@blokcert/node-red-contrib-delayed-job 0.4.0
A Node-RED node for Redis-backed delayed job queues using BullMQ
@blokcert/node-red-contrib-delayed-job
A Node-RED node for Redis-backed delayed job queues using BullMQ.
Each node acts as both producer and consumer — messages are serialized into a Redis queue on input, and a background worker picks them up and sends them to the output.
Features
- Delayed execution — schedule jobs to run after a specified delay
- Job priority — lower number = higher priority
- TTL (Time-to-live) — automatically discard expired jobs
- Rate limiting — control the interval between job processing
- Concurrency — process multiple jobs simultaneously
- Crash recovery — jobs persist in Redis; restarting Node-RED picks up unfinished jobs
- Distributed workers — multiple Node-RED instances sharing the same queue name form a worker pool
- Buffer support —
Bufferobjects are preserved through serialization - i18n — English and Traditional Chinese (zh-TW)
Install
cd ~/.node-red
npm install @blokcert/node-red-contrib-delayed-job
Requires a running Redis server (or compatible, e.g. Valkey, Dragonfly).
Nodes
delayed-job
The main node. Drag it into your flow, configure the Redis connection, and wire it up.
Input: messages are serialized and added to the Redis queue.
Output: when a job is picked up by the worker, the deserialized message is sent out.
Node Settings
| Setting | Default | Description |
|---|---|---|
| Redis | (required) | Redis connection config |
| Concurrency | 1 | Number of jobs processed simultaneously |
| Interval | 0 ms | Minimum time between job processing (rate limit) |
Message Properties
| Property | Type | Description |
|---|---|---|
msg.delay |
number | Delay in milliseconds before the job is processed |
msg.priority |
number | Job priority (lower = higher priority) |
msg.ttl |
number | Time-to-live in seconds. Expired jobs are discarded. Default: 7 days |
msg.keepAfter |
number | Keep job in Redis for N seconds after completion. Default: 7 days |
delayed-job-redis (Config Node)
Shared Redis connection configuration.
| Setting | Default | Description |
|---|---|---|
| Host | 127.0.0.1 | Redis server hostname |
| Port | 6379 | Redis server port |
| Password | — | Authentication password (stored encrypted) |
| DB | 0 | Redis database index |
| TLS | off | Enable TLS/SSL |
| Queue Name | default | Queue name prefix. Same name = shared queue across instances |
How It Works
[inject] → [delayed-job] → [debug]
↕ Redis
- A message arrives at the input
- The node serializes it (removing
_msgid) and adds it to the BullMQ queue in Redis - The background worker picks up the job, deserializes the message, and sends it to the output
- Node-RED assigns a new
_msgid
Queue Isolation
Each node instance gets a unique queue: {queueName}-{nodeId}. To share a queue across multiple Node-RED instances (distributed worker pool), use the same Queue Name in the Redis config.
Crash Recovery
Jobs are stored in Redis and retained for 7 days after completion by default. If Node-RED crashes or restarts, the worker will pick up any remaining jobs automatically.
Limitations
msg.reqandmsg.res(HTTP request/response objects) cannot be serialized and will be lost- Non-JSON-serializable properties will be dropped
Example Flow
[
{
"id": "inject1",
"type": "inject",
"payload": "hello",
"wires": [["delayed1"]]
},
{
"id": "delayed1",
"type": "delayed-job",
"name": "my queue",
"wires": [["debug1"]]
},
{
"id": "debug1",
"type": "debug",
"name": "output"
}
]
Testing
Requires a local Redis server running.
npm test
Set REDIS_HOST and REDIS_PORT environment variables to use a non-default Redis server.
License
MIT
