54 lines
1.8 KiB
ReStructuredText
54 lines
1.8 KiB
ReStructuredText
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========================================
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``psmq`` Publish Subscribe Message Queue
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========================================
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``psmq`` is publish subscribe message queue. It's a set of programs and libraries
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to implement publish/subscribe way of inter-process communication on top of
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POSIX message queue.
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Manuals, source code and more info at: https://psmq.bofc.pl
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Little demo using ``psmqd`` broker, ``psmq_pub`` and ``psmq_sub``:
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Start broker and make it log to file::
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nsh> psmqd -b/brok -p/sd/psmqd/psmqd.log &
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Start subscribe thread that will read all messages send on ``/can/*`` and
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``/adc/*`` topic, and dump all readings to file::
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nsh> psmq_sub -n/sub -b/brok -t/can/* -t/adc/* -o/sd/psmq-sub/can.log &
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n/connected to broker /brok
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n/subscribed to: /can/*
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n/subscribed to: /adc/*
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n/start receiving data
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n/reply timeout set 100
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Publish some messages::
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nsh> psmq_pub -b/brok -t/can/engine/rpm -m50
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nsh> psmq_pub -b/brok -t/adc/volt -m30
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nsh> psmq_pub -b/brok -t/can/room/10/temp -m23
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nsh> psmq_pub -b/brok -t/pwm/fan1/speed -m300
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Check out subscribe thread logs::
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nsh> cat /sd/psmq-sub/can.log
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[2021-05-23 17:53:59] p:0 l: 3 /can/engine/rpm 50
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[2021-05-23 17:53:59] p:0 l: 3 /adc/volt 30
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[2021-05-23 17:53:59] p:0 l: 3 /can/room/10/temp 23
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As you can see ``/pwm/fan1/speed`` hasn't been received by subscribe thread,
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since we didn't subscribe to it.
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Content:
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- ``psmqd`` – broker, relays messages between clients.
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- ``psmq_sub`` – listens to specified topics, can be used as logger for
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communication (optional).
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- ``psmq_pub`` – publishes messages directly from shell. Can send binary data, but
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requires pipes, so on nuttx it can only send ASCII.
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- ``libpsmq`` – library used to communicate with the broker and send/receive
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messages.
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