Add basic plugins documentations

Closes #195

Author: yamalight

docs/Advanced.md

@@ -72,3 +72,9 @@ Current caveats:
 
 - Currently secrets only work for environment variables
 - Currently secrets work only for normal deployments (any template or recipe that uses `startFromParams` won't have secrets expanded)
+
+## Plugins
+
+Exoframe-Server supports extension of core features using plugins.  
+Plugins are installed and loaded automatically once corresponding config is added to [server configuration](ServerConfiguration.md).  
+Refer to specific plugins docs to see how to configure them.

docs/PluginsGuide.md

@@ -0,0 +1,54 @@
+# Plugins guide
+
+Exoframe allows extending the core functionality of Exoframe-Server using third party plugins.  
+This guide aims to explain basics you need to know to create your own plugins.  
+If you are looking for plugins usage - please see [Advanced](Advanced.md) part of the docs.
+
+## Basics
+
+Exoframe uses [yarn](https://yarnpkg.com/) to install and remove third-party plugins.  
+The plugins then are added to Exoframe-Server using Node.js `require()` method.  
+So, make sure that your plugin's `package.json` has correct `main` attribute.
+
+Your plugins main script needs to export the following variables and methods:
+
+```js
+module.exports = {
+  // plugin default config
+  config: {
+    // plugin name
+    name: 'exoframe-plugin-swarm',
+    // whether plugin requires exclusive hooks to exoframe methods
+    // exclusive hooks are the only ones being executed
+    // make sure you only run ONE exclusive plugin at a time
+    exclusive: true,
+  },
+
+  /* plugin functions that hook into Exoframe-Server methods */
+  // server init function hook
+  // should initialize traefik, setup networks, etc
+  init,
+  // exoframe start function hook
+  // should start a deployment from files
+  start,
+  // exoframe startFromParams function hook
+  // should start a deployment from given set of params
+  startFromParams,
+  // exoframe list function hook
+  // should list currently active deployments
+  list,
+  // exoframe logs function hook
+  // should get logs for a given deployment
+  logs,
+  // exoframe remove function hook
+  // should remove a given deployment
+  remove,
+  // exoframe compose template extension
+  // can affect how docker-compose template is executed
+  compose,
+};
+```
+
+## Examples
+
+- [Swarm plugin](https://github.com/exoframejs/exoframe-plugin-swarm)

docs/ServerConfiguration.md

@@ -1,4 +1,3 @@
-
 ## Server Configuration
 
 Exoframe stores its config in `~/.exoframe/server.config.yml`.  
@@ -45,6 +44,16 @@ publicKeysPath: '/path/to/your/public/keys'
 
 # whether Exoframe server whould be running in swarm mode, default "false"
 swarm: false
+
+# plugins config
+plugins:
+  # list of plugins that has to be installed and loaded by exoframe-server on startup
+  install: ['exoframe-plugin-swarm']
+  # specific plugin config (see plugins docs to know what property they use)
+  swarm:
+    enabled: true
 ```
 
-_Warning:_ Most changes to config are applied immediately. With exception of Letsencrypt config. If you are enabling letsencrypt after Traefik instance has been started, you'll need to remove Traefik and then restart Exoframe server for changes to take effect.
+_Warning:_ Most changes to config are applied immediately. With exception of Letsencrypt config and Plugins config.  
+If you are enabling letsencrypt after Traefik instance has been started, you'll need to remove Traefik and then restart Exoframe server for changes to take effect.  
+If you are adding plugins after server has been started, you'll need to restart the server so that it can install and load newly added plugins.