Google Cloud Storage (GCS) debug options

sample.go

import (
	"context"
	"fmt"
	"io"
	"net/http"
	"path"
	"strings"
	"time"

	"cloud.google.com/go/storage"
	"github.com/AlexAkulov/clickhouse-backup/config"
	"github.com/apex/log"
	"google.golang.org/api/iterator"
	"google.golang.org/api/option"
	"google.golang.org/api/option/internaloption"
	googleHTTPTransport "google.golang.org/api/transport/http"
)

// GCS - presents methods for manipulate data on GCS
type GCS struct {
	client *storage.Client
	Config *config.GCSConfig
	buffer []byte
}

type debugGCSTransport struct {
	base http.RoundTripper
}

func (w debugGCSTransport) RoundTrip (r *http.Request) (*http.Response, error) {
	log.Info("=======================================")
	log.Info("[GCS_REQUEST]")
	log.Infof("%v %v", r.Method, r.URL.String())
	for h, values := range r.Header {
		for _, v := range values {
			log.Infof("%v: %v", h, v)
		}
	}
	resp, err := w.base.RoundTrip(r)
	log.Info("[GCS_RESPONSE]")
	if err != nil {
		log.Errorf("GCS_ERROR: %v", err)
		return resp, err
	}
	for h, values := range resp.Header {
		for _, v := range values {
			log.Infof("%v: %v", h, v)
		}
	}
	return resp, err
}

// Connect - connect to GCS
func (gcs *GCS) Connect() error {
	var err error
	clientOptions := make([]option.ClientOption, 0)
	gcs.buffer = make([]byte, 4*1024*1024)
	ctx := context.Background()

	if gcs.Config.CredentialsJSON != "" {
		clientOptions = append(clientOptions, option.WithCredentialsJSON([]byte(gcs.Config.CredentialsJSON)))
	} else if gcs.Config.CredentialsFile != "" {
		clientOptions = append(clientOptions, option.WithCredentialsFile(gcs.Config.CredentialsFile))
	}

	if gcs.Config.Debug {
		clientOptions = append([]option.ClientOption{option.WithScopes(storage.ScopeFullControl)}, clientOptions...)

		clientOptions = append(clientOptions, internaloption.WithDefaultEndpoint("https://storage.googleapis.com/storage/v1/"))
		clientOptions = append(clientOptions, internaloption.WithDefaultMTLSEndpoint("https://storage.mtls.googleapis.com/storage/v1/"))

		debugClient, _, err := googleHTTPTransport.NewClient(ctx, clientOptions...)
		if err !=nil {
			return fmt.Errorf("googleHTTPTransport.NewClient error: %v", err)
		}
		debugClient.Transport = debugGCSTransport{base: debugClient.Transport}
		clientOptions = append(clientOptions, option.WithHTTPClient(debugClient))
	}

	gcs.client, err = storage.NewClient(ctx, clientOptions...)
	return err
}