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Getting started with the Deno Slack SDK

Workflow apps require a paid plan

Join the Developer Program and provision a sandbox with access to all Slack features for free.

In the following guide, you'll install the Slack CLI and authorize it in your workspace. Then, you'll use the Slack CLI to scaffold a fully-functional workflow app and run it locally.

Don't have a workspace yet? You can get up and running by provisioning a sandbox with an associated workspace by following this guide. Come on back when you're ready!

Step 1: Install the Slack CLI​

Run the automated installer from your terminal window:

curl -fsSL https://downloads.slack-edge.com/slack-cli/install.sh | bash

This will install the Slack CLI and all required dependencies, including Deno, the runtime environment for workflow apps. If you have VSCode installed, the VSCode Deno extension will be installed.

Optional: Use an alias for the Slack CLI binary

If you have another CLI tool in your path called slack, you can rename the slack binary to a different name before you add it to your path.

To do this, pass the -s argument to the installer script:

curl -fsSL https://downloads.slack-edge.com/slack-cli/install.sh | bash -s <your-preferred-alias>

The alias you use should come after any flags used in the installation script. For example, if you use both flags noted below to pass a version and skip the Deno installation, your install script might look like this:

curl -fsSL https://downloads.slack-edge.com/slack-cli/install.sh | bash -s -- -v 2.1.0 -d <your-preferred-alias>

You can also copy the Slack CLI into any folder that is already in your path (such as /usr/local/bin—you can useecho $PATH to find these), or add a new folder to your path by listing the folder you installed the Slack CLI to in /etc/paths.

If you don't rename the slack binary to a different name, the installation script will detect existing binaries named slack and bail if it finds one—it will not overwrite your existing slack binary.

Optional: customize installation using flags

There are two optional flags available to customize the installation.

  1. Specify a version you'd like to install using the version flag, -v. The absence of this flag will ensure the latest Slack CLI version is installed.
curl -fsSL https://downloads.slack-edge.com/slack-cli/install.sh | bash -s -- -v 2.1.0
  1. Skip the Deno installation by using the -d flag, like this:
curl -fsSL https://downloads.slack-edge.com/slack-cli/install.sh | bash -s -- -d
Troubleshooting

Errors​

Error: Failed to create a symbolic link! The installer doesn't have write access to /usr/local/bin. Please check permission and try again...

Solution: Sudo actions within the scripts were removed so as not to create any security concerns. The $HOME env var is updated to /root — however, the installer is using $HOME for both Deno and the SDK install, which causes the whole install to be placed under /root, making both Deno and the SDK unusable for users without root permissions.

  • For users who do not have root permissions, run the sudo actions manually as follows: sudo mkdir -p -m 775 /usr/local/bin, then sudo ln -sf "$slack_cli_bin_path" "/usr/local/bin/$SLACK_CLI_NAME" where $slack_cli_bin_path is typically $HOME/.slack/bin/slack and $SLACK_CLI_NAME is typically the alias (by default it’s slack).
  • For users who do have root permissions, you can run the installation script as sudo curl -fsSL https://downloads.slack-edge.com/slack-cli/install.sh | bash. In this case, the script is executed as root.
info

The minimum required Slack CLI version for Enterprise Grid as of September 19th, 2023 is v2.9.0. If you attempt to log in with an older version, you'll receive a cli_update_required error from the Slack API. Run slack upgrade to get the latest version.

Step 2: Authorize the Slack CLI​

With the Slack CLI installed, authorize the Slack CLI in your workspace with the following command:

slack login

In your terminal window, you should see an authorization ticket in the form of a slash command, and a prompt to enter a challenge code:

$ slack login

📋 Run the following slash command in any Slack channel or DM
   This will open a modal with user permissions for you to approve
   Once approved, a challenge code will be generated in Slack

/slackauthticket ABC123defABC123defABC123defABC123defXYZ

? Enter challenge code

Copy the slash command and paste it into any Slack conversation in the workspace you will be developing in.

When you send the message containing the slash command, a modal will pop up, prompting you to grant certain permissions to the Slack CLI. Click the Confirm button in the modal to move to the next step.

A new modal with a challenge code will appear. Copy that challenge code, and paste it back into your terminal:

? Enter challenge code eXaMpLeCoDe

✅ You've successfully authenticated! 🎉
   Authorization data was saved to ~/.slack/credentials.json

💡 Get started by creating a new app with slack create my-app
   Explore the details of available commands with slack help

Verify that your Slack CLI is set up by running slack auth list in your terminal window:

$ slack auth list

myworkspace (Team ID: T123ABC456)
User ID: U123ABC456
Last updated: 2023-01-01 12:00:00 -07:00
Authorization Level: Workspace

You should see an entry for the workspace you just authorized. If you don't, get a new authorization ticket with slack login to try again.

You're now ready to begin building workflow apps! In the next step, we'll get started with a sample app.

Step 3: Create an app from a template​

info

Evaluate third-party apps Exercise caution when using third-party applications and automations (those outside of slack-samples). Review all source code created by third-parties before running slack create or slack deploy.

The create command is how you create a workflow app.

For this guide, we'll be creating a Slack app using the Deno Starter Template as a template:

slack create my-app --template https://github.com/slack-samples/deno-starter-template

The Slack CLI creates an app project folder and fills it with the sample app code. Once it has finished, cd into your new project directory:

cd my-app

Then continue to the next step.

Step 4: Run the app in local development mode​

While building your app, you can see your changes propagated to your workspace in real-time by running slack run within your app's directory.

slack run

When you execute slack run, you'll be asked to select a local environment:

? Choose a local environment
> Install to a new workspace or organization

Since you've not installed your app to any workspaces, select Install to a new workplace. Then select the workspace you authenticated in.

The Slack CLI will attempt to list any triggers, and in this case, will inform you there are no existing triggers installed for the app.

Triggers are what cause workflows to run. A link trigger generates a Shortcut URL which, when posted in a channel or added as a bookmark, becomes a link.

Triggers are created from trigger definition files. The Slack CLI will then look for any trigger definition files and prompt you to select one. In this case, there is only one trigger: sample_trigger.ts. Select it.

? Choose a trigger definition file:
> triggers/sample_trigger.ts
  Do not create a trigger

Once your app's trigger is created, you will see the following output:

⚡ Trigger successfully created!

  Sample trigger (local) Ft0123ABC456 (shortcut)
  Created: 2023-01-01 12:00:00 -07:00 (1 second ago)
  Collaborators: 
    You! @You U123ABC456DE
  Can be found and used by:
    everyone in the workspace
  https://slack.com/shortcuts/Ft0123ABC456/XYZ123

The Slack CLI will also start a local development server, syncing changes to your workspace's development version of your app. You'll know your local development server is up and running when your terminal window tells you it's Connected, awaiting events.

Step 5: Use your app​

Grab the Shortcut URL you generated in the previous step and paste it in a public channel in your workspace. You will see the shortcut unfurl with a "Start Workflow" button. Click the button to execute the shortcut.

In the modal that appears, select a channel, and enter a message. When you click the "Send message" button, you should see your message appear in the channel you specified.

When you want to turn off the local development server, use Ctrl+c in the command prompt.

Onward​

At this point your Slack CLI is fully authorized and ready to create new projects. It's time to choose the next path of adventure.

We have curated a collection of sample apps. Many have tutorials. All highlight features of workflow apps. Learn how to:

Each tutorial will expose you to many aspects of the workflow automations. If you'd rather explore the documentation on your own, here are a few places to start. You can learn how to: