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47 lines
1.7 KiB
Markdown
47 lines
1.7 KiB
Markdown
node-red-node-daemon
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====================
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A <a href="http://nodered.org" target="_new">Node-RED</a> node that runs and
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monitors a long running system command.
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Similar to the **exec** node - but this calls the command at start time and
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then pipes any input to the node to the STDIN of the running command, and feeds
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any STDOUT to the first output.
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Useful for monitoring command line based processes.
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Install
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-------
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Either use the Editor - Menu - Manage Palette - Install option or
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run the following command in your Node-RED user directory - typically `~/.node-red`
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npm i node-red-node-daemon
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Usage
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-----
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Calls out to a long running system command. Sends `msg.payload` to stdin of the process.
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**Note** Only the command itself should be placed in the command field.
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All parameters **must** be placed in the arguments field.
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The command provides 3 outputs... stdout, stderr, and return code, from the running command.
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If the called program stops (i.e. a return code is produced), this node can attempt
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to restart the command automatically.
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Setting `msg.kill` to a signal name (e.g. SIGINT, SIGHUP) will stop the process - but if the restart flag is set it will then auto restart.
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Sending `msg.start` will also re-start the process.
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**Note:** Some applications will automatically buffer lines of output. It is advisable to turn off this behaviour.
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For example, if running a Python app, the `-u` parameter will stop the output being buffered.
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For example it can be used to run and then monitor the
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<a href="https://github.com/antirez/dump1090" target="_new">dump1090</a> plane
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spotter, and also to interact with various python apps that everyone seem to write
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these days :-)
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