false {
        fmt.Println("MYSQL_URL not found")
        return
    }

    u, err := dburl.Parse(mysqlURL + "?charset=utf8&parseTime=True&loc=Local")
    if err != nil {
        fmt.Println(err)
        return
    }

    _, err = gorm.Open(mysql.Open(u.DSN), &gorm.Config{})
    if err != nil {
        fmt.Println(err)
        return
    }

    fmt.Println("connected to database successfully")
}

MYSQL_URL is a URL, but gorm expects a DSN, so you can use github.com/xo/dburl to parse the DSN from the URL

ByronOP•17mo ago

well, that gets me farther! its not crashing, new error though

invalid database source: &{0xc000282a10} is not a valid type

invalid database source: &{0xc000282a10} is not a valid type

ByronOP•17mo ago

for some context, this is what the rest of my main.go looks like. After connecting to the db, I do an automigrate a bunch of gorm models (example in img 2). Then run a method for populating initial data in some of the tables (img 3). Then start a cron scheduler (that currently does nothing but print to the log), and then expose a graphql http route

Brody•17mo ago

can you show me where that error comes from @agi_marvin

ByronOP•17mo ago

its also in the deploy logs

Brody•17mo ago

i meant where in the code does that error get logged

ByronOP•17mo ago

it doesnt. you're looking at the entire project pretty much in those 3 images above. this is the full main.go

Brody•17mo ago

wdym it doesnt?? where is that error logged from??

ByronOP•17mo ago

its not getting logged from anything in my project

ByronOP•17mo ago

i dont know where its coming from. If its a gorm error, a railway error. searching it I get nothing

Brody•17mo ago

you are printing an err returned from a function call, what print is printing that error

ByronOP•17mo ago

ByronOP•17mo ago

from gorm.Open

Brody•17mo ago

the code in the production if block is not the same as mine

Brody•17mo ago

gorm.Open(mysql.Open(u.DSN), &gorm.Config{})

gorm.Open(mysql.Open(u.DSN), &gorm.Config{})

Brody•17mo ago

are you useing an outdated gorm package or something?

ByronOP•17mo ago

this block you included threw an error

    _, err = gorm.Open(mysql.Open(u.DSN), &gorm.Config{})
    if err != nil {
        fmt.Println(err)
        return
    }

    _, err = gorm.Open(mysql.Open(u.DSN), &gorm.Config{})
    if err != nil {
        fmt.Println(err)
        return
    }

Brody•17mo ago

ByronOP•17mo ago

im checking. i just started the project yesterday, so it shouldnt be

Brody•17mo ago

im using gorm.io/gorm yeah thats a fork of gorm from 2021 i know what the issue is now, but first update your code to use gorm.io/gorm

ByronOP•17mo ago

alright, I'm updated to gorm.io

ByronOP•17mo ago

tested it locally and its good there. Automigrate now failing on the railway db though

Brody•17mo ago

okay next issue you are throwing out the *gorm.DB return value while on railway

Brody•17mo ago

also, instead of setting your own ENV variable, just use the one automatically provided by railway https://docs.railway.app/develop/variables#railway-provided-variables

ByronOP•17mo ago

ah good catch. copy / paste failure on my part. we are up and running! thanks for your help! and yeah, i'll switch that over

Brody•17mo ago

yeah a nil pointer is not going to be a valid database source lol

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Mysql + Golang App