package metrics import ( "fmt" "sync" "github.com/prometheus/client_golang/prometheus" ) type Labels map[string]string // NewNamespace returns a namespaces that is responsible for managing a collection of // metrics for a particual namespace and subsystem // // labels allows const labels to be added to all metrics created in this namespace // and are commonly used for data like application version and git commit func NewNamespace(name, subsystem string, labels Labels) *Namespace { if labels == nil { labels = make(map[string]string) } return &Namespace{ name: name, subsystem: subsystem, labels: labels, } } // Namespace describes a set of metrics that share a namespace and subsystem. type Namespace struct { name string subsystem string labels Labels mu sync.Mutex metrics []prometheus.Collector } // WithConstLabels returns a namespace with the provided set of labels merged // with the existing constant labels on the namespace. // // Only metrics created with the returned namespace will get the new constant // labels. The returned namespace must be registered separately. func (n *Namespace) WithConstLabels(labels Labels) *Namespace { n.mu.Lock() ns := &Namespace{ name: n.name, subsystem: n.subsystem, labels: mergeLabels(n.labels, labels), } n.mu.Unlock() return ns } func (n *Namespace) NewCounter(name, help string) Counter { c := &counter{pc: prometheus.NewCounter(n.newCounterOpts(name, help))} n.Add(c) return c } func (n *Namespace) NewLabeledCounter(name, help string, labels ...string) LabeledCounter { c := &labeledCounter{pc: prometheus.NewCounterVec(n.newCounterOpts(name, help), labels)} n.Add(c) return c } func (n *Namespace) newCounterOpts(name, help string) prometheus.CounterOpts { return prometheus.CounterOpts{ Namespace: n.name, Subsystem: n.subsystem, Name: makeName(name, Total), Help: help, ConstLabels: prometheus.Labels(n.labels), } } func (n *Namespace) NewTimer(name, help string) Timer { t := &timer{ m: prometheus.NewHistogram(n.newTimerOpts(name, help)), } n.Add(t) return t } func (n *Namespace) NewLabeledTimer(name, help string, labels ...string) LabeledTimer { t := &labeledTimer{ m: prometheus.NewHistogramVec(n.newTimerOpts(name, help), labels), } n.Add(t) return t } func (n *Namespace) newTimerOpts(name, help string) prometheus.HistogramOpts { return prometheus.HistogramOpts{ Namespace: n.name, Subsystem: n.subsystem, Name: makeName(name, Seconds), Help: help, ConstLabels: prometheus.Labels(n.labels), } } func (n *Namespace) NewGauge(name, help string, unit Unit) Gauge { g := &gauge{ pg: prometheus.NewGauge(n.newGaugeOpts(name, help, unit)), } n.Add(g) return g } func (n *Namespace) NewLabeledGauge(name, help string, unit Unit, labels ...string) LabeledGauge { g := &labeledGauge{ pg: prometheus.NewGaugeVec(n.newGaugeOpts(name, help, unit), labels), } n.Add(g) return g } func (n *Namespace) newGaugeOpts(name, help string, unit Unit) prometheus.GaugeOpts { return prometheus.GaugeOpts{ Namespace: n.name, Subsystem: n.subsystem, Name: makeName(name, unit), Help: help, ConstLabels: prometheus.Labels(n.labels), } } func (n *Namespace) Describe(ch chan<- *prometheus.Desc) { n.mu.Lock() defer n.mu.Unlock() for _, metric := range n.metrics { metric.Describe(ch) } } func (n *Namespace) Collect(ch chan<- prometheus.Metric) { n.mu.Lock() defer n.mu.Unlock() for _, metric := range n.metrics { metric.Collect(ch) } } func (n *Namespace) Add(collector prometheus.Collector) { n.mu.Lock() n.metrics = append(n.metrics, collector) n.mu.Unlock() } func (n *Namespace) NewDesc(name, help string, unit Unit, labels ...string) *prometheus.Desc { name = makeName(name, unit) namespace := n.name if n.subsystem != "" { namespace = fmt.Sprintf("%s_%s", namespace, n.subsystem) } name = fmt.Sprintf("%s_%s", namespace, name) return prometheus.NewDesc(name, help, labels, prometheus.Labels(n.labels)) } // mergeLabels merges two or more labels objects into a single map, favoring // the later labels. func mergeLabels(lbs ...Labels) Labels { merged := make(Labels) for _, target := range lbs { for k, v := range target { merged[k] = v } } return merged } func makeName(name string, unit Unit) string { if unit == "" { return name } return fmt.Sprintf("%s_%s", name, unit) }