From ee19890828f0aab44a0c6f073211c319b6745627 Mon Sep 17 00:00:00 2001
From: Jacob <2606873+unitoftime@users.noreply.github.com>
Date: Wed, 30 Oct 2024 16:30:31 -0400
Subject: [PATCH] Add an example for hot reloading

---
 example/hot/main.go          | 39 ++++++++++++++++++++++++++++++++++++
 example/hot/plugin/plugin.go | 16 +++++++++++++++
 example/hot/rebuild.sh       | 30 +++++++++++++++++++++++++++
 3 files changed, 85 insertions(+)
 create mode 100644 example/hot/main.go
 create mode 100644 example/hot/plugin/plugin.go
 create mode 100644 example/hot/rebuild.sh

diff --git a/example/hot/main.go b/example/hot/main.go
new file mode 100644
index 0000000..9161462
--- /dev/null
+++ b/example/hot/main.go
@@ -0,0 +1,39 @@
+package main
+
+import (
+	"time"
+
+	"github.com/unitoftime/flow/example/hot/plugin"
+	"github.com/unitoftime/flow/hot"
+)
+
+// Steps:
+// 1. run rebuild.sh to build the initial plugin *.so file
+// 2. Run main.go
+// 3. Change something in the HelloWorld function in ./plugin/plugin.go
+// 4. run rebuild.sh to rebuild the plugin *.so file. the main() function below will detect, reload the symbol and run it once
+
+// Note: You need to run rebuild.sh to build the plugin *.so file
+
+func main() {
+	// You can directly import the plugin package to use it immediately
+	plugin.HelloWorld()
+
+	// This will search the provided directory for .so files and try to load them
+	p := hot.NewPlugin("./plugin/build/lib/")
+
+	for {
+		time.Sleep(1 * time.Second)
+		if !p.Check() { continue } // When this becomes true, it means a new plugin is loaded
+
+		// With our new plugin, we can lookup our symbol `HelloWorld`
+		sym, err := p.Lookup("HelloWorld")
+		if err != nil {
+			panic(err)
+		}
+		hello := sym.(func())
+
+		// Then we can call our Looked up symbol
+		hello()
+	}
+}
diff --git a/example/hot/plugin/plugin.go b/example/hot/plugin/plugin.go
new file mode 100644
index 0000000..90dec32
--- /dev/null
+++ b/example/hot/plugin/plugin.go
@@ -0,0 +1,16 @@
+package plugin
+
+import (
+	"fmt"
+)
+
+// Note: Here you can change one function to the other while main.go is running.
+
+func HelloWorld() {
+	fmt.Println("Hello World")
+}
+
+
+// func HelloWorld() {
+// 	fmt.Println("Goodbye Moon")
+// }
diff --git a/example/hot/rebuild.sh b/example/hot/rebuild.sh
new file mode 100644
index 0000000..c488133
--- /dev/null
+++ b/example/hot/rebuild.sh
@@ -0,0 +1,30 @@
+#!/bin/bash
+
+set -e
+
+PLUGIN_DIR=./plugin/
+BUILD_DIR=./plugin/build/
+BUILD_PKG_DIR=${BUILD_DIR}/pkg/
+BUILD_LIB_DIR=${BUILD_DIR}/lib/
+
+mkdir -p ${BUILD_PKG_DIR}
+mkdir -p ${BUILD_LIB_DIR}
+
+rm -f ${BUILD_LIB_DIR}/*.so
+
+VAR=$RANDOM
+
+# Note: I usually leave this uncommented, but I didnt want to accidentally wipe someones computer
+#rm -rf ${BUILD_PKG_DIR}/*
+mkdir -p ${BUILD_PKG_DIR}/tmp$VAR
+
+cp ${PLUGIN_DIR}/*.go ${BUILD_PKG_DIR}/tmp$VAR
+
+cd ${BUILD_PKG_DIR}/tmp$VAR
+sed -i 's/package plugin/package main/g' *.go
+cd -
+
+go build -gcflags=all=-d=checkptr=0 -buildmode=plugin -o ${BUILD_LIB_DIR}/tmp$VAR.so ${BUILD_PKG_DIR}/tmp$VAR
+
+echo "Finished Rebuild" $VAR
+tree