--- schema_version: "1" id: 6ccaf7f4eac2e523b5382d541f84069d13b701537f090293e5010c13158572fa title: Group-Based Aggregator Example collection: mulesoft version: current locale: en-us portal_url: https://docs.salesforce.com/mulesoft/current/en-us/aggregators-module/latest/aggregators-group-example.md canonical_url: https://docs.mulesoft.com/aggregators-module/latest/aggregators-group-example source_site: docs.mulesoft.com content_type: documentation content_hash: 39cf5776d6829ad27a298bcf0a1cc3e3c0eaf32814d9198d8fb56059715a6d72 description: MuleSoft Documentation Site release: "1.1" latest: true --- --- product: Aggregators Module version: 1.1 is-latest-version: true --- # Group-Based Aggregator Example > For the full documentation index, see: https://docs.mulesoft.com/llms.txt The Aggregators module **Group based aggregator** scope enables you to aggregate elements into groups by group ID. The following example shows how to configure this scope to aggregate up to `3` HTTP request calls per group based on the group ID sent in the request. The application uses DataWeave to set the payload of each call with a random ID number. For each group that completes the aggregation of `3` elements, the application logs all the aggregated random ID number elements of the group. ![Group-Based Aggregator Flow Example in Anypoint Studio Canvas](/mulesoft/current/en-us/aggregators-module/latest/_images/aggregator-group-example.png) Figure 1. Group-Based Aggregator Flow Example To test this example in your own environment, you must create the Mule application and test it with curl commands. ## Create the Mule Application To create the Mule flow in Anypoint Studio: 1. In **Mule Palette**, select **HTTP Listener** and drag it onto the canvas. The source initiates the flow by listening for incoming HTTP message attributes. 2. In **Connector configuration**, select **HTTP\_Listener\_config**. 3. Set **Path** to `/test`. 4. Drag a **Transform message** component to the right of **Listener**. 5. In the DataSense preview window of the **Transform message** component, add the following DataWeave expression, which sets to each HTTP request payload a `Source Name` as `"group-based"` and a `Source ID` as `random() as String`. The expression also obtains the `GroupId` value of the request based on `message.attributes['queryParams'].groupId`: ```DataWeave %dw 2.0 output application/json --- { "Source Name": "group-based", "GroupId": message.attributes['queryParams'].groupId, "Source ID": (random() as String) } ``` 6. Drag the **Group based aggregator** scope to the right of **Transform message**. 7. Set **Name** to `groupBasedAggregator`. 8. Set **Content** to `payload`, which is the expression that defines what to aggregate: in this case, the transformed HTTP requests. 9. Set **Group id** to `payload.GroupId`, which is the expression to evaluate for every new message received that gets the group ID where the element is aggregated. 10. Set **Group size** to `3`, which is the maximum size of elements to aggregate to the group with the group ID resolved. 11. Drag a **Logger** component into the **Incremental aggregation** route. 12. In the **Logger** configuration screen, set **Message** to `Doing incremental aggregation.` 13. Drag a **Logger** component into the **Aggregation complete** route. 14. Set **Message** to `Aggregation complete`. 15. Drag another **Logger** component to the right of the first **Logger** component in **Aggregation complete**. 16. Set **Message** to the following expression, which returns all the aggregated elements: ```xml output application/json --- payload ``` 17. Save the project. 18. In **Package Explorer**, click **Run > Run As > Mule Application**. 19. Test the app by sending the following curl command twice: + `curl -X POST [http://localhost:8081/test?groupId=1](http://localhost:8081/test?groupId=1)` . This generates two HTTP requests to aggregate to the group ID `1`. 20. Send the command `curl -X POST [http://localhost:8081/test?groupId=2](http://localhost:8081/test?groupId=2)` to aggregate one request to the group ID `2`. 21. Send another command `curl -X POST [http://localhost:8081/test?groupId=1](http://localhost:8081/test?groupId=1)` to aggregate a request to group ID `1`. 22. Navigate to the **Console** view to read the logger message: ```none INFO 2021-06-14 16:34:33,921 [[MuleRuntime].uber.12: [aggregator-group-demo].aggregator-group-demoFlow.CPU_INTENSIVE @2c3478b5] [processor: aggregator-group-demoFlow/processors/1/route/0/processors/0; event: 8beae010-cd47-11eb-8b82-f01898ad2638] org.mule.runtime.core.internal.processor.LoggerMessageProcessor: Doing incremental aggregation INFO 2021-06-14 16:34:43,618 [[MuleRuntime].uber.12: [aggregator-group-demo].aggregator-group-demoFlow.CPU_INTENSIVE @2c3478b5] [processor: aggregator-group-demoFlow/processors/1/route/0/processors/0; event: 91b93be0-cd47-11eb-8b82-f01898ad2638] org.mule.runtime.core.internal.processor.LoggerMessageProcessor: Doing incremental aggregation INFO 2021-06-14 16:34:47,203 [[MuleRuntime].uber.12: [aggregator-group-demo].aggregator-group-demoFlow.CPU_INTENSIVE @2c3478b5] [processor: aggregator-group-demoFlow/processors/1/route/0/processors/0; event: 93d8e790-cd47-11eb-8b82-f01898ad2638] org.mule.runtime.core.internal.processor.LoggerMessageProcessor: Doing incremental aggregation INFO 2021-06-14 16:34:51,380 [[MuleRuntime].uber.12: [aggregator-group-demo].aggregator-group-demoFlow.CPU_INTENSIVE @2c3478b5] [processor: aggregator-group-demoFlow/processors/1/route/1/processors/0; event: 96566ab0-cd47-11eb-8b82-f01898ad2638] org.mule.runtime.core.internal.processor.LoggerMessageProcessor: Aggregation complete INFO 2021-06-14 16:34:51,409 [[MuleRuntime].uber.12: [aggregator-group-demo].aggregator-group-demoFlow.CPU_INTENSIVE @2c3478b5] [processor: aggregator-group-demoFlow/processors/1/route/1/processors/1; event: 96566ab0-cd47-11eb-8b82-f01898ad2638] org.mule.runtime.core.internal.processor.LoggerMessageProcessor: [ { "Source Name": "group-based", "GroupId": "1", "Source ID": "0.5127046416902801" }, { "Source Name": "group-based", "GroupId": "1", "Source ID": "0.20239307122656847" }, { "Source Name": "group-based", "GroupId": "1", "Source ID": "0.7505233647798346" } ] ``` This example logger message shows that for the first two HTTP requests with group ID `1` and the third request with group ID `2`, the **Logger** component in the **Incremental aggregator** route logs the message `Doing incremental aggregation.` After you send the fourth HTTP request, which is the third request with group ID `1`, the aggregation group `1` is complete because of the group size of `3` calls per group. The first **Logger** component in the **Aggregation complete** route logs the message `Aggregation complete`, and the second **Logger** component returns the aggregated payload elements of the group, which are the random ID numbers. If you send another two commands `curl -X POST [http://localhost:8081/test?groupId=2](http://localhost:8081/test?groupId=2)` to aggregate calls to group `2`, the **Console** view returns the logger message: ```none INFO 2021-06-14 16:53:56,262 [[MuleRuntime].uber.12: [aggregator-group-demo].aggregator-group-demoFlow.CPU_INTENSIVE @2c3478b5] [processor: aggregator-group-demoFlow/processors/1/route/0/processors/0; event: 40c07200-cd4a-11eb-8b82-f01898ad2638] org.mule.runtime.core.internal.processor.LoggerMessageProcessor: Doing incremental aggregation INFO 2021-06-14 16:53:58,686 [[MuleRuntime].uber.01: [aggregator-group-demo].aggregator-group-demoFlow.CPU_INTENSIVE @2c3478b5] [processor: aggregator-group-demoFlow/processors/1/route/1/processors/0; event: 42329fa0-cd4a-11eb-8b82-f01898ad2638] org.mule.runtime.core.internal.processor.LoggerMessageProcessor: Aggregation complete INFO 2021-06-14 16:53:58,689 [[MuleRuntime].uber.01: [aggregator-group-demo].aggregator-group-demoFlow.CPU_INTENSIVE @2c3478b5] [processor: aggregator-group-demoFlow/processors/1/route/1/processors/1; event: 42329fa0-cd4a-11eb-8b82-f01898ad2638] org.mule.runtime.core.internal.processor.LoggerMessageProcessor: [ { "Source Name": "group-based", "GroupId": "2", "Source ID": "0.8390326267445475" }, { "Source Name": "group-based", "GroupId": "2", "Source ID": "0.8931962767228987" }, { "Source Name": "group-based", "GroupId": "2", "Source ID": "0.6514448303865373" } ] ``` ## XML for Group-Based Aggregator Example Paste this code into your Studio XML editor to quickly load the flow for this example into your Mule app: ```xml ``` ## See Also - [Aggregators Module Examples](https://docs.mulesoft.com/aggregators-module/latest/aggregators-examples) - [Salesforce Help](https://help.salesforce.com)