feat(wasm): override random_get

pkg/workflows/wasm/host/test/rand/cmd/main.go

@@ -0,0 +1,55 @@
+//go:build wasip1
+
+package main
+
+import (
+ "bytes"
+ "crypto/rand"
+ "errors"
+
+ "github.com/smartcontractkit/chainlink-common/pkg/capabilities/cli/cmd/testdata/fixtures/capabilities/basictrigger"
+ "github.com/smartcontractkit/chainlink-common/pkg/workflows/sdk"
+ "github.com/smartcontractkit/chainlink-common/pkg/workflows/wasm"
+)
+
+func BuildWorkflow(config []byte) *sdk.WorkflowSpecFactory {
+ workflow := sdk.NewWorkflowSpecFactory(
+ sdk.NewWorkflowParams{
+ Name: "tester",
+ Owner: "ryan",
+ },
+ )
+
+ triggerCfg := basictrigger.TriggerConfig{Name: "trigger", Number: 100}
+ trigger := triggerCfg.New(workflow)
+
+ sdk.Compute1[basictrigger.TriggerOutputs, bool](
+ workflow,
+ "transform",
+ sdk.Compute1Inputs[basictrigger.TriggerOutputs]{Arg0: trigger},
+ func(sdk sdk.Runtime, outputs basictrigger.TriggerOutputs) (bool, error) {
+ b := make([]byte, 5)
+ _, err := rand.Read(b)
+ if err != nil {
+ return false, err
+ }
+
+ deterministic := bytes.Compare(b, []byte{0x53, 0x8c, 0x7f, 0x96, 0xb1}) == 0
+
+ if !deterministic {
+ return false, errors.New("expected deterministic output")
+ }
+
+ return deterministic, nil
+ })
+
+ return workflow
+}
+
+func main() {
+
+ runner := wasm.NewRunner()
+ workflow := BuildWorkflow(runner.Config())
+ runner.Run(workflow)
+
+}

pkg/workflows/wasm/host/wasip1.go

@@ -2,7 +2,10 @@ package host
 
 import (
  "encoding/binary"
+ "io"
+ "math/rand"
  "time"
+ "unsafe"
 
  "github.com/bytecodealliance/wasmtime-go/v23"
  "github.com/jonboulle/clockwork"
@@ -41,9 +44,34 @@ func newWasiLinker(engine *wasmtime.Engine) (*wasmtime.Linker, error) {
  return nil, err
  }
 
+ err = linker.FuncWrap(
+ "wasi_snapshot_preview1",
+ "random_get",
+ randomGet,
+ )
+ if err != nil {
+ return nil, err
+ }
+
  return linker, nil
 }
 
+func randomGet(caller *wasmtime.Caller, buf, bufLen int32) int32 {
+ // Get slice of memory for the buffer
+ bufPtr := &buf
+ bufFromPtr := (*[4]byte)(unsafe.Pointer(bufPtr))[:]
+
+ // Fix the random source with a hardcoded seed
+ randSource := rand.New(rand.NewSource(42)) //nolint:gosec
+
+ // Fill the buffer with random bytes
+ if _, err := io.ReadAtLeast(randSource, bufFromPtr, int(bufLen)); err != nil {
+ return ErrnoFault
+ }
+
+ return ErrnoSuccess
+}
+
 const (
  clockIDRealtime = iota
  clockIDMonotonic

pkg/workflows/wasm/host/wasm_test.go

@@ -42,6 +42,8 @@ const (
  envBinaryCmd = "test/env/cmd"
  logBinaryLocation = "test/log/cmd/testmodule.wasm"
  logBinaryCmd = "test/log/cmd"
+ randBinaryLocation = "test/rand/cmd/testmodule.wasm"
+ randBinaryCmd = "test/rand/cmd"
 )
 
 func createTestBinary(outputPath, path string, compress bool, t *testing.T) []byte {
@@ -375,6 +377,33 @@ func TestModule_Sandbox_ReadEnv(t *testing.T) {
  assert.Nil(t, err)
 }
 
+func TestModule_Sandbox_RandRead(t *testing.T) {
+ binary := createTestBinary(randBinaryCmd, randBinaryLocation, true, t)
+
+ m, err := NewModule(&ModuleConfig{Logger: logger.Test(t)}, binary)
+ require.NoError(t, err)
+
+ m.Start()
+
+ req := &wasmpb.Request{
+ Id: uuid.New().String(),
+ Message: &wasmpb.Request_ComputeRequest{
+ ComputeRequest: &wasmpb.ComputeRequest{
+ Request: &capabilitiespb.CapabilityRequest{
+ Inputs: &valuespb.Map{},
+ Config: &valuespb.Map{},
+ Metadata: &capabilitiespb.RequestMetadata{
+ ReferenceId: "transform",
+ },
+ },
+ },
+ },
+ }
+
+ _, err = m.Run(req)
+ assert.Nil(t, err)
+}
+
 type Entry struct {
  Log zapcore.Entry
  Fields []zapcore.Field