103 lines
3.4 KiB
Go
103 lines
3.4 KiB
Go
// Copyright 2014 Prometheus Team
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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 local
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import (
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"io"
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clientmodel "github.com/prometheus/client_golang/model"
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"github.com/prometheus/prometheus/storage/metric"
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)
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// chunks is just a chunk slice. No methods are defined for this named type.
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// TODO: Perhaps we should remove it? It might avoid errors if it's
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// syntactically clear that we are dealing with a vanilly slice and not some
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// kind of more complex collection.
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type chunks []chunk
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// chunk is the interface for all chunks. Chunks are generally not
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// goroutine-safe.
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type chunk interface {
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// add adds a SamplePair to the chunks, performs any necessary
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// re-encoding, and adds any necessary overflow chunks. It returns the
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// new version of the original chunk, followed by overflow chunks, if
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// any. The first chunk returned might be the same as the original one
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// or a newly allocated version. In any case, take the returned chunk as
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// the relevant one and discard the orginal chunk.
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add(*metric.SamplePair) chunks
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clone() chunk
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firstTime() clientmodel.Timestamp
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lastTime() clientmodel.Timestamp
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newIterator() chunkIterator
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marshal(io.Writer) error
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unmarshal(io.Reader) error
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// values returns a channel, from which all sample values in the chunk
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// can be received in order. The channel is closed after the last
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// one. It is generally not safe to mutate the chunk while the channel
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// is still open.
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values() <-chan *metric.SamplePair
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}
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// A chunkIterator enables efficient access to the content of a chunk. It is
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// generally not safe to use a chunkIterator concurrently with or after chunk
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// mutation.
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type chunkIterator interface {
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// Gets the two values that are immediately adjacent to a given time. In
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// case a value exist at precisely the given time, only that single
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// value is returned. Only the first or last value is returned (as a
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// single value), if the given time is before or after the first or last
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// value, respectively.
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getValueAtTime(clientmodel.Timestamp) metric.Values
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// Gets all values contained within a given interval.
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getRangeValues(metric.Interval) metric.Values
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// Whether a given timestamp is contained between first and last value
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// in the chunk.
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contains(clientmodel.Timestamp) bool
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}
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func transcodeAndAdd(dst chunk, src chunk, s *metric.SamplePair) chunks {
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numTranscodes.Inc()
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head := dst
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body := chunks{}
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for v := range src.values() {
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newChunks := head.add(v)
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body = append(body, newChunks[:len(newChunks)-1]...)
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head = newChunks[len(newChunks)-1]
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}
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newChunks := head.add(s)
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body = append(body, newChunks[:len(newChunks)-1]...)
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head = newChunks[len(newChunks)-1]
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return append(body, head)
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}
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func chunkType(c chunk) byte {
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switch c.(type) {
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case *deltaEncodedChunk:
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return 0
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default:
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panic("unknown chunk type")
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}
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}
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func chunkForType(chunkType byte) chunk {
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switch chunkType {
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case 0:
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return newDeltaEncodedChunk(d1, d0, true)
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default:
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panic("unknown chunk type")
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}
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}
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