Mendix Event Broker

1 Introduction

Based on Apache Kafka, the Mendix Event Broker is single-tenant and can only be used by apps running on nodes provisioned for your company.

Events are published to a Kafka topic. Apps are subscribed to a Kafka topic to receive events, and messages use standard CloudEvents payload format.

There is a single Kafka broker for Free Apps that your company Free Apps can connect to. All Free Apps in your company publish and consume from the same Kafka broker. Events are published to one shared Kafka topic, and any Free App in your company can receive these events.

2 Mendix Event Broker License

Purchase a license to the Mendix Event Broker to deploy unlimited apps on production environments in the Mendix Cloud. Ask your Customer Success Manager or Account Manager to reach out to purchase a license. See the Mendix Event Broker platform service page for more details.

A license for the Mendix Event Broker is available for any Mendix region, but once selected, you can only run on a single region (no multi-region support). This license is available for all customers. You can also run business events on your own Kafka cluster.

2.1 Enabling the Mendix Event Broker Service

Once a license is purchased, a Technical Contact must enable the Event Broker Service on the Developer Portal for the Mendix Cloud in the following places:

1. On the app level under Environments > Services
2. On the Environment Details page for each environment

The Event Broker must be enabled on both the app and specific environment levels in order to use the Event Broker services.

2.2 Managing the Mendix Event Broker

Technical Contacts with a license to the Mendix Event Broker can manage its features on the Event Broker Manager page.

2.2.1 Environments and Spaces

Space define which applications can exchange events with each other. When Business Events is enabled for an environment, it is placed in an Event Broker Space based on the environment name. This enables apps deployed under the same Space to publish and consume events. For example, apps in acceptance environment can only exchange events with other apps’ acceptance environments. You can check the Space of an app’s environment on the Event Broker Manager page.

Spaces are created and assigned based on the app environment name and allow isolation of your business events. The default behavior can be changed if needed. Contact Mendix Support if you would like to change the Space of a specific app environment.

See Enabling the Mendix Event Broker Service for more information.

2.2.2 Topics and Channels

Events are placed in channels, sometimes called topics. Apps subscribed to a channel will receive events published to this channel.

Events published by Free Apps are published to one shared company channel on a multi-tenant free Event Broker. Events published by apps running on licensed nodes are published to their own channels on the company Event Broker. These channels, implemented as topics on Kafka, are automatically created upon deployment of the app publishing the events.

3 Mendix Event Broker Bridges

Mendix Event Broker Bridges allow for the integration of the Mendix Event Broker with other technologies, such as AWS SQS, AWS S3, or Google Pub/Sub, to send and receive events between your Mendix Public Cloud landscape and technologies outside of your Mendix Public Cloud landscape.

3.1 Standard Message Format

To move an event from SQS to Mendix Event Broker, a message must contain the following message attributes and start with ce_:

• id as ce_id
• source as ce_source
• specversion as ce_specversion
• type as ce_type

See CloudEvents for more information on required attributes.

3.2 Configuring a Bridge with AWS SQS

Technical Contacts with a license to the Mendix Event Broker can manage this feature from the Event Broker Bridges tab on the Event Broker Manager page.

The creation process contains three steps on the Mendix side and policies that need to be implemented on the AWS side.

3.3 Select a Service to Configure

Within the scope of the current Public Beta for this feature, Mendix Event Broker Bridges can transport events between the Mendix Event Broker and AWS SQS. Other options in the list are currently not available for use.

3.4 Configuration Details

The next step of configuration is to select a Space, Name, and Region for the bridge to operate in.

3.5 Choose the Business Events to Integrate

The user must select events from the Event Broker landscape of events to send to or receive from AWS SQS. To do this, do the following:

1. Select *Add Business Events and search for the appropriate events.

2. Select the checkbox for the event you want to add, then click Select.

   

3. Configure each event with its own SQS URL for each direction that the event will be integrated.

   

4. Confirm the configuration with the AWS Access Policy.

   

5. After all events have been configured, click Start to start the Mendix Event Broker Bridge. This process will take several minutes to complete.

   

Once the Mendix Event Broker Bridge has been successfully deployed, its configuration and status can be viewed on the Overview page.

3.6 Configure AWS Acesss Policy for Sending Messages to Mendix

Add this object to your Access Policy of the AWS SQS queue if it is sending messages to Mendix.

{
  "Sid": "__sender_statement",
  "Effect": "Allow",
  "Principal": {
    "AWS": [
      "arn:aws:iam::044806572671:role/mendix-event-broker-bridge"
    ]
  },
  "Action": [
    "SQS:SendMessage"
  ],
  "Resource": "<Tenant SQS ARN>"
}

3.7 Configure AWS Acesss Policy for Receiving Messages from Mendix

Add this object to your Access Policy of the AWS SQS queue if it is receiving messages from Mendix.

{
  "Sid": "__receiver_statement",
  "Effect": "Allow",
  "Principal": {
    "AWS": [
      "arn:aws:iam::044806572671:role/mendix-event-broker-bridge"
    ]
  },
  "Action": [
    "SQS:ChangeMessageVisibility",
    "SQS:DeleteMessage",
    "SQS:ReceiveMessage"
  ],
  "Resource": "<Tenant SQS ARN>"
}