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// Copyright 2015 Google LLC
//
// 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 bigquery
import (
"context"
"fmt"
"io"
"net/http"
"time"
"cloud.google.com/go/internal"
"cloud.google.com/go/internal/version"
gax "github.com/googleapis/gax-go/v2"
bq "google.golang.org/api/bigquery/v2"
"google.golang.org/api/googleapi"
"google.golang.org/api/option"
)
const (
// Scope is the Oauth2 scope for the service.
// For relevant BigQuery scopes, see:
// https://developers.google.com/identity/protocols/googlescopes#bigqueryv2
Scope = "https://www.googleapis.com/auth/bigquery"
userAgentPrefix = "gcloud-golang-bigquery"
)
var xGoogHeader = fmt.Sprintf("gl-go/%s gccl/%s", version.Go(), version.Repo)
func setClientHeader(headers http.Header) {
headers.Set("x-goog-api-client", xGoogHeader)
}
// Client may be used to perform BigQuery operations.
type Client struct {
// Location, if set, will be used as the default location for all subsequent
// dataset creation and job operations. A location specified directly in one of
// those operations will override this value.
Location string
projectID string
bqs *bq.Service
}
// NewClient constructs a new Client which can perform BigQuery operations.
// Operations performed via the client are billed to the specified GCP project.
func NewClient(ctx context.Context, projectID string, opts ...option.ClientOption) (*Client, error) {
o := []option.ClientOption{
option.WithScopes(Scope),
option.WithUserAgent(fmt.Sprintf("%s/%s", userAgentPrefix, version.Repo)),
}
o = append(o, opts...)
bqs, err := bq.NewService(ctx, o...)
if err != nil {
return nil, fmt.Errorf("bigquery: constructing client: %v", err)
}
c := &Client{
projectID: projectID,
bqs: bqs,
}
return c, nil
}
// Close closes any resources held by the client.
// Close should be called when the client is no longer needed.
// It need not be called at program exit.
func (c *Client) Close() error {
return nil
}
// Calls the Jobs.Insert RPC and returns a Job.
func (c *Client) insertJob(ctx context.Context, job *bq.Job, media io.Reader) (*Job, error) {
call := c.bqs.Jobs.Insert(c.projectID, job).Context(ctx)
setClientHeader(call.Header())
if media != nil {
call.Media(media)
}
var res *bq.Job
var err error
invoke := func() error {
res, err = call.Do()
return err
}
// A job with a client-generated ID can be retried; the presence of the
// ID makes the insert operation idempotent.
// We don't retry if there is media, because it is an io.Reader. We'd
// have to read the contents and keep it in memory, and that could be expensive.
// TODO(jba): Look into retrying if media != nil.
if job.JobReference != nil && media == nil {
err = runWithRetry(ctx, invoke)
} else {
err = invoke()
}
if err != nil {
return nil, err
}
return bqToJob(res, c)
}
// Convert a number of milliseconds since the Unix epoch to a time.Time.
// Treat an input of zero specially: convert it to the zero time,
// rather than the start of the epoch.
func unixMillisToTime(m int64) time.Time {
if m == 0 {
return time.Time{}
}
return time.Unix(0, m*1e6)
}
// runWithRetry calls the function until it returns nil or a non-retryable error, or
// the context is done.
// See the similar function in ../storage/invoke.go. The main difference is the
// reason for retrying.
func runWithRetry(ctx context.Context, call func() error) error {
// These parameters match the suggestions in https://cloud.google.com/bigquery/sla.
backoff := gax.Backoff{
Initial: 1 * time.Second,
Max: 32 * time.Second,
Multiplier: 2,
}
return internal.Retry(ctx, backoff, func() (stop bool, err error) {
err = call()
if err == nil {
return true, nil
}
return !retryableError(err), err
})
}
// This is the correct definition of retryable according to the BigQuery team. It
// also considers 502 ("Bad Gateway") and 503 ("Service Unavailable") errors
// retryable; these are returned by systems between the client and the BigQuery
// service.
func retryableError(err error) bool {
e, ok := err.(*googleapi.Error)
if !ok {
return false
}
var reason string
if len(e.Errors) > 0 {
reason = e.Errors[0].Reason
}
return e.Code == http.StatusServiceUnavailable || e.Code == http.StatusBadGateway || reason == "backendError" || reason == "rateLimitExceeded"
}