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Wasmtime 是由 bytecodealliance 开源的 WebAssembly 和 WASI 的小型高效运行时。它在 Web 内部运行 WebAssembly 代码,既能够用作命令行实用程序,也能够用作更大应用程序中嵌入的库。
具备以下特点:
轻量级
。Wasmtime 是 WebAssembly 的独立运行时,可依据您的需要进行扩大。它适宜于微型芯片,也能够应用大型服务器。Wasmtime 也能够嵌入简直所有应用程序中。快
。Wasmtime 建设在优化的 Cranelift 代码生成器上,可在运行时疾速生成高质量的机器代码。可配置
。无论您是须要提前预编译 wasm,应用 Lightbeam 疾速生成代码还是在运行时进行解释,Wasmtime 都能满足您执行 wasm 的所有需要。WASI
。Wasmtime 反对一组丰盛的 API,用于通过 WASI 规范与主机环境进行交互。规范
。Wasmtime 通过了官网的 WebAssembly 测试套件,实现了 wasm 的官网 C API,并且还实现了 WebAssembly 的 proposals。Wasmtime 开发人员也始终与 WebAssembly 规范流程密切相关。
目前反对语言:
- Rust – the
["https://crates.io/crates/wasmtime">wasmtime crate](https://zhuanlan.zhihu.com/p/224862650/%3C/code)
- C – the
f="https://bytecodealliance.github.io/wasmtime/c-api/">wasm.h, wasi.h, and wasmtime.h headers
- Python – the
["https://pypi.org/project/wasmtime/">wasmtime PyPI package](https://zhuanlan.zhihu.com/p/224862650/%3C/code)
- .NET – the
["https://www.nuget.org/packages/Wasmtime">Wasmtime NuGet package](https://zhuanlan.zhihu.com/p/224862650/%3C/code)
- Go – the
[wasmtime-go repository](https://zhuanlan.zhihu.com/p/224862650/ht%3C/code%3Etps://pkg.go.dev/github.com/bytecodealliance/wasmtime-go)
装置
在 macos 和 linux 上装置 Wasmtime CLI 非常简单,只需执行以下命令即可:
$ curl https://wasmtime.dev/install.sh -sSf | bash
Windows 或是其余操作系统用户,须要到 GitHub Releases 下载。
因为我的操作系统是 centos,所以可能展示的与您有所不同。我执行装置脚本之后,有如下输入:
curl https://wasmtime.dev/install.sh -sSf | bash
Installing latest version of Wasmtime (dev)
Checking for existing Wasmtime installation
Fetching archive for Linux, version dev
https://github.com/cranestation/wasmtime/releases/download/dev/wasmtime-dev-x86_64-linux.tar.xz
######################################################################## 100.0%
Creating directory layout
Extracting Wasmtime binaries
wasmtime-dev-x86_64-linux/
wasmtime-dev-x86_64-linux/wasmtime
wasmtime-dev-x86_64-linux/LICENSE
wasmtime-dev-x86_64-linux/README.md
Editing user profile (/root/.bashrc)
Warning: Your profile (/root/.bashrc) already mentions Wasmtime and has not been changed.
Finished installation. Open a new terminal to start using Wasmtime!
而后咱们查看以下是否胜利装置了 wasmtime:
# wasmtime
wasmtime 0.19.0
Wasmtime WebAssembly Runtime
USAGE:
wasmtime <SUBCOMMAND>
FLAGS:
-h, --help Prints help information
-V, --version Prints version information
SUBCOMMANDS:
config Controls Wasmtime configuration settings
help Prints this message or the help of the given subcommand(s)
run Runs a WebAssembly module
wasm2obj Translates a WebAssembly module to native object file
wast Runs a WebAssembly test script file
If a subcommand is not provided, the `run` subcommand will be used.
Usage examples:
Running a WebAssembly module with a start function:
wasmtime example.wasm
Passing command line arguments to a WebAssembly module:
wasmtime example.wasm arg1 arg2 arg3
Invoking a specific function (e.g. `add`) in a WebAssembly module:
wasmtime example.wasm --invoke add 1 2
装置结束,咱们接下来 Hello world 搞起。
Demo
Wasmtime 可作为 Go 模块应用。接下来介绍如何将 Wasmtime 增加到您的我的项目中,并提供一些示例阐明能够应用 WebAssembly 模块实现的操作。
确保您正在应用带有模块反对的 Go 1.12 或更高版本。
首先创立一个 go 模块我的项目:
$ mkdir hello-wasm
$ cd hello-wasm
$ go mod init hello-wasm
而后编写 main.go,具体代码如下:
package main
import (
"fmt"
"github.com/bytecodealliance/wasmtime-go"
)
func main() {engine := wasmtime.NewEngine()
// Almost all operations in wasmtime require a contextual `store`
// argument to share, so create that first
store := wasmtime.NewStore(engine)
// Compiling modules requires WebAssembly binary input, but the wasmtime
// package also supports converting the WebAssembly text format to the
// binary format.
wasm, err := wasmtime.Wat2Wasm(`
(module
(import """hello" (func $hello))
(func (export "run")
(call $hello))
)
`)
check(err)
// Once we have our binary `wasm` we can compile that into a `*Module`
// which represents compiled JIT code.
module, err := wasmtime.NewModule(engine, wasm)
check(err)
// Our `hello.wat` file imports one item, so we create that function
// here.
item := wasmtime.WrapFunc(store, func() {fmt.Println("Hello from Go!")
})
// Next up we instantiate a module which is where we link in all our
// imports. We've got one import so we pass that in here.
instance, err := wasmtime.NewInstance(store, module, []*wasmtime.Extern{item.AsExtern()})
check(err)
// After we've instantiated we can lookup our `run` function and call
// it.
run := instance.GetExport("run").Func()
_, err = run.Call()
check(err)
}
func check(e error) {
if e != nil {panic(e)
}
}
最初运行:
$ go run main.go
Hello from Go!
当然当咱们 wasm 模块代码比拟宏大的时候,咱们能够将该代码放到一个以.wat 结尾的文件中。而后应用 NewModuleFromFile 函数,从指定 wat 文件中加载模块代码。
例如:
咱们创立以下 wasm 文本模块,次要导出用于计算两个数字的最大公分母的函数。命名为 gcd.wat。
(module
(func $gcd (param i32 i32) (result i32)
(local i32)
block ;; label = @1
block ;; label = @2
local.get 0
br_if 0 (;@2;)
local.get 1
local.set 2
br 1 (;@1;)
end
loop ;; label = @2
local.get 1
local.get 0
local.tee 2
i32.rem_u
local.set 0
local.get 2
local.set 1
local.get 0
br_if 0 (;@2;)
end
end
local.get 2
)
(export "gcd" (func $gcd))
)
而后批改咱们的 main.go 文件,如下:
package main
import (
"fmt"
"github.com/bytecodealliance/wasmtime-go"
)
func main() {engine := wasmtime.NewEngine()
store := wasmtime.NewStore(engine)
module, err := wasmtime.NewModuleFromFile(engine, "gcd.wat")
check(err)
instance, err := wasmtime.NewInstance(store, module, []*wasmtime.Extern{})
check(err)
gcd := instance.GetExport("gcd").Func()
val, err := gcd.Call(6, 27)
fmt.Printf("gcd(6, 27) = %dn", val.(int32))
check(err)
}
func check(e error) {
if e != nil {panic(e)
}
}
运行 main.go 有如下输入:
$ go run main.go
gcd(6, 27) = 3
结语
其实 wasm 对于 go 的反对并不是特地好。在当前的文章中,咱们应用 rust 语言创立一个 wasm 程序,而后间接应用诸如 wasmtime example.wasm
执行。