Merge pull request 'Added CONTEXT_PATH option when running via docker' (#57) from di/DashMachine:add-context_path-option into master

Reviewed-on: https://git.wolf-house.net/ross/DashMachine/pulls/57

Awesome, good work!

README.md

@@ -30,7 +30,16 @@ docker create \
   --restart unless-stopped \
   rmountjoy/dashmachine:latest
 ```
-
+To run in a subfolder, use a CONTEXT_PATH environment variable. For example, to run at localhost:5000/dash:
+```
+docker create \
+  --name=dashmachine \
+  -p 5000:5000 \
+  -e CONTEXT_PATH=/dash
+  -v path/to/data:/dashmachine/dashmachine/user_data \
+  --restart unless-stopped \
+  rmountjoy/dashmachine:latest
+```
 ### Python
 Instructions are for linux.
 ```

dashmachine/__init__.py

@@ -11,8 +11,8 @@ from dashmachine.paths import user_data_folder
 if not os.path.isdir(user_data_folder):
     os.mkdir(user_data_folder)
 
-
-app = Flask(__name__)
+context_path = os.getenv('CONTEXT_PATH', '')
+app = Flask(__name__, static_url_path=context_path + '/static')
 cache = Cache(app, config={"CACHE_TYPE": "simple"})
 api = Api(app)
 
@@ -32,10 +32,10 @@ from dashmachine.error_pages.routes import error_pages
 from dashmachine.settings_system.routes import settings_system
 from dashmachine import sources
 
-app.register_blueprint(main)
-app.register_blueprint(user_system)
-app.register_blueprint(error_pages)
-app.register_blueprint(settings_system)
+app.register_blueprint(main, url_prefix=context_path)
+app.register_blueprint(user_system, url_prefix=context_path)
+app.register_blueprint(error_pages, url_prefix=context_path)
+app.register_blueprint(settings_system, url_prefix=context_path)
 
 
 from dashmachine.rest_api.resources import *