/
deadletter.go
253 lines (236 loc) · 6.7 KB
/
deadletter.go
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package redis
import (
"errors"
"fmt"
"time"
"github.com/bitleak/lmstfy/engine"
go_redis "github.com/go-redis/redis/v8"
)
const (
luaRespawnDeadletterScript = `
local deadletter = KEYS[1]
local queue = KEYS[2]
local poolPrefix = KEYS[3]
local limit = tonumber(ARGV[1])
local respawnTTL = tonumber(ARGV[2])
for i = 1, limit do
local data = redis.call("RPOPLPUSH", deadletter, queue)
if data == false then
return i - 1 -- deadletter is empty
end
-- unpack the jobID, and set the TTL
local _, jobID = struct.unpack("HHc0", data)
if respawnTTL > 0 then
redis.call("EXPIRE", poolPrefix .. "/" .. jobID, respawnTTL)
end
end
return limit -- deadletter has more data when return value is >= limit
`
luaDeleteDeadletterScript = `
local deadletter = KEYS[1]
local poolPrefix = KEYS[2]
local limit = tonumber(ARGV[1])
for i = 1, limit do
local data = redis.call("RPOP", deadletter)
if data == false then
return i - 1
end
-- unpack the jobID, and delete the job from the job pool
local _, jobID = struct.unpack("HHc0", data)
redis.call("DEL", poolPrefix .. "/" .. jobID)
end
return limit
`
)
var (
respawnDeadletterSHA string
deleteDeadletterSHA string
)
// Because the DeadLetter is not like Timer which is a singleton,
// DeadLetters are transient objects like Queue. So we have to preload
// the lua scripts separately.
func PreloadDeadLetterLuaScript(redis *RedisInstance) error {
sha, err := redis.Conn.ScriptLoad(dummyCtx, luaRespawnDeadletterScript).Result()
if err != nil {
return fmt.Errorf("failed to preload lua script: %s", err)
}
respawnDeadletterSHA = sha
sha, err = redis.Conn.ScriptLoad(dummyCtx, luaDeleteDeadletterScript).Result()
if err != nil {
return fmt.Errorf("failed to preload luascript: %s", err)
}
deleteDeadletterSHA = sha
return nil
}
// DeadLetter is where dead job will be buried, the job can be respawned into ready queue
type DeadLetter struct {
redis *RedisInstance
namespace string
queue string
}
// NewDeadLetter return an instance of DeadLetter storage
func NewDeadLetter(namespace, queue string, redis *RedisInstance) (*DeadLetter, error) {
dl := &DeadLetter{
redis: redis,
namespace: namespace,
queue: queue,
}
if respawnDeadletterSHA == "" || deleteDeadletterSHA == "" {
return nil, errors.New("dead letter's lua script is not preloaded")
}
return dl, nil
}
func (dl *DeadLetter) Name() string {
return join(DeadLetterPrefix, dl.namespace, dl.queue)
}
// Add a job to dead letter. NOTE the data format is the same
// as the ready queue (lua struct `HHc0`), by doing this we could directly pop
// the dead job back to the ready queue.
//
// NOTE: this method is not called any where except in tests, but this logic is
// implement in the timer's pump script. please refer to that.
func (dl *DeadLetter) Add(jobID string) error {
val := structPack(1, jobID)
if err := dl.redis.Conn.Persist(dummyCtx, PoolJobKey2(dl.namespace, dl.queue, jobID)).Err(); err != nil {
return err
}
return dl.redis.Conn.LPush(dummyCtx, dl.Name(), val).Err()
}
func (dl *DeadLetter) Peek() (size int64, jobID string, err error) {
val, err := dl.redis.Conn.LIndex(dummyCtx, dl.Name(), -1).Result()
switch err {
case nil:
// continue
case go_redis.Nil:
return 0, "", engine.ErrNotFound
default:
return 0, "", err
}
tries, jobID, err := structUnpack(val)
if err != nil || tries != 1 {
return 0, "", fmt.Errorf("failed to unpack data: %s", err)
}
size, err = dl.redis.Conn.LLen(dummyCtx, dl.Name()).Result()
if err != nil {
return 0, "", err
}
return size, jobID, nil
}
func (dl *DeadLetter) Delete(limit int64) (count int64, err error) {
if limit > 1 {
poolPrefix := PoolJobKeyPrefix(dl.namespace, dl.queue)
var batchSize int64 = 100
if batchSize > limit {
batchSize = limit
}
for {
val, err := dl.redis.Conn.EvalSha(dummyCtx, deleteDeadletterSHA, []string{dl.Name(), poolPrefix}, batchSize).Result()
if err != nil {
if isLuaScriptGone(err) {
if err := PreloadDeadLetterLuaScript(dl.redis); err != nil {
logger.WithField("err", err).Error("Failed to load deadletter lua script")
}
continue
}
return count, err
}
n, _ := val.(int64)
count += n
if n < batchSize { // Dead letter is empty
break
}
if count >= limit {
break
}
if limit-count < batchSize {
batchSize = limit - count // This is the last batch, we should't respawn jobs exceeding the limit.
}
}
return count, nil
} else if limit == 1 {
data, err := dl.redis.Conn.RPop(dummyCtx, dl.Name()).Result()
if err != nil {
if err == go_redis.Nil {
return 0, nil
}
return 0, err
}
_, jobID, err := structUnpack(data)
if err != nil {
return 1, err
}
err = dl.redis.Conn.Del(dummyCtx, PoolJobKey2(dl.namespace, dl.queue, jobID)).Err()
if err != nil {
return 1, fmt.Errorf("failed to delete job data: %s", err)
}
return 1, nil
} else {
return 0, nil
}
}
func (dl *DeadLetter) Respawn(limit, ttlSecond int64) (count int64, err error) {
defer func() {
if err != nil && count != 0 {
metrics.deadletterRespawnJobs.WithLabelValues(dl.redis.Name).Add(float64(count))
}
}()
queueName := (&QueueName{
Namespace: dl.namespace,
Queue: dl.queue,
}).String()
poolPrefix := PoolJobKeyPrefix(dl.namespace, dl.queue)
if limit > 1 {
var batchSize = BatchSize
if batchSize > limit {
batchSize = limit
}
for {
val, err := dl.redis.Conn.EvalSha(dummyCtx, respawnDeadletterSHA, []string{dl.Name(), queueName, poolPrefix}, batchSize, ttlSecond).Result() // Respawn `batchSize` jobs at a time
if err != nil {
if isLuaScriptGone(err) {
if err := PreloadDeadLetterLuaScript(dl.redis); err != nil {
logger.WithField("err", err).Error("Failed to load deadletter lua script")
}
continue
}
return 0, err
}
n, _ := val.(int64)
count += n
if n < batchSize { // Dead letter is empty
break
}
if count >= limit {
break
}
if limit-count < batchSize {
batchSize = limit - count // This is the last batch, we should't respawn jobs exceeding the limit.
}
}
return count, nil
} else if limit == 1 {
data, err := dl.redis.Conn.RPopLPush(dummyCtx, dl.Name(), queueName).Result()
if err != nil {
if err == go_redis.Nil {
return 0, nil
}
return 0, err
}
_, jobID, err := structUnpack(data)
if err != nil {
return 1, err
}
if ttlSecond > 0 {
err = dl.redis.Conn.Expire(dummyCtx, PoolJobKey2(dl.namespace, dl.queue, jobID), time.Duration(ttlSecond)*time.Second).Err()
}
if err != nil {
return 1, fmt.Errorf("failed to set TTL on respawned job[%s]: %s", jobID, err)
}
return 1, nil
} else {
return 0, nil
}
}
func (dl *DeadLetter) Size() (size int64, err error) {
return dl.redis.Conn.LLen(dummyCtx, dl.Name()).Result()
}