GetInstancesMaxLag occasionally unnecessarily noisy

[sjmudd]

This code looks wrong given the way it's called in various places.

// GetInstancesMaxLag returns the maximum lag in a set of instances
func GetInstancesMaxLag(instances [](*Instance)) (maxLag int64, err error) {
        if len(instances) == 0 {
                return 0, log.Errorf("No instances found in GetInstancesMaxLag")
        }
...
}

It looks to me as if len(instances) may be 0 in some cases. I've seen this error and think that probably in this case you should just return 0, nil as otherwise you need to special case various routines that call this to check first.

[shlomi-noach]

Returning 0 means there a 0 lag. But there isn't such a lag.

However do notice that the functions that call this code use:

    if err != nil {
        return 0, err
    }

as in https://github.com/outbrain/orchestrator/blob/master/go/inst/instance_dao.go#L1112-L1114

Therefore you get the 0 you wished for, and it's on you to care or not care about the error.