Middleware upgrade (#554)

* Adds root level middleware

* Added todo

* Better way for extensions to be added.

* Bad conflict merge?

docs/contributors/README.md

@@ -0,0 +1,3 @@
+# Docs for Contributors
+
+* [Writing Extensions](extending.md)

docs/contributors/extensions.md

@@ -0,0 +1,95 @@
+# Writing Extensions
+
+Fn is extensible so you can add custom functionality and extend the project without needing to modify the core.
+
+There are multiple ways to extend the functionality of Fn.
+
+1. Listeners - listen to API events such as a route getting updated and react accordingly.
+1. Middleware - a chain of middleware is executed before an API handler is called.
+1. Add API Endpoints - extend the default Fn API.
+
+To create an extension, there are just a couple of rules to follow.
+
+* All config should be via ENV vars.
+
+## Code
+
+Your extension code needs to register itself with an `init()` method which states it's name and a function
+to be called during setup:
+
+```go
+func init() {
+    server.RegisterExtension(&fnext.Extension{
+        Name:  "logspam",
+        Setup: setup, // Fn will call this during startup
+    })
+}
+
+func setup(s *fnext.ExtServer) error {
+    // Add all the hooks you extension needs here
+    s.AddCallListener(&LogSpam{})
+}
+```
+
+## Listeners
+
+Listeners are the main way to extend Fn.
+
+The following listener types are supported:
+
+* App Listeners - [GoDoc](https://godoc.org/github.com/fnproject/fn/api/server#AppListener)
+* Call Listeners - [GoDoc](https://godoc.org/github.com/fnproject/fn/api/server#CallListener)
+
+### Creating a Listener
+
+You can easily use add listeners by creating a struct with valid methods satisfying the interface
+for the respective listener, adding it to `main.go` then compiling.
+
+Example:
+
+```go
+package main
+
+import (
+    "context"
+
+    "github.com/fnproject/fn/api/server"
+    "github.com/fnproject/fn/api/models"
+)
+
+type myCustomListener struct{}
+
+func (c *myCustomListener) BeforeAppCreate(ctx context.Context, app *models.App) error { return nil }
+func (c *myCustomListener) AfterAppCreate(ctx context.Context, app *models.App) error { return nil }
+
+func (c *myCustomListener) BeforeAppUpdate(ctx context.Context, app *models.App) error { return nil }
+func (c *myCustomListener) AfterAppUpdate(ctx context.Context, app *models.App) error { return nil }
+
+func (c *myCustomListener) BeforeAppDelete(ctx context.Context, app *models.App) error { return nil }
+func (c *myCustomListener) BeforeAppDelete(ctx context.Context, app *models.App) error { return nil }
+
+function main () {
+    srv := server.New(/* Here all required parameters to initialize the server */)
+
+    srv.AddAppListener(myCustomListener)
+
+    srv.Run()
+}
+```
+
+## Middleware
+
+Middleware enables you to add functionality to every API request. For every request, the chain of Middleware will be called
+in order, allowing you to modify or reject requests, as well as write output and cancel the chain.
+
+NOTES:
+
+* middleware is responsible for writing output if it's going to cancel the chain.
+
+See examples of this in [examples/middleware/main.go](../../examples/middleware/main.go).
+
+## Adding API Endpoints
+
+You can add API endpoints to the Fn server by using the `AddEndpoint` and `AddEndpointFunc` methods.
+
+See examples of this in [examples/extensions/main.go](../../examples/extensions/main.go).

docs/operating/extending.md

@@ -1,73 +1,25 @@
-# Extending Fn
+# Building Custom Server with Extensions
 
-FN is extensible so you can add custom functionality and extend the project without needing to modify the core.
+You can easily add any number of extensions to Fn and then build your own custom image.
 
-There are multiple ways to extend the functionality of Fn.
+Simply create an `ext.yaml` file with the extensions you want added:
 
-1. Listeners - listen to API events such as a route getting updated and react accordingly.
-1. Middleware - a chain of middleware is executed before an API handler is called.
-1. Add API Endpoints - extend the default Fn API.
-
-## Listeners
-
-Listeners are the main way to extend Fn.
-
-The following listener types are supported:
-
-* App Listeners - [GoDoc](https://godoc.org/github.com/fnproject/fn/api/server#AppListener)
-* Call Listeners - [GoDoc](https://godoc.org/github.com/fnproject/fn/api/server#CallListener)
-
-### Creating a Listener
-
-You can easily use add listeners by creating a struct with valid methods satisfying the interface
-for the respective listener, adding it to `main.go` then compiling.
-
-Example:
-
-```
-package main
-
-import (
-    "context"
-
-    "github.com/fnproject/fn/api/server"
-    "github.com/fnproject/fn/api/models"
-)
-
-type myCustomListener struct{}
-
-func (c *myCustomListener) BeforeAppCreate(ctx context.Context, app *models.App) error { return nil }
-func (c *myCustomListener) AfterAppCreate(ctx context.Context, app *models.App) error { return nil }
-
-func (c *myCustomListener) BeforeAppUpdate(ctx context.Context, app *models.App) error { return nil }
-func (c *myCustomListener) AfterAppUpdate(ctx context.Context, app *models.App) error { return nil }
-
-func (c *myCustomListener) BeforeAppDelete(ctx context.Context, app *models.App) error { return nil }
-func (c *myCustomListener) BeforeAppDelete(ctx context.Context, app *models.App) error { return nil }
-
-function main () {
-    srv := server.New(/* Here all required parameters to initialize the server */)
-
-    srv.AddAppListener(myCustomListener)
-
-    srv.Run()
-}
+```yaml
+extensions:
+  - name: github.com/treeder/fn-ext-example/logspam
+  - name: github.com/treeder/fn-ext-example/logspam2
 ```
 
-## Middleware
+Build it:
 
-Middleware enables you to add functionality to every API request. For every request, the chain of Middleware will be called
-in order, allowing you to modify or reject requests, as well as write output and cancel the chain.
+```sh
+fn build-server -t imageuser/imagename
+```
 
-NOTES:
+`-t` takes the same input as `docker build -t`, tagging your image.
 
-* middleware is responsible for writing output if it's going to cancel the chain.
-* cancel the chain by returning an error from your Middleware's Serve method.
+Now run your new server:
 
-See examples of this in [examples/middleware/main.go](../../examples/middleware/main.go).
-
-## Adding API Endpoints
-
-You can add API endpoints to the Fn server by using the `AddEndpoint` and `AddEndpointFunc` methods.
-
-See examples of this in [examples/extensions/main.go](../../examples/extensions/main.go).
+```sh
+docker run --rm --name fnserver -it -v /var/run/docker.sock:/var/run/docker.sock -v $PWD/data:/app/data -p 8080:8080 imageuser/imagename
+```