/
subscriptiontracker.go
78 lines (68 loc) · 2.71 KB
/
subscriptiontracker.go
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// Licensed to the Apache Software Foundation (ASF) under one or more
// contributor license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright ownership.
// The ASF licenses this file to You 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 nativepubsubio
// The SubscriptionRTracker maintains a single entry string to keep up with
// the PubSub subscription being used in the NativeRead SDF.
type SubscriptionRTracker struct {
Subscription string
Done bool
}
// NewSubscriptionRTracker returns an RTracker wrapping the
// provided subscription and a "Done" boolean.
func NewSubscriptionRTracker(entry string) *SubscriptionRTracker {
return &SubscriptionRTracker{Subscription: entry, Done: false}
}
// TryClaim returns true iff the given position is a string and matches the underlying
// subscription ID.
func (s *SubscriptionRTracker) TryClaim(pos interface{}) bool {
posString, ok := pos.(string)
return ok && posString == s.Subscription
}
// TrySplit is a no-op for the StaticRTracker in the normal case and moves the subscription
// to the residual in the checkpointing case, marking itself as done to keep the logical checks
// around SDF data loss happy.
func (s *SubscriptionRTracker) TrySplit(frac float64) (primary, residual interface{}, err error) {
if frac == 0.0 {
resid := s.Subscription
s.Subscription = ""
s.Done = true
return "", resid, nil
}
return s.Subscription, "", nil
}
// GetError is a no-op.
func (s *SubscriptionRTracker) GetError() error {
return nil
}
// GetProgress returns complete just so the runner doesn't try to do much in the way of
// splitting.
func (s *SubscriptionRTracker) GetProgress() (done float64, remaining float64) {
done = 1.0
remaining = 0.0
return
}
// IsDone returns whether or not the StaticRTracker is complete (e.g. has stopped processing.)
func (s *SubscriptionRTracker) IsDone() bool {
return s.Done
}
// IsBounded always returns false, as the StaticRTracker represents an unbounded number
// of reads from PubSub.
func (s *SubscriptionRTracker) IsBounded() bool {
return false
}
// GetRestriction returns the name of the subscription.
func (s *SubscriptionRTracker) GetRestriction() interface{} {
return s.Subscription
}