There are two ways to add new features based on APISIX.
1. modify the source of APISIX and redistribute it (not so recommended)
1. setup the `extra_lua_path` and `extra_lua_cpath` in `conf/config.yaml` to load your own code. Your own code will be loaded instead of the builtin one with the same name, so you can use this way to override the builtin behavior if needed.
For example, you can create a directory structure like this:
```
├── example
│ └── apisix
│ ├── plugins
│ │ └── 3rd-party.lua
│ └── stream
│ └── plugins
│ └── 3rd-party.lua
```
Then add this configuration into your `conf/config.yaml`:
```yaml
apisix:
...
extra_lua_path: "/path/to/example/?.lua"
```
Now using `require "apisix.plugins.3rd-party"` will load your plugin, just like `require "apisix.plugins.jwt-auth"` will load the `jwt-auth` plugin.
Note : The priority of the new plugin cannot be the same as the priority of any existing plugin. In addition, plugins with a high priority value will be executed first in a given phase (see the definition of `phase` in [choose-phase-to-run](#choose-phase-to-run)). For example, the priority of example-plugin is 0 and the priority of ip-restriction is 3000. Therefore, the ip-restriction plugin will be executed first, then the example-plugin plugin.
To enable your plugin, copy this plugin list into `conf/config.yaml`, and add your plugin name. For instance:
```yaml
apisix:
admin_key:
- name: "admin"
# yamllint disable rule:comments-indentation
key: edd1c9f034335f136f87ad84b625c8f1 # using fixed API token has security risk, please update it when you deploy to production environment
# yamllint enable rule:comments-indentation
role: admin
plugins: # copied from config-default.yaml
...
- your-plugin
```
If your plugin has a new code directory of its own, and you need to redistribute it with the APISIX source code, you will need to modify the `Makefile` to create directory, such as:
In addition, if the plugin needs to use some metadata, we can define the plugin `metadata_schema`, and then we can dynamically manage these metadata through the `admin api`. Example:
```lua
local metadata_schema = {
type = "object",
properties = {
ikey = {type = "number", minimum = 0},
skey = {type = "string"},
},
required = {"ikey", "skey"},
additionalProperties = false,
}
local plugin_name = "example-plugin"
local _M = {
version = 0.1,
priority = 0, -- TODO: add a type field, may be a good idea
You might have noticed the key-auth plugin has `type = 'auth'` in its definition.
When we set the type of plugin to `auth`, it means that this plugin is an authentication plugin.
An authentication plugin needs to choose a consumer after execution. For example, in key-auth plugin, it calls the `consumer.attach_consumer` to attach a consumer, which is chosen via the `apikey` header.
To interact with the `consumer` resource, this type of plugin needs to provide a `consumer_schema` to check the `plugins` configuration in the `consumer`.
Here is the consumer configuration for key-auth plugin:
Determine which phase to run, generally access or rewrite. If you don't know the [Openresty life cycle](https://openresty-reference.readthedocs.io/en/latest/Directives/), it's
recommended to know it in advance. For example key-auth is an authentication plugin, thus the authentication should be completed
**Note : we can't invoke `ngx.exit` or `core.respond.exit` in rewrite phase and access phase. if need to exit, just return the status and body, the plugin engine will make the exit happen with the returned status and body. [example](https://github.com/apache/apisix/blob/35269581e21473e1a27b11cceca6f773cad0192a/apisix/plugins/limit-count.lua#L177)**
The above test case represents a simple scenario. Most scenarios will require multiple steps to validate. To do this, create multiple tests `=== TEST 1`, `=== TEST 2`, and so on. These tests will be executed sequentially, allowing you to break down scenarios into a sequence of atomic steps.
Additionally, there are some convenience testing endpoints which can be found [here](https://github.com/apache/apisix/blob/master/t/lib/server.lua#L36). For example, see [proxy-rewrite](https://github.com/apache/apisix/blob/master/t/plugin/proxy-rewrite.lua). In test 42, the upstream `uri` is made to redirect `/test?new_uri=hello` to `/hello` (which always returns `hello world`). In test 43, the response body is confirmed to equal `hello world`, meaning the proxy-rewrite configuration added with test 42 worked correctly.
A plugin can register API which exposes to the public. Take jwt-auth plugin as an example, this plugin registers `GET /apisix/plugin/jwt/sign` to allow client to sign its key:
```lua
local function gen_token()
...
end
function _M.api()
return {
{
methods = {"GET"},
uri = "/apisix/plugin/jwt/sign",
handler = gen_token,
}
}
end
```
Note that the public API is exposed to the public.
You may need to use [interceptors](plugin-interceptors.md) to protect it.
### Register control API
If you only want to expose the API to the localhost or intranet, you can expose it via [Control API](./control-api.md).
If you don't change the default control API configuration, the plugin will be expose `GET /v1/plugin/example-plugin/hello` which can only be accessed via `127.0.0.1`.
