development.txt

Instructions for creating a local development environment to build/test features.

These instructions are specific to Mac development.
They should be easily adjusted for *nix environments, and with a bit more effort adapted for Windows.

Reference Links:

* https://slack.dev/bolt-python/tutorial/getting-started
* https://slack.dev/node-slack-sdk/tutorials/local-development

Summary:

You will be creating a Slack application, and installing it in a Slack workspace.  That slack application
will connect to a locally running python service, which can connect to your MySQL database.  You can then
make changes to the python code, and invoke those changes from your slack application.

Python Requirements:
In addition to requirements.txt (listing requirements needed by the lambda), locally you may need a few other dependencies:
* yaml (for generate.py)
* mysql-connector-python (for connecting to a local python db)

Steps:

1. Your slack app will need to connect to your local python server.  You can do this in one of two ways:
Socket mode, or via a publicly accessible URL.  This approach uses the publicly accessible URL approach.

1a. Install ngrok (https://ngrok.com)
1b. Create a free ngrok account
1b. Run it:

# Launch ngrok, gives you a URL which will redirect requests to localhost:3000
ngrok http 3000

Outpu:

Session Status                online
Account                       Your Name(Plan: Free)
Update                        update available (version 3.0.7, Ctrl-U to update)
Version                       3.0.6
Region                        United States (us)
Latency                       -
Web Interface                 http://127.0.0.1:4040
Forwarding                    https://unique-guid.ngrok.io -> http://localhost:3000

Note the Forwarding URL.  You will need this.

2. Generate your slack manifest file.

python generate.py -n [ngrok forwarding url]

This will generate three files in an generate subfolder:
* generate/aws_config.yaml: Configuration for deployment of a lambda with appropriate setup
* generate/manifest.yaml: Slack manifest file that references the provided ngrok URL
* generate/setup: Environment variables that will be needed.  More on this later.

3. Create a new Slack App using the generated manifest (or update an existing one).
You'll need the Signing Secret and a Bot Token.  Get the Signing Secret from the App Info,
and the Bot Token from the OAuth section.

4.  Create the database tables in your MySQL database.
4a. Create a new db schema.
4b. Create the tables from sql scripts in db/tables
4c. In order, apply any scripts from db/scripts folder

5. Create your Environment file.  Using environment.json as a template, create a second JSON file
and set all variables as appropriate (DB connection parameters from step #4, Slack parameters from step #3).

6. Generate a new environment file that combines your environment with other parameters (slack scopes, for example)
using the provided generate script (again; like you did in step #2)

python generate.py -n [ngrok forwarding url] -f [your environment file]

The second file - this now has the environment variables you will need to run the python stack.

7. Launch the Bolt app, after updating the environment.

source ./generate/setup
python app.py

You should see "Bolt app is running! (development server)"

NOTE: bolt does not automatically reload on file changes.  You can manually stop/start the process to pick up
code changes.  OR, you can consider using the provided reload.py script, which will watch for changes and restart

python reload.py python app.py

8.  Back to Slack.  Verify your redirect URL.  Go back to App Manifest option.  Re-install the Manifest
or click the "Update" link.  The link should be your ngrok URL, and you should now be able to have Slack verify.

9.  Install your App into your test workspace.

10. Test it!  Type "/hello".  You should see a response ("Thanks") in Slack and you should see your local python
bolt server be invoked:

127.0.0.1 - - [27/Aug/2022 17:45:05] "POST /slack/events HTTP/1.1" 200 -

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This setup does NOT use OAuth, so that part of the overall setup is not configured.