Querylog -- Read from querylog files when answering to /querylog API, it now survives restarts.

This commit is contained in:
Eugene Bujak 2018-10-07 02:17:22 +03:00
parent 0ee112e8a0
commit a63fe958ae
2 changed files with 92 additions and 0 deletions

View File

@ -88,6 +88,11 @@ func handleQueryLog(w http.ResponseWriter, r *http.Request) {
logBufferLock.RLock() logBufferLock.RLock()
values := logBuffer values := logBuffer
logBufferLock.RUnlock() logBufferLock.RUnlock()
if len(values) < queryLogAPI {
values = appendFromLogFile(values, queryLogAPI, time.Hour*24)
}
var data = []map[string]interface{}{} var data = []map[string]interface{}{}
for _, entry := range values { for _, entry := range values {
var q *dns.Msg var q *dns.Msg

View File

@ -144,3 +144,90 @@ func periodicQueryLogRotate(t time.Duration) {
} }
} }
} }
func appendFromLogFile(values []logEntry, maxLen int, timeWindow time.Duration) []logEntry {
now := time.Now()
// read from querylog files, try newest file first
files := []string{
queryLogFileName + ".gz",
queryLogFileName + ".gz.1",
}
a := []logEntry{}
// read from all files
for _, file := range files {
if len(a) >= maxLen {
// previous file filled us with enough fresh entries
break
}
if _, err := os.Stat(file); os.IsNotExist(err) {
// do nothing, file doesn't exist
continue
}
trace("Opening file %s", file)
f, err := os.Open(file)
if err != nil {
log.Printf("Failed to open file \"%s\": %s", file, err)
// try next file
continue
}
defer f.Close()
trace("Creating gzip reader")
zr, err := gzip.NewReader(f)
if err != nil {
log.Printf("Failed to create gzip reader: %s", err)
continue
}
trace("Creating json decoder")
d := json.NewDecoder(zr)
i := 0
// entries on file are in oldest->newest order
// we want maxLen newest
for d.More() {
var entry logEntry
err := d.Decode(&entry)
if err != nil {
log.Printf("Failed to decode: %s", err)
// next entry can be fine, try more
continue
}
if now.Sub(entry.Time) > timeWindow {
trace("skipping entry")
continue
}
i++
a = append(a, entry)
if len(a) > maxLen {
toskip := len(a) - maxLen
a = a[toskip:]
}
}
err = zr.Close()
if err != nil {
log.Printf("Encountered error while closing gzip reader: %s", err)
}
log.Printf("file \"%s\": read %d entries", file, i)
}
// now that we've read all eligible entries, reverse the slice to make it go from newest->oldest
for left, right := 0, len(a)-1; left < right; left, right = left+1, right-1 {
a[left], a[right] = a[right], a[left]
}
// append it to values
values = append(values, a...)
// then cut off of it is bigger than maxLen
if len(values) > maxLen {
values = values[:maxLen]
}
return values
}