client.Do() is not safe for concurrent use

[gnuletik]

During automated tests, that runs concurrent rdap queries, I've seen the following panic:

github.com/openrdap/rdap/bootstrap.(*Client).Lookup(0xc00118e690, 0xc000e80960)
	/home/actions-runner/go/pkg/mod/github.com/openrdap/rdap@v0.9.1/bootstrap/client.go:340 +0x4d4
github.com/openrdap/rdap.(*Client).Do(0xc000427bf0, 0xc000e923c0)
	/home/actions-runner/go/pkg/mod/github.com/openrdap/rdap@v0.9.1/client.go:150 +0x4c5

I was able to reproduce this issue locally while running

$ go test -race
==================
WARNING: DATA RACE
Read at 0x00c00047acc0 by goroutine 33:
  github.com/openrdap/rdap.(*Client).Do()
...

Previous write at 0x00c00047acc0 by goroutine 40:
  github.com/openrdap/rdap.(*Client).Do()
      /home/actions-runner/go/pkg/mod/github.com/openrdap/rdap@v0.9.1/client.go:96 +0xe4

Would it be possible to make the client.Do function safe for concurrent use?
If not, would it be possible to show it in the documentation?

Thanks!

[wolveix]

Hey @gnuletik! Thanks for catching this data race. I'm going to look into this soon, and include a fix in one of our next releases. Thank you!

[cph6]

Here is the simplest case that crashes consistently for me.

package main

import (
	"fmt"
	"os"
	"sync"

	"github.com/openrdap/rdap"
)

func doLookup(client *rdap.Client, ip string) {
	r, err := client.QueryIP(ip)
	if err != nil {
		fmt.Fprintf(os.Stderr, "RDAP query failed for %s: %w", ip, err)
	} else {
		fmt.Printf("%s\n", r.StartAddress)
	}
}

func main() {
	client := &rdap.Client{}
	var wg sync.WaitGroup
	wg.Go(func () {doLookup(client, "0::0")})
	wg.Go(func () { doLookup(client, "8.8.8.8")})
	wg.Go(func () {doLookup(client, "0::0")})
	wg.Wait()
}