--- name: azion-install-the-limit-payload-size-integration description: >- Install Limit Payload Size from Azion Marketplace and run it on a firewall to deny requests whose Content-Length exceeds a limit you set. --- # Install the Limit Payload Size integration You install the Limit Payload Size integration from Azion Marketplace and run it on a [Firewall](/en/documentation/platform/firewall/), from Azion Console. The function evaluates request data and denies payloads that exceed a limit you set. It checks the payload size through the `Content-Length` header, not the body: the header is required, so reading it is safe, it protects against changes to the header's value, and it performs better than reading the body. Five objects have to exist before a request is checked: the installed function, a firewall carrying the **Functions** module, a function instance holding the limit, a Rules Engine rule with the **Run Function** behavior, and a workload deployment bound to the firewall. Each section below creates one of them. --- ## Prerequisites - An Azion account. To sign in, refer to [How to access Azion Console](/en/documentation/guides/platform/account-and-billing/how-to-access-azion-console/). - An application served by a [workload](/en/documentation/platform/workloads/), whose deployment you bind to the firewall in the last section. - The [Azion CLI](/en/documentation/devtools/cli/) installed and authorized, for the last section. - Turning on a product or a module can generate usage costs. For more information, refer to [Pricing](/en/documentation/fundamentals/pricing/). --- ## Install the integration The function is installed once per account. To install it: 1. **Open Marketplace** Access [Azion Console](https://console.azion.com/) > **Marketplace**. 2. **Find the integration** Enter `Limit Payload Size` in the **Search on Marketplace** field, then select the integration's card. Browsing the cards and the categories reaches the same page. 3. **Select Install** The card shows `Successfully installed!` and `Latest version installed!`, and the function appears in the **Function** list of the **Create Instance** drawer. --- ## Create the firewall The firewall is where the function is instanced and where the rule that runs it lives. To create one: 1. **Open the Firewalls page** Access [Azion Console](https://console.azion.com/) > **Firewalls**, then create a firewall. 2. **Name the firewall** In the **General** section, enter a **Name**. For example: `limit-payload-firewall`. 3. **Turn on the Functions module** In the **Modules** section, turn on the **Functions** switch. 4. **Save the firewall** The firewall shows a **Functions Instances** tab while the **Functions** module stays on. To use an existing firewall instead, turn on its **Functions** module and save it. For every setting on this form, refer to [Set a firewall's main settings](/en/documentation/guides/application-security/firewall-and-waf/firewall-configure-main-settings/). --- ## Create the function instance The instance holds the maximum payload size that the function accepts. To create it: 1. **Open the Functions Instances tab** In **Firewalls**, select your firewall, then select the **Functions Instances** tab. 2. **Select + Function** A firewall that has no instance shows the same action as **Function Instance**. The **Create Instance** drawer opens. 3. **Name the instance** In **Name**, enter a name. For example: `limit-payload-size`. 4. **Select the installed function** In **Function**, select the Limit Payload Size function. The list holds only the functions that run on a firewall. 5. **Enter the arguments** In **Arguments**, the editor is prefilled with the integration's default arguments in JSON. Set the limit, as the next section describes. 6. **Select Save** The instance is listed in the **Functions Instances** tab. ### Arguments The instance takes one argument: ```json { "max_content_length": "10kb" } ``` `max_content_length` is the maximum payload size that the function accepts: - The value accepts bytes, kilobytes, and megabytes. - A value without a unit is read as bytes. - Without an argument, the function bypasses the execution. - A payload larger than the limit gets a `403` error. --- ## Create the rule The instance checks nothing until a rule runs it. A [Rules Engine for Firewall](/en/documentation/platform/firewall/rules-engine/) rule selects the requests that reach the instance, through a **Run Function** behavior. To create the rule: 1. **Open the Rules Engine tab** In **Firewalls**, select your firewall, then select the **Rules Engine** tab. 2. **Select + Rule** 3. **Name the rule** In **Name**, enter a name. For example: `Run Limit Payload Size`. 4. **Set the criterion** In the **Criteria** section, select the domains that run the integration. For example: if `Host` *matches* `yourdomain.com`. 5. **Add the Run Function behavior** In the **Behaviors** section, select **Run Function**, then select the instance by the name you gave it. 6. **Select Save** The firewall runs the instance on every request to the domain in the criterion. --- ## Bind the firewall to the workload The binding is on the workload's deployment, so create a deployment that names both the application and the firewall: ```bash azion create workload-deployment --workload-id --name \ --application-id --firewall-id --strategy-type default \ --active true --current true ``` The command prints the id of the new deployment: ```text Created Workload Deployment with ID 123456 ``` Requests to the workload's domain reach the firewall, and the rule runs the Limit Payload Size instance on each one. --- ## Next steps - [Marketplace integrations](/en/documentation/platform/marketplace/integrations.md): Every integration Azion Marketplace offers, and where each one runs. - [Rules Engine for Firewall](/en/documentation/platform/firewall/rules-engine.md): Every criterion and behavior a firewall rule accepts. - [Update an integration](/en/documentation/guides/application-development/integrations/update-an-integration.md): Move an installed integration to its latest version.