Micro Queue

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This is a very simple single-instance ultra-lightweight queue microservice that uses the filesystem for persistency.

• No additional server-side services required!

• No client dependencies - just simple HTTP calls.

• Running multiple instances in active-active mode is outside the scope of this project as it would require a much more complex logic.

  Running multiple nodes in failover- or active-standby-mode behind a load-balancer should be possible if you use a distributed filesystem. (just make sure only one node is active at a time)

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Usage

Config

Create a Config file: Example

Executable

Get the Executable

• Docker: oxlorg/micro-queue or build it yourself

• Standalone: Download from Releases or build it yourself

Run

Start the Server:

• Docker: docker run -d --name micro-queue --volume "$(pwd)/testdata/config.yml:/etc/queue/config.yml" oxlorg/micro-queue

• Standalone: build/micro-queue -c $(pwd)/testdata/config.yml

Use

Use the queue:

API: http://<SERVER>:<PORT>/<in|out|compact>/<queue-name>

# add job to queue - token requires 'post' permission
curl -v -X POST -H "Authorization: Bearer aa9d7b0a-8bee-47e4-887c-bdb799533793" http://127.0.0.1:10000/in/fetcher --data '{"context": "test"}'

# gets written to disk
tree /tmp/queue/
> /tmp/queue/
> ├── fetcher
> │   ├── data.log
> │   └── meta.json
> └── manager-reload
>     ├── data.log
>     └── meta.json

# read from queue - token requires 'get' permission
curl -v -X GET -H "Authorization: Bearer bb9d7b0a-8bee-47e4-887c-bdb799533773" http://127.0.0.1:10000/out/fetcher
> {"context": "test"}

For more detailed logging set the MODE_DEBUG=1 env-var.

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Build

Use the script: cd ${REPO} && bash scripts/build.sh

Or manually: cd ${REPO} && go build -o micro-queue ./cmd/main.go

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Monitor

You can enable a prometheus exporter by setting settings.metric_exporter: true.

It records the amount of messages that did go in and out by queue:

curl -v http://127.0.0.1:10000/metrics | grep oxl
> # HELP oxl_micro_queue_messages_in_total Total number of messages put into a queue
> # TYPE oxl_micro_queue_messages_in_total counter
> oxl_micro_queue_messages_in_total{queue_name="fetcher"} 3
> # HELP oxl_micro_queue_messages_out_total Total number of messages taken out of a queue
> # TYPE oxl_micro_queue_messages_out_total counter
> oxl_micro_queue_messages_out_total{queue_name="fetcher"} 1

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Roadmap

• Adding a broadcast queue-mode where messages should be processed by every subscriber (one-to-many)