Demo app that shows how to create a subscribe/unsubscribe feature that uses a long-running Temporal Workflow to send weekly email messages.

Start a Temporal server.

Then run the following command to start the web server:

go run server/main.go

In another window, run the following command to start a Worker process:

go run worker/main.go

Visit http://localhost:4000 and add your email to subscribe.

Visit http://localhost:4000/unsubscribe and add your email to unsubscribe.

The repository contains the following files:

├── README.md         <- This file.
├── go.mod
├── go.sum
├── mails             <- Emails for the campaign
│   ├── 1.md
│   ├── 2.md
│   ├── 3.md
│   ├── goodbye.md    <- The unsubscribe message
│   └── welcome.md    <- A welcome message
├── server
│   └── main.go       <- The web server
├── worker
│   └── main.go       <- The Temporal worker
└── subscribe.go      <- The application code including Workflows and Activities.

The server/main.go file contains a basic Go web server that exposes three endpoints:

• /: Displays the signup form
• /subscribe: Processes the signup request and executes the Temporal Workflow to handle subscriptions.
• /unsubscribe: Supports GET and POST:
  • GET /unsubscribe: Displays the unsubscribe form
  • POST /unsubscribe: processes the unsubscribe request for the form by sending a cancellation request to the Workflow.

The worker/main.go file contains the Temporal Worker that executes Workflows and Activities.

The subscribe.go file contains the Temporal Workflow and Activity for subscriptions.

• UserSubscriptionWorkflow accepts a Subscription which is made up of the email address and the email campaign to send. The campaign is a struct that specifies the email messages that make up the campaign, including the welcome message, the unsubscribe message, and the messages that make up the campaign's contents.
• SendContentEmail is an Activity that accepts an EmailInfo struct which contains the message to send and email address.
• The UserSubscriptionWorkflow sends the welcome message and the first message of the campaign, and then sleeps for the duration specified by the duration value in the UserSubscriptionWorkflow function.