Merge pull request #859 from MichaelMure/webui-debug

webui: add a flag to log handling errors

3 files changed, 73 insertions, 2 deletions

diff --git a/api/graphql/graphql_test.go b/api/graphql/graphql_test.go
index 350e489a..2ddfb314 100644
--- a/api/graphql/graphql_test.go
+++ b/api/graphql/graphql_test.go
@@ -22,7 +22,7 @@ func TestQueries(t *testing.T) {
 	_, err := mrc.RegisterDefaultRepository(repo)
 	require.NoError(t, err)
 
-	handler := NewHandler(mrc)
+	handler := NewHandler(mrc, nil)
 
 	c := client.New(handler)
 
diff --git a/api/graphql/handler.go b/api/graphql/handler.go
index 00141f01..1d30bf72 100644
--- a/api/graphql/handler.go
+++ b/api/graphql/handler.go
@@ -20,11 +20,15 @@ type Handler struct {
 	io.Closer
 }
 
-func NewHandler(mrc *cache.MultiRepoCache) Handler {
+func NewHandler(mrc *cache.MultiRepoCache, errorOut io.Writer) Handler {
 	rootResolver := resolvers.NewRootResolver(mrc)
 	config := graph.Config{Resolvers: rootResolver}
 	h := handler.NewDefaultServer(graph.NewExecutableSchema(config))
 
+	if errorOut != nil {
+		h.Use(&Tracer{Out: errorOut})
+	}
+
 	return Handler{
 		Handler: h,
 		Closer:  rootResolver,
diff --git a/api/graphql/tracer.go b/api/graphql/tracer.go
new file mode 100644
index 00000000..11448a3a
--- /dev/null
+++ b/api/graphql/tracer.go
@@ -0,0 +1,67 @@
+package graphql
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/99designs/gqlgen/graphql"
+
+	"github.com/MichaelMure/git-bug/util/colors"
+)
+
+// adapted from https://github.com/99designs/gqlgen/blob/master/graphql/handler/debug/tracer.go
+
+type Tracer struct {
+	Out io.Writer
+}
+
+var _ interface {
+	graphql.HandlerExtension
+	graphql.ResponseInterceptor
+} = &Tracer{}
+
+func (a Tracer) ExtensionName() string {
+	return "error tracer"
+}
+
+func (a *Tracer) Validate(schema graphql.ExecutableSchema) error {
+	return nil
+}
+
+func stringify(value interface{}) string {
+	valueJson, err := json.MarshalIndent(value, "  ", "  ")
+	if err == nil {
+		return string(valueJson)
+	}
+
+	return fmt.Sprint(value)
+}
+
+func (a Tracer) InterceptResponse(ctx context.Context, next graphql.ResponseHandler) *graphql.Response {
+	resp := next(ctx)
+
+	if len(resp.Errors) == 0 {
+		return resp
+	}
+
+	rctx := graphql.GetOperationContext(ctx)
+
+	_, _ = fmt.Fprintln(a.Out, "GraphQL Request {")
+	for _, line := range strings.Split(rctx.RawQuery, "\n") {
+		_, _ = fmt.Fprintln(a.Out, " ", colors.Cyan(line))
+	}
+	for name, value := range rctx.Variables {
+		_, _ = fmt.Fprintf(a.Out, "  var %s = %s\n", name, colors.Yellow(stringify(value)))
+	}
+
+	_, _ = fmt.Fprintln(a.Out, "  resp:", colors.Green(stringify(resp)))
+	for _, err := range resp.Errors {
+		_, _ = fmt.Fprintln(a.Out, "  error:", colors.Bold(err.Path.String()+":"), colors.Red(err.Message))
+	}
+	_, _ = fmt.Fprintln(a.Out, "}")
+	_, _ = fmt.Fprintln(a.Out)
+	return resp
+}