bunkerweb/docs/plugins.md

# Plugins

BunkerWeb comes with a plugin system making it possible to easily add new features. Once a plugin is installed, you can manage it using additional settings defined by the plugin.

## Official plugins

Here is the list of "official" plugins that we maintain (see the [bunkerweb-plugins](https://github.com/bunkerity/bunkerweb-plugins) repository for more information) :

|      Name      | Version | Description                                                                                                                      |                                                 Link                                                  |
| :------------: | :-----: | :------------------------------------------------------------------------------------------------------------------------------- | :---------------------------------------------------------------------------------------------------: |
|   **ClamAV**   |   1.5   | Automatically scans uploaded files with the ClamAV antivirus engine and denies the request when a file is detected as malicious. |     [bunkerweb-plugins/clamav](https://github.com/bunkerity/bunkerweb-plugins/tree/main/clamav)     |
| **Coraza** |   1.5   | Inspect requests using a the Coraza WAF (alternative of ModSecurity).           | [bunkerweb-plugins/coraza](https://github.com/bunkerity/bunkerweb-plugins/tree/main/coraza) |
|  **CrowdSec**  |   1.5   | CrowdSec bouncer for BunkerWeb.                                                                                                  |   [bunkerweb-plugins/crowdsec](https://github.com/bunkerity/bunkerweb-plugins/tree/main/crowdsec)   |
| **Discord** | 1.5 | Send security notifications to a Discord channel using a Webhook. | [bunkerweb-plugins/discord](https://github.com/bunkerity/bunkerweb-plugins/tree/main/discord) |
| **Slack** | 1.5 | Send security notifications to a Slack channel using a Webhook. | [bunkerweb-plugins/slack](https://github.com/bunkerity/bunkerweb-plugins/tree/main/slack) |
| **VirusTotal** |   1.5   | Automatically scans uploaded files with the VirusTotal API and denies the request when a file is detected as malicious.          | [bunkerweb-plugins/virustotal](https://github.com/bunkerity/bunkerweb-plugins/tree/main/virustotal) |
| **WebHook** | 1.5 | Send security notifications to a custom HTTP endpoint using a	Webhook. | [bunkerweb-plugins/webhook](https://github.com/bunkerity/bunkerweb-plugins/tree/main/webhook) |

## How to use a plugin

### Automatic

If you want to quickly install external plugins, you can use the `EXTERNAL_PLUGIN_URLS` setting. It takes a list of URLs, separated with space, pointing to compressed (zip format) archive containing one or more plugin(s).

You can use the following value if you want to automatically install the official plugins : `EXTERNAL_PLUGIN_URLS=https://github.com/bunkerity/bunkerweb-plugins/archive/refs/tags/v1.5.zip`

### Manual

The first step is to install the plugin by putting the plugin files inside the corresponding `plugins` data folder, the procedure depends on your integration :

=== "Docker"

    When using the [Docker integration](integrations.md#docker), plugins must be written to the volume mounted on `/data/plugins` into the scheduler container.

    The first thing to do is to create the plugins folder :

    ```shell
    mkdir -p ./bw-data/plugins
    ```

    Then, you can drop the plugins of your choice into that folder :

    ```shell
    git clone https://github.com/bunkerity/bunkerweb-plugins && \
    cp -rp ./bunkerweb-plugins/* ./bw-data/plugins
    ```

    !!! warning "Using local folder for persistent data"
        The scheduler runs as an **unprivileged user with UID 101 and GID 101** inside the container. The reason behind this is security : in case a vulnerability is exploited, the attacker won't have full root (UID/GID 0) privileges.
        But there is a downside : if you use a **local folder for the persistent data**, you will need to **set the correct permissions** so the unprivileged user can write data to it. Something like that should do the trick :

        ```shell
        mkdir bw-data && \
        chown root:101 bw-data && \
        chmod 770 bw-data
        ```

        Alternatively, if the folder already exists :

        ```shell
        chown -R root:101 bw-data && \
        chmod -R 770 bw-data
        ```

        If you are using [Docker in rootless mode](https://docs.docker.com/engine/security/rootless) or [podman](https://podman.io/), UIDs and GIDs in the container will be mapped to different ones in the host. You will first need to check your initial subuid and subgid :

        ```shell
        grep ^$(whoami): /etc/subuid && \
        grep ^$(whoami): /etc/subgid
        ```

        For example, if you have a value of **100000**, the mapped UID/GID will be **100100** (100000 + 100) :

        ```shell
        mkdir bw-data && \
        sudo chgrp 100100 bw-data && \
        chmod 770 bw-data
        ```

        Or if the folder already exists :

        ```shell
        sudo chgrp -R 100100 bw-data && \
        chmod -R 770 bw-data
        ```

    Then you can mount the volume when starting your Docker stack :

    ```yaml
    version: '3.5'
    services:
    ...
      bw-scheduler:
        image: bunkerity/bunkerweb-scheduler:1.5.8
        volumes:
          - ./bw-data:/data
    ...
    ```

=== "Docker autoconf"

    When using the [Docker autoconf integration](integrations.md#docker-autoconf), plugins must be written to the volume mounted on `/data/plugins` into the scheduler container.


    The first thing to do is to create the plugins folder :

    ```shell
    mkdir -p ./bw-data/plugins
    ```

    Then, you can drop the plugins of your choice into that folder :

    ```shell
    git clone https://github.com/bunkerity/bunkerweb-plugins && \
    cp -rp ./bunkerweb-plugins/* ./bw-data/plugins
    ```

    Because the scheduler runs as an unprivileged user with UID and GID 101, you will need to edit the permissions :

    ```shell
    chown -R 101:101 ./bw-data
    ```

    Then you can mount the volume when starting your Docker stack :

    ```yaml
    version: '3.5'
    services:
    ...
      bw-scheduler:
        image: bunkerity/bunkerweb-scheduler:1.5.8
        volumes:
          - ./bw-data:/data
    ...
    ```

=== "Swarm"

    When using the [Swarm integration](integrations.md#swarm), plugins must be written to the volume mounted on `/data/plugins` into the scheduler container.

    !!! info "Swarm volume"
        Configuring a Swarm volume that will persist when the scheduler service is running on different nodes is not covered is in this documentation. We will assume that you have a shared folder mounted on `/shared` across all nodes.

    The first thing to do is to create the plugins folder :

    ```shell
    mkdir -p /shared/bw-plugins
    ```

    Then, you can drop the plugins of your choice into that folder :

    ```shell
    git clone https://github.com/bunkerity/bunkerweb-plugins && \
    cp -rp ./bunkerweb-plugins/* /shared/bw-plugins
    ```

    Because the scheduler runs as an unprivileged user with UID and GID 101, you will need to edit the permissions :

    ```shell
    chown -R 101:101 /shared/bw-plugins
    ```

    Then you can mount the volume when starting your Swarm stack :

    ```yaml
    version: '3.5'
    services:
    ...
      bw-scheduler:
        image: bunkerity/bunkerweb-scheduler:1.5.8
        volumes:
          - /shared/bw-plugins:/data/plugins
    ...
    ```

=== "Kubernetes"

    When using the [Kubernetes integration](integrations.md#kubernetes), plugins must be written to the volume mounted on `/data/plugins` into the scheduler container.

    The fist thing to do is to declare a [PersistentVolumeClaim](https://kubernetes.io/docs/concepts/storage/persistent-volumes/) that will contain our plugins data :

    ```yaml
    apiVersion: v1
    kind: PersistentVolumeClaim
    metadata:
      name: pvc-bunkerweb-plugins
    spec:
      accessModes:
        - ReadWriteOnce
    resources:
      requests:
        storage: 5Gi
    ```

    You can now add the volume mount and an init containers to automatically provision the volume :

    ```yaml
    apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: bunkerweb-scheduler
    spec:
      replicas: 1
      strategy:
        type: Recreate
      selector:
        matchLabels:
          app: bunkerweb-scheduler
      template:
        metadata:
          labels:
            app: bunkerweb-scheduler
        spec:
          serviceAccountName: sa-bunkerweb
          containers:
            - name: bunkerweb-scheduler
              image: bunkerity/bunkerweb-scheduler:1.5.8
              imagePullPolicy: Always
              env:
                - name: KUBERNETES_MODE
                  value: "yes"
                - name: "DATABASE_URI"
                  value: "mariadb+pymysql://bunkerweb:changeme@svc-bunkerweb-db:3306/db"
              volumeMounts:
                - mountPath: "/data/plugins"
                  name: vol-plugins
          initContainers:
            - name: bunkerweb-scheduler-init
              image: alpine/git
              command: ["/bin/sh", "-c"]
              args: ["git clone https://github.com/bunkerity/bunkerweb-plugins /data/plugins && chown -R 101:101 /data/plugins"]
              volumeMounts:
                - mountPath: "/data/plugins"
                  name: vol-plugins
          volumes:
            - name: vol-plugins
              persistentVolumeClaim:
                claimName: pvc-bunkerweb-plugins
    ```

=== "Linux"

    When using the [Linux integration](integrations.md#linux), plugins must be written to the `/etc/bunkerweb/plugins` folder :

    ```shell
    git clone https://github.com/bunkerity/bunkerweb-plugins && \
    cp -rp ./bunkerweb-plugins/* /etc/bunkerweb/plugins && \
    chown -R nginx:nginx /etc/bunkerweb/plugins
    ```

## Writing a plugin

### Structure

!!! tip "Existing plugins"

    If the documentation is not enough, you can have a look at the existing source code of [official plugins](https://github.com/bunkerity/bunkerweb-plugins) and the [core plugins](https://github.com/bunkerity/bunkerweb/tree/v1.5.8/src/common/core) (already included in BunkerWeb but they are plugins, technically speaking).

What a plugin structure looks like :
```
plugin /
        confs / conf_type / conf_name.conf
        ui / actions.py
             template.html
        jobs / my-job.py
        plugin.lua
        plugin.json
```

- **conf_name.conf** : add [custom NGINX configurations](quickstart-guide.md#custom-configurations) (as jinja2 templates)

- **actions.py** : script to execute on flask server, this script is running on flask context, you have access to lib and utils like `jinja2`, `requests`, etc...

- **template.html** : custom plugin page you can access from ui

- **jobs py file** : custom python files executed as jobs by the scheduler

- **plugin.lua** : code to execute on NGINX using [NGINX LUA module](https://github.com/openresty/lua-nginx-module)

- **plugin.json** : metadata, settings and jobs for your settings

### Getting started

The first step is to create a folder that will contain the plugin :

```shell
mkdir myplugin && \
cd myplugin
```

### Metadata

A file named **plugin.json** and written at the root of the plugin folder must contain metadata about the plugin. Here is an example :

```json
{
  "id": "myplugin",
  "name": "My Plugin",
  "description": "Just an example plugin.",
  "version": "1.0",
  "stream": "partial",
  "settings": {
    "DUMMY_SETTING": {
      "context": "multisite",
      "default": "1234",
      "help": "Here is the help of the setting.",
      "id": "dummy-id",
      "label": "Dummy setting",
      "regex": "^.*$",
      "type": "text"
    }
  },
  "jobs": [
    {
      "name": "my-job",
      "file": "my-job.py",
      "every": "hour"
    }
  ]
}
```

Here are the details of the fields :

|     Field     | Mandatory |  Type  | Description                                                                                                                                                                                        |
| :-----------: | :-------: | :----: | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
|     `id`      |    yes    | string | Internal ID for the plugin : must be unique among other plugins (including "core" ones) and contain only lowercase chars.                                                                          |
|    `name`     |    yes    | string | Name of your plugin.                                                                                                                                                                               |
| `description` |    yes    | string | Description of your plugin.                                                                                                                                                                        |
|   `version`   |    yes    | string | Version of your plugin.                                                                                                                                                                            |
|   `stream`    |    yes    | string | Information about stream support : `no`, `yes` or `partial`.
|  `settings`   |    yes    |  dict  | List of the settings of your plugin.                                                                                                                                                               |
|    `jobs`     |    no     |  list  | List of the jobs of your plugin.                                                                                                                                                                   |

Each setting has the following fields (the key is the ID of the settings used in a configuration) :

|   Field    | Mandatory |  Type  | Description                                                  |
| :--------: | :-------: | :----: | :----------------------------------------------------------- |
| `context`  |    yes    | string | Context of the setting : `multisite` or `global`.            |
| `default`  |    yes    | string | The default value of the setting.                            |
|   `help`   |    yes    | string | Help text about the plugin (shown in web UI).                |
|    `id`    |    yes    | string | Internal ID used by the web UI for HTML elements.            |
|  `label`   |    yes    | string | Label shown by the web UI.                                   |
|  `regex`   |    yes    | string | The regex used to validate the value provided by the user.   |
|   `type`   |    yes    | string | The type of the field : `text`, `check`, `select` or `password`.         |
| `multiple` |    no     | string | Unique ID to group multiple settings with numbers as suffix. |
|  `select`  |    no     |  list  | List of possible string values when `type` is `select`.      |

Each job has the following fields :

|  Field  | Mandatory |  Type  | Description                                                                                                                             |
| :-----: | :-------: | :----: | :-------------------------------------------------------------------------------------------------------------------------------------- |
| `name`  |    yes    | string | Name of the job.                                                                                                                        |
| `file`  |    yes    | string | Name of the file inside the jobs folder.                                                                                                |
| `every` |    yes    | string | Job scheduling frequency : `minute`, `hour`, `day`, `week` or `once` (no frequency, only once before (re)generating the configuration). |

### Configurations

You can add custom NGINX configurations by adding a folder named **confs** with content similar to the [custom configurations](quickstart-guide.md#custom-configurations). Each subfolder inside the **confs** will contain [jinja2](https://jinja.palletsprojects.com) templates that will be generated and loaded at the corresponding context (`http`, `server-http`, `default-server-http`, `stream`, `server-stream`, `modsec` and `modsec-crs`).

Here is an example for a configuration template file inside the **confs/server-http** folder named **example.conf** :

```conf
location /setting {
	default_type 'text/plain';
    content_by_lua_block {
        ngx.say('{{ DUMMY_SETTING }}')
    }
}
```

`{{ DUMMY_SETTING }}` will be replaced by the value of the `DUMMY_SETTING` chosen by the user of the plugin.

### LUA

#### Main script

Under the hood, BunkerWeb is using the [NGINX LUA module](https://github.com/openresty/lua-nginx-module) to execute code within NGINX. Plugins that need to execute code must provide a lua file at the root directory of the plugin folder using the `id` value of **plugin.json** as its name. Here is an example named **myplugin.lua** :

```lua
local class     = require "middleclass"
local plugin    = require "bunkerweb.plugin"
local utils     = require "bunkerweb.utils"


local myplugin = class("myplugin", plugin)


function myplugin:initialize(ctx)
    plugin.initialize(self, "myplugin", ctx)
    self.dummy = "dummy"
end

function myplugin:init()
    self.logger:log(ngx.NOTICE, "init called")
    return self:ret(true, "success")
end

function myplugin:set()
    self.logger:log(ngx.NOTICE, "set called")
    return self:ret(true, "success")
end

function myplugin:access()
    self.logger:log(ngx.NOTICE, "access called")
    return self:ret(true, "success")
end

function myplugin:log()
    self.logger:log(ngx.NOTICE, "log called")
    return self:ret(true, "success")
end

function myplugin:log_default()
    self.logger:log(ngx.NOTICE, "log_default called")
    return self:ret(true, "success")
end

function myplugin:preread()
    self.logger:log(ngx.NOTICE, "preread called")
    return self:ret(true, "success")
end

function myplugin:log_stream()
    self.logger:log(ngx.NOTICE, "log_stream called")
    return self:ret(true, "success")
end

return myplugin
```

The declared functions are automatically called during specific contexts. Here are the details of each function :

| Function |                                   Context                                    | Description                                                                                                                                               | Return value                                                                                                                                                                                                                                                                                                                            |
| :------: | :--------------------------------------------------------------------------: | :-------------------------------------------------------------------------------------------------------------------------------------------------------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
|  `init`  |   [init_by_lua](https://github.com/openresty/lua-nginx-module#init_by_lua)   | Called when NGINX just started or received a reload order. the typical use case is to prepare any data that will be used by your plugin.                  | `ret`, `msg`<ul><li>`ret` (boolean) : true if no error or else false</li><li>`msg` (string) : success or error message</li></ul>|
|  `set`  |   [set_by_lua](https://github.com/openresty/lua-nginx-module#set_by_lua)   | Called before each request received by the server.The typical use case is for computing before access phase.                 | `ret`, `msg`<ul><li>`ret` (boolean) : true if no error or else false</li><li>`msg` (string) : success or error message</li></ul>|
| `access` | [access_by_lua](https://github.com/openresty/lua-nginx-module#access_by_lua) | Called on each request received by the server. The typical use case is to do the security checks here and deny the request if needed.                     | `ret`, `msg`,`status`,`redirect`<ul><li>`ret` (boolean) : true if no error or else false</li><li>`msg` (string) : success or error message</li><li>`status` (number) : interrupt current process and return [HTTP status](https://github.com/openresty/lua-nginx-module#http-status-constants)</li><li>`redirect` (URL) : if set will redirect to given URL</li></ul> |
|  `log`   |    [log_by_lua](https://github.com/openresty/lua-nginx-module#log_by_lua)    | Called when a request has finished (and before it gets logged to the access logs). The typical use case is to make stats or compute counters for example. | `ret`, `msg`<ul><li>`ret` (boolean) : true if no error or else false</li><li>`msg` (string) : success or error message</li></ul>                                                                                                                                                                                                           |
|  `log_default`   |    [log_by_lua](https://github.com/openresty/lua-nginx-module#log_by_lua)    | Same as `log` but only called on the default server. | `ret`, `msg`<ul><li>`ret` (boolean) : true if no error or else false</li><li>`msg` (string) : success or error message</li></ul>                                                                                                                                                                                                           |
| `preread` | [preread_by_lua](https://github.com/openresty/stream-lua-nginx-module#preread_by_lua_block) | Similar to the `access` function but for stream mode. | `ret`, `msg`,`status`<ul><li>`ret` (boolean) : true if no error or else false</li><li>`msg` (string) : success or error message</li><li>`status` (number) : interrupt current process and return [status](https://github.com/openresty/lua-nginx-module#http-status-constants)</li></ul> |
| `log_stream` | [log_by_lua](https://github.com/openresty/stream-lua-nginx-module#log_by_lua_block) | Similar to the `log` function but for stream mode. | `ret`, `msg`<ul><li>`ret` (boolean) : true if no error or else false</li><li>`msg` (string) : success or error message</li></ul> |

#### Libraries

All directives from [NGINX LUA module](https://github.com/openresty/lua-nginx-module) and are available and [NGINX stream LUA module](https://github.com/openresty/stream-lua-nginx-module). On top of that, you can use the LUA libraries included within BunkerWeb : see [this script](https://github.com/bunkerity/bunkerweb/blobsrc/deps/clone.sh) for the complete list.

If you need additional libraries, you can put them in the root folder of the plugin and access them by prefixing them with your plugin ID. Here is an example file named **mylibrary.lua** :

```lua
local _M = {}

_M.dummy = function ()
	return "dummy"
end

return _M
```

And here is how you can use it from the **myplugin.lua** file :

```lua
local mylibrary = require "myplugin.mylibrary"

...

mylibrary.dummy()

...
```

#### Helpers

Some helpers modules provide common helpful helpers :

- `self.variables` : allows to access and store plugins' attributes
- `self.logger` : print logs
- `bunkerweb.utils` : various useful functions
- `bunkerweb.datastore` : access the global shared data on one instance (key/value store)
- `bunkerweb.clusterstore` : access a Redis data store shared between BunkerWeb instances (key/value store)

To access the functions, you first need to **require** the modules :

```lua
local utils       = require "bunkerweb.utils"
local datastore   = require "bunkerweb.datastore"
local clustestore = require "bunkerweb.clustertore"
```

Retrieve a setting value :

```lua
local myvar = self.variables["DUMMY_SETTING"]
if not myvar then
    self.logger:log(ngx.ERR, "can't retrieve setting DUMMY_SETTING")
else
    self.logger:log(ngx.NOTICE, "DUMMY_SETTING = " .. value)
end
```

Store something in the local cache :

```lua
local ok, err = self.datastore:set("plugin_myplugin_something", "somevalue")
if not ok then
    self.logger:log(ngx.ERR, "can't save plugin_myplugin_something into datastore : " .. err)
else
    self.logger:log(ngx.NOTICE, "successfully saved plugin_myplugin_something into datastore")
end
```

Check if an IP address is global :

```lua
local ret, err = utils.ip_is_global(ngx.ctx.bw.remote_addr)
if ret == nil then
    self.logger:log(ngx.ERR, "error while checking if IP " .. ngx.ctx.bw.remote_addr .. " is global or not : " .. err)
elseif not ret then
    self.logger:log(ngx.NOTICE, "IP " .. ngx.ctx.bw.remote_addr .. " is not global")
else
    self.logger:log(ngx.NOTICE, "IP " .. ngx.ctx.bw.remote_addr .. " is global")
end
```

!!! tip "More examples"

    If you want to see the full list of available functions, you can have a look at the files present in the [lua directory](https://github.com/bunkerity/bunkerweb/tree/v1.5.8/src/bw/lua/bunkerweb) of the repository.

### Jobs

BunkerWeb uses an internal job scheduler for periodic tasks like renewing certificates with certbot, downloading blacklists, downloading MMDB files, ... You can add tasks of your choice by putting them inside a subfolder named **jobs** and listing them in the **plugin.json** metadata file. Don't forget to add the execution permissions for everyone to avoid any problems when a user is cloning and installing your plugin.

### Plugin page

Everything related to the web UI is located inside the subfolder **ui** as we seen in the [previous structure section.](#structure).

#### Prerequisites

When you want to create a plugin page, you need two files :

- **template.html** that will be accessible with a **GET /plugins/<*plugin_id*>**.

- **actions.py** where you can add some scripting and logic with a **POST /plugins/<*plugin_id*>**. Notice that this file **need a function with the same name as the plugin** to work. This file is needed even if the function is empty.

#### Basic example

!!! info "Jinja 2 template"
    The **template.html** file is a Jinja2 template, please refer to the [Jinja2 documentation](https://jinja.palletsprojects.com) if needed.

We can put aside the **actions.py** file and start **only using the template on a GET situation**. The template can access app context and libs, so you can use Jinja, request or flask utils.

For example, you can get the request arguments in your template like this :

```html
<p>request args : {{ request.args.get() }}.</p>
```

#### Actions.py

!!! warning "CSRF Token"

    Please note that every form submission is protected via a CSRF token, you will need to include the following snippet into your forms :
    ```html
    <input type="hidden" name="csrf_token" value="{{ csrf_token() }}" />
    ```

You can power-up your plugin page with additional scripting with the **actions.py** file when sending a **POST /plugins/<*plugin_id*>**.

You have two functions by default in **actions.py** :

**pre_render function**

This allows you to retrieve data when you **GET** the template, and to use the data with the pre_render variable available in Jinja to display content more dynamically.

```python
def pre_render(**kwargs)
  return <pre_render_data>
```

BunkerWeb will send you this type of response :


```python
return jsonify({"status": "ok|ko", "code" : XXX, "data": <pre_render_data>}), 200
```

**<*plugin_id*> function**

This allows you to retrieve data when you make a **POST** from the template endpoint, which must be used in AJAX.

```python
def myplugin(**kwargs)
  return <plugin_id_data>
```

BunkerWeb will send you this type of response :

```python
return jsonify({"message": "ok", "data": <plugin_id_data>}), 200
```

**What you can access from action.py**

Here are the arguments that are passed and access on action.py functions:

```python
function(app=app, args=request.args.to_dict() or request.json or None)
```

!!! info "Python libraries"
    In addition, you can use Python libraries that are already available like :
    `Flask`, `Flask-Login`, `Flask-WTF`, `beautifulsoup4`, `docker`, `Jinja2`, `python-magic` and `requests`. To see the full list, you can have a look at the Web UI [requirements.txt](https://github.com/bunkerity/bunkerweb/blobsrc/ui/requirements.txt). If you need external libraries, you can install them inside the **ui** folder of your plugin and then use the classical **import** directive.


**Some examples**

- Retrieve form submitted data

```python
from flask import request

def myplugin(**kwargs) :
	my_form_value = request.form["my_form_input"]
  return my_form_value
```

- Access app config

**action.py**
```python
from flask import request

def pre_render(**kwargs) :
	config = kwargs['app'].config["CONFIG"].get_config(methods=False)
  return config
```

**template**
```html
<!-- metadata + config -->
<div>{{ pre_render }}</div>
```