woanware/bgp-watcher: src/bgp-watcher/historic.go; 40 LoC

Found a possible issue in [woanware/bgp-watcher](https://www.github.com/woanware/bgp-watcher) at [src/bgp-watcher/historic.go](https://github.com/woanware/bgp-watcher/blob/57ce7c368d090517ebb89617ae9a27281a75e2e7/src/bgp-watcher/historic.go#L185-L224)

Below is the message reported by the analyzer for this snippet of code. Beware that the analyzer only reports the first issue it finds, so please do not limit your consideration to the contents of the below message.

> range-loop variable name used in defer or goroutine at line 209

[Click here to see the code in its original context.](https://github.com/woanware/bgp-watcher/blob/57ce7c368d090517ebb89617ae9a27281a75e2e7/src/bgp-watcher/historic.go#L185-L224)

Click here to show the 40 line(s) of Go which triggered the analyzer.

```go
for name := range config.DataSets {
for i := h.Months - 1; i >= 0; i-- {

year = int(ts.AddDate(0, -i, 0).Year())
month = int(ts.AddDate(0, -i, 0).Month())

files, err := ioutil.ReadDir(fmt.Sprintf("./cache/%s/%v/%v", name, year, month))
if err != nil {
log.Fatal(err)
}

var wg sync.WaitGroup
semaphore := make(chan struct{}, h.Processes)
for _, file := range files {
wg.Add(1)

go func(year int, month int, filePath string) {
defer wg.Done()

semaphore <- struct{}{} // Lock
defer func() {
<-semaphore // Unlock
}()

err = mrtParser.ParseAndCollect(h.detector, fmt.Sprintf("./cache/%s/%v/%v/%s", name, year, month, filePath))
if err != nil {
if strings.Contains(err.Error(), "gzip: invalid header") == true {
err = os.Remove(fmt.Sprintf("./cache/%s/%v/%v/%s", name, year, month, filePath))
if err != nil {
fmt.Println("Error deleting malformed BGP file (%s): %v\n", fmt.Sprintf("./cache/%s/%v/%v/%s", name, year, month, filePath), err)
}
} else {
fmt.Println("Error parsing BGP file (%s): %v\n", filePath, err)
}
}
}(year, month, file.Name())
}
wg.Wait()
}
}

```

Leave a reaction on this issue to contribute to the project by classifying this instance as a **Bug** :-1:, **Mitigated** :+1:, or **Desirable Behavior** :rocket:
See the descriptions of the classifications [here](https://github.com/github-vet/rangeclosure-findings#how-can-i-help) for more information.

commit ID: 57ce7c368d090517ebb89617ae9a27281a75e2e7