mirror of
https://github.com/christianselig/apollo-backend
synced 2024-11-12 23:17:44 +00:00
first pass at distributed lock
This commit is contained in:
parent
65fc7a5298
commit
1dd0c3a47d
7 changed files with 212 additions and 9 deletions
11
.github/workflows/test.yml
vendored
11
.github/workflows/test.yml
vendored
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@ -5,6 +5,7 @@ jobs:
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runs-on: ubuntu-latest
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env:
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DATABASE_URL: postgres://postgres:postgres@localhost/apollo_test
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REDIS_URL: redis://redis:6379
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services:
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postgres:
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image: postgres
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@ -18,7 +19,15 @@ jobs:
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--health-retries 5
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ports:
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- 5432:5432
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redis:
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image: redis
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options: >-
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--health-cmd "redis-cli ping"
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--health-interval 10s
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--health-timeout 5s
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--health-retries 5
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ports:
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- 6379:6379
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steps:
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- uses: actions/checkout@v3
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- uses: actions/setup-go@v3
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@ -17,11 +17,5 @@ linters:
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- thelper # detects golang test helpers without t.Helper() call and checks consistency of test helpers
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- unconvert # removes unnecessary type conversions
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- unparam # removes unused function parameters
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- paralleltest
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fast: true
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issues:
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exclude-rules:
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# False positive: https://github.com/kunwardeep/paralleltest/issues/8.
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- linters:
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- paralleltest
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text: "does not use range value in test Run"
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3
Makefile
3
Makefile
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@ -1,8 +1,9 @@
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BREW_PREFIX ?= $(shell brew --prefix)
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DATABASE_URL ?= "postgres://$(USER)@localhost/apollo_test?sslmode=disable"
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REDIS_URL ?= "redis://localhost:6379"
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test:
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@DATABASE_URL=$(DATABASE_URL) go test -race -timeout 1s ./...
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@DATABASE_URL=$(DATABASE_URL) REDIS_URL=$(REDIS_URL) go test -race -timeout 1s ./...
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test-setup: $(BREW_PREFIX)/bin/migrate
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migrate -path migrations/ -database $(DATABASE_URL) up
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72
internal/distributedlock/distributed_lock.go
Normal file
72
internal/distributedlock/distributed_lock.go
Normal file
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@ -0,0 +1,72 @@
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package distributedlock
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import (
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"context"
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"fmt"
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"github.com/go-redis/redis/v8"
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"math/rand"
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"time"
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)
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const lockTopicFormat = "pubsub:locks:%s"
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type DistributedLock struct {
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client *redis.Client
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timeout time.Duration
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}
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func New(client *redis.Client, timeout time.Duration) *DistributedLock {
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return &DistributedLock{
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client: client,
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timeout: timeout,
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}
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}
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func (d *DistributedLock) setLock(ctx context.Context, key string, uid string) error {
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result, err := d.client.SetNX(ctx, key, uid, d.timeout).Result()
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if err != nil {
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return err
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}
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if !result {
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return ErrLockAlreadyAcquired
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}
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return nil
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}
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func (d *DistributedLock) AcquireLock(ctx context.Context, key string) (*Lock, error) {
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uid := generateUniqueID()
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if err := d.setLock(ctx, key, uid); err != nil {
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return nil, err
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}
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return NewLock(d, key, uid), nil
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}
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func (d *DistributedLock) WaitAcquireLock(ctx context.Context, key string, timeout time.Duration) (*Lock, error) {
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uid := generateUniqueID()
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if err := d.setLock(ctx, key, uid); err == nil {
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return NewLock(d, key, uid), nil
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}
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ch := fmt.Sprintf(lockTopicFormat, key)
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pubsub := d.client.Subscribe(ctx, ch)
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select {
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case <-time.After(timeout):
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return nil, ErrLockAcquisitionTimeout
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case <-ctx.Done():
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return nil, ctx.Err()
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case <-pubsub.Channel():
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err := d.setLock(ctx, key, uid)
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if err != nil {
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return nil, err
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}
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return NewLock(d, key, uid), nil
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}
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}
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func generateUniqueID() string {
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return fmt.Sprintf("%d-%d", time.Now().UnixNano(), rand.Int63())
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}
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73
internal/distributedlock/distributed_lock_test.go
Normal file
73
internal/distributedlock/distributed_lock_test.go
Normal file
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@ -0,0 +1,73 @@
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package distributedlock_test
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import (
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"context"
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"fmt"
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"github.com/christianselig/apollo-backend/internal/distributedlock"
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"github.com/go-redis/redis/v8"
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"github.com/stretchr/testify/assert"
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"os"
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"testing"
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"time"
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)
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func NewRedisClient(t *testing.T, ctx context.Context) (*redis.Client, func()) {
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t.Helper()
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opt, err := redis.ParseURL(os.Getenv("REDIS_URL"))
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if err != nil {
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panic(err)
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}
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client := redis.NewClient(opt)
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if err := client.Ping(ctx).Err(); err != nil {
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panic(err)
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}
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return client, func() {
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_ = client.Close()
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}
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}
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func TestDistributedLock_AcquireLock(t *testing.T) {
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ctx := context.Background()
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key := fmt.Sprintf("%d", time.Now().UnixNano())
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client, closer := NewRedisClient(t, ctx)
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defer closer()
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d := distributedlock.New(client, 10*time.Second)
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lock, err := d.AcquireLock(ctx, key)
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assert.NoError(t, err)
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_, err = d.AcquireLock(ctx, key)
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assert.Equal(t, distributedlock.ErrLockAlreadyAcquired, err)
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err = lock.Release(ctx)
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assert.NoError(t, err)
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_, err = d.AcquireLock(ctx, key)
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assert.NoError(t, err)
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}
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func TestDistributedLock_WaitAcquireLock(t *testing.T) {
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ctx := context.Background()
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key := fmt.Sprintf("%d", time.Now().UnixNano())
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client, closer := NewRedisClient(t, ctx)
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defer closer()
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d := distributedlock.New(client, 10*time.Second)
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lock, err := d.AcquireLock(ctx, key)
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assert.NoError(t, err)
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go func(l *distributedlock.Lock) {
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select {
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case <-time.After(100 * time.Millisecond):
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_ = l.Release(ctx)
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}
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}(lock)
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lock, err = d.WaitAcquireLock(ctx, key, 5*time.Second)
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assert.NoError(t, err)
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assert.NotNil(t, lock)
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}
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9
internal/distributedlock/errors.go
Normal file
9
internal/distributedlock/errors.go
Normal file
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package distributedlock
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import "errors"
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var (
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ErrLockAcquisitionTimeout = errors.New("timed out acquiring lock")
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ErrLockAlreadyAcquired = errors.New("lock already acquired")
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ErrLockExpired = errors.New("releasing an expired lock")
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)
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45
internal/distributedlock/lock.go
Normal file
45
internal/distributedlock/lock.go
Normal file
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package distributedlock
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import (
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"context"
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"fmt"
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)
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type Lock struct {
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distributedLock *DistributedLock
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key string
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uid string
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}
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func NewLock(distributedLock *DistributedLock, key string, uid string) *Lock {
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return &Lock{
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distributedLock: distributedLock,
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key: key,
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uid: uid,
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}
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}
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func (l *Lock) Release(ctx context.Context) error {
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script := `
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if redis.call("GET", KEYS[1]) == ARGV[1] then
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redis.call("DEL", KEYS[1])
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redis.call("PUBLISH", KEYS[2], KEYS[1])
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return 1
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else
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return 0
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end
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`
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ch := fmt.Sprintf(lockTopicFormat, l.key)
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result, err := l.distributedLock.client.Eval(ctx, script, []string{l.key, ch}, l.uid).Result()
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if err != nil {
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return err
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}
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if result == int64(0) {
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return ErrLockExpired
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}
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return nil
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}
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