Merge #24

24: feat(go-wasmer) New package to get CLI support r=Hywan a=Hywan Partially address #17. 1. `go install github.com/wasmerio/go-ext-wasm/go-wasmer` 2. `go-wasmer call nbody.wasm main 10` Co-authored-by: Ivan Enderlin <[email protected]>
wasmerio · Jun 3, 2019 · 1b8bfc0 · 1b8bfc0
2 parents b3baaf4 + f7bbf67
commit 1b8bfc0
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diff --git a/README.md b/README.md
@@ -22,12 +22,17 @@ Wasmer is a Go library for executing WebAssembly binaries.
 To install the library, follow the classical:
 
 ```sh
-$ CGO_ENABLED=1 go install github.com/wasmerio/go-ext-wasm/wasmer
+$ go get github.com/wasmerio/go-ext-wasm/wasmer
 ```
 
-The `CGO_ENABLED` part is very likely to be optional. `go install`
-will work on many macOS and Linux distributions. It will not work on
-Windows yet, we are working on it.
+To install the `go-wasmer` CLI, follow the classical:
+
+```sh
+$ go install github.com/wasmerio/go-ext-wasm/go-wasmer
+```
+
+`go install` will work on many macOS and Linux distributions. It will
+not work on Windows yet, we are working on it.
 
 # Documentation
 

diff --git a/go-wasmer/main.go b/go-wasmer/main.go
@@ -0,0 +1,81 @@
+package main
+
+import (
+	"fmt"
+	"github.com/urfave/cli"
+	wasm "github.com/wasmerio/go-ext-wasm/wasmer"
+	"log"
+	"os"
+	"strconv"
+)
+
+func main() {
+	app := cli.NewApp()
+	app.Name = "go-wasmer"
+	app.Usage = "Run WebAssembly binaries."
+	app.Version = "0.1.0"
+
+	app.Commands = []cli.Command{
+		{
+			Name:    "call",
+			Aliases: []string{},
+			Usage:   "Call a WebAssembly exported function with arguments: <wasm-file> <function-name> <arguments...>",
+			Action: func(c *cli.Context) error {
+				if c.NArg() < 2 {
+					return cli.NewExitError(fmt.Sprintf("`call` expects at least 2 arguments: <wasm-file> and <function-name>; given %d.", c.NArg()), 1)
+				}
+
+				arguments := c.Args()
+				wasmFile := arguments[0]
+				functionName := arguments[1]
+				functionArguments := arguments[2:]
+
+				bytes, err := wasm.ReadBytes(wasmFile)
+
+				if err != nil {
+					return cli.NewExitError(fmt.Sprintf("`call` — Failed to read bytes from `%s`: %s.", wasmFile, err), 2)
+				}
+
+				instance, err := wasm.NewInstance(bytes)
+
+				if err != nil {
+					return cli.NewExitError(fmt.Sprintf("`call` — Failed to instantiate `%s`: %s.", wasmFile, err), 3)
+				}
+
+				exportedFunction, exists := instance.Exports[functionName]
+
+				if !exists {
+					return cli.NewExitError(fmt.Sprintf("`call` — Exported function `%s` does not exist on the WebAssembly module `%s`.", functionName, wasmFile), 4)
+				}
+
+				exportedFunctionArguments := make([]interface{}, len(functionArguments))
+
+				for nth, functionArgument := range functionArguments {
+					parsed, err := strconv.ParseInt(functionArgument, 10, 32)
+
+					if err != nil {
+						return cli.NewExitError(fmt.Sprintf("`call` — Failed to parse the #%d argument `%s` of the exported function `%s` of the WebAssembly module `%s`: %s.", nth+1, functionArgument, functionName, wasmFile, err), 5)
+					}
+
+					exportedFunctionArguments[nth] = (int32)(parsed)
+				}
+
+				result, err := exportedFunction(exportedFunctionArguments...)
+
+				if err != nil {
+					return cli.NewExitError(fmt.Sprintf("`call` — Exported function `%s` of the WebAssembly module `%s` failed: %s.", functionName, wasmFile, err), 6)
+				}
+
+				fmt.Println(result)
+
+				return nil
+			},
+		},
+	}
+
+	err := app.Run(os.Args)
+
+	if err != nil {
+		log.Fatal(err)
+	}
+}
diff --git a/go.mod b/go.mod
@@ -2,4 +2,7 @@ module github.com/wasmerio/go-ext-wasm
 
 go 1.12
 
-require github.com/stretchr/testify v1.3.0
+require (
+	github.com/stretchr/testify v1.3.0
+	github.com/urfave/cli v1.20.0
+)
diff --git a/go.sum b/go.sum
@@ -5,3 +5,5 @@ github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZN
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/urfave/cli v1.20.0 h1:fDqGv3UG/4jbVl/QkFwEdddtEDjh/5Ov6X+0B/3bPaw=
+github.com/urfave/cli v1.20.0/go.mod h1:70zkFmudgCuE/ngEzBv17Jvp/497gISqfk5gWijbERA=
diff --git a/justfile b/justfile
@@ -1,4 +1,4 @@
-# Compile the library.
+# Build the `wasmer` library.
 build go-build-args='-v':
 	#!/usr/bin/env bash
 	set -euo pipefail
@@ -19,6 +19,10 @@ build go-build-args='-v':
 	fi
 	go build {{go-build-args}} .
 
+# Build the `go-wasmer` bin.
+build-bin go-build-args='-v':
+	cd go-wasmer && go build {{go-build-args}} -o ../target/go/go-wasmer .
+
 # Compile the Rust part for this specific system.
 rust:
 	cargo build --release