113 lines
3.4 KiB
Go
113 lines
3.4 KiB
Go
// Copyright 2013 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 extraction
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import (
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"io"
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"time"
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"github.com/prometheus/client_golang/model"
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)
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// ProcessOptions dictates how the interpreted stream should be rendered for
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// consumption.
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type ProcessOptions struct {
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// Timestamp is added to each value interpreted from the stream.
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Timestamp time.Time
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// BaseLabels are labels that are accumulated onto each sample, if any.
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BaseLabels model.LabelSet
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}
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// Processor is responsible for decoding the actual message responses from
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// stream into a format that can be consumed with the end result written
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// to the results channel.
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type Processor interface {
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// ProcessSingle treats the input as a single self-contained message body and
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// transforms it accordingly. It has no support for streaming.
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ProcessSingle(in io.Reader, out chan<- *Result, o *ProcessOptions) error
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}
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// Helper function to convert map[string]string into LabelSet.
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//
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// NOTE: This should be deleted when support for go 1.0.3 is removed; 1.1 is
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// smart enough to unmarshal JSON objects into LabelSet directly.
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func labelSet(labels map[string]string) model.LabelSet {
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labelset := make(model.LabelSet, len(labels))
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for k, v := range labels {
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labelset[model.LabelName(k)] = model.LabelValue(v)
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}
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return labelset
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}
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// Helper function to merge a target's base labels ontop of the labels of an
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// exported sample. If a label is already defined in the exported sample, we
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// assume that we are scraping an intermediate exporter and attach
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// "exporter_"-prefixes to Prometheus' own base labels.
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func mergeTargetLabels(entityLabels, targetLabels model.LabelSet) model.LabelSet {
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if targetLabels == nil {
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targetLabels = model.LabelSet{}
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}
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result := model.LabelSet{}
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for label, value := range entityLabels {
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result[label] = value
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}
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for label, labelValue := range targetLabels {
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if _, exists := result[label]; exists {
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result[model.ExporterLabelPrefix+label] = labelValue
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} else {
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result[label] = labelValue
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}
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}
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return result
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}
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// Result encapsulates the outcome from processing samples from a source.
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type Result struct {
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Err error
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Samples model.Samples
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}
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// A basic interface only useful in testing contexts for dispensing the time
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// in a controlled manner.
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type instantProvider interface {
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// The current instant.
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Now() time.Time
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}
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// Clock is a simple means for fluently wrapping around standard Go timekeeping
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// mechanisms to enhance testability without compromising code readability.
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//
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// It is sufficient for use on bare initialization. A provider should be
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// set only for test contexts. When not provided, it emits the current
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// system time.
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type clock struct {
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// The underlying means through which time is provided, if supplied.
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Provider instantProvider
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}
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// Emit the current instant.
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func (t *clock) Now() time.Time {
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if t.Provider == nil {
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return time.Now()
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}
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return t.Provider.Now()
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}
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