Add extra dependencies to extra_require (#133)

* Add extra dependencies to extra_require

* fix lint

requirements.txt

@@ -0,0 +1,3 @@
+-r requirements/install.txt
+-r requirements/docs.txt
+-r requirements/tests.txt

setup.py

@@ -1,3 +1,4 @@
+import re
 from setuptools import find_packages, setup  # type: ignore
 
 
@@ -7,15 +8,87 @@ def readme():
     return content
 
 
-version_file = 'mim/version.py'
-
-
 def get_version():
+    version_file = 'mim/version.py'
     with open(version_file) as f:
         exec(compile(f.read(), version_file, 'exec'))
     return locals()['__version__']
 
 
+def parse_requirements(fname='requirements/runtime.txt', with_version=True):
+    """Parse the package dependencies listed in a requirements file but strips
+    specific versioning information.
+
+    Args:
+        fname (str): path to requirements file
+        with_version (bool, default=False): if True include version specs
+
+    Returns:
+        List[str]: list of requirements items
+
+    CommandLine:
+        python -c "import setup; print(setup.parse_requirements())"
+    """
+    import sys
+    from os.path import exists
+    require_fpath = fname
+
+    def parse_line(line):
+        """Parse information from a line in a requirements text file."""
+        if line.startswith('-r '):
+            # Allow specifying requirements in other files
+            target = line.split(' ')[1]
+            for info in parse_require_file(target):
+                yield info
+        else:
+            info = {'line': line}
+            if line.startswith('-e '):
+                info['package'] = line.split('#egg=')[1]
+            else:
+                # Remove versioning from the package
+                pat = '(' + '|'.join(['>=', '==', '>']) + ')'
+                parts = re.split(pat, line, maxsplit=1)
+                parts = [p.strip() for p in parts]
+
+                info['package'] = parts[0]
+                if len(parts) > 1:
+                    op, rest = parts[1:]
+                    if ';' in rest:
+                        # Handle platform specific dependencies
+                        # http://setuptools.readthedocs.io/en/latest/setuptools.html#declaring-platform-specific-dependencies
+                        version, platform_deps = map(str.strip,
+                                                     rest.split(';'))
+                        info['platform_deps'] = platform_deps
+                    else:
+                        version = rest  # NOQA
+                    info['version'] = (op, version)
+            yield info
+
+    def parse_require_file(fpath):
+        with open(fpath) as f:
+            for line in f.readlines():
+                line = line.strip()
+                if line and not line.startswith('#'):
+                    yield from parse_line(line)
+
+    def gen_packages_items():
+        if exists(require_fpath):
+            for info in parse_require_file(require_fpath):
+                parts = [info['package']]
+                if with_version and 'version' in info:
+                    parts.extend(info['version'])
+                if not sys.version.startswith('3.4'):
+                    # apparently package_deps are broken in 3.4
+                    platform_deps = info.get('platform_deps')
+                    if platform_deps is not None:
+                        parts.append(';' + platform_deps)
+                item = ''.join(parts)
+                yield item
+
+    packages = list(gen_packages_items())
+    return packages
+
+
 setup(
     name='openmim',
     version=get_version(),
@@ -28,14 +101,11 @@ setup(
     packages=find_packages(),
     include_package_data=True,
     python_requires='>=3.6',
-    install_requires=[
-        'Click',
-        'colorama',
-        'requests',
-        'model-index',
-        'pandas',
-        'tabulate',
-    ],
+    install_requires=parse_requirements('requirements/install.txt'),
+    extras_require={
+        'all': parse_requirements('requirements.txt'),
+        'tests': parse_requirements('requirements/tests.txt'),
+    },
     entry_points='''
         [console_scripts]
         mim=mim.cli:cli