Where can I provide filter for Azure Service Bus Topic Subscription from my logic app - azure-logic-apps

Question

I've created a service bus, topic, and subscription to that topic in Azure. I have a logic app that is triggered when a message arrives but I need to apply a filter (or rule?) to that subscription where it looks for a particular value in the message header before the logic app processes the message. I don't see anywhere in the logic app or in the Azure portal to create filters for the subscriptions. What mechanism exists to create a filter for a subscription?

Answer 1

How did you create your topic subscription? did you use ARM Templates?
When you are creating the Subscription, you can add a SqlFilter to the rule applied in the topic subscription.
The ARM Template below (taken from here) shows you how to add a SqlFilter to the Rule in a Topic Subsctiption
"resources": [{
"apiVersion": "[variables('sbVersion')]",
"name": "[parameters('serviceBusNamespaceName')]",
"type": "Microsoft.ServiceBus/Namespaces",
"location": "[variables('location')]",
"sku": {
"name": "Standard",
},
"resources": [{
"apiVersion": "[variables('sbVersion')]",
"name": "[parameters('serviceBusTopicName')]",
"type": "Topics",
"dependsOn": [
"[concat('Microsoft.ServiceBus/namespaces/', parameters('serviceBusNamespaceName'))]"
],
"properties": {
"path": "[parameters('serviceBusTopicName')]"
},
"resources": [{
"apiVersion": "[variables('sbVersion')]",
"name": "[parameters('serviceBusSubscriptionName')]",
"type": "Subscriptions",
"dependsOn": [
"[parameters('serviceBusTopicName')]"
],
"properties": {},
"resources": [{
"apiVersion": "[variables('sbVersion')]",
"name": "[parameters('serviceBusRuleName')]",
"type": "Rules",
"dependsOn": [
"[parameters('serviceBusSubscriptionName')]"
],
"properties": {
"filterType": "SqlFilter",
"sqlFilter": {
"sqlExpression": "StoreName = 'Store1'",
"requiresPreprocessing": "false"
},
"action": {
"sqlExpression": "set FilterTag = 'true'"
}
}
}]
}]
}]
}]
You need to add your filter using Sql like expressions in the properties member of the rules sub-resource
e.g.
"sqlExpression": "YourMessageProperty='YourExpectedValue'",
If you are not using ARM Templates, the Service Bus Explorer allows you to remove the default subscription rule and create a new one with your own SqlFilter.
HTH