flask: Use python dotenv for application deployment

- Use .flaskenv and .env files to set environment variables
- Use dotenv package to automatically load them
- Add quick development notes

.env.example

+## .env
+#
+# flask environment file with local variables
+
+FLASK_ENV="development"

.flaskenv

+## .flaskenv
+#
+# flask environment file with global variables
+
+FLASK_APP="certapi"

.gitignore

@@ -5,7 +5,8 @@
 __pycache__
 *.egg-info/
 
-# Flask main configuration file
+# Flask
+/.env
 /instance/local.cfg
 
 # uwsgi production deployment

README.md

@@ -4,3 +4,14 @@
 [![coverage report](https://gitlab.labs.nic.cz/turris/sentinel/cert-api/badges/master/coverage.svg)](https://gitlab.labs.nic.cz/turris/sentinel/cert-api/commits/master)
 
 Flask application providing HTTP API for Turris:Sentinel authentication backend.
+
+
+## Development usage
+
+- Prepare python virtual environment and install `certapi` package (Consider
+  using `-e` option: `pip install -e .`)
+- Create `.env` file with local environment variables (see `.env.example`)
+- Set the configuration in `instance/local.cfg`
+    - Example configuration can be found in `instance/local.cfg.example`
+    - The default configuration can be found in `certapi/default_settings.py`
+- Run the application using `flask run` (Use wsgi server for production!)

setup.py

@@ -16,6 +16,7 @@ setup(
     packages=["certapi"],
     install_requires=[
         "flask",
+        "python-dotenv",
         "cryptography",
         "redis",
     ],