Deno Hello World Slack App

This sample app demonstrates how to use a function, workflow, and trigger to send a greeting to channel.

Guide Outline:

• Setup
  • Install the Slack CLI
  • Clone the Template
• Create a Link Trigger
• Running Your Project Locally
• Testing
• Deploying Your App
  • Viewing Activity Logs
• Project Structure
• Resources

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Setup

Before getting started, make sure you have a development workspace where you have permissions to install apps. If you don’t have one set up, go ahead and create one. Also, please note that the workspace requires any of the Slack paid plans.

Install the Slack CLI

To use this sample, you first need to install and configure the Slack CLI. Step-by-step instructions can be found in our Quickstart Guide.

Clone the Sample

Start by cloning this repository:

# Clone this project onto your machine
$ slack create my-app -t slack-samples/deno-hello-world

# Change into this project directory
$ cd my-app

Create a Link Trigger

Triggers are what cause workflows to run. These triggers can be invoked by a user, or automatically as a response to an event within Slack.

A link trigger is a type of trigger that generates a Shortcut URL which, when posted in a channel or added as a bookmark, becomes a link. When clicked, the link trigger will run the associated workflow.

Link triggers are unique to each installed version of your app. This means that Shortcut URLs will be different across each workspace, as well as between locally run and deployed apps. When creating a trigger, you must select the Workspace that you'd like to create the trigger in. Each Workspace has a development version (denoted by (dev)), as well as a deployed version.

To create a link trigger for the workflow in this sample, run the following command:

$ slack trigger create --trigger-def triggers/greeting_trigger.ts

After selecting a Workspace, the output provided will include the link trigger Shortcut URL. Copy and paste this URL into a channel as a message, or add it as a bookmark in a channel of the Workspace you selected.

Note: this link won't run the workflow until the app is either running locally or deployed! Read on to learn how to run your app locally and eventually deploy it to Slack hosting.

Running Your Project Locally

While building your app, you can see your changes propagated to your workspace in real-time with slack run. In both the CLI and in Slack, you'll know an app is the development version if the name has the string (dev) appended.

# Run app locally
$ slack run

Connected, awaiting events

Once running, click the previously created Shortcut URL associated with the (dev) version of your app. This should start the included sample workflow.

To stop running locally, press <CTRL> + C to end the process.

Testing

For an example of how to test a function, see functions/greeting_function_test.ts. Test filenames should be suffixed with _test.

Run all tests with deno test:

$ deno test

Deploying Your App

Once you're done with development, you can deploy the production version of your app to Slack hosting using slack deploy:

$ slack deploy

After deploying, create a new link trigger for the production version of your app (not appended with (dev)). Once the trigger is invoked, the workflow should run just as it did in when developing locally.

Viewing Activity Logs

Activity logs for the production instance of your application can be viewed with the slack activity command:

$ slack activity

Project Structure

manifest.ts

The app manifest contains the app's configuration. This file defines attributes like app name and description.

slack.json

Used by the CLI to interact with the project's SDK dependencies. It contains script hooks that are executed by the CLI and implemented by the SDK.

/functions

Functions are reusable building blocks of automation that accept inputs, perform calculations, and provide outputs. Functions can be used independently or as steps in workflows.

/workflows

A workflow is a set of steps that are executed in order. Each step in a workflow is a function.

Workflows can be configured to run without user input or they can collect input by beginning with a form before continuing to the next step.

/triggers

Triggers determine when workflows are executed. A trigger file describes a scenario in which a workflow should be run, such as a user pressing a button or when a specific event occurs.

Resources

To learn more about developing with the CLI, you can visit the following guides:

• Creating a new app with the CLI
• Configuring your app
• Developing locally

To view all documentation and guides available, visit the Overview page.