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client.go
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client.go
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package redis
import (
"encoding/json"
"errors"
"regexp"
"strconv"
"time"
"github.com/garyburd/redigo/redis"
"github.com/elastic/beats/libbeat/common"
"github.com/elastic/beats/libbeat/logp"
"github.com/elastic/beats/libbeat/outputs/transport"
)
var (
versionRegex = regexp.MustCompile(`redis_version:(\d+).(\d+)`)
)
type publishFn func(dest []byte, events []common.MapStr) ([]common.MapStr, error)
type client struct {
*transport.Client
dataType redisDataType
db int
list []byte
password string
publish publishFn
}
type redisDataType uint16
const (
redisListType redisDataType = iota
redisChannelType
)
func newClient(tc *transport.Client, pass string, db int, dest []byte, dt redisDataType) *client {
return &client{
Client: tc,
password: pass,
db: db,
dataType: dt,
list: dest,
}
}
func (c *client) Connect(to time.Duration) error {
debugf("connect")
err := c.Client.Connect()
if err != nil {
return err
}
conn := redis.NewConn(c.Client, to, to)
defer func() {
if err != nil {
conn.Close()
}
}()
if err = initRedisConn(conn, c.password, c.db); err == nil {
c.publish, err = makePublish(conn, c.dataType)
}
return err
}
func initRedisConn(c redis.Conn, pwd string, db int) error {
if pwd != "" {
if _, err := c.Do("AUTH", pwd); err != nil {
return err
}
}
if _, err := c.Do("PING"); err != nil {
return err
}
if db != 0 {
if _, err := c.Do("SELECT", db); err != nil {
return err
}
}
return nil
}
func (c *client) Close() error {
debugf("close connection")
return c.Client.Close()
}
func (c *client) PublishEvent(event common.MapStr) error {
_, err := c.PublishEvents([]common.MapStr{event})
return err
}
func (c *client) PublishEvents(events []common.MapStr) ([]common.MapStr, error) {
return c.publish(c.list, events)
}
func makePublish(conn redis.Conn, dt redisDataType) (publishFn, error) {
if dt == redisChannelType {
return makePublishPUBLISH(conn)
}
return makePublishRPUSH(conn)
}
func makePublishRPUSH(conn redis.Conn) (publishFn, error) {
var major, minor int
var versionRaw [][]byte
respRaw, err := conn.Do("INFO")
resp, err := redis.Bytes(respRaw, err)
if err != nil {
return nil, err
}
versionRaw = versionRegex.FindSubmatch(resp)
if versionRaw == nil {
err = errors.New("unable to read redis_version")
return nil, err
}
major, err = strconv.Atoi(string(versionRaw[1]))
if err != nil {
return nil, err
}
minor, err = strconv.Atoi(string(versionRaw[2]))
if err != nil {
return nil, err
}
// Check Redis version number choosing the method
// how RPUSH shall be used. With version 2.4 RPUSH
// can accept multiple values at once turning RPUSH
// into batch like call instead of relying on pipelining.
//
// Versions 1.0 to 2.3 only accept one value being send with
// RPUSH requiring pipelining.
//
// See: http://redis.io/commands/rpush
multiValue := major > 2 || (major == 2 && minor >= 4)
if multiValue {
return publishEventsBulk(conn, "RPUSH"), nil
}
return publishEventsPipeline(conn, "RPUSH"), nil
}
func makePublishPUBLISH(conn redis.Conn) (publishFn, error) {
return publishEventsPipeline(conn, "PUBLISH"), nil
}
func publishEventsBulk(conn redis.Conn, command string) publishFn {
return func(dest []byte, events []common.MapStr) ([]common.MapStr, error) {
args := make([]interface{}, 1, len(events)+1)
args[0] = dest
events, args = serializeEvents(args, 1, events)
if (len(args) - 1) == 0 {
return nil, nil
}
// RPUSH returns total length of list -> fail and retry all on error
_, err := conn.Do(command, args...)
if err != nil {
logp.Err("Failed to %v to redis list (%v) with %v", command, err)
return events, err
}
return nil, nil
}
}
func publishEventsPipeline(conn redis.Conn, command string) publishFn {
return func(dest []byte, events []common.MapStr) ([]common.MapStr, error) {
var args [2]interface{}
args[0] = dest
serialized := make([]interface{}, 0, len(events))
events, serialized = serializeEvents(serialized, 0, events)
if len(serialized) == 0 {
return nil, nil
}
for _, event := range serialized {
args[1] = event
if err := conn.Send(command, args[:]...); err != nil {
logp.Err("Failed to execute %v: %v", command, err)
return events, err
}
}
if err := conn.Flush(); err != nil {
return events, err
}
failed := events[:0]
var lastErr error
for i := range serialized {
_, err := conn.Receive()
if err != nil {
if _, ok := err.(redis.Error); ok {
logp.Err("Failed to %v event to list (%v) with %v",
command, dest, err)
failed = append(failed, events[i])
lastErr = err
} else {
logp.Err("Failed to %v multiple events to list (%v) with %v",
command, dest, err)
failed = append(failed, events[i:]...)
lastErr = err
break
}
}
}
return failed, lastErr
}
}
func serializeEvents(
to []interface{},
i int,
events []common.MapStr,
) ([]common.MapStr, []interface{}) {
okEvents := events
for _, event := range events {
jsonEvent, err := json.Marshal(event)
if err != nil {
logp.Err("Failed to convert the event to JSON (%v): %#v", err, event)
goto failLoop
}
to = append(to, jsonEvent)
i++
}
return okEvents, to
failLoop:
okEvents = events[:i]
restEvents := events[i+1:]
for _, event := range restEvents {
jsonEvent, err := json.Marshal(event)
if err != nil {
logp.Err("Failed to convert the event to JSON (%v): %#v", err, event)
i++
continue
}
to = append(to, jsonEvent)
i++
}
return okEvents, to
}