Support allowCleartextPasswords of MySQL Driver to enable authenticating using Managed identity credentials to MySQL Instance on Azure

[lmalmeida]

Host operating system: output of uname -a

Linux fake-name 4.18.0-553.22.1.el8_10.x86_64 #1 SMP Wed Sep 11 18:02:00 EDT 2024 x86_64 x86_64 x86_64 GNU/Linux

mysqld_exporter version: output of mysqld_exporter --version

mysqld_exporter, version 0.15.0 (branch: HEAD, revision: 6ca2a42)
build user: root@c4fca471a5b1
build date: 20230624-04:09:04
go version: go1.20.5
platform: linux/amd64
tags: netgo

MySQL server version

8.0 (Azure Flexible Server)

mysqld_exporter command line flags

N/A

What did you do that produced an error?

Tried to connect to an "Azure MySQL Flexible Server" using Azure AD (Entra ID) authentication. Had setup the username as correct username, and MYSQLD_EXPORT_PASSWORD as a valid token.
When connecting, I got the following message:

caller=exporter.go:152 level=error msg="Error pinging mysqld" err="this user requires clear text authentication. If you still want to use it, please add 'allowCleartextPasswords=1' to your DSN"

Adding "allowCleartextPasswords=1" to dsn file didn't produce expected result, which make sense as

mysqld_exporter/config/config.go

Line 165 in 04268cc

func (m MySqlConfig) FormDSN(target string) (string, error) {

doesn't have any logic to handle this additional parameter.

What did you expect to see?

Allow mysql driver to use cleartext passwords

What did you see instead?

Error message