Slack Mention Reminder

"Mention Reminder" is a custom Slack app that allows you to set up reminders simply by mentioning its bot!

With this app, there's no need for you to run the /remind command. Why do we prefer a mention? It could be particularly useful when you aim to automate the creation of reminders within a Slack workflow.

When your workflow sends a message mentioning this app's bot user, this app will set up a reminder with the inputs:

How it works

When you mention this app's bot user with the parameters listed below, the app will schedule a reminder message for you:

• [datetime]: When to send a reminder (in any format new Date() in JavaScript code can parse)
• [channel/user] Who/where to send it (@user or #channel)
• [message]: The text message to send

The format will be as follows. Please note that [xxx] portions can contain embedded values.

@MentionReminder remind [channel/user] at [datetime]\n
[message]

For example, this app delivers a message in #tasks channel at 9am on January 25:

@MentionReminder remind #tasks at 2024-01-25 09:00 +09:00
Hey @kaz, you need to submit this month's expense report by the end of today!

The time format may be in epoch time (in seconds). When using this app along with Slack's workflow builder, you can use a format that can be embedded:

@MentionReminder remind #tasks at 1706183820
Hey @kaz, this is @brian's last week. Could you please check if the following accounts are prepared for termination soon:
• Google Workspace
• Zoom
• Slack
• ...

Set up

Create the app and install it

• Go to https://api.slack.com/apps?new_app=1
  • Choose "From an app manifest" and select the workspace to use
  • Switch to JSON format and past the content in ./manifest.json
• Go to Settings > Install App
  • Install the app into your workspace
  • Save the "Bot User OAuth Token" as SLACK_BOT_TOKEN
• Go to Settings > Basic Information > App-Level Tokens
  • Click "Generate Token and Scopes"
  • Click "Add Scope" and then add "connections:write" scope
  • Name the token and click "Generate"
  • Save the token as SLACK_APP_TOKEN

Run the app

• Install Node.js 20 or newer version
• Clone this repo
• Run npm i to install the dependencies
• Run export SLACK_BOT_TOKEN=xoxb-.... (Settings > Install App)
• Run export SLACK_APP_TOKEN=xapp-... (Settings > Basic Information > App-Level Tokens)
• Run npm start

Invite this app's bot user

• Invite this app's bot user @MentionReminder to the channel where you want to use it

Add a step mentioning this app in your workflow

Create a workflow with the following steps:

• Open a form to collect inputs
  • Where/who to send (Select a channel/user)
  • When to send (Date and time)
  • The text message (Rich messsage composer)
• Send a message mentioning this app's bot user
  • @MentionReminder remind [channe/user] at [datetime]\n[message]

Local development with Slack CLI

Install CLI and grant permissions

If you haven't yet installed Slack CLI, I recommend visiting the guide page to do so, and allowing it to install apps into your sandbox or paid Slack workspaces. To complete this, you will need to run slack login command on your terminal, plus execute /slackauthticket with the given parameter in your Slack workspace.

Please remember that either a sandbox or paid workpace is required to use the CLI.

Start your app on your local machine

Once your CLI obtains the permission to install a local dev app, there is nothing else to prepare before running this template app. Clone this repo and install all the required npm packages:

git clone git@github.com:seratch/slack-mention-reminder.git slack-mention-reminder
cd slack-mention-reminder/
npm i

Now you can execute slack run to activate your first Slack app connected to a workspace via the CLI. The CLI automaticaly creates a new local dev app, which synchronizes the manifest.json data behind the scenes and establishes a Socket Mode connection (WebSocket protocol) with the authorized Slack workspace.

unset SLACK_APP_TOKEN
unset SLACK_BOT_TOKEN
slack run

If you see [INFO] socket-mode:SocketModeClient:0 Now connected to Slack in the console output, the local dev app is successfully connected to your Slack workspace 🎉

Unlike before, you don't need to set any environment variables such as SLACK_BOT_TOKEN. The CLI passes the required variables to your app instance. If you have some env variables in the terminal session, you might need to unset them (e.g., unset SLACK_BOT_TOKEN) to prevent potential misbehavior.

License

The MIT License