CRE-1841: wasm engine abstraction

pkg/workflows/wasm/host/engine/engine.go

@@ -0,0 +1,79 @@
+package engine
+
+import "fmt"
+
+type EngineType string
+
+const (
+	EngineWasmtime EngineType = "wasmtime"
+	EngineWasm3    EngineType = "wasm3"
+)
+
+type MemoryAccessor interface {
+	Memory() []byte
+}
+
+type LoadConfig struct {
+	InitialFuel uint64
+}
+
+type Engine interface {
+	Load(binary []byte, cfg LoadConfig) (Runtime, error)
+}
+
+type Runtime interface {
+	V2ImportName() string
+	NewStore() Store
+	IncrementEpoch()
+	Close()
+}
+
+type Store interface {
+	SetWasi(argv []string)
+	SetFuel(fuel uint64) error
+	SetLimiter(memoryBytes, tableElements, instances, tables, memories int64)
+	SetEpochDeadline(deadline uint64)
+	LinkNoDAG(exec *Execution) (Instance, error)
+	LinkLegacyDAG(exec *LegacyExecution) (Instance, error)
+	Close()
+}
+
+type Instance interface {
+	CallStart() error
+}
+
+type Execution struct {
+	V2ImportName      string
+	SendResponse      func(caller MemoryAccessor, ptr, ptrlen int32) int32
+	CallCapability    func(caller MemoryAccessor, ptr, ptrlen int32) int64
+	AwaitCapabilities func(caller MemoryAccessor, awaitReq, awaitReqLen, respBuf, maxRespLen int32) int64
+	GetSecrets        func(caller MemoryAccessor, req, reqLen, respBuf, maxRespLen int32) int64
+	AwaitSecrets      func(caller MemoryAccessor, awaitReq, awaitReqLen, respBuf, maxRespLen int32) int64
+	Log               func(caller MemoryAccessor, ptr, ptrlen int32)
+	SwitchModes       func(caller MemoryAccessor, mode int32)
+	RandomSeed        func(mode int32) int64
+	Now               func(caller MemoryAccessor, resultTimestamp int32) int32
+	PollOneoff        func(caller MemoryAccessor, subPtr, evPtr, nSubs, resultNEvents int32) int32
+	ClockTimeGet      func(caller MemoryAccessor, id int32, precision int64, resultTs int32) int32
+}
+
+type LegacyExecution struct {
+	SendResponse func(caller MemoryAccessor, ptr, ptrlen int32) int32
+	Fetch        func(caller MemoryAccessor, respPtr, respLenPtr, reqPtr, reqPtrLen int32) int32
+	Emit         func(caller MemoryAccessor, respPtr, respLenPtr, msgPtr, msgLen int32) int32
+	Log          func(caller MemoryAccessor, ptr, ptrlen int32)
+	PollOneoff   func(caller MemoryAccessor, subPtr, evPtr, nSubs, resultNEvents int32) int32
+	ClockTimeGet func(caller MemoryAccessor, id int32, precision int64, resultTs int32) int32
+	RandomGet    func(caller MemoryAccessor, buf, bufLen int32) int32 // nil when determinism is disabled
+}
+
+func NewEngine(engineType EngineType) (Engine, error) {
+	switch engineType {
+	case EngineWasmtime:
+		return &wasmtimeEngine{}, nil
+	case EngineWasm3:
+		return newWasm3Engine()
+	default:
+		return nil, fmt.Errorf("unsupported engine type: %q", engineType)
+	}
+}

pkg/workflows/wasm/host/engine/wasm3.go

@@ -0,0 +1,15 @@
+//go:build wasm3
+
+package engine
+
+import "fmt"
+
+func newWasm3Engine() (Engine, error) {
+	return &wasm3Engine{}, nil
+}
+
+type wasm3Engine struct{}
+
+func (e *wasm3Engine) Load(binary []byte, cfg LoadConfig) (Runtime, error) {
+	return nil, fmt.Errorf("wasm3 engine: not yet implemented")
+}

pkg/workflows/wasm/host/engine/wasm3_stub.go

@@ -0,0 +1,9 @@
+//go:build !wasm3
+
+package engine
+
+import "fmt"
+
+func newWasm3Engine() (Engine, error) {
+	return nil, fmt.Errorf("wasm3 engine not available: build with -tags wasm3")
+}