Create Instance of SAP Event Mesh

1. Open the SAP Business Technology Platform cockpit, Cloud Foundry environment.

2. Navigate to a Space in your Cloud Foundry environment and select Services > Service Marketplace > Event Mesh.

3. Click Instances > New Instance.

4. Select default type service plan from the dropdown and click Next.

5. Specify parameters of the service descriptor using a JSON file.

   {
   "emname": "<yourmessageclientname>",
   "namespace": "<yourorgname>/<yourmessageclientname>/<uniqueID>",
   "version": "1.1.0",
   "options": {
       "management": true,
       "messagingrest": true,
       "messaging": true
   },
   "rules": {
       "queueRules": {
           "publishFilter": [
               "${namespace}/*"
           ],
           "subscribeFilter": [
               "${namespace}/*"
           ]
       },
       "topicRules": {
           "publishFilter": [
               "${namespace}/*"
           ],
           "subscribeFilter": [
               "${namespace}/*"
           ]
       }
   }
   }
   

   Service descriptor defines the message client. Each service instance is a message client that contains a name, namespace and a set of rules.

   The following section describes each parameter used in the service descriptor.

   • emname - It specifies the name of the message client. Should be unique for a subaccount.

   • namespace - The namespace ensures that every message client within a subaccount is unique. The namespace should be provided as a prefix and is not done automatically. The namespace contains exactly 3 segments (max length of 24 characters) with recommended approach as orgName/clientName/uniqueId.

   • options - It is used to define the access channels for the message client.

   • rules - Defines the access privileges for the message client. In order to allow access to a queue or a topic, the namespace of the corresponding owner message client has to be added

   Click Next.

6. Opens another screen. Click Next.

7. Enter the instance name and click Finish. The instance name has to be the same as has been given against the emname parameter in the service descriptor.

   An instance of SAP Event Mesh is created.

   

   Each Event Mesh instance represents a message client. Each message client has a set of queues and topics to which it is associated. All these queues and topics belonging to one message client are exposed to other message clients using its unique credentials. This entire set of queues and topics within different message clients in a subaccount can send and receive messages or events to each other using the service.

When an instance of SAP Event Mesh is created with the steps mentioned above, it stores the information of the protocols, corresponding end-points and authorizations which can be used to bind it to an Application. Service Key holds this information when an instance of SAP Event Mesh is created.
You can create a service key of the instance with the following steps depicted through following three images.

• Click on Create a Service Key
  

• Naming the Service Key
  

• View the created Service Key
  

Do find below a template Service Key of an SAP Event Mesh instance.

{
  "xsappname": "<app-name>",
  "serviceinstanceid": "<instance-id>",
  "messaging": [
    {
        "oa2": {
              "clientid": "<client_id>",
              "clientsecret": "<client_secret>",
              "tokenendpoint": "https://<app-url>/oauth/token",
              "granttype": "client_credentials"
        },
        "protocol": ["amqp10ws"],
        "broker": {
            "type": "sapmgw"
        },
        "uri": "wss://<app-url>/protocols/amqp10ws"
    },
    {
        "oa2": {
                "clientid": "<client_id>",
                "clientsecret": "<client_secret>",
                "tokenendpoint": "https://<app-url>/oauth/token",
                "granttype": "client_credentials"
        },
        "protocol":["mqtt311ws"],
        "broker": {
                    "type": "sapmgw"
        },
        "uri": "wss://<app-url>/protocols/protocols/mqtt311ws"
    },
    {
        "oa2": {
              "clientid": "<client_id>",
              "clientsecret": "<client_secret>",
              "tokenendpoint": "https://<app-url>/oauth/token",
              "granttype": "client_credentials"
        },
        "protocol": ["httprest"],
        "broker": {
              "type": "saprestmgw"
        },
        "uri": " https://<app-url>/"
    }
  ],
  "management": [
      {
        "oa2": {
              "clientid": "<client_id>",
              "clientsecret": "<client_secret>",
              "tokenendpoint": "https://<app-url>/oauth/token",
              "granttype": "client_credentials"
        },
        "uri": " https://<app-url>/"
      }
  ]
}

• The segment management in the service binding information is available only if you set the option management as true during service instance creation.

• The segment httprest in the service binding information is available only if you have set the option messagingrest as true during service instance creation.

Now you can proceed with the tutorial Create Queues and Queue Subscriptions for Event Mesh to create queues and queue subscriptions so you can start working with SAP Event Mesh.