From 9f043e4bbecea199128111e2e4ac1cd48741f23f Mon Sep 17 00:00:00 2001
From: jay <38236622+JayJamieson@users.noreply.github.com>
Date: Mon, 15 Jan 2024 22:39:36 +1300
Subject: [PATCH 1/2] added filesystem access example

---
 README.md | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)

diff --git a/README.md b/README.md
index 379caa4..cda57fd 100644
--- a/README.md
+++ b/README.md
@@ -265,6 +265,105 @@ config := PluginConfig{
 _, err := NewPlugin(ctx, manifest, config, []HostFunction{})
 ```
 
+### Enable filesystem access
+
+WASM plugins can read/write files outside the runtime. To do this we add allowed path mapping of "HOST:PLUGIN" to the `extism.Manifest` of our plugin.
+
+```go
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+
+	extism "github.com/extism/go-sdk"
+)
+
+func main() {
+	manifest := extism.Manifest{
+		AllowedPaths: map[string]string{
+
+			// Here we specifify a host directory data to be linked
+			// to the /mnt directory inside the wasm runtime
+			"data": "/mnt",
+		},
+		Wasm: []extism.Wasm{
+			extism.WasmFile{
+				Path: "plugin.wasm",
+			},
+		},
+	}
+
+	ctx := context.Background()
+	config := extism.PluginConfig{
+		EnableWasi: true,
+	}
+	plugin, err := extism.NewPlugin(ctx, manifest, config, []extism.HostFunction{})
+
+	if err != nil {
+		fmt.Printf("Failed to initialize plugin: %v\n", err)
+		os.Exit(1)
+	}
+
+	data := []byte("Hello world, this is written from within our wasm plugin.")
+	exit, _, err := plugin.Call("write_file", data)
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(int(exit))
+	}
+}
+```
+
+Next we need to setup the runtime to make filesystem APIs available, we do this by calling `__wasm_call_ctors()` exported method in a WASM `_initialize` hook.
+
+```go
+package main
+
+import (
+	"os"
+
+	"github.com/extism/go-pdk"
+)
+
+//export __wasm_call_ctors
+func __wasm_call_ctors()
+
+//export _initialize
+func _initialize() {
+	__wasm_call_ctors()
+}
+
+//export write_file
+func writeFile() int32 {
+	input := pdk.Input()
+
+	err := pluginMain("/mnt/wasm.txt", input)
+
+	if err != nil {
+		pdk.Log(pdk.LogTrace, err.Error())
+		return 1
+	}
+
+	return 0
+}
+
+func pluginMain(filename string, data []byte) error {
+	pdk.Log(pdk.LogInfo, "Writing following data to disk: "+string(data))
+
+	// Write to the file, will be created if it doesn't exist
+	err := os.WriteFile(filename, data, 0644)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func main() {}
+
+```
+
 ## Build example plugins
 
 Since our [example plugins](./plugins/) are also written in Go, for compiling them we use [TinyGo](https://tinygo.org/):

From 67af788a90d556e9af13b9c9ab7fe6409b656b2b Mon Sep 17 00:00:00 2001
From: jay <38236622+JayJamieson@users.noreply.github.com>
Date: Tue, 16 Jan 2024 23:58:39 +1300
Subject: [PATCH 2/2] removed pdk code and added reference to pdk repository

---
 README.md | 54 +++---------------------------------------------------
 1 file changed, 3 insertions(+), 51 deletions(-)

diff --git a/README.md b/README.md
index cda57fd..e811b30 100644
--- a/README.md
+++ b/README.md
@@ -267,7 +267,7 @@ _, err := NewPlugin(ctx, manifest, config, []HostFunction{})
 
 ### Enable filesystem access
 
-WASM plugins can read/write files outside the runtime. To do this we add allowed path mapping of "HOST:PLUGIN" to the `extism.Manifest` of our plugin.
+WASM plugins can read/write files outside the runtime. To do this we add `AllowedPaths` mapping of "HOST:PLUGIN" to the `extism.Manifest` of our plugin.
 
 ```go
 package main
@@ -283,14 +283,13 @@ import (
 func main() {
 	manifest := extism.Manifest{
 		AllowedPaths: map[string]string{
-
 			// Here we specifify a host directory data to be linked
 			// to the /mnt directory inside the wasm runtime
 			"data": "/mnt",
 		},
 		Wasm: []extism.Wasm{
 			extism.WasmFile{
-				Path: "plugin.wasm",
+				Path: "fs_plugin.wasm",
 			},
 		},
 	}
@@ -315,54 +314,7 @@ func main() {
 }
 ```
 
-Next we need to setup the runtime to make filesystem APIs available, we do this by calling `__wasm_call_ctors()` exported method in a WASM `_initialize` hook.
-
-```go
-package main
-
-import (
-	"os"
-
-	"github.com/extism/go-pdk"
-)
-
-//export __wasm_call_ctors
-func __wasm_call_ctors()
-
-//export _initialize
-func _initialize() {
-	__wasm_call_ctors()
-}
-
-//export write_file
-func writeFile() int32 {
-	input := pdk.Input()
-
-	err := pluginMain("/mnt/wasm.txt", input)
-
-	if err != nil {
-		pdk.Log(pdk.LogTrace, err.Error())
-		return 1
-	}
-
-	return 0
-}
-
-func pluginMain(filename string, data []byte) error {
-	pdk.Log(pdk.LogInfo, "Writing following data to disk: "+string(data))
-
-	// Write to the file, will be created if it doesn't exist
-	err := os.WriteFile(filename, data, 0644)
-	if err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func main() {}
-
-```
+> *Note*: In order for filesystem APIs to work the plugin needs to be compiled with WASI target. Source code for the plugin can be found [here](https://github.com/extism/go-pdk/blob/main/example/fs/main.go) and is written in Go, but it could be written in any of our PDK languages.
 
 ## Build example plugins