CODEWITHSUNDEEP
pythonseleniumrobotframework
Rashid
Rashid

Reputation: 65

How to access --variablefile arguments in python

In a shell script I have: 

/usr/local/bin/pybot --variablefile variables.py:$var1:$var2 test_cases.tsv

inside variables.py how can I access var1 and var2 arguments?

I have tried: 

import sys
var1 = sys.argv[1]
var1 = sys.argv[2]

it seems like this doesn't work.

Upvotes: 1

Views: 378

Answers (3)

Bryan Oakley
Bryan Oakley

Reputation: 386342

For you to access the variables, your variable file must define the function get_variables, which will be given the arguments passed from the command line. This function needs to return a dictionary where the keys are the robot variable names.

For example:

def get_variables(arg1, arg2):
    variables = {
        "var1": arg1,
        "var2": arg2
    }
    return variables

If your variable file is based on a class, the class needs to have the get_variables method.

For example:

# variables.py
class variables(object):
    def get_variables(self, arg1, arg2):
        variables = {
            "var1": arg1,
            "var2": arg2
        }
        return variables

When you do the above, your test will have two variables set: ${var1} and ${var2} which will have the values that were passed via the --variablefile argument.

Here is a test that can be used to verify the above:

# example.robot
*** Test cases ***
Example
    should be equal  ${var1}  hello
    should be equal  ${var2}  world

Here is how to run the test in order for it to pass:

$ var1=hello
$ var2=world
$ /usr/local/bin/pybot --variablefile variables.py:$var1:$var2 example.robot

Of course, var1 and var2 are completely arbitrary. You can pass raw strings, too:

$ /usr/local/bin/pybot --variablefile variables.py:hello:world example.robot

Passing arguments is described in the user guide section titled Getting variables from a special function

Upvotes: 2

tripleee
tripleee

Reputation: 189830

You seem to make assumptions about how the arguments are parsed which are not true. Here's how these arguments are passed from the shell to Python:

  • sys.argv[0] is /usr/local/bin/pybot
  • sys.argv[1] is --variablefile
  • sys.argv[2] is variables.py:$var1:$var2 where the values of the shell variables var1 and var2 are substituted.
  • sys.argv[n] is test_cases.tsv

The last one is [n] because without quotes around the argument, sys.argv[2] might actually be split into multiple values. For example, if var1 contains = foo * bar= then actually

  • sys.argv[2] is variables.py:=
  • sys.argv[3] is foo
  • sys.argv[4..n-2] is a list of files in the current directory, and
  • sys.argv[n-1] is =bar:$var2 where similar further processing for the value of var2 may take place.

There are Python argument parsing modules which assign further semantics e.g. to arguments which start with a dash (these will be interpreted as options) but by itself, Python does no such thing. If that's what you want, maybe look at argparse or one of its replacements; but you still need to understand how the basic mechanics work. A common arrangement is to avoid internal structure in arguments, and instead require the user to pass each value as a separate argument -- so perhaps

--variablefile variables.py --variablefile "$var1" --variablefile "$var2"

with quoting to prevent the shell from attempting to perform whitespace tokenization and wildcard expansion on the variable values, and then probably in your script an argparse definition which says to merge multiple option arguments into a list.

parser = argparse.ArgumentParser()
parser.add_argument('--variablefile', action='append')

Upvotes: 0

Ariel Otilibili
Ariel Otilibili

Reputation: 280

sys reads the arguments fron the command line, as they appears to it:

  • sys.argv[0] contains the script name
  • sys.argv[1], the first argument (whatever it is)
  • sys.argv[2], the second, and so on.

You should use argparse, it helps to build comprehensive CLIs. A nice tutorial exists on the Python website.

Upvotes: 0

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