Maybe we should include more context? Perhaps IsAvailable can return an error instead? In that case, maybe we should call it something like CheckConnection?

We should also be careful with how we check the validity of the connection, we probably only want to fail on networking issues. If the issue is caused by an invalid token for example, this is a real failure that should result in repos being removed.

One thing we can probably do is lookup the IP of the codehost to validate that DNS is working correctly as a first check: https://jameshfisher.com/2017/08/03/golang-dns-lookup/

I'll put this comment in the issue. @varsanojidan

Yes, I was thinking something like dialing host-port over TCP:

timeout := 1 * time.Second
conn, err := net.DialTimeout("tcp",fmt.Sprintf("%s:433", host), timeout)
if err != nil {
    return fmt.Errorf("Site unreachable, error: ", err)
}
conn.Close()

But actually starting with a DNS lookup and then doing this makes a lot of sense.

@ryanslade thank you for the comment - indeed it makes sense to return some meaningful error message here, and then name change you proposed seems very fitting

This is done now. If you do not mind, I would like to land this with the

func (...) CheckConnection(ctx context.Context) error {
  return nil
}

implementation, and open another PR to fill these in. I think what I would do is:

1. Implement a DNS lookup utility somewhere in internal (please let me know your feedback: good idea, bad idea?)
2. Use that inside CheckConnection where I can easily get a host name.

Maybe some of the APIs also offer a status/healthz/ping endpoint that's unauthenticated and that we can use for this.

👍 @mrnugget. The point is to reuse a native check of the API, and only alternatively craft one.

@sourcegraph/batchers this pull request extends the Source interface, so there is one change to a fake within batch changes codebase, so wanted to give you an heads up. Please take a look.