in grok.go [364:377]
func (grok *Grok) lookupPattern(grokId string) (string, bool) {
if knownPattern, found := grok.patternDefinitions[grokId]; found {
return knownPattern, found
}
if grok.lookupDefaultPatterns {
if knownPattern, found := patterns.Default[grokId]; found {
return knownPattern, found
}
}
return "", false
}