mirror of
https://github.com/octoleo/restic.git
synced 2024-11-16 01:57:10 +00:00
116 lines
3.1 KiB
Go
116 lines
3.1 KiB
Go
// Copyright 2018 Google Inc. All Rights Reserved.
|
|
//
|
|
// 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 firestore
|
|
|
|
import (
|
|
"io"
|
|
"time"
|
|
|
|
gax "github.com/googleapis/gax-go"
|
|
"golang.org/x/net/context"
|
|
pb "google.golang.org/genproto/googleapis/firestore/v1beta1"
|
|
"google.golang.org/grpc/codes"
|
|
"google.golang.org/grpc/status"
|
|
)
|
|
|
|
// Implementation of realtime updates (a.k.a. watch).
|
|
// This code is closely based on the Node.js implementation,
|
|
// https://github.com/googleapis/nodejs-firestore/blob/master/src/watch.js.
|
|
|
|
var defaultBackoff = gax.Backoff{
|
|
// Values from https://github.com/googleapis/nodejs-firestore/blob/master/src/backoff.js.
|
|
Initial: 1 * time.Second,
|
|
Max: 60 * time.Second,
|
|
Multiplier: 1.5,
|
|
}
|
|
|
|
type watchStream struct {
|
|
ctx context.Context
|
|
c *Client
|
|
target *pb.Target // document or query being watched
|
|
lc pb.Firestore_ListenClient
|
|
backoff gax.Backoff
|
|
}
|
|
|
|
func newWatchStream(ctx context.Context, c *Client, target *pb.Target) *watchStream {
|
|
return &watchStream{
|
|
ctx: ctx,
|
|
c: c,
|
|
target: target,
|
|
backoff: defaultBackoff,
|
|
}
|
|
}
|
|
|
|
// recv receives the next message from the stream. It also handles opening the stream
|
|
// initially, and reopening it on non-permanent errors.
|
|
// recv doesn't have to be goroutine-safe.
|
|
func (s *watchStream) recv() (*pb.ListenResponse, error) {
|
|
var err error
|
|
for {
|
|
if s.lc == nil {
|
|
s.lc, err = s.open()
|
|
if err != nil {
|
|
// Do not retry if open fails.
|
|
return nil, err
|
|
}
|
|
}
|
|
res, err := s.lc.Recv()
|
|
if err == nil || isPermanentWatchError(err) {
|
|
return res, err
|
|
}
|
|
// Non-permanent error. Sleep and retry.
|
|
// TODO: from node:
|
|
// request.addTarget.resumeToken = resumeToken;
|
|
// changeMap.clear();
|
|
dur := s.backoff.Pause()
|
|
// If we're out of quota, wait a long time before retrying.
|
|
if status.Code(err) == codes.ResourceExhausted {
|
|
dur = s.backoff.Max
|
|
}
|
|
if err := gax.Sleep(s.ctx, dur); err != nil {
|
|
return nil, err
|
|
}
|
|
s.lc = nil
|
|
}
|
|
}
|
|
|
|
func (s *watchStream) open() (pb.Firestore_ListenClient, error) {
|
|
lc, err := s.c.c.Listen(s.ctx)
|
|
if err == nil {
|
|
err = lc.Send(&pb.ListenRequest{
|
|
Database: s.c.path(),
|
|
TargetChange: &pb.ListenRequest_AddTarget{AddTarget: s.target},
|
|
})
|
|
}
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return lc, nil
|
|
}
|
|
|
|
func isPermanentWatchError(err error) bool {
|
|
if err == io.EOF {
|
|
// Retry on normal end-of-stream.
|
|
return false
|
|
}
|
|
switch status.Code(err) {
|
|
case codes.Canceled, codes.Unknown, codes.DeadlineExceeded, codes.ResourceExhausted,
|
|
codes.Internal, codes.Unavailable, codes.Unauthenticated:
|
|
return false
|
|
default:
|
|
return true
|
|
}
|
|
}
|