feat(dataverse): handle more properly errors

dataverse/client.go

@@ -22,7 +22,8 @@ type client struct {
 
 func NewDataverseClient(ctx context.Context,
 	dataverseClient dvschema.QueryClient,
-	cognitariumClient cgschema.QueryClient) (Client, error) {
+	cognitariumClient cgschema.QueryClient,
+) (Client, error) {
 	cognitariumAddr, err := getCognitariumAddr(ctx, dataverseClient)
 	if err != nil {
 		return nil, fmt.Errorf("failed to get cognitarium address: %w", err)
@@ -69,16 +70,16 @@ func (c *client) GetResourceGovAddr(_ context.Context, resourceDID string) (stri
 	}
 
 	if len(response.Results.Bindings) != 1 {
-		return "", fmt.Errorf("could not find governance code")
+		return "", NewDVError(ErrNoResult, nil)
 	}
 
 	codeBinding, ok := response.Results.Bindings[0]["code"]
 	if !ok {
-		return "", fmt.Errorf("could not find governance code")
+		return "", NewDVError(ErrVarNotFound, nil)
 	}
 	code, ok := codeBinding.ValueType.(cgschema.URI)
 	if !ok {
-		return "", fmt.Errorf("could not decode governance code")
+		return "", NewDVError(ErrType, fmt.Errorf("expected URI, got %T", codeBinding.ValueType))
 	}
 	return string(*code.Value.Full), nil
 }

dataverse/client_test.go

@@ -131,7 +131,7 @@ func TestClient_GetResourceGovAddr(t *testing.T) {
 				},
 			},
 			responseError: nil,
-			wantErr:       fmt.Errorf("could not find governance code"),
+			wantErr:       dataverse.NewDVError(dataverse.ErrVarNotFound, nil),
 			wantResult:    "",
 		},
 		{
@@ -146,7 +146,7 @@ func TestClient_GetResourceGovAddr(t *testing.T) {
 				},
 			},
 			responseError: nil,
-			wantErr:       fmt.Errorf("could not find governance code"),
+			wantErr:       dataverse.NewDVError(dataverse.ErrNoResult, nil),
 			wantResult:    "",
 		},
 		{
@@ -170,7 +170,7 @@ func TestClient_GetResourceGovAddr(t *testing.T) {
 				},
 			},
 			responseError: nil,
-			wantErr:       fmt.Errorf("could not decode governance code"),
+			wantErr:       dataverse.NewDVError(dataverse.ErrType, fmt.Errorf("expected URI, got %T", cgschema.BlankNode{})),
 			wantResult:    "",
 		},
 	}

dataverse/errors.go

@@ -0,0 +1,30 @@
+package dataverse
+
+import "fmt"
+
+type MessageError string
+
+const (
+	ErrNoResult    MessageError = "no result found in binding"
+	ErrVarNotFound MessageError = "variable not found in binding result"
+	ErrType        MessageError = "variable result type mismatch in binding result"
+)
+
+type DVError struct {
+	message MessageError
+	detail  error
+}
+
+func (e *DVError) Error() string {
+	if e.detail == nil {
+		return fmt.Sprintf("%v", e.message)
+	}
+	return fmt.Sprintf("%v: %v", e.message, e.detail)
+}
+
+func NewDVError(message MessageError, detail error) error {
+	return &DVError{
+		message: message,
+		detail:  detail,
+	}
+}