7c9314f231
* swarm: propagate ctx, enable opentracing * swarm/tracing: log error when tracing is misconfigured
47 lines
1.3 KiB
Go
47 lines
1.3 KiB
Go
// Copyright (c) 2017 Uber Technologies, Inc.
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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 utils
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import (
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"math/rand"
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"sync"
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)
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// lockedSource allows a random number generator to be used by multiple goroutines concurrently.
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// The code is very similar to math/rand.lockedSource, which is unfortunately not exposed.
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type lockedSource struct {
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mut sync.Mutex
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src rand.Source
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}
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// NewRand returns a rand.Rand that is threadsafe.
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func NewRand(seed int64) *rand.Rand {
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return rand.New(&lockedSource{src: rand.NewSource(seed)})
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}
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func (r *lockedSource) Int63() (n int64) {
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r.mut.Lock()
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n = r.src.Int63()
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r.mut.Unlock()
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return
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}
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// Seed implements Seed() of Source
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func (r *lockedSource) Seed(seed int64) {
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r.mut.Lock()
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r.src.Seed(seed)
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r.mut.Unlock()
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}
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