Add Graphite line protocol parsing to exec plugin

closes #637

Godeps

@@ -56,4 +56,4 @@ golang.org/x/text 6d3c22c4525a4da167968fa2479be5524d2e8bd0
 gopkg.in/dancannon/gorethink.v1 6f088135ff288deb9d5546f4c71919207f891a70
 gopkg.in/fatih/pool.v2 cba550ebf9bce999a02e963296d4bc7a486cb715
 gopkg.in/mgo.v2 03c9f3ee4c14c8e51ee521a6a7d0425658dd6f64
-gopkg.in/yaml.v2 f7716cbe52baa25d2e9b0d0da546fcf909fc16b4
+gopkg.in/yaml.v2 f7716cbe52baa25d2e9b0d0da546fcf909fc16b4

Godeps_windows

@@ -60,4 +60,4 @@ golang.org/x/text 6fc2e00a0d64b1f7fc1212dae5b0c939cf6d9ac4
 gopkg.in/dancannon/gorethink.v1 6f088135ff288deb9d5546f4c71919207f891a70
 gopkg.in/fatih/pool.v2 cba550ebf9bce999a02e963296d4bc7a486cb715
 gopkg.in/mgo.v2 03c9f3ee4c14c8e51ee521a6a7d0425658dd6f64
-gopkg.in/yaml.v2 f7716cbe52baa25d2e9b0d0da546fcf909fc16b4
+gopkg.in/yaml.v2 f7716cbe52baa25d2e9b0d0da546fcf909fc16b4

README.md

@@ -159,7 +159,7 @@ Currently implemented sources:
 * disque
 * docker
 * elasticsearch
-* exec (generic JSON-emitting executable plugin)
+* exec (generic executable plugin, support JSON, influx and graphite)
 * haproxy
 * httpjson (generic JSON-emitting http service plugin)
 * influxdb

internal/encoding/encoder.go

@@ -0,0 +1,31 @@
+package encoding
+
+import (
+	"fmt"
+
+	"github.com/influxdata/telegraf"
+)
+
+type Parser interface {
+	InitConfig(configs map[string]interface{}) error
+	Parse(buf []byte) ([]telegraf.Metric, error)
+	ParseLine(line string) (telegraf.Metric, error)
+}
+
+type Creator func() Parser
+
+var Parsers = map[string]Creator{}
+
+func Add(name string, creator Creator) {
+	Parsers[name] = creator
+}
+
+func NewParser(dataFormat string, configs map[string]interface{}) (parser Parser, err error) {
+	creator := Parsers[dataFormat]
+	if creator == nil {
+		return nil, fmt.Errorf("Unsupported data format: %s. ", dataFormat)
+	}
+	parser = creator()
+	err = parser.InitConfig(configs)
+	return parser, err
+}

internal/encoding/graphite/config.go

@@ -0,0 +1,135 @@
+package graphite
+
+import (
+	"fmt"
+	"strings"
+)
+
+const (
+	// DefaultSeparator is the default join character to use when joining multiple
+	// measurment parts in a template.
+	DefaultSeparator = "."
+)
+
+// Config represents the configuration for Graphite endpoints.
+type Config struct {
+	Separator string
+	Templates []string
+}
+
+// Validate validates the config's templates and tags.
+func (c *Config) Validate() error {
+	if err := c.validateTemplates(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (c *Config) validateTemplates() error {
+	// map to keep track of filters we see
+	filters := map[string]struct{}{}
+
+	for i, t := range c.Templates {
+		parts := strings.Fields(t)
+		// Ensure template string is non-empty
+		if len(parts) == 0 {
+			return fmt.Errorf("missing template at position: %d", i)
+		}
+		if len(parts) == 1 && parts[0] == "" {
+			return fmt.Errorf("missing template at position: %d", i)
+		}
+
+		if len(parts) > 3 {
+			return fmt.Errorf("invalid template format: '%s'", t)
+		}
+
+		template := t
+		filter := ""
+		tags := ""
+		if len(parts) >= 2 {
+			// We could have <filter> <template>  or <template> <tags>.  Equals is only allowed in
+			// tags section.
+			if strings.Contains(parts[1], "=") {
+				template = parts[0]
+				tags = parts[1]
+			} else {
+				filter = parts[0]
+				template = parts[1]
+			}
+		}
+
+		if len(parts) == 3 {
+			tags = parts[2]
+		}
+
+		// Validate the template has one and only one measurement
+		if err := c.validateTemplate(template); err != nil {
+			return err
+		}
+
+		// Prevent duplicate filters in the config
+		if _, ok := filters[filter]; ok {
+			return fmt.Errorf("duplicate filter '%s' found at position: %d", filter, i)
+		}
+		filters[filter] = struct{}{}
+
+		if filter != "" {
+			// Validate filter expression is valid
+			if err := c.validateFilter(filter); err != nil {
+				return err
+			}
+		}
+
+		if tags != "" {
+			// Validate tags
+			for _, tagStr := range strings.Split(tags, ",") {
+				if err := c.validateTag(tagStr); err != nil {
+					return err
+				}
+			}
+		}
+	}
+	return nil
+}
+
+func (c *Config) validateTemplate(template string) error {
+	hasMeasurement := false
+	for _, p := range strings.Split(template, ".") {
+		if p == "measurement" || p == "measurement*" {
+			hasMeasurement = true
+		}
+	}
+
+	if !hasMeasurement {
+		return fmt.Errorf("no measurement in template `%s`", template)
+	}
+
+	return nil
+}
+
+func (c *Config) validateFilter(filter string) error {
+	for _, p := range strings.Split(filter, ".") {
+		if p == "" {
+			return fmt.Errorf("filter contains blank section: %s", filter)
+		}
+
+		if strings.Contains(p, "*") && p != "*" {
+			return fmt.Errorf("invalid filter wildcard section: %s", filter)
+		}
+	}
+	return nil
+}
+
+func (c *Config) validateTag(keyValue string) error {
+	parts := strings.Split(keyValue, "=")
+	if len(parts) != 2 {
+		return fmt.Errorf("invalid template tags: '%s'", keyValue)
+	}
+
+	if parts[0] == "" || parts[1] == "" {
+		return fmt.Errorf("invalid template tags: %s'", keyValue)
+	}
+
+	return nil
+}

internal/encoding/graphite/errors.go

@@ -0,0 +1,14 @@
+package graphite
+
+import "fmt"
+
+// An UnsupposedValueError is returned when a parsed value is not
+// supposed.
+type UnsupposedValueError struct {
+	Field string
+	Value float64
+}
+
+func (err *UnsupposedValueError) Error() string {
+	return fmt.Sprintf(`field "%s" value: "%v" is unsupported`, err.Field, err.Value)
+}