03bfa31928
This removes tedium in our examples and docs by using `Runtime.Close` instead of tracking everything. Internal tests still track too much, but anyway at least this stops suggesting others should do it. This also changes our examples to use log.PanicXX so that the line number goes into the console output. Signed-off-by: Adrian Cole <adrian@tetrate.io>
61 lines
1.6 KiB
Go
61 lines
1.6 KiB
Go
package wasi
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import (
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"context"
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"fmt"
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"log"
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"os"
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"github.com/tetratelabs/wazero"
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"github.com/tetratelabs/wazero/sys"
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)
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// This is an example of how to use WebAssembly System Interface (WASI) with its simplest function: "proc_exit".
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//
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// See https://github.com/tetratelabs/wazero/tree/main/examples/wasi for another example.
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func Example() {
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// Choose the context to use for function calls.
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ctx := context.Background()
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// Create a new WebAssembly Runtime.
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r := wazero.NewRuntime()
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// Instantiate WASI, which implements system I/O such as console output.
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wm, err := InstantiateSnapshotPreview1(ctx, r)
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if err != nil {
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log.Panicln(err)
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}
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defer wm.Close(testCtx)
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// Compile the WebAssembly module using the default configuration.
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code, err := r.CompileModule(ctx, []byte(`
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(module
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(import "wasi_snapshot_preview1" "proc_exit" (func $wasi.proc_exit (param $rval i32)))
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(func $main
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i32.const 2 ;; push $rval onto the stack
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call $wasi.proc_exit ;; return a sys.ExitError to the caller
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)
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(export "_start" (func $main))
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)
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`), wazero.NewCompileConfig())
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if err != nil {
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log.Panicln(err)
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}
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defer code.Close(ctx)
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// InstantiateModule runs the "_start" function which is like a "main" function.
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// Override default configuration (which discards stdout).
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mod, err := r.InstantiateModule(ctx, code, wazero.NewModuleConfig().WithStdout(os.Stdout).WithName("wasi-demo"))
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if mod != nil {
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defer mod.Close(ctx)
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}
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// Print the exit code
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if exitErr, ok := err.(*sys.ExitError); ok {
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fmt.Printf("exit_code: %d\n", exitErr.ExitCode())
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}
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// Output:
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// exit_code: 2
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}
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