Tag Archives: DigitalOcean

Golang and MySQL – DigitalOcean managed cluster

Hey everyone,

Just sharing a helper function to get you started when trying to connect to a mysql managed cluster on DigitalOcean with Golang.

Before we get into the code you’ll need to grab a couple of things from the database dashboard (on DigitalOcean).

  • Open the databases tab
  • Look for the “Connection Details” section
  • Download your ca cert file
  • Copy down your “public network” settings
    • If you’re moving this into a cluster you can use the “private network” settings instead
// initDb creates initialises the connection to mysql
func initDb(connectionString string, caCertPath string) (*sql.DB, error) {

	log.Infof("initialising db connection")

	// Prepare ssl if required: https://stackoverflow.com/a/54189333/522859
	if caCertPath != "" {

		log.Infof("Loading the ca-cert: %v", caCertPath)

		// Load the CA cert
		certBytes, err := ioutil.ReadFile(caCertPath)
		if err != nil {
			log.Fatal("unable to read in the cert file", err)
		}

		caCertPool := x509.NewCertPool()
		if ok := caCertPool.AppendCertsFromPEM(certBytes); !ok {
			log.Fatal("failed-to-parse-sql-ca", err)
		}

		tlsConfig := &tls.Config{
			InsecureSkipVerify: false,
			RootCAs:            caCertPool,
		}

		mysql.RegisterTLSConfig("bbs-tls", tlsConfig)
	}

	var sqlDb, err = sql.Open("mysql", connectionString)
	if err != nil {
		return nil, fmt.Errorf("failed to connect to the database: %v", err)
	}

	// Ensure that the database can be reached
	err = sqlDb.Ping()
	if err != nil {
		return nil, fmt.Errorf("error on opening database connection: %s", err.Error())
	}

	return sqlDb, nil
}

A couple of things to note in the helper above.

  1. You’ll need to provide the path to your downloaded ca-cert as the second argument
  2. Your connection string will need to look something like the following: USERNAME:PASSWORD@tcp(HOST_NAME:PORT_NUMBER)/DB_NAME

Note that the “tcp(…)” bit is required, see the following post for more info: https://whatibroke.com/2021/11/27/failed-to-connect-to-the-database-default-addr-for-network-unknown-mysql-and-golang/

Depending on which version of the mysql driver you’re using you may also need to revert to the legacy auth mechanism: https://docs.digitalocean.com/products/databases/mysql/resources/troubleshoot-connections/#authentication

failed to connect to the database: default addr for network unknown – MySql and Golang

Hey everyone,

I’m currently setting up a mysql database on DigitalOcean and hit the following error when connecting:

failed to connect to the database: default addr for "DATABASE_CONN_STR" network unknown 

Luckily this turned out to be a pretty easy fix. In the mysql driver repo you can see that the only scenario where this error is shown is when the network doesn’t match “tcp” or “unix”.

// Set default network if empty
	if cfg.Net == "" {
		cfg.Net = "tcp"
	}

	// Set default address if empty
	if cfg.Addr == "" {
		switch cfg.Net {
		case "tcp":
			cfg.Addr = "127.0.0.1:3306"
		case "unix":
			cfg.Addr = "/tmp/mysql.sock"
		default:
			return errors.New("default addr for network '" + cfg.Net + "' unknown")
		}

	} else if cfg.Net == "tcp" {
		cfg.Addr = ensureHavePort(cfg.Addr)
	}

To fix it, all that was required was to wrap part of the connection string in tcp or unix.

root:password@db-mysite.com:1234/db_name?ssl-mode=required&timeout=10s
root:password@tcp(db-mysite.com:1234)/db_name?ssl-mode=required&timeout=10s

Note that the host name and port on the second line is now wrapped in “tcp(…)”. In my case I didn’t have either set so I find it a bit strange that the “set default address if empty” check was triggered.

Thanks to this stackoverflow post and github link for the info:

Configure AWS Route53 domain to point to DigitalOcean name servers

Hey everyone,

This is a quick post on how to point your AWS Route53 domain to DigitalOcean. I’m currently messing around with Kubernetes on DigitalOcean (DOKS) and want to use their name servers to nginx.

The guide I was following (https://github.com/digitalocean/Kubernetes-Starter-Kit-Developers/blob/main/03-setup-ingress-controller/nginx.md) was missing a specific walkthrough for Route53 so I’m just posting what I did in case anyone else finds it useful.

To start, open up the “Registered Domains” tab on Route 53: https://console.aws.amazon.com/route53/home#DomainListing

Then click on your domain and under name servers click “Add or edit name servers”:

Replace the existing aws nameservers with the digital ocean ones and then click update:

The values that you’ll need to use are:

  • ns1.digitalocean.com
  • ns2.digitalocean.com
  • ns3.digitalocean.com

Note that these changes aren’t immediate. However, you should see a success message and receive an email notification stating the changes have been requested.

I found the AWS doco useful when trying to sort this one out: https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/domain-name-servers-glue-records.html#updating-name-servers-other-dns-service

No matches for kind “Deployment” in version “apps/v1beta2” – DigitalOcean

Hey everyone,

I’ve been working on a small golang app and decided to try out Kubernetes on DigitalOcean instead of the usual Azure or AWS. In order to get started I followed the tutorial at this link: https://www.digitalocean.com/community/tutorials/webinar-series-a-closer-look-at-kubernetes

I ran into a small issue while trying to using the provided deployment.yaml.

error: unable to recognize "./api/deploy/prod/deployment.yaml": no matches for kind "Deployment" in version "apps/v1beta2"

This turned out to be an issue with the apiVersion being used. Changing the first line to apps/v1 resolved it:

apiVersion: apps/v1beta2
kind: Deployment
metadata:

apiVersion: apps/v1
kind: Deployment
metadata:

Thanks to this link on github for pointing me in the right direction: https://github.com/coreos/etcd-operator/issues/2126