Slack Workflow Project Structure

Slack automation workflow with custom functions, triggers, and workflow steps using the Slack CLI.

#slack #workflow #automation #typescript #deno

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Project Directory

my-workflow/

manifest.ts

App manifest and permissions

slack.json

Slack CLI configuration

import_map.json

Deno import mappings

functions/

Custom functions

my_function/

definition.ts

Function schema

handler.ts

Function logic

handler_test.ts

send_notification/

definition.ts

handler.ts

workflows/

Workflow definitions

my_workflow.ts

Main workflow

onboarding_workflow.ts

triggers/

Workflow triggers

link_trigger.ts

Shareable link

scheduled_trigger.ts

Time-based

event_trigger.ts

Slack events

datastores/

Data storage

my_datastore.ts

Datastore schema

types/

Custom types

my_custom_type.ts

README.md

.gitignore

LICENSE

Why This Structure?

Slack's new automation platform uses Deno and TypeScript. Workflows chain functions together, and triggers start workflows. Functions are reusable building blocks with defined inputs/outputs. Datastores provide persistent storage within Slack.

Key Directories

manifest.ts-App definition, scopes, and features
functions/-Reusable custom functions with handlers
workflows/-Workflow definitions chaining functions
triggers/-How workflows are started (link, schedule, event)

Function Definition

// functions/greeting/definition.ts
import { DefineFunction, Schema } from "deno-slack-sdk/mod.ts";

export const GreetingFunction = DefineFunction({
  callback_id: "greeting_function",
  title: "Generate Greeting",
  source_file: "functions/greeting/handler.ts",
  input_parameters: {
    properties: {
      user_id: { type: Schema.slack.types.user_id },
    },
    required: ["user_id"],
  },
  output_parameters: {
    properties: {
      greeting: { type: Schema.types.string },
    },
    required: ["greeting"],
  },
});

Getting Started

Install Slack CLI: curl -fsSL https://downloads.slack-edge.com/slack-cli/install.sh | bash
slack create my-workflow
slack run for local development
Create trigger: slack trigger create --trigger-def triggers/link_trigger.ts
slack deploy to production

When To Use This

Automating repetitive Slack tasks
Custom approval workflows
Scheduled notifications and reminders
Data collection from team members
Integration between Slack and external services

Trigger Types

Link triggers-Shareable URLs that start workflows
Scheduled-Run on a schedule (daily, weekly)
Event-React to Slack events (reaction added, message)
Webhook-External systems can trigger workflows

Best Practices

Keep functions small and focused
Use datastores for persistent data, not external DBs
Test handlers with deno test
Use link triggers for user-initiated workflows
Handle errors gracefully with proper output

Trade-offs

Deno runtime-Different from Node.js, limited npm support
Slack-hosted-Runs on Slack infrastructure, limited customization
Paid plan required-Workflows require Slack paid plans