Add tls support for mysql client

[db-will]

Close: #185

Add tls config for connecting mysql with tls enabled

Manually test:

[ec2-user@ip-10-0-19-25 cert]$ ./go-tpc -H 10.0.153.232 -U u1 -P 4000 tpcc --warehouses 1 prepare
2024/11/23 21:42:36 maxprocs: Leaving GOMAXPROCS=4: CPU quota undefined
failed to ping db, err Error 1045 (28000): Access denied for user 'u1'@'10.0.19.25' (using password: NO)
panic: failed to connect to database when loading data

goroutine 1 [running]:
github.com/pingcap/go-tpc/tpcc.NewWorkloader(0x59c338?, 0xc0003e9540?)
        /Users/Projects/db-will/go-tpc/tpcc/workload.go:110 +0x8bd
main.executeTpcc({0xb4c776, 0x7})
        /Users/Projects/db-will/go-tpc/cmd/go-tpc/tpcc.go:66 +0x205
main.registerTpcc.func1(0xc000144900?, {0xb49b4c?, 0x4?, 0xb49b50?})
        /Users/Projects/db-will/go-tpc/cmd/go-tpc/tpcc.go:96 +0x1f
github.com/spf13/cobra.(*Command).execute(0xc0003a9b88, {0xc00012a380, 0x8, 0x8})
        /Users/go/pkg/mod/github.com/spf13/cobra@v1.0.0/command.go:846 +0x671
github.com/spf13/cobra.(*Command).ExecuteC(0xc0003a9348)
        /Users/go/pkg/mod/github.com/spf13/cobra@v1.0.0/command.go:950 +0x389
github.com/spf13/cobra.(*Command).Execute(...)
        /Users/go/pkg/mod/github.com/spf13/cobra@v1.0.0/command.go:887
main.main()
        /Users/Projects/db-will/go-tpc/cmd/go-tpc/main.go:274 +0x846
[ec2-user@ip-10-0-19-25 cert]$ ./go-tpc -H 10.0.153.232 -U u1 -P 4000 --ssl-ca ./root.crt --ssl-cert ./client.crt --ssl-key ./client.key  tpcc --warehouses 1 clean
2024/11/23 21:42:54 maxprocs: Leaving GOMAXPROCS=4: CPU quota undefined
DROP TABLE IF EXISTS item
DROP TABLE IF EXISTS customer
DROP TABLE IF EXISTS district
DROP TABLE IF EXISTS history
DROP TABLE IF EXISTS new_order
DROP TABLE IF EXISTS order_line
DROP TABLE IF EXISTS orders
DROP TABLE IF EXISTS stock
DROP TABLE IF EXISTS warehouse
Finished

[CLAassistant]

All committers have signed the CLA.

[dveeden]

Suggested change

	if len(sslCA) > 0 {
	if len(sslCA) > 0 || len(sslKey) > 0 || len(sslCert) > 0 {

[db-will]

Refer https://docs.pingcap.com/tidb/stable/enable-tls-between-clients-and-servers#enable-authentication

By default, the server-to-client authentication is optional. Even if the client does not present its certificate of identification during the TLS handshake, the TLS connection can be still established.

If sslKey and sslCert are not provided, we will only authenticate the TiDB server from the MySQL client.

[dveeden]

I think valid configurations are:

• Only sslCA provided
• sslCA, sslCert, sslKey all provided.

Not valid:

• sslCert and/or sslKey set, but no sslCA.
• sslCert set, but not sslKey
• sslKey set, but not sslCert

So I think we should set the tlsName to custom if any of sslCert, sslKey or sslCA is set and then later on verify if it is valid (which might already be done)

[dveeden]

Please make sure this handles the situation correctly if sslKey or sslCert is set, but not sslCA. Otherwise LGTM.

[Yui-Song]

@dveeden Please sign the CLA.