Merge pull request #237 from fnproject/marleung/hotreload

Doc for hot reload feature in Fn CLI for local Functions development

Author: marvin659

HotReload/README.md

@@ -0,0 +1,61 @@
+# Enable Hot Reload when developing OCI Functions locally
+
+When developing Functions locally, Fn allows you to enable hot reload. When hot reload is enabled, your changes will be
+automatically detected and will trigger function local deployment to the application that you have specified.
+
+## Before you Begin
+* Set aside about 15 minutes to complete this tutorial.
+* Make sure Fn server is up and running by completing the [Install and Start Fn Tutorial](../install/README.md).
+    * Make sure you have set your Fn context registry value for local development. (for example, "fndemouser". [See here](https://github.com/fnproject/tutorials/blob/master/install/README.md#configure-your-context).)
+
+As you make your way through this tutorial, look out for this icon. ![User Input
+Icon](images/userinput.png) Whenever you see it, it's time for you to perform an
+action.
+
+
+## Start Fn
+In the terminal, type the following to start Fn. Optionally, you could start with "--log-level DEBUG" arguments so you
+could see more messages.
+
+![User Input Icon](images/userinput.png)
+>```sh
+> fn start --log-level DEBUG
+>```
+
+![Start Fn Server](images/fnstart.png)
+
+## Hot Reload for Python Function
+
+Suppose you have an application called "myapp" that setup locally, and you have initialized a function called "myfunc". Under the
+functions directory, where the func.yaml located, you could run the following to enable Hot Reload.
+
+![User Input Icon](images/userinput.png)
+>```sh
+> fn watch -app myapp
+>```
+
+![Enable Hot Reload](images/fnwatch.png)
+
+Now you could change the code for Functions. Here we modify the output string from "Hello" to "Hi".
+
+You could see that the local deployment will be triggered automatically.
+
+
+![Local Deployment Triggered](images/hotreload.png)
+
+If you invoke the function, you could see the new change:
+
+![Fn Invoke](images/fninvoke.png)
+
+
+## Supported Language
+All languages supported by OCI Functions have hot reload feature supported.
+
+## Ignoring paths
+`fn watch` ignores these directories by default:
+
+- `.git`, `.fn`, `node_modules`, `target`, `dist`, `vendor`, `Dockerfile-fn-tmp*`
+
+You can add more ignore rules by creating a `.fnignore` file in the watched directory (one pattern per line; `#` comments supported), and/or by passing `--ignore` flags.
+
+

HotReload/images/fninvoke.png

@@ -24,12 +24,12 @@ Official:
 * [Fn Development with Multiple Contexts](basics/UsingContexts/README.md) - Shows how to setup and use multiple Fn configuration contexts for development.
 * [Using Fn RuntimeContext with a Function](basics/UsingRuntimeContext/README.md) - See how to set Fn Application and Function variables and access them in your function using the Runtime Context.
 
-
 ## Test and Monitor Functions
 
 * [Monitor Fn metrics with Grafana and Prometheus](grafana/README.md) - Learn how to view Fn server metrics with Prometheus and Grafana.
 * [Troubleshoot and Log functions](Troubleshooting/README.md) - Resolve issues at both development and deployment time.
 * [Debug functions locally](LocalDebug/README.md) - Deploy functions locally and debug.
+* [Enable Hot Reload when developing OCI Functions locally](HotReload/README.md) - Enable hot reload when developing Functions locally with Fn Server
 
 ## Orchestrate with Fn Flow