initial commit

Signed-off-by: Derek McQuay <derekmcquay@gmail.com>

vendor/cloud.google.com/go/pubsub/service.go

@@ -0,0 +1,120 @@
+// Copyright 2016 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 pubsub
+
+import (
+	"fmt"
+	"math"
+	"strings"
+
+	pb "google.golang.org/genproto/googleapis/pubsub/v1"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+// maxPayload is the maximum number of bytes to devote to actual ids in
+// acknowledgement or modifyAckDeadline requests. A serialized
+// AcknowledgeRequest proto has a small constant overhead, plus the size of the
+// subscription name, plus 3 bytes per ID (a tag byte and two size bytes). A
+// ModifyAckDeadlineRequest has an additional few bytes for the deadline. We
+// don't know the subscription name here, so we just assume the size exclusive
+// of ids is 100 bytes.
+//
+// With gRPC there is no way for the client to know the server's max message size (it is
+// configurable on the server). We know from experience that it
+// it 512K.
+const (
+	maxPayload       = 512 * 1024
+	reqFixedOverhead = 100
+	overheadPerID    = 3
+	maxSendRecvBytes = 20 * 1024 * 1024 // 20M
+)
+
+func convertMessages(rms []*pb.ReceivedMessage) ([]*Message, error) {
+	msgs := make([]*Message, 0, len(rms))
+	for i, m := range rms {
+		msg, err := toMessage(m)
+		if err != nil {
+			return nil, fmt.Errorf("pubsub: cannot decode the retrieved message at index: %d, message: %+v", i, m)
+		}
+		msgs = append(msgs, msg)
+	}
+	return msgs, nil
+}
+
+func trunc32(i int64) int32 {
+	if i > math.MaxInt32 {
+		i = math.MaxInt32
+	}
+	return int32(i)
+}
+
+// Logic from https://github.com/GoogleCloudPlatform/google-cloud-java/blob/master/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/StatusUtil.java.
+func isRetryable(err error) bool {
+	s, ok := status.FromError(err)
+	if !ok { // includes io.EOF, normal stream close, which causes us to reopen
+		return true
+	}
+	switch s.Code() {
+	case codes.DeadlineExceeded, codes.Internal, codes.Canceled, codes.ResourceExhausted:
+		return true
+	case codes.Unavailable:
+		return !strings.Contains(s.Message(), "Server shutdownNow invoked")
+	default:
+		return false
+	}
+}
+
+// Split req into a prefix that is smaller than maxSize, and a remainder.
+func splitRequest(req *pb.StreamingPullRequest, maxSize int) (prefix, remainder *pb.StreamingPullRequest) {
+	const int32Bytes = 4
+
+	// Copy all fields before splitting the variable-sized ones.
+	remainder = &pb.StreamingPullRequest{}
+	*remainder = *req
+	// Split message so it isn't too big.
+	size := reqFixedOverhead
+	i := 0
+	for size < maxSize && (i < len(req.AckIds) || i < len(req.ModifyDeadlineAckIds)) {
+		if i < len(req.AckIds) {
+			size += overheadPerID + len(req.AckIds[i])
+		}
+		if i < len(req.ModifyDeadlineAckIds) {
+			size += overheadPerID + len(req.ModifyDeadlineAckIds[i]) + int32Bytes
+		}
+		i++
+	}
+
+	min := func(a, b int) int {
+		if a < b {
+			return a
+		}
+		return b
+	}
+
+	j := i
+	if size > maxSize {
+		j--
+	}
+	k := min(j, len(req.AckIds))
+	remainder.AckIds = req.AckIds[k:]
+	req.AckIds = req.AckIds[:k]
+	k = min(j, len(req.ModifyDeadlineAckIds))
+	remainder.ModifyDeadlineAckIds = req.ModifyDeadlineAckIds[k:]
+	remainder.ModifyDeadlineSeconds = req.ModifyDeadlineSeconds[k:]
+	req.ModifyDeadlineAckIds = req.ModifyDeadlineAckIds[:k]
+	req.ModifyDeadlineSeconds = req.ModifyDeadlineSeconds[:k]
+	return req, remainder
+}