Command Line Arguments and Import issue about dronekit-python HOT 8 CLOSED

Import issue was caused by PATH issues and file permission issues. This has be resolved. Still curious about command line arguments though.

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Ok so I just figured out that "api start script.py" takes its arguments from "mavproxy.py [args]".

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@djnugent Is this still an issue? Should this be documented better?

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@tcr3dr @djnugent This is still an issue because I haven't documented command line arguments to api start (at all) and I don't understand enough from this post to do so :-(

1. When you say this takes its arguments from "mavproxy.py [args]" do you mean that when you run a script with api start filename.py the arguments recieved will be whatever you already passed when you started mavproxy? In most cases that will just be the id of the master/connection?
   • If so, can you pass arbitrary commands to mavproxy and still pick them up in your script (ie launch mavproxy with parameters that mean nothing to mavproxy but which are relevant to the script?
2. The full question here is "how to interact with the script" - both with command line arguments and by making the script interactive - ie able to wait on and take some form of input. I might (for example) want to be able to send a message to my script from a GCS telling it to change behaviour in some way. Is this reasonable, and if so, can we have a separate issue for it?

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So I believe the issue is more specifically, "What is sys.argv populated with?" and the answer for this is "The sys.argv visible to mavproxy.py".

To pass "arguments" to your script in the current configuration, the best choice would be environment variables. We could extend api start to fix this.

However, I think punting on this issue is preferable, as in a post-MAVProxy scenario we'd be able to control sys.argv and stdin, leaving it implementation-specific. As such, I'm marking this wontfix.

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@tcr3dr Makes sense to me. #188 will make a lot of things more "sensible".

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@tcr3dr Reopening to continue discussion.

Just found that in theory at least you can pass arguments to the script! See http://python.dronekit.io/examples/flight_replay.html

mission_id = int(local_arguments[0])

Any ideas of best place to document this in our current structure? We don't (yet) have best practices or programming idioms doc. Maybe a stand alone doc "Communicating with the script". WOuld be a bit "thin".

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We can now close this, since a public build of DKPY2 is in the wild.

Recommendation: use sys.argv!

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