Value parser, for parsing a single value into a metric

closes #849

plugins/parsers/value/parser.go

@@ -0,0 +1,68 @@
+package value
+
+import (
+	"bytes"
+	"fmt"
+	"strconv"
+	"time"
+
+	"github.com/influxdata/telegraf"
+)
+
+type ValueParser struct {
+	MetricName  string
+	DataType    string
+	DefaultTags map[string]string
+}
+
+func (v *ValueParser) Parse(buf []byte) ([]telegraf.Metric, error) {
+	// separate out any fields in the buffer, ignore anything but the last.
+	values := bytes.Fields(buf)
+	if len(values) < 1 {
+		return []telegraf.Metric{}, nil
+	}
+	valueStr := string(values[len(values)-1])
+
+	var value interface{}
+	var err error
+	switch v.DataType {
+	case "", "int", "integer":
+		value, err = strconv.Atoi(valueStr)
+	case "float", "long":
+		value, err = strconv.ParseFloat(valueStr, 64)
+	case "str", "string":
+		value = valueStr
+	case "bool", "boolean":
+		value, err = strconv.ParseBool(valueStr)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	fields := map[string]interface{}{"value": value}
+	metric, err := telegraf.NewMetric(v.MetricName, v.DefaultTags,
+		fields, time.Now().UTC())
+	if err != nil {
+		return nil, err
+	}
+
+	return []telegraf.Metric{metric}, nil
+}
+
+func (v *ValueParser) ParseLine(line string) (telegraf.Metric, error) {
+	metrics, err := v.Parse([]byte(line))
+
+	if err != nil {
+		return nil, err
+	}
+
+	if len(metrics) < 1 {
+		return nil, fmt.Errorf("Can not parse the line: %s, for data format: value", line)
+	}
+
+	return metrics[0], nil
+}
+
+func (v *ValueParser) SetDefaultTags(tags map[string]string) {
+	v.DefaultTags = tags
+}