// Interpolate takes a counter value sampled at variable intervals and aligns each value with a <duration> ms boundary.
// The initial value is not output unless it appears exactly on a ms boundary.
// Runs of two or more missing values will be filled by NaN
func Interpolate(duration uint64, input *oproto.ValueStream) *oproto.ValueStream {
output := &oproto.ValueStream{}
var previousValue *oproto.Value
var timestamp uint64
for _, v := range input.Value {
if previousValue == nil {
if v.Timestamp%duration == 0 {
// Value is exactly on a timestamp
output.Value = append(output.Value, v)
previousValue = v
timestamp = v.Timestamp + duration
} else {
previousValue = v
previousValue.Timestamp = v.Timestamp / duration * duration
timestamp = previousValue.Timestamp + duration
}
continue
}
if v.Timestamp >= timestamp {
// Fill in any missing values before this one
rate := float64((v.DoubleValue - previousValue.DoubleValue))
for ; timestamp <= v.Timestamp; timestamp += duration {
pct := float64(timestamp-previousValue.Timestamp) / float64(v.Timestamp-previousValue.Timestamp)
newValue := previousValue.DoubleValue + (rate * pct)
output.Value = append(output.Value, &oproto.Value{
Timestamp: timestamp,
DoubleValue: newValue,
})
}
if previousValue.Timestamp < v.Timestamp {
if v.Timestamp%duration == 0 {
// Value is exactly on a timestamp
output.Value = append(output.Value, v)
previousValue = v
timestamp += duration
} else {
previousValue = v
}
}
}
}
return output
}
func Encode(input *oproto.ValueStream) *oproto.ValueStream {
output := &oproto.ValueStream{Variable: input.Variable}
var last *oproto.Value
for _, value := range input.Value {
if last == nil {
last = value
continue
}
if last.StringValue != "" && value.StringValue != "" {
if last.StringValue == value.StringValue {
if value.EndTimestamp > value.Timestamp {
last.EndTimestamp = value.EndTimestamp
} else {
last.EndTimestamp = value.Timestamp
}
continue
}
} else {
if last.DoubleValue == value.DoubleValue {
if value.EndTimestamp > value.Timestamp {
last.EndTimestamp = value.EndTimestamp
} else {
last.EndTimestamp = value.Timestamp
}
continue
}
}
if last.EndTimestamp == 0 && last.Timestamp != 0 {
last.EndTimestamp = last.Timestamp
}
output.Value = append(output.Value, last)
last = value
}
if last != nil {
if last.EndTimestamp == 0 && last.Timestamp != 0 {
last.EndTimestamp = last.Timestamp
}
output.Value = append(output.Value, last)
}
return output
}
func findFirstMatchingPolicy(value *oproto.Value, policies []*oproto.RetentionPolicyItem) *oproto.RetentionPolicyItem {
now := openinstrument.NowMs()
valueStartAge := now - value.Timestamp
if value.EndTimestamp == 0 && value.Timestamp != 0 {
value.EndTimestamp = value.Timestamp
}
valueEndAge := now - value.EndTimestamp
for _, item := range policies {
if len(item.Variable) == 0 {
// No variables supplied, this matches everything
return item
}
for _, i := range item.Variable {
// Look for policies that match the variable age
v := variable.NewFromProto(i)
if v.TimestampInsideRange(valueStartAge) || v.TimestampInsideRange(valueEndAge) {
return item
}
}
}
return nil
}