feat: Allow setting JSON type schema max depth (#1844)

#### Summary

#1819 fixed it for the gRPC message, but it seems our backend [can't handle](https://github.com/cloudquery/cloudquery-private/actions/runs/10164552583/job/28110217028#step:13:10) the size of the Stripe `tables.json` (see https://stackoverflow.com/questions/59209884/cloud-run-request-limit).
With the current default max depth of 4 it's ~40MB.
Setting it to 3 lowers it to ~11MB.

---

Author: erezrokah

transformers/options.go

@@ -68,3 +68,10 @@ func WithPrimaryKeyComponents(fields ...string) StructTransformerOption {
 		t.pkComponentFields = fields
 	}
 }
+
+// WithMaxJSONTypeSchemaDepth allows to specify the maximum depth of JSON type schema
+func WithMaxJSONTypeSchemaDepth(maxDepth int) StructTransformerOption {
+	return func(t *structTransformer) {
+		t.maxJSONTypeSchemaDepth = maxDepth
+	}
+}

transformers/struct.go

@@ -14,7 +14,7 @@ import (
 	"github.com/thoas/go-funk"
 )
 
-const maxJSONTypeSchemaDepth = 4
+const DefaultMaxJSONTypeSchemaDepth = 4
 
 type structTransformer struct {
 	table                         *schema.Table
@@ -29,6 +29,8 @@ type structTransformer struct {
 	pkFieldsFound                 []string
 	pkComponentFields             []string
 	pkComponentFieldsFound        []string
+
+	maxJSONTypeSchemaDepth int
 }
 
 func isFieldStruct(reflectType reflect.Type) bool {
@@ -196,6 +198,7 @@ func TransformWithStruct(st any, opts ...StructTransformerOption) schema.Transfo
 		typeTransformer:          DefaultTypeTransformer,
 		resolverTransformer:      DefaultResolverTransformer,
 		ignoreInTestsTransformer: DefaultIgnoreInTestsTransformer,
+		maxJSONTypeSchemaDepth:   DefaultMaxJSONTypeSchemaDepth,
 	}
 	for _, opt := range opts {
 		opt(t)
@@ -294,7 +297,7 @@ func (t *structTransformer) fieldToJSONSchema(field reflect.StructField, depth i
 				continue
 			}
 			// Avoid infinite recursion
-			if columnType == types.ExtensionTypes.JSON && depth < maxJSONTypeSchemaDepth {
+			if columnType == types.ExtensionTypes.JSON && depth < t.maxJSONTypeSchemaDepth {
 				fieldsMap[name] = t.fieldToJSONSchema(structField, depth+1)
 				continue
 			}

transformers/struct_test.go

@@ -486,6 +486,7 @@ func TestJSONTypeSchema(t *testing.T) {
 	tests := []struct {
 		name       string
 		testStruct any
+		maxDepth   int
 		want       map[string]string
 	}{
 		{
@@ -625,6 +626,30 @@ func TestJSONTypeSchema(t *testing.T) {
 				"level0": `{"level1":{"level2":{"level3":{"level4":{"level5":"json"}}}}}`,
 			},
 		},
+		{
+			name:     "stops at the configured depth",
+			maxDepth: 2,
+			testStruct: struct {
+				Level0 struct {
+					Level1 struct {
+						Level2 struct {
+							Level3 struct {
+								Level4 struct {
+									Level5 struct {
+										Level6 struct {
+											Name string `json:"name"`
+										} `json:"level6"`
+									} `json:"level5"`
+								} `json:"level4"`
+							} `json:"level3"`
+						} `json:"level2"`
+					} `json:"level1"`
+				} `json:"level0"`
+			}{},
+			want: map[string]string{
+				"level0": `{"level1":{"level2":{"level3":"json"}}}`,
+			},
+		},
 		{
 			name: "ignores non exported and ignored types",
 			testStruct: struct {
@@ -648,7 +673,11 @@ func TestJSONTypeSchema(t *testing.T) {
 			table := schema.Table{
 				Name: "test",
 			}
-			transformer := TransformWithStruct(tt.testStruct)
+			opts := []StructTransformerOption{}
+			if tt.maxDepth > 0 {
+				opts = append(opts, WithMaxJSONTypeSchemaDepth(tt.maxDepth))
+			}
+			transformer := TransformWithStruct(tt.testStruct, opts...)
 			err := transformer(&table)
 			if err != nil {
 				t.Fatal(err)