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> [!NOTE]
> **Note:** Apigee Extensions are available in the Edge UI to Google Cloud Apigee customers with an Enterprise [support](https://cloud.google.com/apigee/pricing) plan.

In the [previous step](https://docs.apigee.com/api-platform/tutorials/add-extension/policy-deployment), you logged a static message that said
"This is a test". A more realistic use case is logging the value of a
[message flow variable](https://docs.apigee.com/api-platform/fundamentals/introduction-flow-variables) in an
API proxy flow.

In this step, you'll log your client IP address, which is a property of the [`client`](https://docs.apigee.com/api-platform/reference/variables-reference#client)
flow variable.

**To log your client IP address with your extension:**

1. In the API proxy editor, select the **Develop** tab.
2. Click your extension logging policy and change the value of `message`:

   ```
   FROM:
   "message": "This is a test"
   TO:
   "message": "Client IP: {client.ip}"
   ```
3. **Save** the proxy.
4. Select the **Trace** tab.
5. Click **Start Trace Session** , and click **Send**.
6. Open the GCP console and go to **Logging**.
7. Select the following:
   - **Global**
   - **example-log**
   - **Last Hour**

   You should see a log entry with your client IP address.

   ![](https://docs.apigee.com/static/api-platform/images/extensions-proxy-client-ip.png)
8. To delete Stackdriver log entries and start fresh, see [gcloud beta
   logging logs delete](https://cloud.google.com/sdk/gcloud/reference/beta/logging/logs/delete).

> [!TIP]
>
> ### Congratulations!
>
> You've logged a message flow variable with an extension!

### Next step

That's it! You're done for now. Go get a snack.