53 lines
1.6 KiB
Go
53 lines
1.6 KiB
Go
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// Copyright 2019, OpenCensus Authors
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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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//
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package tag
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const (
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// valueTTLNoPropagation prevents tag from propagating.
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valueTTLNoPropagation = 0
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// valueTTLUnlimitedPropagation allows tag to propagate without any limits on number of hops.
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valueTTLUnlimitedPropagation = -1
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)
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// TTL is metadata that specifies number of hops a tag can propagate.
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// Details about TTL metadata is specified at https://github.com/census-instrumentation/opencensus-specs/blob/master/tags/TagMap.md#tagmetadata
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type TTL struct {
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ttl int
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}
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var (
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// TTLUnlimitedPropagation is TTL metadata that allows tag to propagate without any limits on number of hops.
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TTLUnlimitedPropagation = TTL{ttl: valueTTLUnlimitedPropagation}
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// TTLNoPropagation is TTL metadata that prevents tag from propagating.
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TTLNoPropagation = TTL{ttl: valueTTLNoPropagation}
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)
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type metadatas struct {
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ttl TTL
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}
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// Metadata applies metadatas specified by the function.
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type Metadata func(*metadatas)
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// WithTTL applies metadata with provided ttl.
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func WithTTL(ttl TTL) Metadata {
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return func(m *metadatas) {
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m.ttl = ttl
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}
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}
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