Overview

With workflows, you can automate many things in Brezel. They are programs that should perform a single task in your business logic.

Structure

Sync/Async

Workflows can be either sync or async. Synchronous workflows are executed and completed synchronously in the same process (usually during the HTTP request cycle), while asynchronous workflows are queued and executed by a process running in the background.

If a workflow runs actions that send HTTP responses, they should be made sync and need to be called during a HTTP request.

Actions that take longer than the recommended 30 seconds execution time should be made async.

Elements

Workflows always consist of at least one element. A workflow element is the basic building block of a workflow – it can be plugged into other elements, can receive and output data through its ports, carry context information as well as be configured with options that control its behavior.

Here is a very simple workflow:

{
  "identifier": "MyWorkflow",
  "title": "A title for my workflow.",
  "async": false,
  "elements": [
    {
      "name": "Get all users",
      "type": "source/entities",
      "options": {
        "module": "users"
      },
      "to": {
        "default": {
          "Log": ["default"]
        }
      }
    },
    {
      "name": "Log",
      "type": "action/log"
    }
  ],
  "events": [
    {
      "identifier": "on_update",
      "type": "update"
    }
  ]
}

The first element here is of type source/entities. The second element is the built-in action/log element that is used to log data to the console.

You can see that we give the element a name and type. The type is always in the format <category>/<type>. The name is required so that other elements can reference it.

The options property is unique to each element and allows to configure the behavior of that element. For example, the action/log element can have the level option set to info, warn, error or debug.

The to property is where we define the connections of this element. More on that in the next section.

Ports

Elements have ports. Ports are used to exchange data between elements. Ports can be either input or output ports. Elements can have multiple ports of each type.

The example workflow above has two ports:

• The default output port of the source/entities element.
• The default input port of the action/log element.

You can see that we define the connections in the to property of the source/entities element.

Connections

Connections define how data flows between elements. Each connection is a link between a port of the first element and a port of the second element. Connections are uni-directional, meaning that data can flow from the first element to the second but not the other way around.

In the example workflow above, we have defined a connection from the default port of the source/entities element to the default port of the action/log element. This connection defines that any data that comes out of the default port of the source/entities element will be forwarded to the default port of the action/log element.

Connections can be defined in the to property of elements, between a port of the first element and multiple ports of the second element.