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+# plugin-architecture
+
+## Fundamental plugin concepts
+
+- Discovery
+- Registration
+- Application hooks to which plugins attach (aka. "mount points")
+- Exposing application capabilities back to plugins (aka. extension API)
+
+#### Discovery
+
+This is the mechanism by which a running application can find out which plugins it has at its disposal. 
+To "discover" a plugin, one has to look in certain places, and also know what to look for. In our example, 
+the discover_plugins function implements this - plugins are Python classes that inherit from a known base class, 
+contained in modules located in known places.
+
+#### Registration
+
+This is the mechanism by which a plugin tells an application - "I'm here, ready to do work". 
+Admittedly, registration usually has a large overlap with discovery, 
+but I still want to keep the two concepts separate since it makes things more explicit 
+(not in all languages registration is as automatic as our example demonstrates).
+
+#### Application hooks
+
+Hooks are also called "mount points" or "extension points". 
+These are the places where the plugin can "attach" itself to the application, 
+signaling that it wants to know about certain events and participate in the flow. 
+The exact nature of hooks is very much dependent on the application. 
+In our example, hooks allow plugins to intervene in the text-to-HTML transformation process performed by the application. 
+The example also demonstrates both coarse grained hooks (processing the whole contents) and fine grained hooks 
+(processing only certain marked-up chunks).
+
+#### Exposing application API to plugins
+
+To make plugins truly powerful and versatile, the application needs to give them access to itself, 
+by means of exposing an API the plugins can use. 
+In our example the API is relatively simple - the application simply passes some of its own internal objects to the plugins. 
+APIs tend to get much more complex when multiple languages are involved. I hope to show some interesting examples in future articles.
+
+**[Read full blog here](https://eli.thegreenplace.net/2012/08/07/fundamental-concepts-of-plugin-infrastructures)**