When running Python scripts, how to you set which version of Python is being used?

Trying_to_learn · 28 July 2020 03:28

Forgetting pythonshell, nodes seem to have (or be able to have) python code in them.

How do I know which version of python they invoke?

krambriw · 28 July 2020 03:46

To check

Trying_to_learn · 28 July 2020 03:50

AFAICS, (as far as I can see) there is no mention of python being used.

(Just checked.) NO.

No mention.

Now I can't even find the node in the library.

This one.

afelix · 28 July 2020 09:10

Turns out it is hardcoded for this node.

github.com

erfanjahanshahlo/node-red-contrib-pifacecad/blob/8457ae3afbcb844e80a3d3cf8d5df5bca698f398/pfc_lcd.js#L8


      
          module.exports = function(RED) {
              var exec = require("child_process").exec;
              function PFC_LiquidCrystal(config) {
                  RED.nodes.createNode(this, config);
                  var node = this;
                  this.on("input", function(msg) {
          			text = msg.payload.replace(" ", "#/@$%");
          			exec('python2 "' + __dirname + '/pfc_lcd.py" ' + text, function(err, stdout, stderr) {
          				if (err) {
          					node.error(err, msg); 
          					node.status({fill: "red", shape: "dot", text: "ERROR"});
          				} else {
          					node.status({fill: "green", shape: "dot", text: "OK"});
          				}
          			});
                  });
                  this.on("close", function() {
                  });

This line tells you it will use Python 2.x, likely 2.7 which has been End Of Life since January 1st.

As such, the instructions for installing dependencies are odd:

That last line will install the pifacecad python library for both python2 and python3, yet hardcoded uses python2.

Trying_to_learn · 28 July 2020 09:27

Thanks.

So 2.7 should be it.

I shall stick to trying the code with that then.

zenofmud · 28 July 2020 09:39

@Trying_to_learn - I would open an issue on GitHub pointing out the hard coded version and that it hit EOL

TotallyInformation · 29 July 2020 16:32

To repeat what Lena said - Python 2.x is end of life and will no longer get updates. You really do need to upgrade.

Good spot Lena.

system · 27 September 2020 16:32

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When running Python scripts, how to you set which version of Python is being used?

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