contrib/gorm.io/gorm.v1: add WithErrorCheck option (#940)

Add a new option to allow filtering out errors.

Closes #915

contrib/gorm.io/gorm.v1/gorm.go

@@ -121,5 +121,9 @@ func after(db *gorm.DB, operationName string, cfg *config) {
 	}
 
 	span, _ := tracer.StartSpanFromContext(ctx, operationName, opts...)
-	span.Finish(tracer.WithError(db.Error))
+	var dbErr error
+	if cfg.errCheck(db.Error) {
+		dbErr = db.Error
+	}
+	span.Finish(tracer.WithError(dbErr))
 }

contrib/gorm.io/gorm.v1/gorm_test.go

@@ -343,3 +343,42 @@ func TestContext(t *testing.T) {
 		assert.Equal(t, testCtx.Value(key(contextKey)), ctx.Value(key(contextKey)))
 	})
 }
+
+func TestError(t *testing.T) {
+	mt := mocktracer.Start()
+	defer mt.Stop()
+
+	assertErrCheck := func(t *testing.T, mt mocktracer.Tracer, errExist bool, opts ...Option) {
+		sqltrace.Register("pgx", &stdlib.Driver{})
+		sqlDb, err := sqltrace.Open("pgx", pgConnString)
+		assert.Nil(t, err)
+
+		db, err := Open(postgres.New(postgres.Config{Conn: sqlDb}), &gorm.Config{}, opts...)
+		assert.Nil(t, err)
+		db.AutoMigrate(&Product{})
+		db.First(&Product{}, Product{Code: "L1210", Price: 2000})
+
+		spans := mt.FinishedSpans()
+		assert.True(t, len(spans) > 1)
+
+		// Get last span (gorm.db)
+		s := spans[len(spans)-1]
+
+		assert.Equal(t, errExist, s.Tag(ext.Error) != nil)
+	}
+
+	t.Run("defaults", func(t *testing.T) {
+		mt := mocktracer.Start()
+		defer mt.Stop()
+		assertErrCheck(t, mt, true)
+	})
+
+	t.Run("errcheck", func(t *testing.T) {
+		mt := mocktracer.Start()
+		defer mt.Stop()
+		errFn := func(err error) bool {
+			return err != gorm.ErrRecordNotFound
+		}
+		assertErrCheck(t, mt, false, WithErrorCheck(errFn))
+	})
+}

contrib/gorm.io/gorm.v1/option.go

@@ -15,6 +15,7 @@ type config struct {
 	serviceName   string
 	analyticsRate float64
 	dsn           string
+	errCheck      func(err error) bool
 }
 
 // Option represents an option that can be passed to Register, Open or OpenDB.
@@ -28,6 +29,7 @@ func defaults(cfg *config) {
 	} else {
 		cfg.analyticsRate = math.NaN()
 	}
+	cfg.errCheck = func(error) bool { return true }
 }
 
 // WithServiceName sets the given service name when registering a driver,
@@ -60,3 +62,12 @@ func WithAnalyticsRate(rate float64) Option {
 		}
 	}
 }
+
+// WithErrorCheck specifies a function fn which determines whether the passed
+// error should be marked as an error. The fn is called whenever a gorm operation
+// finishes
+func WithErrorCheck(fn func(err error) bool) Option {
+	return func(cfg *config) {
+		cfg.errCheck = fn
+	}
+}