forked from segmentio/logspout-fluentd
/
logspout.go
144 lines (120 loc) · 3.15 KB
/
logspout.go
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package fluentd
import (
"encoding/json"
"errors"
"log"
"net"
"strings"
"time"
"github.com/gliderlabs/logspout/router"
)
// FluentdAdapter is an adapter for streaming JSON to a fluentd collector.
type FluentdAdapter struct {
conn net.Conn
route *router.Route
transport router.AdapterTransport
}
func init() {
router.AdapterFactories.Register(NewFluentdAdapter, "fluentd")
}
// NewFluentdAdapter creates a Logspout fluentd adapter instance.
func NewFluentdAdapter(route *router.Route) (router.LogAdapter, error) {
transport, found := router.AdapterTransports.Lookup(route.AdapterTransport("tcp"))
if !found {
return nil, errors.New("bad transport: " + route.Adapter)
}
conn, err := transport.Dial(route.Address, route.Options)
if err != nil {
return nil, err
}
return &FluentdAdapter{
conn: conn,
route: route,
transport: transport,
}, nil
}
// Stream handles a stream of messages from Logspout. Implements router.logAdapter.
func (adapter *FluentdAdapter) Stream(logstream chan *router.Message) {
for message := range logstream {
timestamp := int32(time.Now().Unix())
tag := "docker/" + message.Container.Config.Hostname
record := make(map[string]string)
record["message"] = message.Data
record["docker/hostname"] = message.Container.Config.Hostname
record["docker/id"] = message.Container.ID
record["docker/image"] = message.Container.Config.Image
record["docker/name"] = message.Container.Name
for key, value := range message.Container.Config.Labels {
label := strings.Replace(key, ".", "-", -1)
record["docker/label/"+label] = value
}
data := []interface{}{tag, timestamp, record}
json, err := json.Marshal(data)
if err != nil {
log.Println("fluentd-adapter: ", err)
continue
}
_, err = adapter.conn.Write(json)
if err != nil {
err = adapter.retry(json, err)
if err != nil {
log.Println("fluentd-adapter: ", err)
return
}
}
}
}
func (adapter *FluentdAdapter) retry(json []byte, err error) error {
if opError, ok := err.(*net.OpError); ok {
if opError.Temporary() || opError.Timeout() {
retryErr := adapter.retryTemporary(json)
if retryErr == nil {
return nil
}
}
}
return adapter.reconnect()
}
func (adapter *FluentdAdapter) retryTemporary(json []byte) error {
log.Println("fluentd-adapter: retrying tcp up to 11 times")
err := retryExp(func() error {
_, err := adapter.conn.Write(json)
if err == nil {
log.Println("fluentd-adapter: retry successful")
return nil
}
return err
}, 11)
if err != nil {
log.Println("fluentd-adapter: retry failed")
return err
}
return nil
}
func (adapter *FluentdAdapter) reconnect() error {
log.Println("fluentd-adapter: reconnecting forever")
for {
conn, err := adapter.transport.Dial(adapter.route.Address, adapter.route.Options)
if err != nil {
time.Sleep(10 * time.Second)
continue
}
log.Println("fluentd-adapter: reconnected")
adapter.conn = conn
return nil
}
}
func retryExp(fun func() error, tries uint) error {
try := uint(0)
for {
err := fun()
if err == nil {
return nil
}
try++
if try > tries {
return err
}
time.Sleep((1 << try) * 10 * time.Millisecond)
}
}