From ed8bc523fd0d1a66acf3fa449c453508035efdfc Mon Sep 17 00:00:00 2001 From: Kevin Lyda Date: Sun, 12 Feb 2017 14:38:12 +0000 Subject: Initial pass at prometheus support. (#56) --- .../prometheus/client_golang/prometheus/desc.go | 200 +++++++++++++++++++++ 1 file changed, 200 insertions(+) create mode 100644 vendor/github.com/prometheus/client_golang/prometheus/desc.go (limited to 'vendor/github.com/prometheus/client_golang/prometheus/desc.go') diff --git a/vendor/github.com/prometheus/client_golang/prometheus/desc.go b/vendor/github.com/prometheus/client_golang/prometheus/desc.go new file mode 100644 index 0000000..1835b16 --- /dev/null +++ b/vendor/github.com/prometheus/client_golang/prometheus/desc.go @@ -0,0 +1,200 @@ +// Copyright 2016 The Prometheus Authors +// Licensed 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 prometheus + +import ( + "errors" + "fmt" + "sort" + "strings" + + "github.com/golang/protobuf/proto" + "github.com/prometheus/common/model" + + dto "github.com/prometheus/client_model/go" +) + +// reservedLabelPrefix is a prefix which is not legal in user-supplied +// label names. +const reservedLabelPrefix = "__" + +// Labels represents a collection of label name -> value mappings. This type is +// commonly used with the With(Labels) and GetMetricWith(Labels) methods of +// metric vector Collectors, e.g.: +// myVec.With(Labels{"code": "404", "method": "GET"}).Add(42) +// +// The other use-case is the specification of constant label pairs in Opts or to +// create a Desc. +type Labels map[string]string + +// Desc is the descriptor used by every Prometheus Metric. It is essentially +// the immutable meta-data of a Metric. The normal Metric implementations +// included in this package manage their Desc under the hood. Users only have to +// deal with Desc if they use advanced features like the ExpvarCollector or +// custom Collectors and Metrics. +// +// Descriptors registered with the same registry have to fulfill certain +// consistency and uniqueness criteria if they share the same fully-qualified +// name: They must have the same help string and the same label names (aka label +// dimensions) in each, constLabels and variableLabels, but they must differ in +// the values of the constLabels. +// +// Descriptors that share the same fully-qualified names and the same label +// values of their constLabels are considered equal. +// +// Use NewDesc to create new Desc instances. +type Desc struct { + // fqName has been built from Namespace, Subsystem, and Name. + fqName string + // help provides some helpful information about this metric. + help string + // constLabelPairs contains precalculated DTO label pairs based on + // the constant labels. + constLabelPairs []*dto.LabelPair + // VariableLabels contains names of labels for which the metric + // maintains variable values. + variableLabels []string + // id is a hash of the values of the ConstLabels and fqName. This + // must be unique among all registered descriptors and can therefore be + // used as an identifier of the descriptor. + id uint64 + // dimHash is a hash of the label names (preset and variable) and the + // Help string. Each Desc with the same fqName must have the same + // dimHash. + dimHash uint64 + // err is an error that occurred during construction. It is reported on + // registration time. + err error +} + +// NewDesc allocates and initializes a new Desc. Errors are recorded in the Desc +// and will be reported on registration time. variableLabels and constLabels can +// be nil if no such labels should be set. fqName and help must not be empty. +// +// variableLabels only contain the label names. Their label values are variable +// and therefore not part of the Desc. (They are managed within the Metric.) +// +// For constLabels, the label values are constant. Therefore, they are fully +// specified in the Desc. See the Opts documentation for the implications of +// constant labels. +func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *Desc { + d := &Desc{ + fqName: fqName, + help: help, + variableLabels: variableLabels, + } + if help == "" { + d.err = errors.New("empty help string") + return d + } + if !model.IsValidMetricName(model.LabelValue(fqName)) { + d.err = fmt.Errorf("%q is not a valid metric name", fqName) + return d + } + // labelValues contains the label values of const labels (in order of + // their sorted label names) plus the fqName (at position 0). + labelValues := make([]string, 1, len(constLabels)+1) + labelValues[0] = fqName + labelNames := make([]string, 0, len(constLabels)+len(variableLabels)) + labelNameSet := map[string]struct{}{} + // First add only the const label names and sort them... + for labelName := range constLabels { + if !checkLabelName(labelName) { + d.err = fmt.Errorf("%q is not a valid label name", labelName) + return d + } + labelNames = append(labelNames, labelName) + labelNameSet[labelName] = struct{}{} + } + sort.Strings(labelNames) + // ... so that we can now add const label values in the order of their names. + for _, labelName := range labelNames { + labelValues = append(labelValues, constLabels[labelName]) + } + // Now add the variable label names, but prefix them with something that + // cannot be in a regular label name. That prevents matching the label + // dimension with a different mix between preset and variable labels. + for _, labelName := range variableLabels { + if !checkLabelName(labelName) { + d.err = fmt.Errorf("%q is not a valid label name", labelName) + return d + } + labelNames = append(labelNames, "$"+labelName) + labelNameSet[labelName] = struct{}{} + } + if len(labelNames) != len(labelNameSet) { + d.err = errors.New("duplicate label names") + return d + } + vh := hashNew() + for _, val := range labelValues { + vh = hashAdd(vh, val) + vh = hashAddByte(vh, separatorByte) + } + d.id = vh + // Sort labelNames so that order doesn't matter for the hash. + sort.Strings(labelNames) + // Now hash together (in this order) the help string and the sorted + // label names. + lh := hashNew() + lh = hashAdd(lh, help) + lh = hashAddByte(lh, separatorByte) + for _, labelName := range labelNames { + lh = hashAdd(lh, labelName) + lh = hashAddByte(lh, separatorByte) + } + d.dimHash = lh + + d.constLabelPairs = make([]*dto.LabelPair, 0, len(constLabels)) + for n, v := range constLabels { + d.constLabelPairs = append(d.constLabelPairs, &dto.LabelPair{ + Name: proto.String(n), + Value: proto.String(v), + }) + } + sort.Sort(LabelPairSorter(d.constLabelPairs)) + return d +} + +// NewInvalidDesc returns an invalid descriptor, i.e. a descriptor with the +// provided error set. If a collector returning such a descriptor is registered, +// registration will fail with the provided error. NewInvalidDesc can be used by +// a Collector to signal inability to describe itself. +func NewInvalidDesc(err error) *Desc { + return &Desc{ + err: err, + } +} + +func (d *Desc) String() string { + lpStrings := make([]string, 0, len(d.constLabelPairs)) + for _, lp := range d.constLabelPairs { + lpStrings = append( + lpStrings, + fmt.Sprintf("%s=%q", lp.GetName(), lp.GetValue()), + ) + } + return fmt.Sprintf( + "Desc{fqName: %q, help: %q, constLabels: {%s}, variableLabels: %v}", + d.fqName, + d.help, + strings.Join(lpStrings, ","), + d.variableLabels, + ) +} + +func checkLabelName(l string) bool { + return model.LabelName(l).IsValid() && + !strings.HasPrefix(l, reservedLabelPrefix) +} -- cgit v1.2.3