Merge pull request #4 from ZhengnanZhao/cli

Use argparse to handle CLI

README.md

@@ -6,15 +6,34 @@ Ever wondered which third-party dependencies your project relies on? `iscan` wil
 $ pip install iscan
 ```
 
+## Dependencies
+`iscan` is light-weight and doesn't rely on anything outside the standard library. The core functionality leverages the built-in [ast](https://docs.python.org/3/library/ast.html) module. `pytest` is an optional dependency for running tests.
+
 ## Usage
 Specify the path to the directory you wish to scan. Both absolute and relative paths are accepted.
 ```
 $ iscan path/to/dir
 ```
 
-Optionally, you can provide a second argument, specifying a directory to be _excluded_ when `iscan` looks for imported packages. For instance, the following command will scan all python files in the `foo` directory except those in `foo/tests`, which will be ignored.
+Optionally, you can provide a second argument to specify a directory to be _excluded_ when `iscan` looks for imported packages. For instance, the following command will scan all python files in the `foo` directory except those in `foo/tests`, which will be ignored.
+```
+$ iscan foo -x foo/tests
+```
+
+The complete help message is shown below.
 ```
-$ iscan foo foo/tests
+$ iscan --help
+usage: iscan [-h] [-x DIR_TO_EXCLUDE] DIR_TO_SCAN
+
+Scan python files in a given directory for third-party
+dependencies.
+
+positional arguments:
+  DIR_TO_SCAN        target directory to scan
+
+optional arguments:
+  -h, --help         show this help message and exit
+  -x DIR_TO_EXCLUDE  directory to exclude during scanning
 ```
 
 ## Example output with `pandas`
@@ -27,7 +46,7 @@ Third-party packages imported across all python files in /Users/zhengnan/Desktop
 
 If you are not interested in, say, packages imported during testing, you can specify the path to the tests directory for the entire directory to be ignored.
 ```
-$ iscan ~/Desktop/pandas/pandas/ ~/Desktop/pandas/pandas/tests/
+$ iscan ~/Desktop/pandas/pandas/ -x ~/Desktop/pandas/pandas/tests/
 Third-party packages imported across all python files in /Users/zhengnan/Desktop/pandas/pandas/, EXCLUDING those in /Users/zhengnan/Desktop/pandas/pandas/tests/
 ['AppKit', 'Foundation', 'IPython', 'PyQt4', 'PyQt5', '_csv', 'botocore', 'bs4', 'cycler', 'dateutil', 'fastparquet', 'hypothesis', 'jedi', 'lxml', 'matplotlib', 'mpl_toolkits', 'numba', 'numexpr', 'numpy', 'odf', 'openpyxl', 'pandas', 'pg8000', 'pkg_resources', 'psycopg2', 'py', 'pyarrow', 'pylab', 'pymysql', 'pytest', 'pytz', 'pyxlsb', 'qtpy', 's3fs', 'scipy', 'sqlalchemy', 'tables', 'xarray', 'xlrd', 'xlsxwriter', 'xlwt']
 ```

iscan/__init__.py

@@ -0,0 +1 @@
+__version__ = '0.3.1'

iscan/scan.py

@@ -1,6 +1,7 @@
 """This module provides functionality to scan a directory and aggregate
 the names of packages imported across all python files in said directory.
 """
+import argparse
 import ast
 import sys
 from os import walk
@@ -116,14 +117,28 @@ def scan_directory(dir_to_scan: str, dir_to_exclude: str) -> list:
     return sorted(set(map(get_base_name, all_imports)))
 
 
+def cli() -> argparse.Namespace:
+    """Command line interface."""
+    parser = argparse.ArgumentParser(
+        allow_abbrev=False,
+        description='Scan python files in a given directory for third-party dependencies.'
+    )
+    parser.add_argument(
+        'DIR_TO_SCAN',
+        help='target directory to scan'
+    )
+    parser.add_argument(
+        '-x',
+        default=None,
+        dest='DIR_TO_EXCLUDE',
+        help='directory to exclude during scanning'
+    )
+    return parser.parse_args()
+
+
 def main():
-    args = sys.argv[1:]
-    if len(args) == 1:
-        dir_to_scan, dir_to_exclude = args[0], None
-    elif len(args) == 2:
-        dir_to_scan, dir_to_exclude = args
-    else:
-        raise ValueError('You may pass either one or two arguments.')
+    args = cli()
+    dir_to_scan, dir_to_exclude = args.DIR_TO_SCAN, args.DIR_TO_EXCLUDE
 
     unique_imports = scan_directory(dir_to_scan, dir_to_exclude)
     unique_imports = filter_out_std_lib(unique_imports)

setup.py

@@ -1,21 +1,32 @@
+import re
+from pathlib import Path
+
 import setuptools
 
 
+PATH_TO_INIT = Path('iscan') / '__init__.py'
+VERSION = re.search(
+    r'\'(.+?)\'',
+    PATH_TO_INIT.read_text()
+).groups()[0]
+
+
 with open('README.md', 'r') as f:
-    long_description = f.read()
+    LONG_DESCRIPTION = f.read()
 
 
 setuptools.setup(
     name='iscan',
-    version='0.3.0',
+    version=VERSION,
     author='Zhengnan Zhao',
     description='iscan helps you identify your project\'s third-party dependencies',
-    long_description=long_description,
+    long_description=LONG_DESCRIPTION,
     long_description_content_type='text/markdown',
     url='https://github.com/ZhengnanZhao/iscan',
     packages=setuptools.find_packages(),
     extras_require={
-        'dev': ['pytest', 'setuptools', 'twine', 'wheel']
+        'build': ['setuptools', 'twine', 'wheel'],
+        'dev': ['pytest']
     },
     entry_points={'console_scripts': ['iscan=iscan.scan:main']},
     classifiers=[