feat: add new Go bindings to perform HTTP requests

docs/docs/languages/go.md

@@ -21,7 +21,7 @@ In this example, the worker will get a request and print all the related informa
 1. Add the Wasm Workers Server Go dependency
 
     ```
-    go get -u github.com/vmware-labs/wasm-workers-server/kits/go/worker
+    go get -u github.com/vmware-labs/wasm-workers-server/kits/go/worker@v1.3.0
     ```
 
 1. Create a `worker.go` file with the following contents:
@@ -142,7 +142,7 @@ To add a KV store to your worker, follow these steps:
 1. Add the Wasm Workers Server Go dependency
 
     ```
-    go get -u github.com/vmware-labs/wasm-workers-server/kits/go/worker
+    go get -u github.com/vmware-labs/wasm-workers-server/kits/go/worker@v1.3.0
     ```
 
 1. Create a `worker-kv.go` file with the following contents:

examples/go-basic/go.mod

@@ -0,0 +1,12 @@
+module go-basic
+
+go 1.20
+
+require github.com/vmware-labs/wasm-workers-server v1.3.0
+
+require (
+	github.com/tidwall/gjson v1.14.4 // indirect
+	github.com/tidwall/match v1.1.1 // indirect
+	github.com/tidwall/pretty v1.2.1 // indirect
+	github.com/tidwall/sjson v1.2.5 // indirect
+)

examples/go-basic/go.sum

@@ -0,0 +1,12 @@
+github.com/tidwall/gjson v1.14.2/go.mod h1:/wbyibRr2FHMks5tjHJ5F8dMZh3AcwJEMf5vlfC0lxk=
+github.com/tidwall/gjson v1.14.4 h1:uo0p8EbA09J7RQaflQ1aBRffTR7xedD2bcIVSYxLnkM=
+github.com/tidwall/gjson v1.14.4/go.mod h1:/wbyibRr2FHMks5tjHJ5F8dMZh3AcwJEMf5vlfC0lxk=
+github.com/tidwall/match v1.1.1 h1:+Ho715JplO36QYgwN9PGYNhgZvoUSc9X2c80KVTi+GA=
+github.com/tidwall/match v1.1.1/go.mod h1:eRSPERbgtNPcGhD8UCthc6PmLEQXEWd3PRB5JTxsfmM=
+github.com/tidwall/pretty v1.2.0/go.mod h1:ITEVvHYasfjBbM0u2Pg8T2nJnzm8xPwvNhhsoaGGjNU=
+github.com/tidwall/pretty v1.2.1 h1:qjsOFOWWQl+N3RsoF5/ssm1pHmJJwhjlSbZ51I6wMl4=
+github.com/tidwall/pretty v1.2.1/go.mod h1:ITEVvHYasfjBbM0u2Pg8T2nJnzm8xPwvNhhsoaGGjNU=
+github.com/tidwall/sjson v1.2.5 h1:kLy8mja+1c9jlljvWTlSazM7cKDRfJuR/bOJhcY5NcY=
+github.com/tidwall/sjson v1.2.5/go.mod h1:Fvgq9kS/6ociJEDnK0Fk1cpYF4FIW6ZF7LAe+6jwd28=
+github.com/vmware-labs/wasm-workers-server v1.3.0 h1:Sm+Ycp327kRIaQIlWDXjKUITnCsaZaEqUDnPQZGPrKk=
+github.com/vmware-labs/wasm-workers-server v1.3.0/go.mod h1:cigUhoitjUTLsUzR4+q0cz2FymdvJtfrfIS2hYAj69c=

examples/go-fetch/README.md

@@ -0,0 +1,31 @@
+# Go fetch example
+
+Compile a Go worker to WebAssembly and run it in Wasm Workers Server. It performs a POST call to the [JSON placeholder API](https://jsonplaceholder.typicode.com/).
+
+## Prerequisites
+
+* Wasm Workers Server (wws):
+
+  ```shell-session
+  curl -fsSL https://workers.wasmlabs.dev/install | bash
+  ```
+
+* [Go](https://go.dev/)
+* [TinyGo](https://tinygo.org/getting-started/install/)
+
+## Build
+
+```shell-session
+tinygo build -o index.wasm -target wasi main.go
+```
+
+## Run
+
+```shell-session
+wws .
+```
+
+## Resources
+
+* [Go documentation](https://workers.wasmlabs.dev/docs/languages/go)
+* [Announcing Go support for Wasm Workers Server](https://wasmlabs.dev/articles/go-support-on-wasm-workers-server/)

examples/go-fetch/go.mod

@@ -0,0 +1,15 @@
+module go-basic
+
+go 1.20
+
+require github.com/vmware-labs/wasm-workers-server v1.3.0
+
+require (
+	github.com/tidwall/gjson v1.14.4 // indirect
+	github.com/tidwall/match v1.1.1 // indirect
+	github.com/tidwall/pretty v1.2.1 // indirect
+	github.com/tidwall/sjson v1.2.5 // indirect
+)
+
+replace github.com/vmware-labs/wasm-workers-server => ../../
+replace github.com/vmware-labs/wasm-workers-server/kits/go/worker/bindings => ../../kits/go/worker/bindings

examples/go-fetch/go.sum

@@ -0,0 +1,12 @@
+github.com/tidwall/gjson v1.14.2/go.mod h1:/wbyibRr2FHMks5tjHJ5F8dMZh3AcwJEMf5vlfC0lxk=
+github.com/tidwall/gjson v1.14.4 h1:uo0p8EbA09J7RQaflQ1aBRffTR7xedD2bcIVSYxLnkM=
+github.com/tidwall/gjson v1.14.4/go.mod h1:/wbyibRr2FHMks5tjHJ5F8dMZh3AcwJEMf5vlfC0lxk=
+github.com/tidwall/match v1.1.1 h1:+Ho715JplO36QYgwN9PGYNhgZvoUSc9X2c80KVTi+GA=
+github.com/tidwall/match v1.1.1/go.mod h1:eRSPERbgtNPcGhD8UCthc6PmLEQXEWd3PRB5JTxsfmM=
+github.com/tidwall/pretty v1.2.0/go.mod h1:ITEVvHYasfjBbM0u2Pg8T2nJnzm8xPwvNhhsoaGGjNU=
+github.com/tidwall/pretty v1.2.1 h1:qjsOFOWWQl+N3RsoF5/ssm1pHmJJwhjlSbZ51I6wMl4=
+github.com/tidwall/pretty v1.2.1/go.mod h1:ITEVvHYasfjBbM0u2Pg8T2nJnzm8xPwvNhhsoaGGjNU=
+github.com/tidwall/sjson v1.2.5 h1:kLy8mja+1c9jlljvWTlSazM7cKDRfJuR/bOJhcY5NcY=
+github.com/tidwall/sjson v1.2.5/go.mod h1:Fvgq9kS/6ociJEDnK0Fk1cpYF4FIW6ZF7LAe+6jwd28=
+github.com/vmware-labs/wasm-workers-server v1.3.0 h1:Sm+Ycp327kRIaQIlWDXjKUITnCsaZaEqUDnPQZGPrKk=
+github.com/vmware-labs/wasm-workers-server v1.3.0/go.mod h1:cigUhoitjUTLsUzR4+q0cz2FymdvJtfrfIS2hYAj69c=

examples/go-fetch/main.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"bytes"
+	"io"
+	"net/http"
+
+	"github.com/vmware-labs/wasm-workers-server/kits/go/worker"
+
+	"github.com/tidwall/sjson"
+)
+
+func main() {
+	worker.ServeFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Build a JSON body
+		body, _ := sjson.Set("", "title", "New POST!")
+		body, _ = sjson.Set(body, "body", "This is the body")
+		body, _ = sjson.Set(body, "userId", 1)
+
+		url := "https://jsonplaceholder.typicode.com/posts"
+
+		// Create the request
+		req, err := http.NewRequest(http.MethodPost, url, bytes.NewBufferString(body))
+		if err != nil {
+			panic(err)
+		}
+		req.Header.Set("Content-Type", "application/json")
+
+		res, err := worker.SendHttpRequest(req)
+		if err != nil {
+			panic(err)
+		}
+
+		// Read the response
+		resBody, err := io.ReadAll(res.Body)
+		if err != nil {
+			panic(err)
+		}
+		res.Body.Close()
+
+		w.Header().Set("x-generated-by", "wasm-workers-server")
+		w.Write([]byte(resBody))
+	})
+}

kits/go/worker/README.md

@@ -0,0 +1,61 @@
+# Go kit
+
+This folder contains the Go kit or SDK for Wasm Workers Server. Currently, it uses the regular STDIN / STDOUT approach to receive the request and provide the response. In the latest version we introduced the new HTTP bindings to send HTTP requests from inside the worker.
+
+## Bindings
+
+Wasm Workers Server is on the road to adopt Wasm components, but it's not there yet. However, we started adopting WIT to generate the bindings for the different languages.
+
+The host (Wasm Workers Server) and other languages like Rust and JavaScript rely on [wit-bindgen v0.2](https://github.com/bytecodealliance/wit-bindgen/tree/v0.2.0). However, the Go bindings were not available on that version so it caused some extra work to generate the Go bindings.
+
+These are the steps to recreate the current Go bindings:
+
+- Clone the wit-binding repository and checkout to the [35cb45f2](https://github.com/bytecodealliance/wit-bindgen/commit/35cb45f25eb113b54406f269778d46a37716a7c5) commit (between v0.6 - v0.7). This commit produces compatible binding identifiers and fixes an error with the types on the generated C / Go code:
+
+    ```shell-session
+    git clone https://github.com/bytecodealliance/wit-bindgen/tree/main && \
+      git checkout 35cb45f25eb113b54406f269778d46a37716a7c5
+    ```
+
+- Compile the project:
+
+    ```shell-session
+    cargo build --release
+    ```
+
+- Change your current directory to `wasm-workers-server/kits/go/worker/bindings`.
+- Now, you need to use the compiled `wit-bindgen`:
+
+    ```shell-session
+    ~/YOUR_LOCATION/wit-bindgen/target/release/wit-bindgen tiny-go ../../../../wit/go-ephemeral/
+    ```
+
+- Just note that we're using a specific `wit` folder for Go. The reason is that the syntax changed from v0.3. We will consolidate it once we adopt components.
+- Edit the `bindings.c` file to define the `canonical_abi_realloc` and `canonical_abi_free`. wit-bindgen v0.2 expects these methods to be exported. However, the first method was renamed to `cabi_realloc` and the second was removed on v3.0. To fix it, locate the `__attribute__((__weak__, __export_name__("cabi_realloc")))` and replace it with the following two methods:
+
+    ```c
+    __attribute__((__weak__, __export_name__("canonical_abi_realloc"))) void *cabi_realloc(void *ptr, size_t old_size, size_t align, size_t new_size)
+    {
+      if (new_size == 0)
+        return (void *)align;
+      void *ret = realloc(ptr, new_size);
+      if (!ret)
+        abort();
+      return ret;
+    }
+
+    __attribute__((weak, export_name("canonical_abi_free"))) void canonical_abi_free(
+        void *ptr,
+        size_t size,
+        size_t align)
+    {
+      free(ptr);
+    }
+    ```
+
+- Done!
+
+## References
+
+* [Go documentation](https://workers.wasmlabs.dev/docs/languages/go)
+* [Announcing Go Support for Wasm Workers Server](https://wasmlabs.dev/articles/go-support-on-wasm-workers-server/)