Fast zero-configuration single-binary simple queue service.
Currently, queued supports Linux only.
queued requires persistent storage, and it's preferred to provide a block device directly (e.g. /dev/my_block_device), to bypass the file system. Alternatively, a standard file can be used too (e.g. /var/lib/queued/data). In either case, the entire device/file will be used, and it must have a size that's a multiple of 1024 bytes.
```
cargo install queued
queued --device /dev/myblockdevice --format ```
queued --device /dev/my_block_device
``` 🌐 POST localhost:3333/push { "contents": "Hello, world!" } ✅ 200 OK { "index": 190234 }
🌐 POST localhost:3333/poll { "visibilitytimeoutsecs": 30 } ✅ 200 OK { "message": { "contents": "Hello, world!", "created": "2023-01-03T12:00:00Z", "index": 190234, "pollcount": 1, "polltag": "f914659685fcea9d60" } }
🌐 POST localhost:3333/delete { "index": 190234, "poll_tag": "f914659685fcea9d60" } ✅ 200 OK {} ```
On a machine with an Intel Core i5-12400 CPU, Samsung 970 EVO Plus 1TB NVMe SSD, and Linux 5.17, with 2048 concurrent clients, queued manages around 50,000 operations (push, poll, or delete) per second.
At the API layer, only a successful response (i.e. 2xx) means that the request has been successfully persisted to disk. Assume any interrupted or failed requests did not safely get stored, and retry as appropriate.
Internally, queued records a hash of persisted data (including metadata and data of messages), to verify integrity when starting the server. It's recommended to use error-detecting-and-correcting durable storage when running in production, like any other stateful workload.
Performing backups can be done by stopping the process and taking a copy of the contents of the file/device. Using compression can reduce bandwidth (when transferring) and storage usage.
GET /metrics returns metrics in the Prometheus format.
GET /healthz returns the current build version.
POST /suspend can suspend specific API endpoints, useful for temporary debugging or emergency intervention without stopping the server. It takes a request body like:
json
{
"delete": true,
"poll": true,
"push": false
}
Set a property to true to disable that endpoint, and false to re-enable it. Disabled endpoints will return 503 Service Unavailable. Use GET /suspend to get currently suspended endpoints.