Use optional package installs (#666)

* Make dependencies optional

resolves #219

* Tweak install options and update installation instructions in readme

* update to latest conclusion

* rename default -> standard

* Incoroporate other reqs

* Added setup.py to black test, previous merge made me remove all double quotes in it

* Added setup.py to lint script to match test script

* Lint setup.py

* Removed leftover from merge that was incorrect

* Trying to be more explicit about the 2 install options

* Spelling

* Newlines

* Better wording

* Websockets vs wsproto more relevant in extras

Co-authored-by: Carl George <carl@george.computer>
Co-authored-by: Almar Klein <almar.klein@gmail.com>

README.md

@@ -33,6 +33,26 @@ Install using `pip`:
 $ pip install uvicorn
 ```
 
+This will install uvicorn with minimal (pure Python) dependencies.
+
+```shell
+$ pip install uvicorn[standard]
+```
+
+This will install uvicorn with "Cython-based" dependencies (where possible) and other "optional extras".
+
+In this context, "Cython-based" means the following:
+
+- the event loop `uvloop` will be installed and used if possible.
+- the http protocol will be handled by `httptools` if possible.
+
+Moreover, "optional extras" means that:
+
+- the websocket protocol will be handled by `websockets` (should you want to use `wsproto` you'd need to install it manually) if possible.
+- the `--reloader` flag in development mode will use `watchgod`.
+- windows users will have `colorama` installed for the colored logs.
+- `python-dotenv` will be install should you want to use the `--env-file` option. 
+
 Create an application, in `example.py`:
 
 ```python

requirements.txt

@@ -1,3 +1,4 @@
+# Minimal
 click
 h11
 
@@ -6,6 +7,8 @@ httptools; sys_platform != 'win32'
 uvloop>=0.14.0; sys_platform != 'win32'
 websockets==8.*
 wsproto==0.13.*
+watchgod>=0.6,<0.7
+python_dotenv==0.13.*
 
 # Packaging
 twine
@@ -26,5 +29,3 @@ seed-isort-config
 mkdocs
 mkdocs-material
 
-# Efficient debug reload
-watchgod>=0.6,<0.7

setup.py

@@ -34,21 +34,28 @@ def get_packages(package):
     ]
 
 
-env_marker = (
+env_marker_cpython = (
     "sys_platform != 'win32'"
     " and sys_platform != 'cygwin'"
     " and platform_python_implementation != 'PyPy'"
 )
 
-requirements = [
+env_marker_win = "sys_platform == 'win32'"
+
+
+minimal_requirements = [
     "click==7.*",
     "h11>=0.8,<0.10",
-    "websockets==8.*",
-    "httptools==0.1.* ;" + env_marker,
-    "uvloop>=0.14.0 ;" + env_marker,
 ]
 
-extras_require = {"watchgodreload": ["watchgod>=0.6,<0.7"]}
+extra_requirements = [
+    "websockets==8.*",
+    "httptools==0.1.* ;" + env_marker_cpython,
+    "uvloop>=0.14.0 ;" + env_marker_cpython,
+    "colorama>=0.4.*;" + env_marker_win,
+    "watchgod>=0.6,<0.7",
+    "python-dotenv==0.13.*",
+]
 
 
 setup(
@@ -62,8 +69,8 @@ def get_packages(package):
     author="Tom Christie",
     author_email="tom@tomchristie.com",
     packages=get_packages("uvicorn"),
-    install_requires=requirements,
-    extras_require=extras_require,
+    install_requires=minimal_requirements,
+    extras_require={"standard": extra_requirements},
     include_package_data=True,
     classifiers=[
         "Development Status :: 4 - Beta",