120 lines
3.7 KiB
Go
120 lines
3.7 KiB
Go
// Copyright 2016 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package pubsub
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import (
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"fmt"
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"math"
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"strings"
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pb "google.golang.org/genproto/googleapis/pubsub/v1"
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"google.golang.org/grpc/codes"
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"google.golang.org/grpc/status"
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)
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// maxPayload is the maximum number of bytes to devote to actual ids in
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// acknowledgement or modifyAckDeadline requests. A serialized
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// AcknowledgeRequest proto has a small constant overhead, plus the size of the
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// subscription name, plus 3 bytes per ID (a tag byte and two size bytes). A
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// ModifyAckDeadlineRequest has an additional few bytes for the deadline. We
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// don't know the subscription name here, so we just assume the size exclusive
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// of ids is 100 bytes.
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//
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// With gRPC there is no way for the client to know the server's max message size (it is
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// configurable on the server). We know from experience that it
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// it 512K.
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const (
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maxPayload = 512 * 1024
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reqFixedOverhead = 100
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overheadPerID = 3
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maxSendRecvBytes = 20 * 1024 * 1024 // 20M
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)
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func convertMessages(rms []*pb.ReceivedMessage) ([]*Message, error) {
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msgs := make([]*Message, 0, len(rms))
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for i, m := range rms {
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msg, err := toMessage(m)
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if err != nil {
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return nil, fmt.Errorf("pubsub: cannot decode the retrieved message at index: %d, message: %+v", i, m)
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}
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msgs = append(msgs, msg)
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}
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return msgs, nil
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}
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func trunc32(i int64) int32 {
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if i > math.MaxInt32 {
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i = math.MaxInt32
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}
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return int32(i)
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}
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// Logic from https://github.com/GoogleCloudPlatform/google-cloud-java/blob/master/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/StatusUtil.java.
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func isRetryable(err error) bool {
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s, ok := status.FromError(err)
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if !ok { // includes io.EOF, normal stream close, which causes us to reopen
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return true
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}
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switch s.Code() {
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case codes.DeadlineExceeded, codes.Internal, codes.Canceled, codes.ResourceExhausted:
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return true
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case codes.Unavailable:
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return !strings.Contains(s.Message(), "Server shutdownNow invoked")
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default:
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return false
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}
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}
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// Split req into a prefix that is smaller than maxSize, and a remainder.
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func splitRequest(req *pb.StreamingPullRequest, maxSize int) (prefix, remainder *pb.StreamingPullRequest) {
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const int32Bytes = 4
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// Copy all fields before splitting the variable-sized ones.
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remainder = &pb.StreamingPullRequest{}
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*remainder = *req
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// Split message so it isn't too big.
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size := reqFixedOverhead
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i := 0
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for size < maxSize && (i < len(req.AckIds) || i < len(req.ModifyDeadlineAckIds)) {
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if i < len(req.AckIds) {
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size += overheadPerID + len(req.AckIds[i])
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}
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if i < len(req.ModifyDeadlineAckIds) {
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size += overheadPerID + len(req.ModifyDeadlineAckIds[i]) + int32Bytes
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}
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i++
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}
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min := func(a, b int) int {
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if a < b {
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return a
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}
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return b
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}
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j := i
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if size > maxSize {
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j--
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}
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k := min(j, len(req.AckIds))
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remainder.AckIds = req.AckIds[k:]
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req.AckIds = req.AckIds[:k]
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k = min(j, len(req.ModifyDeadlineAckIds))
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remainder.ModifyDeadlineAckIds = req.ModifyDeadlineAckIds[k:]
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remainder.ModifyDeadlineSeconds = req.ModifyDeadlineSeconds[k:]
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req.ModifyDeadlineAckIds = req.ModifyDeadlineAckIds[:k]
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req.ModifyDeadlineSeconds = req.ModifyDeadlineSeconds[:k]
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return req, remainder
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}
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