a1dc1f56a0
Currently, we have custom code in wapc-go because our library forces a failure when a module that uses WASI doesn't define a "_start" function. Using the same pragmatism that resulted in us not enforcing the WASI table, this makes the "_start" function optional. This doesn't add a flag as the spec is not a proper version anyway (snapshot-01), so there's no need to further complicate configuration. If a "_start" function exists, we enforce it is of the proper signature and succeeds. Otherwise, we allow it to be absent. Signed-off-by: Adrian Cole <adrian@tetrate.io> Co-authored-by: Takeshi Yoneda <takeshi@tetrate.io>
94 lines
2.6 KiB
Go
94 lines
2.6 KiB
Go
package wazero
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import (
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"bytes"
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"context"
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_ "embed"
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"testing"
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"github.com/stretchr/testify/require"
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"github.com/tetratelabs/wazero/wasm"
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)
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// TestStartWASICommand_DoesntEnforce_Start ensures wapc-go work when modules import WASI, but don't export "_start".
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func TestStartWASICommand_DoesntEnforce_Start(t *testing.T) {
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r := NewRuntime()
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wasi, err := r.InstantiateModule(WASISnapshotPreview1())
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require.NoError(t, err)
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defer wasi.Close()
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// Start the module as a WASI command. This will fail if the context wasn't as intended.
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mod, err := StartWASICommandFromSource(r, []byte(`(module $wasi_test.go
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(memory 1)
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(export "memory" (memory 0))
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)`))
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require.NoError(t, err)
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require.NoError(t, mod.Close())
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}
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func TestStartWASICommand_UsesRuntimeContext(t *testing.T) {
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type key string
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config := NewRuntimeConfig().WithContext(context.WithValue(context.Background(), key("wa"), "zero"))
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r := NewRuntimeWithConfig(config)
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// Define a function that will be re-exported as the WASI function: _start
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var calledStart bool
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start := func(ctx wasm.Module) {
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calledStart = true
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require.Equal(t, config.ctx, ctx.Context())
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}
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host, err := r.NewModuleBuilder("").ExportFunction("start", start).Instantiate()
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require.NoError(t, err)
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defer host.Close()
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wasi, err := r.InstantiateModule(WASISnapshotPreview1())
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require.NoError(t, err)
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defer wasi.Close()
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// Start the module as a WASI command. This will fail if the context wasn't as intended.
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mod, err := StartWASICommandFromSource(r, []byte(`(module $wasi_test.go
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(import "" "start" (func $start))
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(memory 1)
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(export "_start" (func $start))
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(export "memory" (memory 0))
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)`))
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require.NoError(t, err)
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defer mod.Close()
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require.True(t, calledStart)
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}
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// wasiArg was compiled from examples/testdata/wasi_arg.wat
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//go:embed examples/testdata/wasi_arg.wasm
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var wasiArg []byte
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func TestStartWASICommandWithConfig(t *testing.T) {
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r := NewRuntime()
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stdout := bytes.NewBuffer(nil)
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// Configure WASI to write stdout to a buffer, so that we can verify it later.
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sys := NewSysConfig().WithStdout(stdout)
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wasi, err := r.InstantiateModule(WASISnapshotPreview1())
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require.NoError(t, err)
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defer wasi.Close()
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m, err := r.CompileModule(wasiArg)
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require.NoError(t, err)
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// Re-use the same module many times.
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for _, tc := range []string{"a", "b", "c"} {
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mod, err := StartWASICommandWithConfig(r, m.WithName(tc), sys.WithArgs(tc))
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require.NoError(t, err)
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// Ensure the scoped configuration applied. As the args are null-terminated, we append zero (NUL).
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require.Equal(t, append([]byte(tc), 0), stdout.Bytes())
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stdout.Reset()
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require.NoError(t, mod.Close())
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}
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}
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