Bolt for Java Template App

This is a generic Bolt for Java template app used to build out Slack apps.

Before getting started, make sure you have a development workspace where you have permissions to install apps. If you don’t have one setup, go ahead and create one.

Installation

Create a Slack App

1. Open https://api.slack.com/apps/new and choose "From an app manifest"
2. Choose the workspace you want to install the application to
3. Copy the contents of manifest.json into the text box that says *Paste your manifest code here* (within the JSON tab) and click Next
4. Review the configuration and click Create
5. Click Install to Workspace and Allow on the screen that follows. You'll then be redirected to the App Configuration dashboard.

Environment Variables

Before you can run the app, you'll need to store some environment variables.

1. Open your app's configuration page from this list, click OAuth & Permissions in the left hand menu, then copy the Bot User OAuth Token. You will store this in your environment as SLACK_BOT_TOKEN.
2. Click Basic Information from the left hand menu and follow the steps in the App-Level Tokens section to create an app-level token with the connections:write scope. Copy this token. You will store this in your environment as SLACK_APP_TOKEN.

# Replace with your app token and bot token
export SLACK_BOT_TOKEN=<your-bot-token>
export SLACK_APP_TOKEN=<your-app-token>

Setup Your Local Project

# Clone this project onto your machine
git clone https://github.com/slack-samples/bolt-java-starter-template.git

# Change into this project directory
cd bolt-java-template

Maven: Run

Ensure maven is installed on your local environment.

• We recommend using brew to install Maven on macOS

# Install the dependencies and compile
mvn clean compile

# apply linter to your project
mvn spotless:apply

# Install the dependencies and test
mvn clean test

# Compile and start your local server
mvn clean compile exec:java -Dexec.mainClass="Main"

NOTE: If you chose to use Maven as your build tool you can remove the builde.gradle file from this project.

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Gradle: Run

Ensure gradle is installed on your local environment.

• We recommend using brew to install Gradle on macOS

# Run tests
gradle test

# Apply linter to project
gradle spotlessApply

# Start your local server
gradle run

NOTE: If you chose to use Gradle as your build tool you can remove the pom.xml file from this project.

Project Structure

manifest.json

manifest.json is a configuration for Slack apps. With a manifest, you can create an app with a pre-defined configuration, or adjust the configuration of an existing app.

Main.java

./src/main/java/Main.java is the entry point for the application and is the file you'll run to start the server. This project aims to keep this file as thin as possible, primarily using it as a way to route inbound requests.

/listeners

Every incoming request is routed to a "listener". Inside this directory, we group each listener based on the Slack Platform feature used, so /listeners/shortcuts handles incoming Shortcuts requests, /listeners/views handles View submissions, and so on.

/logback.xml

logback-classic is imported as a dependency to configure the logs of the project, this configuration is defined in a logback.xml found in src/main/resources/logback.xml. Note that by default the project should be logging debug level logs for slack dependencies.

Tests

This project provides some sample unit tests. They can be found in src/test. They are to be used as examples to show how unit tests can be implemented. As you modify this project don't hesitate to modify, add, or remove these tests.

App Distribution / OAuth

Only implement OAuth if you plan to distribute your application across multiple workspaces. A separate OAuthMain.java file can be found with relevant OAuth settings.

When using OAuth, Slack requires a public URL where it can send requests. In this template app, we've used ngrok. Checkout this guide for setting it up.

Start ngrok to access the app on an external network and create a redirect URL for OAuth.

ngrok http 3000

This output should include a forwarding address for http and https (we'll use https). It should look something like the following:

Forwarding   https://3cb89939.ngrok.io -> http://localhost:3000

Navigate to OAuth & Permissions in your app configuration and click Add a Redirect URL. The redirect URL should be set to your ngrok forwarding address with the slack/oauth/callback path appended. For example:

https://3cb89939.ngrok.io/slack/oauth/callback

NOTE: if you do not require OAuth you can remove all OAUTH DEPENDENCIES in the pom.xml or build.gradle files, along with src/main/java/OAuthMain.java