groles.py

#!/usr/local/bin/python3

"""
This script makes it slightly easier to discover and inspect GCP IAM roles via CLI.


MIT License

Copyright (c) 2022 JP Jorissen

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
"""

import os
import sys
import json
import pickle
import shutil
import logging
import functools

logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)
logger.addHandler(logging.StreamHandler())

from pathlib import Path

CACHE_DIR = Path('/tmp/groles')

def install(requirements):
    import pip
    input(f"Would you like to install {requirements}? [y/N]>").lower() in ["y", "yes"] or sys.exit(1)
    pip.main(["install", *requirements])

try:
    import fire
    from googleapiclient import discovery
    from oauth2client.client import GoogleCredentials
except ImportError:
    install(["google-api-python-client", "oauth2client", "fire"])
    sys.exit(1)


def cache(dest):
    dest = Path(dest)
    def deco(func):
        @functools.wraps(func)
        def wrapper(*args, **kwargs):
            if dest.exists():
                with open(dest, 'rb') as pickle_rb:
                    return pickle.load(pickle_rb)
            result = func(*args, **kwargs)
            os.makedirs(dest.parent, exist_ok=True)
            with open(dest, 'wb') as pickle_wb:
                pickle.dump(result, pickle_wb)
            return result
        return wrapper
    return deco

def stream_json(func):
    @functools.wraps(func)
    def wrapper(*args, **kwargs):
        res = func(*args, **kwargs)
        if isinstance(res, list):
            for item in res:
                print(json.dumps(item))
            return
        print(json.dumps(res))
    return wrapper

@cache(CACHE_DIR / 'fetch.pickle')
def fetch_roles():
    logger.info("We need to fetch the roles. This could take quite some time.")
    credentials = GoogleCredentials.get_application_default()

    service = discovery.build('iam', 'v1', credentials=credentials)

    roles = []
    request = service.roles().list()
    while True:
        response = request.execute()
        current_roles = response.get('roles', [])
        for role in current_roles:
            logger.debug(role['name'])
            request_2 = service.roles().get(name=role['name'])
            response_2 = request_2.execute()
            role['permissions'] = response_2.get('includedPermissions', [])
        roles.extend(current_roles)
        request = service.projects().roles().list_next(previous_request=request, previous_response=response)
        if request is None:
            break
    return roles

class IAM:
    class cache:
        @staticmethod
        def clear():
            shutil.rmtree(str(CACHE_DIR), ignore_errors=True)

    @staticmethod
    def show():
        roles = fetch_roles()
        return json.dumps(roles, indent=2)

    class roles:
        @staticmethod
        def show():
            return IAM.show()
        
        @staticmethod
        @stream_json
        def get(*args, by='name', hide_perms=False):
            args = set(args)
            by_ok = {'name', 'perms', 'permissions', 'title'}
            roles = fetch_roles()
            if 'perms' in by:
                permission_map = {}
                for role in roles:
                    perms = getattr(role, 'pop' if hide_perms else 'get')("permissions", [])
                    for perm in perms:
                        if perm in permission_map:
                            permission_map[perm].append(role)
                        else:
                            permission_map[perm] = [role]
                results = []
                for arg in args:
                    results.extend(permission_map.get(arg, None))
                return results
            if by not in by_ok:
                return print(f"Expected by to be one of {by_ok}, got {by}", file=sys.stderr)
            return [role for role in roles if role[by] in args]

        @staticmethod
        @stream_json
        def search(*args, by='name', hide_perms=False):
            args = set(args)
            by_ok = {'name', 'perms', 'permissions', 'title'}
            roles = fetch_roles()
            if 'perms' in by:
                permission_map = {}
                for role in roles:
                    perms = getattr(role, 'pop' if hide_perms else 'get')("permissions", [])
                    for perm in perms:
                        if perm in permission_map:
                            permission_map[perm].append(role)
                        else:
                            permission_map[perm] = [role]
                candidate_perms = []
                for arg in args:
                    candidate_perms.extend([perm for perm in permission_map if arg.lower() in perm.lower()])
                results = []
                for p in candidate_perms:
                    results.extend(permission_map.get(p, []))
                return results
            if by not in by_ok:
                return print(f"Expected by to be one of {by_ok}, got {by}", file=sys.stderr)
            candidate_roles = []
            for arg in args:
                candidate_roles.extend([role for role in roles if arg.lower() in role[by].lower()])
            return candidate_roles
            

if __name__ == '__main__':
    fire.Fire(IAM)