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Getting started with Bolt for Python

This quickstart guide aims to help you get a Slack app using Bolt for Python up and running as soon as possible!

When complete, you'll have a local environment configured with a customized app running to modify and make your own.

Reference for readers

In search of the complete guide to building an app from scratch? Check out the building an app guide.

Prerequisites​

A few tools are needed for the following steps. We recommend using the Slack CLI for the smoothest experience, but other options remain available.

You can also begin by installing git and downloading Python 3.6 or later, or the latest stable version of Python. Refer to Python's setup and building guide for more details.

Install the latest version of the Slack CLI to get started:

Then confirm a successful installation with the following command:

$ slack version

An authenticated login is also required if this hasn't been done before:

$ slack login
A place to belong

A workspace where development can happen is also needed.

We recommend using developer sandboxes to avoid disruptions where real work gets done.

Creating a project​

With the toolchain configured, it's time to set up a new Bolt project. This contains the code that handles logic for your app.

If you don’t already have a project, let’s create a new one!

A starter template can be used to start with project scaffolding:

$ slack create first-bolt-app --template slack-samples/bolt-python-getting-started-app
$ cd first-bolt-app

After a project is created you'll have a requirements.txt file for app dependencies and a .slack directory for Slack CLI configuration.

A few other files exist too, but we'll visit these later.

We recommend using a Python virtual environment to manage your project's dependencies. This is a great way to prevent conflicts with your system's Python packages. Let's create and activate a new virtual environment with Python 3.6 or later:

$ python3 -m venv .venv
$ source .venv/bin/activate
$ pip install -r requirements.txt

Confirm the virtual environment is active by checking that the path to python3 is inside your project (a similar command is available on Windows):

$ which python3
# Output: /path/to/first-bolt-app/.venv/bin/python3

Running the app​

Before you can start developing with Bolt, you will want a running Slack app.

The getting started app template contains a manifest.json file with details about an app that we will use to get started. Use the following command and select "Create a new app" to install the app to the team of choice:

$ slack run
...
⚡️ Bolt app is running!

With the app running, you can test it out with the following steps in Slack:

  1. Open a direct message with your app or invite the bot @first-bolt-app (local) to a public channel.
  2. Send "hello" to the current conversation and wait for a response.
  3. Click the attached button labelled "Click Me" to post another reply.

After confirming the app responds, celebrate, then interrupt the process by pressing CTRL+C in the terminal to stop your app from running.

Updating the app​

At this point, you've successfully run the getting started Bolt for Python app!

The defaults included leave opportunities abound, so to personalize this app let's now edit the code to respond with a kind farewell.

Responding to a farewell​

Chat is a common thing apps do and responding to various types of messages can make conversations more interesting.

Using an editor of choice, open the app.py file and add the following import to the top of the file, and message listener after the "hello" handler:

import random

@app.message("goodbye")
def message_goodbye(say):
    responses = ["Adios", "Au revoir", "Farewell"]
    parting = random.choice(responses)
    say(f"{parting}!")

Once the file is updated, save the changes and then we'll make sure those changes are being used.

Run the following command and select the app created earlier to start, or restart, your app with the latest changes:

$ slack run
...
⚡️ Bolt app is running!

After finding the above output appears, open Slack to perform these steps:

  1. Return to the direct message or public channel with your bot.
  2. Send "goodbye" to the conversation.
  3. Receive a parting response from before and repeat "goodbye" to find another one.

Your app can be stopped again by pressing CTRL+C in the terminal to end these chats.

Customizing app settings​

The created app will have some placeholder values and a small set of scopes to start, but we recommend exploring the customizations possible on app settings.

Open app settings for your app with the following command:

$ slack app settings

This will open the following page in a web browser:

Basic Information page

On these pages you're free to make changes such as updating your app icon, configuring app features, and perhaps even distributing your app!

Next steps​

Congrats once more on getting up and running with this quick start.

Dive deeper

Follow along with the steps that went into making this app on the building an app guide for an educational overview.

You can now continue customizing your app with various features to make it right for whatever job's at hand. Here are some ideas about what to explore next:

  • Explore the different events your bot can listen to with the app.event() method. All of the events are listed on the API docs site.
  • Bolt allows you to call Web API methods with the client attached to your app. There are over 200 methods on the API docs site.
  • Learn more about the different token types and authentication setups. Your app might need different tokens depending on the actions you want to perform or for installations to multiple workspaces.
  • Receive events using HTTP for various deployment methods, such as deploying to Heroku or AWS Lambda.
  • Read on app design and compose fancy messages with blocks using Block Kit Builder to prototype messages.