Text application for Supply Depot

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We're using a tool called pipenv to create/manage a python virtual environment for the app.

The virtual environment allows the python package dependencies to be installed in thier own little world separate from whatever packages might be installed globally on the developer's workstation. It prevents python package dependency version conflicts and helps the application setup stay repeatable in the future as python packages change.

First, make sure that you are using the pip that is associated with python 3, not python 3:

$ pip --version
pip 21.3.1 from /usr/local/lib/python3.6/site-packages/pip (python 3.6)

Note the python 3 at the end, not python 2.7.

If you see python2, use pip3 instead.

Next, install pipenv with pip install pipenv

Finally, you should be able to install all of the package dependencies for the project (pulled from the Pipfile) with pipenv install

Once the packages are installed, you are ready to enter the virtual environment and start working on the app!

The pipenv shell command will enter into a new shell session within the virtual environment.

Alternatively, you can run a single command within the virtual environment (without modifying your current shell session) with pipenv run <your command here>

We are using the .env file to store our secrets and some application configuration values. The python-dotenv package we installed will parse this file when the application starts and load the variables inside the file as system environment variables. Then the python code can access them with os.environ.get(...).

Twilio offers a service where our application can be notified every time someone sends an SMS message to the text line.

This recieve-sms service works via Webhook. That means that Twilio sends an HTTP request to our application. Here's Twilio's own diagram of how this works:

When we run the server application during development, it's not reachable over the network or the internet, we can only connect to it locally. So of course, Twilio can't connect to our app from thier servers.

In order to solve this problem, we're currently using forest's greenhouse cloud service.

1. Sign up for a greenhouse account
2. Install greenhouse on your computer
3. Configure a greenhouse HTTPS tunnel to http://localhost:5000
4. Log into the Twilio administration console and set the SMS messaging Webhook URL to whatever your greenhouse tunnel URL is, plus /receive_sms at the end, like so:

Here is what your .env file should look like:

ACCOUNT_SID="ACq398hgbuiblahblahblahblahblahblah"
AUTH_TOKEN="kii923ggbuiblahblahblahblahblahblah"
TEXTLINE_NUMBER="+17633632275"

sudo apt install postgresql

sudo systemctl start postgresql.service

sudo systemctl status postgresql.service

$ sudo -u postgres psql
psql (12.12 (Ubuntu 12.12-0ubuntu0.20.04.1))
Type "help" for help.

postgres=# create database "depottextline";
CREATE DATABASE
postgres=# create user "depottextline" WITH PASSWORD 'blah';
CREATE ROLE
postgres=# grant all privileges on database "depottextline" to "depottextline";
GRANT
postgres=# quit

If you are already in the virtual environment:

flask --app app run

Otherwise:

pipenv run flask --app app run

Then you should be able to load it up in your web browser at http://127.0.0.1:5000