Unix Source command equivalent in Python

Question

In Unix we have a SOURCE command that can load a text file inside the shell script and all those parameters inside the text file is available as variables inside the script. Do we have an equivalent to that in python ? I need to load a properties file from the edge node to the .py script and based on the values take decisions inside the .py script.

Sample job.properties file in edge node is below.
databaseName=employee
hdfspath=/tenancy/ida/data
....

I need to load this job.properties file inside the .py script so that i need not pass these as command line arguments. Kindly advise

Make use of the `import` mechanism, I'd have thought. – SiHa Nov 06 '19 at 12:09 — SiHa, Nov 06 '19 at 12:09

score 1 · Answer 1 · answered Nov 06 '19 at 12:06

You could use 'exec' to achieve something similar to 'source'. It is not a nice thing to do.

It would look like:

with open("variables.py") as fi:
    exec(fi.read())

Easiest option is to use configparser module for ini files. If that is not desirable, try modules like yaml or json.

score 1 · Accepted Answer · answered Nov 06 '19 at 12:37

You can in fact customize the import mechanism for such purposes. However, let me provide a quick hack instead:

def source(filename):
    variables = {}
    with open(filename) as f:
        for line in f:
            try:
                name, value = line.strip().split('=')
            except:
                continue
            variables[name] = value
    return variables

variables = source('job.properties')
print(variables)

The function source iterates over the lines in the supplied file and store the assignments in the dictionary variables. In case of lines not containing assignment, the try/except will simply skip it.

To emulate the behavior of shell sourcing further, you might add

globals().update(variables)

if working at the module (non-function) level, which will make databaseName and hdfspath available as Python variables.

Note that all "sourced" variables will be strs, even for lines such as my_int=42 in the sourced file.

Unix Source command equivalent in Python

2 Answers2