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https://github.com/csalih/redis-ru102py

Solutions for Redis for Python Developers
https://github.com/csalih/redis-ru102py

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Solutions for Redis for Python Developers

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README 

          
# RediSolar Python



This is the sample application codebase for the Redis University course [RU102PY, Redis for Python Developers](https://university.redis.com/courses/ru102py/).



## Setup



![Preview of running application - Solar Site Map with markers](preview.png)



### Prerequisites



To start and run this application, you will need:



* [Python 3.8](https://www.python.org/downloads/) (**Note**: It must be version 3.8).  We suggest using [pyenv](https://github.com/pyenv/pyenv) to manage multiple versions of Python

* Access to a local or remote installation of [Redis](https://redis.io/download) version 5 or newer

* Your Redis installation should have the RedisTimeSeries module installed. You can find the installation instructions at: https://oss.redis.com/redistimeseries/#setup



**Note**: If you don't have Redis installed but do have Docker or Podman and want to get started quickly,

run `make timeseries-docker` or `make timeseries-podman`. This starts a Redis container with RedisTimeSeries installed. (Podman is a Docker replacement for Fedora users.)



If you're using Windows, check out the following resources for help with running Redis:



* [Redis Labs Blog - Running Redis on Windows 10](https://redis.com/blog/redis-on-windows-10/)

* [Microsoft - Windows Subsystem for Linux Installation Guide for Windows 10](https://docs.microsoft.com/en-us/windows/wsl/install-win10)



### Setting up Python dependencies with make



This project automates setting up its Python dependencies with `make`.



To get started, run `make env`. This command creates a virtual environment

and installs the project and its dependencies into the environment.



### Setting up dependencies manually



Follow the steps in this section if you want to manually set up the project.



Note that the Makefile provides targets (e.g. `make all`, `make backend_dev`,

and `make frontend_dev`) that automate everything you should need to do, so

manually setting up the project is not necessary.



#### Virtualenv



If you want to create a virtualenv manually instead of using `make env`, run the

following command from the base directory of the project:



    python3.8 -m venv env



#### Dependencies



Before installing dependencies, activate the virtualenv:



    source env/bin/activate



Install the app and its dependencies by running the following commands from the

base directory of the project:



    pip install --upgrade pip

    pip install wheel pip-tools -e .

    pip-sync requirements.txt requirements-dev.txt



### Redis



This project requires a connection to Redis. The default settings expect Redis

to run on localhost at port 6379 without password protection.



#### RedisTimeSeries



This project uses the RedisTimeSeries module. You can either install it manually

or run Redis with the module enabled using Docker.



Check the project's web site for installation instructions: https://oss.redis.com/redistimeseries/



**Note**: As mentioned earlier in this document, if you have Docker installed and want to get started quickly, run

`make timeseries-docker`, which starts a Docker container running Redis with the

RedisTimeSeries module enabled.



#### Username and password protection



If you use Redis with a username (via the new ACL system in Redis 6) and/or a

password, make sure to set the `REDISOLAR_REDIS_USERNAME` and/or

`REDISOLAR_REDIS_PASSWORD` environment variables before running project-related

`make` commands or manual commands.



You can set these on the command line like so:



    $ REDISOLAR_REDIS_USERNAME=your-username make load



However, doing so keeps a record of these variables around in your shell history.



The example project is configured to read environment variables from a `.env`

file, so if you do need to use environment variables, we recommend adding them

to this file.



*Note*: The `.env` file is ignored by git because we added it to the

`.gitignore` file. If you use a `.env` file, you should avoid adding it to git,

so your credentials don't end up in git's history.



Finally, credential management is a big topic. This is just a demo project --

make sure you follow your company's guidelines for credentials management.



#### Using a different hostname and/or port for Redis



**Important note**: If you are not using Redis on localhost at port 6379, you

need to update the following files:



- `redisolar/instance/dev.cfg`

- `redisolar/instance/testing.cfg`



In the referenced files, change the values of `REDIS_HOST` and `REDIS_PORT` to

the correct values for your Redis instance.



#### Key prefixes



This project prefixes all keys with a string. By default, the dev server and

sample data loader use the prefix "ru102py-app:", while the test suite uses

"ru102py-test:".



When you run the tests, they add keys to the same Redis database that the

running Flask application uses, but with the prefix "test:". Then when the

tests finish, the test runner deletes all the keys prefixed with "test:".



You can change the prefix used for keys by changing the `REDIS_KEY_PREFIX`

option in the following files:



- `redisolar/instance/dev.cfg`

- `redisolar/instance/testing.cfg`



## Loading sample data



Before the example app will do anything interesting, it needs data.



You can use the command `make load` to load solar sites and generate example

readings. `make load` loads data into the Redis instance that you configured in

`redisolar/instance/dev.cfg`, using the `REDIS_HOST` and `REDIS_PORT` defined there.



**Note**: Read through the "Redis" section in this README to make sure you've properly configured the sample application to connect to Redis before you load sample data.



## Running the dev server



Run the development server with `make dev`.



**Note:** By default, the server runs with geographic features disabled. To run

with geo features enabled, set the option `USE_GEO_SITE_API` in

`redisolar/instance/dev.cfg` to `True`.



After running `make dev` access http://localhost:8081 to see the app.



**Don't see any data?**

The first time you run `make dev`, you may see a map with nothing on it. In

order to see sites on the map, you'll need to do two things:



1. Follow the instructions in this README to load data

2. Complete Challenge #1 in the course



### Running the dev server manually



If you need to override command-line flags when running Flask, you can use the `flask` command to run the dev server manually.



To do, first activate the project's virtual environment:



    $ source env/bin/activate



Then run the `flask` command:



    $ FLASK_APP=redisolar flask run --port=8001



## Running tests



You can run `make test` to run the unit tests. Doing so will build

a virtualenv automatically if you have not already done so.



### Running tests manually



You can run individual tests by calling `pytest` manually. To do, first activate the project's virtual environment:



    $ source env/bin/activate



Then run `pytest` with whatever options you want. For example, here is how you

run a specific test:



    $ pytest -k test_set_get



## FAQ



### Why do I get a "Python 3.8 is not installed!" error when I try to run `make` commands?



This project requires Python 3.8. See the "Prerequisites" section of this

README. You will need to install Python 3.8 on your machine, or else use our

"lab" Docker image -- see the "Setup" tab in the course for more details.



### Why do I get a ConnectionError when I run the tests or dev server?



You might see an error like this (or many of them) when you try to run the

tests:



    ERROR tests/scripts/test_update_if_lowest.py::test_update_if_lowest_unchanged - redis.exceptions.ConnectionError: Error 61 connecting to localhost:6379. Connection refused.



The error is telling you that Redis is not running on port 6379. Make sure

you've started Redis -- exactly how to do so depends on your operation system

and the way you installed Redis. For example, if you installed via Homebrew on a

Mac, the command is:



    brew services start redis



### Why do I get an "Authentication required" error when I try to run the tests/dev server?



Your Redis instance requires a username and/or password to connect. First, find

out what those are. Then follow the "Username and password protection" section

of this README to configure the project to connect with those credentials.



### Why do I get an "unknown command `TS.ADD`" when I try to run the tests?



Your Redis instance does not have the RedisTimeSeries module installed. See the section "RedisTimeSeries" in this README for instructions.



## Questions?



Chat with our teaching assistants on the [Redis University Discord Server](https://discord.gg/k5wr43E).



## Subscribe to our YouTube Channel / Follow us on Twitch



We'd love for you to [check out our YouTube channel](https://youtube.com/redisinc), and subscribe if you want to see more Redis videos!  We also stream regularly on our [Twitch.tv channel](https://www.twitch.tv/redisinc) - follow us to be notified when we're live or check out our [streaming schedule](https://developer.redis.com/redis-live/).



## License



This project is released under the MIT license. See LICENSE for the full text.