Dynamically loads modules in Python 3 at runtime… here is a solution to the problem.
Dynamically loads modules in Python 3 at runtime
What is the recommended way to lazy load files in Python 3?
I built this function by copying from Python 2 code
def get_command(self, ctx, cmd_name):
ns = {}
fn = os.path.join(cmd_folder, 'cmd_{}.py'.format(cmd_name))
with open(fn) as f:
code = compile(f.read(), str(fn), 'exec')
eval(code, ns, ns)
return ns['cli']
But I’m not sure if that’s the right approach. It uses compile
and eval
Edit
After using import
like this:
def get_command(self, ctx, cmd_name):
cmd_mod = import_module('{}.cmd_{}'.format(cmd_folder, cmd_name))
Here is the result:
File "aws_iam_cli/cli.py", line 23, in get_command
cmd_mod = import_module('{}.cmd_{}'.format(cmd_folder, cmd_name))
File "/Users/salvatoremazzarino/awsiam/venv/lib/python3.6/importlib/__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 994, in _gcd_import
File "<frozen importlib._bootstrap>", line 971, in _find_and_load
File "<frozen importlib._bootstrap>", line 941, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
File "<frozen importlib._bootstrap>", line 994, in _gcd_import
File "<frozen importlib._bootstrap>", line 971, in _find_and_load
File "<frozen importlib._bootstrap>", line 953, in _find_and_load_unlocked
ModuleNotFoundError: No module named '/Users/salvatoremazzarino/awsiam/aws_iam_cli/commands'
Edit #2:
def get_command(self, ctx, cmd_name):
mod = import_module('aws_iam_cli.commands.cmd_{}'
.format(cmd_name))
return mod.cli
and error:
File "/Users/salvatoremazzarino/awsiam/venv/lib/python3.6/importlib/__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 994, in _gcd_import
File "<frozen importlib._bootstrap>", line 971, in _find_and_load
File "<frozen importlib._bootstrap>", line 941, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
File "<frozen importlib._bootstrap>", line 994, in _gcd_import
File "<frozen importlib._bootstrap>", line 971, in _find_and_load
File "<frozen importlib._bootstrap>", line 941, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
File "<frozen importlib._bootstrap>", line 994, in _gcd_import
File "<frozen importlib._bootstrap>", line 971, in _find_and_load
File "<frozen importlib._bootstrap>", line 953, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'aws_iam_cli'
This is the directory tree:
├── aws_iam_cli
│ ├── __init__.py
│ ├── cli.py
│ ├── commands
│ │ ├── __init__.py
│ │ ├── __pycache__
│ │ └── cmd_dump.py
│ └── provider
│ ├── __init__.py
│ ├── policy.py
│ └── role.py
Internal command I have a module that I call inside the module:
from aws_iam_cli.provider.role import fetch_roles
Solution
You can use importlib.import_module to dynamically load modules at runtime. For example:
from importlib import import_module
# load module
pckg_name = 'commands' # I assume all your commands are in this pckg
cmd_mod = import_module('{}.cmd_{}'.format(pckg_name, cmd_name))
# run command (I'm assuming the module contains a function with the 'cmd_name')
cmd_mod.cmd_name()
I think this approach will be cleaner, safer, and should work with what you’re doing.