Setup extras (#2831)

* 🎨 use package extras

* 🎨 get extras from reqs

* 🎨 .

* 📝 docs

* 🎨 .

.github/CONTRIBUTING.md

@@ -137,7 +137,7 @@ formatting errors. In certain cases, a missing blank line or a wrong indent can
 Run these commands
 
 ```bash
-pip install -r requirements/docs.txt
+pip install ".[docs]"
 cd docs
 make html
 ```
@@ -159,8 +159,7 @@ Testing your work locally will help you speed up the process since it allows you
 To setup a local development environment, install both local and test dependencies:
 
 ```bash
-python -m pip install -r requirements/devel.txt
-python -m pip install -r requirements/examples.txt
+python -m pip install ".[dev, examples]"
 python -m pip install pre-commit
 ```
 

setup.py

@@ -12,21 +12,23 @@ except ImportError:
 
 # https://packaging.python.org/guides/single-sourcing-package-version/
 # http://blog.ionelmc.ro/2014/05/25/python-packaging/
-
 PATH_ROOT = os.path.dirname(__file__)
 builtins.__LIGHTNING_SETUP__ = True
 
 import pytorch_lightning  # noqa: E402
 
 
-def load_requirements(path_dir=PATH_ROOT, comment_char='#'):
-    with open(os.path.join(path_dir, 'requirements', 'base.txt'), 'r') as file:
+def load_requirements(path_dir=PATH_ROOT, file_name='base.txt', comment_char='#'):
+    with open(os.path.join(path_dir, 'requirements', file_name), 'r') as file:
         lines = [ln.strip() for ln in file.readlines()]
     reqs = []
     for ln in lines:
         # filer all comments
         if comment_char in ln:
-            ln = ln[:ln.index(comment_char)]
+            ln = ln[:ln.index(comment_char)].strip()
+        # Make slight syntax alteration to git dependency for PL's sphinx theme
+        if ln.startswith('git') and file_name == 'docs.txt':
+            ln = f'pt_lightning_sphinx_theme @ {ln}#egg=pt-lightning-sphinx-theme'
         if ln:  # if requirement is not empty
             reqs.append(ln)
     return reqs
@@ -43,6 +45,19 @@ def load_long_description():
     return text
 
 
+# https://setuptools.readthedocs.io/en/latest/setuptools.html#declaring-extras
+# Define package extras. These are only installed if you specify them.
+# From remote, use like `pip install pytorch-lightning[dev, docs]`
+# From local copy of repo, use like `pip install ".[dev, docs]"`
+extras = {
+    'docs': load_requirements(file_name='docs.txt'),
+    'examples': load_requirements(file_name='examples.txt'),
+    'extra': load_requirements(file_name='extra.txt'),
+    'test': load_requirements(file_name='test.txt')
+}
+extras['dev'] = extras['extra'] + extras['test']
+extras['all'] = extras['dev'] + extras['examples'] + extras['docs']
+
 # https://packaging.python.org/discussions/install-requires-vs-requirements /
 # keep the meta-data here for simplicity in reading this file... it's not obvious
 # what happens and to non-engineers they won't know to look in init ...
@@ -67,7 +82,8 @@ setup(
     keywords=['deep learning', 'pytorch', 'AI'],
     python_requires='>=3.6',
     setup_requires=[],
-    install_requires=load_requirements(PATH_ROOT),
+    install_requires=load_requirements(),
+    extras_require=extras,
 
     project_urls={
         "Bug Tracker": "https://github.com/PyTorchLightning/pytorch-lightning/issues",