// parseDate converts the given datestring (from one of the allowable formats) into a millisecond offset from the Unix epoch.
func parseDate(date string, now time.Time) (int64, error) {
if date == "now" {
return now.Unix() * 1000, nil
}
// Millisecond epoch timestamp.
if epoch, err := strconv.ParseInt(date, 10, 0); err == nil {
return epoch, nil
}
relativeTime, err := function.StringToDuration(date)
if err == nil {
// A relative date.
if relativeTime > 0 {
return -1, fmt.Errorf("relative times should be negative: %s", date)
}
return now.Add(relativeTime).Unix() * 1000, nil
}
errorMessage := fmt.Sprintf("Expected formatted date or relative time but got '%s'", date)
for _, format := range dateFormats {
t, err := time.Parse(format, date)
if err == nil {
return t.Unix()*1000 + int64(t.Nanosecond()/1000000), nil
}
}
return -1, errors.New(errorMessage)
}
func (p *Parser) addDurationNode(value string) {
duration, err := function.StringToDuration(value)
p.pushNode(&durationExpression{value, duration})
if err != nil {
p.flagSyntaxError(SyntaxError{
token: value,
message: fmt.Sprintf("'%s' is not a valid duration: %s", value, err.Error()),
})
}
}
func (p *Parser) insertPropertyKeyValue() {
valueNode, ok := p.popNode(evaluationContextValuePointer).(*evaluationContextValue)
if !ok {
p.flagTypeAssertion()
return
}
keyNode, ok := p.popNode(evaluationContextKeyPointer).(*evaluationContextKey)
if !ok {
p.flagTypeAssertion()
return
}
contextNode, ok := p.popNode(evaluationContextNodePointer).(*evaluationContextNode)
if !ok {
p.flagTypeAssertion()
return
}
key := keyNode.key
value := valueNode.value
// Authenticate the validity of the given key and value...
// The key must be one of "sample"(by), "from", "to", "resolution"
// First check that the key has been assigned only once:
if contextNode.assigned[key] {
p.flagSyntaxError(SyntaxError{
token: key,
message: fmt.Sprintf("Key %s has already been assigned", key),
})
}
contextNode.assigned[key] = true
switch key {
case "sample":
// If the key is "sample", it means we're in a "sample by" declaration.
// Only three possible sample methods are defined: min, max, or mean.
switch value {
case "max":
contextNode.SampleMethod = api.SampleMax
case "min":
contextNode.SampleMethod = api.SampleMin
case "mean":
contextNode.SampleMethod = api.SampleMean
default:
p.flagSyntaxError(SyntaxError{
token: value,
message: fmt.Sprintf("Expected sampling method 'max', 'min', or 'mean' but got %s", value),
})
}
case "from", "to":
var unix int64
var err error
now := time.Now()
if unix, err = parseDate(value, now); err != nil {
p.flagSyntaxError(SyntaxError{
token: value,
message: err.Error(),
})
}
if key == "from" {
contextNode.Start = unix
} else {
contextNode.End = unix
}
case "resolution":
// The value must be determined to be an int if the key is "resolution".
if intValue, err := strconv.ParseInt(value, 10, 64); err == nil {
contextNode.Resolution = intValue
} else if duration, err := function.StringToDuration(value); err == nil {
contextNode.Resolution = int64(duration / time.Millisecond)
} else {
p.flagSyntaxError(SyntaxError{
token: value,
message: fmt.Sprintf("Expected number but parse failed; %s", err.Error()),
})
}
default:
p.flagSyntaxError(SyntaxError{
token: key,
message: fmt.Sprintf("Unknown property key %s", key),
})
}
p.pushNode(contextNode)
}