fix: add more context to errors

Signed-off-by: Soumil Paranjpay <[email protected]>

transformer/external/wasmtransformer.go

@@ -82,19 +82,19 @@ func (t *WASM) GetConfig() (transformertypes.Transformer, *environment.Environme
 func (t *WASM) DirectoryDetect(dir string) (map[string][]transformertypes.Artifact, error) {
 	vm, err := t.initVm([]string{dir + ":" + dir})
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to initialize WASM VM: %w", err)
 	}
 
 	allocateResult, err := vm.Execute("malloc", int32(len(dir)+1))
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to alloc memory for directory: %w", err)
 	}
 	dirPointer := allocateResult[0].(int32)
 	mod := vm.GetActiveModule()
 	mem := mod.FindMemory("memory")
 	memData, err := mem.GetData(uint(dirPointer), uint(len(dir)+1))
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to load wasm memory region: %w", err)
 	}
 	copy(memData, dir)
 	memData[len(dir)] = 0
@@ -106,19 +106,20 @@ func (t *WASM) DirectoryDetect(dir string) (map[string][]transformertypes.Artifa
 	directoryDetectOutputPointer := directoryDetectOutput[0].(int32)
 	memData, err = mem.GetData(uint(directoryDetectOutputPointer), 8)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to load directoryDetect output: %w", err)
 	}
 	resultPointer := binary.LittleEndian.Uint32(memData[:4])
 	resultLength := binary.LittleEndian.Uint32(memData[4:])
 	memData, err = mem.GetData(uint(resultPointer), uint(resultLength))
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to read directoryDetect output: %w", err)
 	}
-	logrus.Debug(string(memData))
 
 	services := map[string][]transformertypes.Artifact{}
-	// will handles errors
 	err = json.Unmarshal(memData, &services)
+	if err != nil {
+		err = fmt.Errorf("failed to unmarshal directoryDetect output: %w", err)
+	}
 	return services, err
 }
 
@@ -131,7 +132,7 @@ func (t *WASM) Transform(newArtifacts []transformertypes.Artifact, alreadySeenAr
 	data["oldArtifacts"] = alreadySeenArtifacts
 	dataByt, err := json.Marshal(data)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to marshal transform input: %w", err)
 	}
 	dataStr := string(dataByt)
 
@@ -174,33 +175,33 @@ func (t *WASM) Transform(newArtifacts []transformertypes.Artifact, alreadySeenAr
 
 	vm, err := t.initVm(finalPreopens)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to initialize VM (transform): %w", err)
 	}
 
 	allocateResult, err := vm.Execute("malloc", int32(len(dataStr)+1))
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to alloc memory for transform input: %w", err)
 	}
 	dataPointer := allocateResult[0].(int32)
 	mod := vm.GetActiveModule()
 	mem := mod.FindMemory("memory")
 	memData, err := mem.GetData(uint(dataPointer), uint(len(dataStr)+1))
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to load wasm memory region: %w", err)
 	}
 	copy(memData, dataStr)
 	memData[len(dataStr)] = 0
 	transformOutput, err := vm.Execute("transform", dataPointer)
 	transformOutputPointer := transformOutput[0].(int32)
 	memData, err = mem.GetData(uint(transformOutputPointer), 8)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to load transform output: %w", err)
 	}
 	resultPointer := binary.LittleEndian.Uint32(memData[:4])
 	resultLength := binary.LittleEndian.Uint32(memData[4:])
 	memData, err = mem.GetData(uint(resultPointer), uint(resultLength))
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, fmt.Errorf("failed to read transform output: %w", err)
 	}
 	logrus.Debug(string(memData))
 	var output transformertypes.TransformOutput
@@ -227,19 +228,19 @@ func (t *WASM) initVm(preopens []string) (*wasmedge.VM, error) {
 
 	err := vm.LoadWasmFile(filepath.Join(t.Env.GetEnvironmentContext(), t.WASMConfig.WASMModule))
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to load wasm module %s: %w", t.WASMConfig.WASMModule, err)
 	}
 	err = vm.Validate()
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to validate VM: %w", err)
 	}
 	err = vm.Instantiate()
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to instantiate VM: %w", err)
 	}
 	_, err = vm.Execute("_start")
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to execute _start: %w", err)
 	}
 
 	return vm, nil