# Automation using Programmable Configlets

## What is Programmable Configlets?

Programmable Configlets allow network administrators to automate configuration changes across multiple devices. Instead of manually applying configuration changes one device at a time, these configlets define conditions and execute commands dynamically. This helps in managing large networks efficiently by enabling bulk changes and real-time adjustments.

## What are the benefits of Programmable Configlets & scripts?

### 1. Conditional configuration

Programmable Configlets enable administrators to define specific conditions and apply configuration changes only when these conditions are met.

- **Benefit:** Streamlines processes by targeting only the necessary devices or components for updates.

### 2. Looping configuration operations

Loops can be used to iterate through multiple devices and apply configuration changes consistently.

- **Benefit:** Saves time and reduces manual effort for repetitive tasks, such as updating interface descriptions, enabling SNMP settings, or enforcing security policies on devices.

### 3. Secure handling of sensitive data

Sensitive information, like passwords, can be predefined and hidden within the configlet template.

- **Benefit:** Protects confidential data from unauthorized access and accidental exposure.

### 4. Efficient bulk configuration

Bulk operations enable administrators to modify settings across multiple interfaces or VLANs in one go.

- **Benefit:** Enhances efficiency in managing network configurations, such as bulk updates for interfaces and VLAN settings.

## How to create a new Programmable Configlet?

Follow the steps given below to add a programmable configlet in Network Configuration Manager:

- Go to **"Config Automation" >> "Configlets" >> "Programmable Configlets"** and click the **"Add"** icon at the top right.
- In the UI that opens:
  - Enter a name in the **Name** field.
  - Select the appropriate vendor (or leave it as **All**).
  - Provide a description in the **Description** field.
- Under the **Execution Context** section, choose whether to execute the configlet on a single device or multiple devices.
- In the **Configlet Content** field, use the following syntaxes:

| Syntax | Description |
|---|---|
| `$device.execute("command")` | To execute a single command on a device |
| `$device.executeBulk(["command1", "command2"])` | To execute multiple commands at once |
| `$device.execute("command", "prompt")` | To specify the command and prompt |
| `$device.execute("command", "prompt", timeout, delay, "msgSuffix")` | To specify prompt, timeout, delay, and message suffix |
| `$device.executeTimeout("command", timeout)` | To specify the command and timeout |
| `$device.executeTimeout("command", timeout, "prompt")` | To specify the timeout along with the prompt |
| `$device.executeDelay("command", delay)` | To specify the command and delay |
| `$device.executeDelay("command", delay, "prompt")` | To specify the delay along with the prompt |

- Refer to this guide for more information on various functions used in Programmable Configlets:  
  [link](https://www.manageengine.com/network-configuration-manager/kb/how-to/use-various-functions-programmable-configlets.html)
- Use `$<variable_name>` to create variables.  
  Example:  
  `$device.execute("show interface $name")`
- Click **Next**.
- Provide:
  - **Display Name**
  - **Description**
  - Select the [data type](https://www.manageengine.com/network-configuration-manager/kb/faq.html?utm_source=inproduct#pc5)
- Optionally set a **Default Value**.
- To hide sensitive variables, enable **Hidden variables**.
- For text variables, you can specify or create a regex:  
  [Create a new regex](https://www.manageengine.com/network-configuration-manager/kb/how-to/create-a-new-NCM-regex.html)
- Add predefined values under **Selection Fields** if needed.
- Click **Save**.

The new configlet will be added to the list of Programmable Configlets.

## Practical applications

### 1. Cisco – SNMP Trap Settings for Access Ports

**Objective:**  
Configure SNMP Trap Settings for interfaces with admin access.

**Configlet content:**

```
#foreach( $interface in $device.interfaces() )
    #set( $switchport = $device.execute("switch show interface switchport $interface") )
    #if( $switchport.toString().contains("Administrative Mode: access"))
        $device.execute("config t")
        $device.execute("interface $interface")
        $device.execute("snmp trap mac-notification")
        $device.execute("exit")
    #end
#end
```

**Execution explanation:**

- Iterates through each interface using `$device.interfaces()`.
- Checks if the interface is in **access mode**.
- If true, enters **configuration mode** and enables SNMP MAC notifications.

**Configlet execution:**

![Configlet execution](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAqYAAAE5CAYAAABCo+KU...)

**Example execution:**

**Iteration 1:**

- **Interface:** GigabitEthernet 0/0
- **Current Mode:** Administrative Mode: trunk
- **Condition Check:** `$switchport.contains("Administrative Mode: access") = false`
- **Action:** No update performed.

**Iteration 2:**

- **Interface:** GigabitEthernet 0/1
- **Current Mode:** Administrative Mode: access
- **Condition Check:** `$desc.contains("Administrative Mode: access") = true`
- **Action:** Updates SNMP trap settings.

---

### 2. Firmware upgrade – General

**Objective:**  
Automate firmware upgrades for network devices.

**Configlet content:**

```
$device.execute("copy tftp flash", "]?")
$device.execute($TFTP_SERVER_IP, "]?")
$device.execute($SOURCE_FILE_NAME, "]?")
$device.execute($DESTINATION_FILE_NAME)
#set( $flashVal = $device.execute("show flash"))
#if ( $flashVal.toString().contains($DESTINATION_FILE_NAME) )
$device.execute("reload", "confirm]")
$device.execute("y","$NO_RESPONSE",-1,<timeout>,"")
$device.execute("config t")
$device.execute("boot system $DESTINATION_FILE_NAME")
$device.execute("exit")
$device.execute("show version")
#end
```

**Execution explanation:**

- Copy firmware from the TFTP server.
- Verify if the file exists.
- If present:
  - Reload the device.
  - Configure the boot system.
  - Run `show version` to confirm the upgrade.

---

### 3. Model-based execution

**Objective:**  
Configure device settings based on model.

**Configlet content:**

```
#if( $device.model().contains("9300"))
    #set ( $mtu_size = "9000" )
#elseif( $device.model().contains("2900"))
    #set ($mtu_size = "1500" )
#else
    #set ( $mtu_size = "1000" )
#end
$device.execute("conf t")
$device.execute("system mtu $mtu_size")
$device.execute("exit")
```

**Explanation:**

- Checks device model using `$device.model()`.
- Sets MTU size accordingly.
- Applies the `system mtu` command in global configuration mode.

**For Cisco device with model "9300":**

![Cisco device with model 9300](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAnEAAADdCAYAAADUzCSE...)

**For Cisco device with model "2900":**

![Cisco device with model 2900](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAiQAAACoCAYAAADQHvX6...)

**For other model devices:**

![Other model devices](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAmsAAADZCAYAAAB/0Xez...)

**Example execution:**

- **Cisco 9300 Series:** MTU = **9000 bytes**
- **Cisco 2900 Series:** MTU = **1500 bytes**
- **Other devices:** MTU = **1000 bytes**