TopicFilters

Topic Subscription Filters

This sample illustrates creating filtered subscriptions for topics. It shows a simple true-filter that lets all messages pass, a filter with a composite SQL-like condition, a rule combining a filter with a set of actions, and a correlation filter condition.

Read more about topic filters in the documentation.

Refer to the main README document for setup instructions.

Sample Code

The sample is documented inline in the TopicFilters.java file.

The setup template creates the topic for this example with 4 subscriptions.

{
    "apiVersion": "[variables('apiVersion')]",
    "name": "TopicFilterSampleTopic",
    "type": "topics",
    "dependsOn": [
    "[concat('Microsoft.ServiceBus/namespaces/', 
           parameters('serviceBusNamespaceName'))]",
    ],
    "properties": {},
    "resources": [
    

The first subscription selects all messages with a "true" filter, which is a SQL filter with an expression that is trivially true:

 {
    "apiVersion": "[variables('apiVersion')]",
    "name": "AllOrders",
    "type": "subscriptions",
    "dependsOn": [ "TopicFilterSampleTopic" ],
    "properties": {},
    "resources": [
      {
         "apiVersion": "[variables('apiVersion')]",
         "name": "rule1",
         "type": "rules",
         "dependsOn": [ "AllOrders" ],
         "properties": {
            "filterType": "SqlFilter",
            "sqlFilter": {
               "sqlExpression": "1=1",
               "requiresPreprocessing": false
            }
         }
      }
     ]
   },

The second subscription selects all messages with a SQL filter with the user property 'color' having the value 'blue' and the 'quantity' user property having the value 10.

    {
        "apiVersion": "[variables('apiVersion')]",
        "name": "ColorBlueSize10Orders",
        "type": "subscriptions",
        "dependsOn": [ "TopicFilterSampleTopic" ],
        "properties": {},
        "resources": [
         {
            "apiVersion": "[variables('apiVersion')]",
            "name": "rule1",
            "type": "rules",
            "dependsOn": [ "ColorBlueSize10Orders" ],
            "properties": {
            "filterType": "SqlFilter",
               "sqlFilter": {
                  "sqlExpression": "color = 'blue' AND quantity = 10",
                  "requiresPreprocessing": false
               }
            }
         }
        ]
    },

The third subscription selects all messages with a SQL filter with the user property 'color' having the value 'red'.

    {
        "apiVersion": "[variables('apiVersion')]",
        "name": "ColorRed",
        "type": "subscriptions",
        "dependsOn": [ "TopicFilterSampleTopic" ],
        "properties": {
        },
        "resources": [
         {
            "apiVersion": "[variables('apiVersion')]",
            "name": "rule1",
            "type": "rules",
            "dependsOn": [ "ColorRed" ],
            "properties": {
            "filterType": "SqlFilter",
               "sqlFilter": {
                  "sqlExpression": "color = 'red'",
                  "requiresPreprocessing": false
               },
               "action": {
                  "sqlExpression": "SET quantity = quantity / 2; 
                                    REMOVE priority; 
                                    SET sys.CorrelationId = 'low';"
               }
            }
         }
        ]
    },

The forth subscription selects all messages using a correlation filter with the Label property having the value 'red' and the CorrelationId property having the value 'high'

    {
        "apiVersion": "[variables('apiVersion')]",
        "name": "HighPriorityOrders",
        "type": "subscriptions",
        "dependsOn": [ "TopicFilterSampleTopic" ],
        "properties": {
        },
        "resources": [
        {
            "apiVersion": "[variables('apiVersion')]",
            "name": "rule1",
            "type": "rules",
            "dependsOn": [ "HighPriorityOrders" ],
            "properties": {
            "filterType": "CorrelationFilter",
            "correlationFilter": {
                "label": "red",
                "correlationId": "high"
            }
            }
        }
        ]
    }
    ]
}