argument errors when using using Python to access to aws ecr

Question

here is the function:

def sh(*command, read_output=False, **kwargs):
    command_text = " ".join(command)
    print(f"\t> {command_text}")
    try:
        if read_output:
            return check_output(command, **kwargs).decode("utf8")
        else:
            check_call(command, **kwargs)
    except CalledProcessError as failure:
        print(
            f'ERROR: "{command_text}" command reported failure! Return code {failure.returncode}.'
        )
        sys.exit(failure.returncode)

I'm trying to use this function to get aws erc get-login first, then use that returned login command to login to aws erc. here is my codes:

result = sh('aws', 'ecr', 'get-login', '--no-include-email', read_output=True)
re = result.split()
sh(re)

then I get error:

command_text = " ".join(command)
TypeError: sequence item 0: expected str instance, list found

I think the sh function expect arguments something like `('docker', 'login', '-u', 'AWS', '-p'...), but how can I achieve this?

Answer 1

You can use * to unpack list/tuple and function get it as many arguments

sh( *re )

Or you can remove * from *command in definiton

def sh(command, ...)

and then you can send it only as list/tuple

sh( re )

but you can also check if command is list or string

if isinstance(command, str): 
    command_text = command 
elif isinstance(command, list, tuple): 
    command_text = " ".join(command)

so then you can send it directly as one string.

sh( 'aws ecr get-login --no-include-email' )

or list with strings

sh( ['aws', 'ecr', 'get-login', '--no-include-email'] )

---

BTW: Similar way works ** with dictionary and named arguments

def fun(a=0, b=0, c=0):
    print('a:', a)
    print('b:', b)
    print('c:', c)

data = {'b':2}

fun(**data)