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package easyproto_test
import (
"fmt"
"github.com/VictoriaMetrics/easyproto"
)
// Timeseries is a named time series.
//
// It has the following protobuf v3 definition:
//
// message timeseries {
// string name = 1;
// repeated sample samples = 2;
// }
type Timeseries struct {
Name string
Samples []Sample
}
// Sample represents a sample for the named time series.
//
// It has the following protobuf v3 definition:
//
// message sample {
// double value = 1;
// int64 timestamp = 2;
// }
type Sample struct {
Value float64
Timestamp int64
}
// MarshalProtobuf marshals ts into protobuf message, appends this message to dst and returns the result.
//
// This function doesn't allocate memory on repeated calls.
func (ts *Timeseries) MarshalProtobuf(dst []byte) []byte {
m := mp.Get()
ts.marshalProtobuf(m.MessageMarshaler())
dst = m.Marshal(dst)
mp.Put(m)
return dst
}
func (ts *Timeseries) marshalProtobuf(mm *easyproto.MessageMarshaler) {
mm.AppendString(1, ts.Name)
for _, s := range ts.Samples {
s.marshalProtobuf(mm.AppendMessage(2))
}
}
func (s *Sample) marshalProtobuf(mm *easyproto.MessageMarshaler) {
mm.AppendDouble(1, s.Value)
mm.AppendInt64(2, s.Timestamp)
}
var mp easyproto.MarshalerPool
// UnmarshalProtobuf unmarshals ts from protobuf message at src.
func (ts *Timeseries) UnmarshalProtobuf(src []byte) (err error) {
// Set default Timeseries values
ts.Name = ""
ts.Samples = ts.Samples[:0]
// Parse Timeseries message at src
var fc easyproto.FieldContext
for len(src) > 0 {
src, err = fc.NextField(src)
if err != nil {
return fmt.Errorf("cannot read next field in Timeseries message")
}
switch fc.FieldNum {
case 1:
name, ok := fc.String()
if !ok {
return fmt.Errorf("cannot read Timeseries name")
}
// name refers to src. This means that the name changes when src changes.
// Make a copy with strings.Clone(name) if needed.
ts.Name = name
case 2:
data, ok := fc.MessageData()
if !ok {
return fmt.Errorf("cannot read Timeseries sample data")
}
ts.Samples = append(ts.Samples, Sample{})
s := &ts.Samples[len(ts.Samples)-1]
if err := s.UnmarshalProtobuf(data); err != nil {
return fmt.Errorf("cannot unmarshal sample: %w", err)
}
}
}
return nil
}
// UnmarshalProtobuf unmarshals s from protobuf message at src.
func (s *Sample) UnmarshalProtobuf(src []byte) (err error) {
// Set default Sample values
s.Value = 0
s.Timestamp = 0
// Parse Sample message at src
var fc easyproto.FieldContext
for len(src) > 0 {
src, err = fc.NextField(src)
if err != nil {
return fmt.Errorf("cannot read next field in sample")
}
switch fc.FieldNum {
case 1:
value, ok := fc.Double()
if !ok {
return fmt.Errorf("cannot read sample value")
}
s.Value = value
case 2:
timestamp, ok := fc.Int64()
if !ok {
return fmt.Errorf("cannot read sample timestamp")
}
s.Timestamp = timestamp
}
}
return nil
}
func Example() {
ts := &Timeseries{
Name: "foo",
Samples: []Sample{
{
Value: 123,
Timestamp: -453426,
},
{
Value: -234.344,
Timestamp: 23328434,
},
},
}
data := ts.MarshalProtobuf(nil)
var tsNew Timeseries
if err := tsNew.UnmarshalProtobuf(data); err != nil {
fmt.Printf("unexpected error: %s\n", err)
return
}
fmt.Printf("name: %s\n", tsNew.Name)
fmt.Printf("samples:\n")
for _, s := range tsNew.Samples {
fmt.Printf(" {value:%v, timestamp:%d}\n", s.Value, s.Timestamp)
}
// Output:
// name: foo
// samples:
// {value:123, timestamp:-453426}
// {value:-234.344, timestamp:23328434}
}
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