{ "id": "go", "title": "Redis job queue with go-redis", "url": "https://redis.io/docs/latest/develop/use-cases/job-queue/go/", "summary": "Implement a Redis job queue in Go with go-redis", "tags": [ "docs", "develop", "stack", "oss", "rs", "rc" ], "last_updated": "2026-05-14T08:58:05-05:00", "children": [], "page_type": "content", "content_hash": "a25e7a76ba2e6c3357eacee3cd1cdf70e1f37a0431a4b0d527feacc06ea21f24", "sections": [ { "id": "overview", "title": "Overview", "role": "overview", "text": "This guide shows you how to implement a Redis-backed job queue in Go with [`go-redis`](https://redis.io/docs/latest/develop/clients/go). It includes a small local web server built with the Go standard library so you can enqueue jobs, watch a pool of workers drain them, and see the reclaimer recover jobs from a simulated worker crash." }, { "id": "overview", "title": "Overview", "role": "overview", "text": "A job queue lets your application offload background work — sending email, processing payments, image transcoding, ML inference, webhooks — from the request path. Producers enqueue jobs in milliseconds and return to the user; workers pull from the queue and process them on their own schedule.\n\nThat gives you:\n\n* Low-latency user-facing requests, even when downstream work is slow or bursty\n* Horizontal scale across many worker processes that share one Redis instance\n* At-least-once delivery so a worker crash doesn't lose work\n* Visibility-timeout reclaim that returns stuck jobs to the queue automatically\n* Job metadata, retry counts, and completion results in Redis hashes with TTL\n\nIn this example, each job is identified by a random hex ID and its payload, status, and result live in a Redis hash under `queue:jobs:job:{id}`. Pending IDs sit in a list, claimed IDs move atomically to a *processing* list, and completed or failed IDs land in short history lists." }, { "id": "how-it-works", "title": "How it works", "role": "content", "text": "The flow looks like this:\n\n1. The application calls `queue.Enqueue(ctx, payload)`\n2. The helper writes the job metadata hash and `LPUSH`es the job ID onto the pending list\n3. A worker calls `queue.Claim(ctx, timeoutMs)`\n4. The helper runs `BLMOVE` to atomically move the next pending ID into the processing list and writes a per-claim `claim_token` plus `claimed_at_ms` on the hash\n5. The worker runs the job and calls `queue.Complete(ctx, job, result)` or `queue.Fail(ctx, job, errMsg)`\n6. `Complete` removes the job from the processing list, writes the result, and `LPUSH`es the ID onto the completed history (with `LTRIM` and an `EXPIRE` on the hash for cleanup)\n7. `Fail` either retries the job (back to pending) or moves it to the failed list once retries are exhausted\n\nIf a worker dies before completing a job, the job sits in the processing list with a `claimed_at_ms` older than the visibility timeout. A periodic call to `queue.ReclaimStuck(ctx)` finds those jobs and moves them back to pending so another worker can pick them up.\n\nEvery state change holds the token: a worker that has been reclaimed cannot later complete or fail a job another worker has already claimed." }, { "id": "the-job-queue-helper", "title": "The job queue helper", "role": "content", "text": "The `RedisJobQueue` type wraps the queue operations\n([source](https://github.com/redis/docs/blob/main/content/develop/use-cases/job-queue/go/job_queue.go)):\n\n[code example]" }, { "id": "data-model", "title": "Data model", "role": "content", "text": "Each job's state lives in a Redis hash plus a position in one of four lists:\n\n[code example]\n\nA job's hash carries:\n\n[code example]\n\nThe implementation uses:\n\n* [`LPUSH`](https://redis.io/docs/latest/commands/lpush) to add new job IDs to the pending list\n* [`BLMOVE`](https://redis.io/docs/latest/commands/blmove) to atomically claim a job into the processing list (the modern replacement for the deprecated [`BRPOPLPUSH`](https://redis.io/docs/latest/commands/brpoplpush))\n* [`LREM`](https://redis.io/docs/latest/commands/lrem) to remove a claimed job from the processing list on complete or fail\n* [`LTRIM`](https://redis.io/docs/latest/commands/ltrim) to cap the completed and failed history lists\n* [`HSET`](https://redis.io/docs/latest/commands/hset) / [`HGETALL`](https://redis.io/docs/latest/commands/hgetall) for job metadata\n* [`EXPIRE`](https://redis.io/docs/latest/commands/expire) on completed and failed hashes for automatic cleanup\n* [`PUBLISH`](https://redis.io/docs/latest/commands/publish) on `queue:jobs:events` for completion signalling\n* [Lua scripting](https://redis.io/docs/latest/develop/programmability/eval-intro) ([`EVALSHA`](https://redis.io/docs/latest/commands/evalsha)) for the complete, fail, and reclaim flows so each runs atomically against the processing list and metadata hash" }, { "id": "enqueueing-jobs", "title": "Enqueueing jobs", "role": "content", "text": "`Enqueue()` writes the metadata hash and pushes the job ID onto the pending list in one pipeline:\n\n[code example]\n\nThe payload is stored as JSON so the queue can carry arbitrary nested structures without forcing every field into a hash." }, { "id": "claiming-jobs-with-blmove", "title": "Claiming jobs with BLMOVE", "role": "content", "text": "A worker blocks until a job is available, then atomically pops it from the pending list and pushes it onto the processing list. `BLMOVE` does both in a single Redis call:\n\n[code example]\n\nThe `claim_token` is the worker's proof of ownership for this attempt. Every subsequent state change (complete, fail) checks it before touching the processing list, so a worker that hung past the visibility timeout cannot interfere with the new claimant.\n\n`BLMOVE` is the modern replacement for `BRPOPLPUSH`, which was deprecated in Redis 6.2. `go-redis` exposes both for backwards compatibility but the helper uses `BLMOVE` with `RIGHT`/`LEFT` arguments to match `BRPOPLPUSH` semantics." }, { "id": "completing-jobs", "title": "Completing jobs", "role": "content", "text": "`Complete()` runs a Lua script so the processing-list removal, the metadata write, and the history push happen atomically:\n\n[code example]\n\nThe Lua script checks the token first and returns `0` if the worker no longer owns the job (because the reclaimer moved it back to pending). The metadata hash also gets an `EXPIRE` so completed jobs are cleaned up automatically." }, { "id": "failing-and-retrying", "title": "Failing and retrying", "role": "content", "text": "`Fail()` either retries the job (back to pending) or moves it to the failed list once retries are exhausted:\n\n[code example]\n\nThe attempt counter is incremented on every `Claim()`, so a job that fails three times is moved to the failed list with `attempts = 3` and the final `last_error` preserved." }, { "id": "reclaiming-stuck-jobs", "title": "Reclaiming stuck jobs", "role": "content", "text": "If a worker dies mid-job — the process is killed, the host loses power, the network partitions — the job sits in the processing list with a `claimed_at_ms` that never advances. A periodic call to `ReclaimStuck()` walks the processing list and moves any job past the visibility timeout back to pending:\n\n[code example]\n\nThe Lua script also handles a narrower race: a worker that crashed between `BLMOVE` and writing `claimed_at_ms`. Those jobs are reclaimed after `2 × visibility_ms` using `enqueued_at_ms` as a fallback timer, so they aren't stranded forever." }, { "id": "stats-and-history", "title": "Stats and history", "role": "content", "text": "`Stats()` reports queue depth plus per-process counters:\n\n[code example]\n\nThe completed and failed lists are capped via `LTRIM` so they never grow unbounded; a real deployment would also write completion events to a longer-term audit log if needed." }, { "id": "prerequisites", "title": "Prerequisites", "role": "content", "text": "* Redis 6.2 or later running locally on the default port (6379). `BLMOVE` requires Redis 6.2+; earlier servers can fall back to the deprecated `BRPOPLPUSH` exposed on the same client.\n* Go 1.21 or later.\n* The `go-redis` client. The included `go.mod` pins:\n\n [code example]" }, { "id": "running-the-demo", "title": "Running the demo", "role": "content", "text": "" }, { "id": "get-the-source-files", "title": "Get the source files", "role": "content", "text": "The demo consists of five files. Download them from the [`go` source folder](https://github.com/redis/docs/tree/main/content/develop/use-cases/job-queue/go) on GitHub, or grab them with `curl`:\n\n[code example]" }, { "id": "start-the-demo-server", "title": "Start the demo server", "role": "content", "text": "From that directory, create a tiny `main.go` to start the server. Go's `package main` can't live in the same directory as `package jobqueue`, so put it in a subdirectory:\n\n[code example]\n\nThen build and run:\n\n[code example]\n\nYou should see:\n\n[code example]\n\nOpen [http://127.0.0.1:8792](http://127.0.0.1:8792) in a browser. You can:\n\n* Enqueue jobs of different kinds (email, webhook, thumbnail, invoice) in batches.\n* Start a pool of workers with configurable size, work latency, and *failure* / *hang* rates. A non-zero hang rate simulates worker crashes.\n* Click **Run reclaim sweep** to move any timed-out processing jobs back to pending.\n* Watch pending / processing / completed / failed lists update every 800 ms.\n\nIf your Redis server is running elsewhere, start the demo with `-redis-host` and `-redis-port`. You can also tune the visibility timeout with `-visibility-ms` and the queue keyspace with `-queue-name`." }, { "id": "the-mock-worker-pool", "title": "The mock worker pool", "role": "content", "text": "The demo includes a small `Worker` and `WorkerPool` ([source](https://github.com/redis/docs/blob/main/content/develop/use-cases/job-queue/go/worker.go)) that stands in for whatever real background work your application would run. Each worker:\n\n* Blocks on `queue.Claim()` for new jobs.\n* Sleeps `workLatencyMs` to simulate doing the work.\n* Either completes successfully, fails (calling `queue.Fail()`), or *hangs* — returning without completing or failing the job so the reclaimer has to recover it.\n\nThe `failRate` and `hangRate` knobs let you watch the at-least-once delivery and reclaim behaviours from the UI without writing test code." }, { "id": "production-usage", "title": "Production usage", "role": "content", "text": "" }, { "id": "choose-a-visibility-timeout-that-matches-your-worst-case-job-latency", "title": "Choose a visibility timeout that matches your worst-case job latency", "role": "content", "text": "The visibility timeout has to exceed the longest real job time, with margin. If it's too short, a healthy worker that's running a slow job will get its work duplicated when the reclaimer fires. If it's too long, a real crash takes longer to detect. Most production deployments use a per-queue value tuned to the 99th-percentile job latency — for example, 2 minutes for email and 30 minutes for video transcoding." }, { "id": "run-the-reclaimer-on-a-schedule", "title": "Run the reclaimer on a schedule", "role": "content", "text": "The demo only reclaims when you click the button. In production, run `ReclaimStuck()` from a periodic goroutine (every few seconds for fast queues, every minute for slow ones), or from each worker before it blocks on `Claim()`. Both patterns work as long as *someone* runs the sweep." }, { "id": "use-a-separate-redis-database-or-key-prefix-per-queue", "title": "Use a separate Redis database or key prefix per queue", "role": "content", "text": "The helper takes a `QueueName` option so you can run multiple independent queues against one Redis instance — for example, one queue per priority level, or one per job kind. Keep queue keys under a clearly-namespaced prefix (here, `queue:jobs:*`) so they're easy to inspect and easy to clear without touching application data." }, { "id": "cap-the-completed-and-failed-history", "title": "Cap the completed and failed history", "role": "content", "text": "The demo keeps the last 50 completed and 50 failed job IDs via `LTRIM`. If you need longer history for audit purposes, write completion events to a separate Redis Stream (or to an external store) and keep the in-queue history short. Stream consumer groups give you the same fan-out semantics with a much richer history." }, { "id": "tune-maxattempts-per-job-kind", "title": "Tune `MaxAttempts` per job kind", "role": "content", "text": "A blanket `MaxAttempts = 3` is a reasonable default for transient failures (network timeouts, rate limits). Jobs that talk to non-idempotent external systems — for example, posting a Stripe charge — need either application-level idempotency keys or a much lower retry count. The helper exposes `MaxAttempts` so each queue can pick its own policy." }, { "id": "use-context-context-for-clean-shutdown", "title": "Use `context.Context` for clean shutdown", "role": "content", "text": "Workers in the demo run as goroutines that block in `Claim()` (`BLMOVE` is a blocking Redis call). The `WorkerPool` holds a parent `context.Context`; calling `pool.Stop()` cancels each worker's child context so the next `BLMOVE` returns and the goroutine exits. Wire your real worker pool to your service's shutdown context so `SIGTERM` produces a clean drain instead of a hard kill." }, { "id": "inspect-queue-state-directly-in-redis", "title": "Inspect queue state directly in Redis", "role": "content", "text": "Because the queue is just lists and hashes, you can inspect it with `redis-cli`:\n\n[code example]" }, { "id": "learn-more", "title": "Learn more", "role": "related", "text": "This example uses the following Redis commands:\n\n* [`LPUSH`](https://redis.io/docs/latest/commands/lpush) to enqueue a job ID.\n* [`BLMOVE`](https://redis.io/docs/latest/commands/blmove) to atomically claim a job into the processing list.\n* [`LREM`](https://redis.io/docs/latest/commands/lrem) to remove a job from the processing list on complete or fail.\n* [`LRANGE`](https://redis.io/docs/latest/commands/lrange) and [`LLEN`](https://redis.io/docs/latest/commands/llen) to read queue depth and list contents.\n* [`LTRIM`](https://redis.io/docs/latest/commands/ltrim) to cap the completed and failed history.\n* [`HSET`](https://redis.io/docs/latest/commands/hset) and [`HGETALL`](https://redis.io/docs/latest/commands/hgetall) for job metadata.\n* [`HINCRBY`](https://redis.io/docs/latest/commands/hincrby) for the attempt counter.\n* [`EXPIRE`](https://redis.io/docs/latest/commands/expire) for automatic cleanup of completed and failed jobs.\n* [`PUBLISH`](https://redis.io/docs/latest/commands/publish) for job-completion notifications.\n* [`EVALSHA`](https://redis.io/docs/latest/commands/evalsha) for atomic complete, fail, and reclaim flows.\n\nSee the [`go-redis` documentation](https://redis.io/docs/latest/develop/clients/go) for full client reference." } ], "examples": [ { "id": "the-job-queue-helper-ex0", "language": "go", "code": "import (\n \"context\"\n\n \"github.com/redis/go-redis/v9\"\n \"jobqueue\"\n)\n\nclient := redis.NewClient(&redis.Options{Addr: \"localhost:6379\"})\nqueue := jobqueue.NewRedisJobQueue(client, jobqueue.Options{\n VisibilityMs: 5000,\n})\n\nctx := context.Background()\njobID, _ := queue.Enqueue(ctx, map[string]any{\n \"kind\": \"email\",\n \"recipient\": \"alice@example.com\",\n})\n\n// In a worker goroutine:\njob, _ := queue.Claim(ctx, 1000)\nif job != nil {\n // ... run the job ...\n if _, err := queue.Complete(ctx, job, map[string]any{\"sent_at\": \"2026-05-11T15:00:00Z\"}); err != nil {\n queue.Fail(ctx, job, err.Error())\n }\n}\n\n// In a periodic sweeper:\nreclaimed, _ := queue.ReclaimStuck(ctx)\n_ = reclaimed", "section_id": "the-job-queue-helper" }, { "id": "data-model-ex0", "language": "text", "code": "queue:jobs:pending (list) pending job IDs, oldest at the right\nqueue:jobs:processing (list) claimed but not yet completed\nqueue:jobs:completed (list) recent successes (LTRIM-capped history)\nqueue:jobs:failed (list) terminally failed jobs\nqueue:jobs:job:{id} (hash) per-job metadata\nqueue:jobs:events (pubsub) completion notifications", "section_id": "data-model" }, { "id": "data-model-ex1", "language": "text", "code": "queue:jobs:job:9a4f...\n id = 9a4f...\n payload = {\"kind\":\"email\",\"recipient\":\"alice@example.com\"}\n status = pending | processing | completed | failed\n attempts = 1\n enqueued_at_ms = 1715441000000\n claimed_at_ms = 1715441000123\n claim_token = b3c0d1e2... (per-claim random token)\n completed_at_ms = 1715441000456\n result = {\"sent_at\":\"...\"}\n last_error = \"smtp timeout\"", "section_id": "data-model" }, { "id": "enqueueing-jobs-ex0", "language": "go", "code": "func (q *RedisJobQueue) Enqueue(ctx context.Context, payload map[string]any) (string, error) {\n jobID := tokenHex(8)\n payloadJSON, _ := json.Marshal(payload)\n now := nowMs()\n meta := map[string]interface{}{\n \"id\": jobID,\n \"payload\": string(payloadJSON),\n \"status\": \"pending\",\n \"attempts\": 0,\n \"enqueued_at_ms\": now,\n \"claim_token\": \"\",\n }\n pipe := q.client.Pipeline()\n pipe.HSet(ctx, q.metaKey(jobID), meta)\n pipe.LPush(ctx, q.pendingKey, jobID)\n if _, err := pipe.Exec(ctx); err != nil {\n return \"\", err\n }\n return jobID, nil\n}", "section_id": "enqueueing-jobs" }, { "id": "claiming-jobs-with-blmove-ex0", "language": "go", "code": "func (q *RedisJobQueue) Claim(ctx context.Context, timeoutMs int) (*ClaimedJob, error) {\n timeout := time.Duration(timeoutMs) * time.Millisecond\n if timeout < 100*time.Millisecond {\n timeout = 100 * time.Millisecond\n }\n jobID, err := q.client.BLMove(ctx, q.pendingKey, q.processingKey, \"RIGHT\", \"LEFT\", timeout).Result()\n if err == redis.Nil {\n return nil, nil\n }\n if err != nil {\n return nil, err\n }\n\n token := tokenHex(8)\n now := nowMs()\n metaKey := q.metaKey(jobID)\n\n pipe := q.client.Pipeline()\n pipe.HSet(ctx, metaKey, map[string]interface{}{\n \"status\": \"processing\",\n \"claimed_at_ms\": now,\n \"claim_token\": token,\n })\n pipe.HIncrBy(ctx, metaKey, \"attempts\", 1)\n getAll := pipe.HGetAll(ctx, metaKey)\n if _, err := pipe.Exec(ctx); err != nil {\n return nil, err\n }\n // ... parse payload and attempts from getAll.Val() ...\n return &ClaimedJob{ID: jobID, Payload: payload, Attempts: attempts, ClaimToken: token}, nil\n}", "section_id": "claiming-jobs-with-blmove" }, { "id": "completing-jobs-ex0", "language": "go", "code": "func (q *RedisJobQueue) Complete(ctx context.Context, job *ClaimedJob, result map[string]any) (bool, error) {\n resultJSON, _ := json.Marshal(result)\n keys := []string{q.metaPrefix, q.processingKey, q.completedKey}\n args := []interface{}{\n job.ID,\n job.ClaimToken,\n \"completed\",\n nowMs(),\n string(resultJSON),\n q.completedTTL,\n q.completedHistory,\n }\n res, err := q.completeScript.Run(ctx, q.client, keys, args...).Result()\n if err != nil {\n return false, err\n }\n n, _ := res.(int64)\n if n != 1 {\n return false, nil\n }\n eventPayload, _ := json.Marshal(map[string]any{\"id\": job.ID, \"status\": \"completed\"})\n q.client.Publish(ctx, q.eventsChannel, string(eventPayload))\n return true, nil\n}", "section_id": "completing-jobs" }, { "id": "failing-and-retrying-ex0", "language": "go", "code": "func (q *RedisJobQueue) Fail(ctx context.Context, job *ClaimedJob, errMsg string) (bool, error) {\n retry := job.Attempts < q.maxAttempts\n retryArg := \"0\"\n if retry {\n retryArg = \"1\"\n }\n keys := []string{q.metaPrefix, q.processingKey, q.pendingKey, q.failedKey}\n args := []interface{}{\n job.ID, job.ClaimToken, errMsg, nowMs(),\n q.completedTTL, q.completedHistory, retryArg,\n }\n res, err := q.failScript.Run(ctx, q.client, keys, args...).Result()\n if err != nil {\n return false, err\n }\n n, _ := res.(int64)\n return n != 0, nil\n}", "section_id": "failing-and-retrying" }, { "id": "reclaiming-stuck-jobs-ex0", "language": "go", "code": "func (q *RedisJobQueue) ReclaimStuck(ctx context.Context) ([]string, error) {\n keys := []string{q.pendingKey, q.processingKey, q.metaPrefix}\n args := []interface{}{nowMs(), q.visibilityMs}\n res, err := q.reclaimScript.Run(ctx, q.client, keys, args...).Result()\n if err != nil {\n return nil, err\n }\n raw, _ := res.([]interface{})\n out := make([]string, 0, len(raw))\n for _, item := range raw {\n if s, ok := item.(string); ok {\n out = append(out, s)\n }\n }\n return out, nil\n}", "section_id": "reclaiming-stuck-jobs" }, { "id": "stats-and-history-ex0", "language": "go", "code": "func (q *RedisJobQueue) Stats(ctx context.Context) (map[string]any, error) {\n pipe := q.client.Pipeline()\n pendingCmd := pipe.LLen(ctx, q.pendingKey)\n processingCmd := pipe.LLen(ctx, q.processingKey)\n completedCmd := pipe.LLen(ctx, q.completedKey)\n failedCmd := pipe.LLen(ctx, q.failedKey)\n if _, err := pipe.Exec(ctx); err != nil {\n return nil, err\n }\n return map[string]any{\n \"enqueued_total\": q.enqueuedN,\n \"completed_total\": q.completedN,\n \"failed_total\": q.failedN,\n \"reclaimed_total\": q.reclaimedN,\n \"pending_depth\": pendingCmd.Val(),\n \"processing_depth\": processingCmd.Val(),\n \"completed_depth\": completedCmd.Val(),\n \"failed_depth\": failedCmd.Val(),\n \"visibility_ms\": q.visibilityMs,\n }, nil\n}", "section_id": "stats-and-history" }, { "id": "prerequisites-ex0", "language": "text", "code": "require github.com/redis/go-redis/v9 v9.18.0", "section_id": "prerequisites" }, { "id": "get-the-source-files-ex0", "language": "bash", "code": "mkdir job-queue-demo && cd job-queue-demo\nBASE=https://raw.githubusercontent.com/redis/docs/main/content/develop/use-cases/job-queue/go\ncurl -O $BASE/job_queue.go\ncurl -O $BASE/worker.go\ncurl -O $BASE/demo_server.go\ncurl -O $BASE/go.mod\ncurl -O $BASE/go.sum", "section_id": "get-the-source-files" }, { "id": "start-the-demo-server-ex0", "language": "bash", "code": "mkdir -p cmd/demo\ncat > cmd/demo/main.go <<'EOF'\npackage main\n\nimport \"jobqueue\"\n\nfunc main() { jobqueue.RunDemoServer() }\nEOF", "section_id": "start-the-demo-server" }, { "id": "start-the-demo-server-ex1", "language": "bash", "code": "go mod tidy\ngo run ./cmd/demo", "section_id": "start-the-demo-server" }, { "id": "start-the-demo-server-ex2", "language": "text", "code": "Redis job-queue demo server listening on http://127.0.0.1:8792\nUsing Redis at localhost:6379\nVisibility timeout: 5000 ms", "section_id": "start-the-demo-server" }, { "id": "inspect-queue-state-directly-in-redis-ex0", "language": "bash", "code": "# How many pending jobs?\nredis-cli LLEN queue:jobs:pending\n\n# Look at the next 5 jobs to be picked up.\nredis-cli LRANGE queue:jobs:pending -5 -1\n\n# Read a job's metadata.\nredis-cli HGETALL queue:jobs:job:9a4f0d1c\n\n# How many jobs are currently being processed?\nredis-cli LLEN queue:jobs:processing\n\n# Clear everything for this queue (be careful — this deletes work).\nredis-cli --scan --pattern 'queue:jobs:*' | xargs redis-cli DEL", "section_id": "inspect-queue-state-directly-in-redis" } ] }