analysis/internal/bqutil/json.go

// Copyright 2024 The LUCI Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package bqutil

import (
	"google.golang.org/protobuf/encoding/protojson"
	"google.golang.org/protobuf/types/known/structpb"

	rdbpb "go.chromium.org/luci/resultdb/proto/v1"

	"go.chromium.org/luci/analysis/pbutil"
)

// VariantJSON returns the JSON equivalent for a variant.
// Each key in the variant is mapped to a top-level key in the
// JSON object.
// e.g. `{"builder":"linux-rel","os":"Ubuntu-18.04"}`
func VariantJSON(variant *rdbpb.Variant) (string, error) {
	return pbutil.VariantToJSON(pbutil.VariantFromResultDB(variant))
}

// MarshalStructPB serialises a structpb.Struct as a JSONPB.
func MarshalStructPB(s *structpb.Struct) (string, error) {
	if s == nil {
		// There is no string value we can send to BigQuery that will
		// interpret as a NULL value for a JSON column:
		// - "" (empty string) is rejected as invalid JSON.
		// - "null" is interpreted as the JSON value null, not the
		//   absence of a value.
		// Consequently, the next best thing is to return an empty
		// JSON object.
		return pbutil.EmptyJSON, nil
	}
	// Structs are persisted as JSONPB strings.
	// See also https://bit.ly/chromium-bq-struct
	b, err := (&protojson.MarshalOptions{}).Marshal(s)
	if err != nil {
		return "", err
	}
	return string(b), nil
}