n8n Workflow: Detect Holiday Conflicts & Suggest Meeting Reschedules with Google Calendar and Slack

This n8n workflow automates the process of identifying potential meeting conflicts with upcoming holidays and proactively suggesting reschedule options via Slack. It helps teams maintain productivity by ensuring meetings don't clash with important dates.

What it does

This workflow performs the following key steps:

1. Triggers on a Schedule: The workflow is set to run periodically (e.g., daily, weekly) to check for upcoming conflicts.
2. Fetches Holiday Data: It makes an HTTP request to an external API to retrieve a list of public holidays.
3. Processes Holiday Data: It transforms and formats the retrieved holiday data into a usable structure.
4. Loops Through Holidays: For each holiday, it performs the following:
   • Retrieves Google Calendar Events: It fetches events from a specified Google Calendar for the holiday period.
   • Checks for Conflicts: It uses an "If" condition to determine if any meetings overlap with the holiday.
   • Notifies via Slack: If a conflict is found, it sends a notification to a designated Slack channel, detailing the conflicting meeting and the holiday.
5. Suggests Reschedules (Implicit): While not explicitly defined in the provided JSON, the typical use case for such a workflow would involve the Slack notification prompting manual or further automated steps to reschedule the conflicting meetings.

Prerequisites/Requirements

To use this workflow, you will need:

• n8n Instance: A running n8n instance.
• Google Calendar Account: Configured with credentials in n8n to access the relevant calendar(s).
• Slack Account: Configured with credentials in n8n to post messages to a channel.
• Holiday API: Access to a public holiday API (e.g., a free or paid service that provides holiday data). The "HTTP Request" node is configured to call such an API.
• Basic JavaScript Knowledge: For understanding and potentially modifying the "Code" node.

Setup/Usage

1. Import the Workflow:
   • Copy the provided JSON code.
   • In your n8n instance, go to "Workflows" and click "New".
   • Click the "Import from JSON" button and paste the JSON code.
2. Configure Credentials:
   • Google Calendar: Click on the "Google Calendar" node and select or create your Google Calendar OAuth2 credentials. Ensure the credentials have read access to the calendars you want to monitor.
   • Slack: Click on the "Slack" node and select or create your Slack API credentials. Ensure the Slack app has permission to post messages to the desired channel.
3. Configure HTTP Request (Holiday API):
   • Click on the "HTTP Request" node.
   • Update the URL field with the endpoint of your chosen holiday API.
   • Adjust any Headers, Query Parameters, or Authentication methods required by your holiday API.
4. Configure "Code" Node:
   • The "Code" node is currently empty. You will need to add JavaScript logic here to parse the response from your holiday API and extract the holiday dates and names in a format suitable for the subsequent nodes.
5. Configure "If" Node (Conflict Detection):
   • Click on the "If" node.
   • Review and adjust the conditions to accurately detect overlaps between Google Calendar events and the holiday dates. This will likely involve comparing start and end times of events with the holiday date.
6. Configure "Slack" Node:
   • Click on the "Slack" node.
   • Specify the Channel where you want to receive notifications.
   • Customize the Text message to include relevant details about the conflicting meeting and holiday using expressions (e.g., {{ $json.eventName }}, {{ $json.holidayName }}).
7. Activate the Workflow: Once all configurations are complete, activate the workflow by toggling the "Active" switch in the top right corner of the n8n editor.
8. Adjust Schedule: Modify the "Schedule Trigger" node to run at your desired interval (e.g., once a day, once a week).