clearer & simpler API. move out single_label_provider as a separate case
Signed-off-by: Eugene <eugene@amberpixels.io>
This commit is contained in:
Eugene
parent
aa7e203147
commit
80149ab4d4
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@ -53,140 +53,78 @@ func SetPromsafeTag(tag string) {
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promsafeTag = tag
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}
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// labelProviderMarker is a marker interface for enforcing type-safety.
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// With its help we can force our label-related functions to only accept SingleLabelProvider or StructLabelProvider.
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type labelProviderMarker interface {
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marker()
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}
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// SingleLabelProvider is a type used for declaring a single label.
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// When used as labelProviderMarker it provides just a label name.
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// It's meant to be used with single-label metrics only!
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// Use StructLabelProvider for multi-label metrics.
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type SingleLabelProvider string
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var _ labelProviderMarker = SingleLabelProvider("")
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func (s SingleLabelProvider) marker() {
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panic("marker interface method should never be called")
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// labelsProviderMarker is a marker interface for enforcing type-safety of StructLabelProvider.
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type labelsProviderMarker interface {
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labelsProviderMarker()
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}
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// StructLabelProvider should be embedded in any struct that serves as a label provider.
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type StructLabelProvider struct{}
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var _ labelProviderMarker = (*StructLabelProvider)(nil)
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var _ labelsProviderMarker = (*StructLabelProvider)(nil)
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func (s StructLabelProvider) marker() {
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panic("marker interface method should never be called")
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func (s StructLabelProvider) labelsProviderMarker() {
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panic("labelsProviderMarker interface method should never be called")
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}
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// handler is a helper struct that helps us to handle type-safe labels
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// It holds a label name in case if it's the only label (when SingleLabelProvider is used).
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type handler[T labelProviderMarker] struct {
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theOnlyLabelName string
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// newEmptyLabels creates a new empty labels instance of type T
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// It's a bit tricky as we want to support both structs and pointers to structs
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// e.g. &MyLabels{StructLabelProvider} or MyLabels{StructLabelProvider}
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func newEmptyLabels[T labelsProviderMarker]() T {
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var emptyLabels T
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// Let's Support both Structs or Pointer to Structs given as T
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val := reflect.ValueOf(&emptyLabels).Elem()
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if val.Kind() == reflect.Ptr {
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val.Set(reflect.New(val.Type().Elem()))
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}
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func newHandler[T labelProviderMarker](labelProvider T) handler[T] {
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var h handler[T]
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if s, ok := any(labelProvider).(SingleLabelProvider); ok {
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h.theOnlyLabelName = string(s)
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}
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return h
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}
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// extractLabelsWithValues extracts labels names+values from a given labelProviderMarker (SingleLabelProvider or StructLabelProvider)
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func (h handler[T]) extractLabels(labelProvider T) []string {
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if any(labelProvider) == nil {
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return nil
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}
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if s, ok := any(labelProvider).(SingleLabelProvider); ok {
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return []string{string(s)}
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}
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// Here, then, it can be only a struct, that is a parent of StructLabelProvider
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labels := extractLabelFromStruct(labelProvider)
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labelNames := make([]string, 0, len(labels))
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for k := range labels {
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labelNames = append(labelNames, k)
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}
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return labelNames
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}
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// extractLabelsWithValues extracts labels names+values from a given labelProviderMarker (SingleLabelProvider or StructLabelProvider)
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func (h handler[T]) extractLabelsWithValues(labelProvider T) prometheus.Labels {
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if any(labelProvider) == nil {
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return nil
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}
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// TODO: let's handle defaults as well, why not?
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if s, ok := any(labelProvider).(SingleLabelProvider); ok {
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return prometheus.Labels{h.theOnlyLabelName: string(s)}
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}
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// Here, then, it can be only a struct, that is a parent of StructLabelProvider
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return extractLabelFromStruct(labelProvider)
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}
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// extractLabelValues extracts label string values from a given labelProviderMarker (SingleLabelProvider or StructLabelProvider)
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func (h handler[T]) extractLabelValues(labelProvider T) []string {
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m := h.extractLabelsWithValues(labelProvider)
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labelValues := make([]string, 0, len(m))
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for _, v := range m {
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labelValues = append(labelValues, v)
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}
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return labelValues
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return emptyLabels
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}
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// NewCounterVecT creates a new CounterVecT with type-safe labels.
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func NewCounterVecT[T labelProviderMarker](opts prometheus.CounterOpts, labels T) *CounterVecT[T] {
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h := newHandler(labels)
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func NewCounterVecT[T labelsProviderMarker](opts prometheus.CounterOpts) *CounterVecT[T] {
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emptyLabels := newEmptyLabels[T]()
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var inner *prometheus.CounterVec
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if factory != nil {
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inner = factory.NewCounterVec(opts, h.extractLabels(labels))
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inner = factory.NewCounterVec(opts, extractLabelNames(emptyLabels))
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} else {
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inner = prometheus.NewCounterVec(opts, h.extractLabels(labels))
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inner = prometheus.NewCounterVec(opts, extractLabelNames(emptyLabels))
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}
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return &CounterVecT[T]{
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handler: h,
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inner: inner,
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}
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return &CounterVecT[T]{inner: inner}
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}
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// CounterVecT is a wrapper around prometheus.CounterVecT that allows type-safe labels.
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type CounterVecT[T labelProviderMarker] struct {
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handler[T]
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// CounterVecT is a wrapper around prometheus.CounterVec that allows type-safe labels.
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type CounterVecT[T labelsProviderMarker] struct {
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inner *prometheus.CounterVec
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}
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// GetMetricWithLabelValues behaves like prometheus.CounterVec.GetMetricWithLabelValues but with type-safe labels.
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func (c *CounterVecT[T]) GetMetricWithLabelValues(labels T) (prometheus.Counter, error) {
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return c.inner.GetMetricWithLabelValues(c.handler.extractLabelValues(labels)...)
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return c.inner.GetMetricWithLabelValues(extractLabelValues(labels)...)
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}
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// GetMetricWith behaves like prometheus.CounterVec.GetMetricWith but with type-safe labels.
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func (c *CounterVecT[T]) GetMetricWith(labels T) (prometheus.Counter, error) {
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return c.inner.GetMetricWith(c.handler.extractLabelsWithValues(labels))
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return c.inner.GetMetricWith(extractLabelsWithValues(labels))
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}
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// WithLabelValues behaves like prometheus.CounterVec.WithLabelValues but with type-safe labels.
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func (c *CounterVecT[T]) WithLabelValues(labels T) prometheus.Counter {
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return c.inner.WithLabelValues(c.handler.extractLabelValues(labels)...)
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return c.inner.WithLabelValues(extractLabelValues(labels)...)
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}
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// With behaves like prometheus.CounterVec.With but with type-safe labels.
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func (c *CounterVecT[T]) With(labels T) prometheus.Counter {
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return c.inner.With(c.handler.extractLabelsWithValues(labels))
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return c.inner.With(extractLabelsWithValues(labels))
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}
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// CurryWith behaves like prometheus.CounterVec.CurryWith but with type-safe labels.
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// It still returns a CounterVecT, but it's inner prometheus.CounterVec is curried.
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func (c *CounterVecT[T]) CurryWith(labels T) (*CounterVecT[T], error) {
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curriedInner, err := c.inner.CurryWith(c.handler.extractLabelsWithValues(labels))
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curriedInner, err := c.inner.CurryWith(extractLabelsWithValues(labels))
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if err != nil {
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return nil, err
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}
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@ -197,7 +135,7 @@ func (c *CounterVecT[T]) CurryWith(labels T) (*CounterVecT[T], error) {
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// MustCurryWith behaves like prometheus.CounterVec.MustCurryWith but with type-safe labels.
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// It still returns a CounterVecT, but it's inner prometheus.CounterVec is curried.
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func (c *CounterVecT[T]) MustCurryWith(labels T) *CounterVecT[T] {
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c.inner = c.inner.MustCurryWith(c.handler.extractLabelsWithValues(labels))
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c.inner = c.inner.MustCurryWith(extractLabelsWithValues(labels))
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return c
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}
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@ -221,24 +159,110 @@ func NewCounterFuncT(opts prometheus.CounterOpts, function func() float64) prome
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return prometheus.NewCounterFunc(opts, function)
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}
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//
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// Shorthand for Metrics with a single label
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//
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// singleLabelProviderMarker is a marker interface for enforcing type-safety of SingleLabelProvider.
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type singleLabelProviderMarker interface {
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singleLabelProviderMarker()
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}
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// SingleLabelProvider is a type used for declaring a single label only.
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// When declaring a metric it's values used as a label name
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// When calling With() it's values used as a label value
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type SingleLabelProvider string
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var _ singleLabelProviderMarker = SingleLabelProvider("")
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func (s SingleLabelProvider) singleLabelProviderMarker() {
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panic("singleLabelProviderMarker interface method should never be called")
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}
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// NewCounterVecT1 creates a new CounterVecT with the only single label
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func NewCounterVecT1(opts prometheus.CounterOpts, singleLabelProvider singleLabelProviderMarker) *CounterVecT1 {
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// labelName is the string itself
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// and singleLabelProviderMarker here can ONLY be SingleLabelProvider
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labelName := string(singleLabelProvider.(SingleLabelProvider))
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var inner *prometheus.CounterVec
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if factory != nil {
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inner = factory.NewCounterVec(opts, []string{labelName})
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} else {
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inner = prometheus.NewCounterVec(opts, []string{labelName})
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}
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return &CounterVecT1{inner: inner, labelName: labelName}
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}
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// CounterVecT1 is a wrapper around prometheus.CounterVec that allows a single type-safe label.
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type CounterVecT1 struct {
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labelName string
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inner *prometheus.CounterVec
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}
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// GetMetricWithLabelValues behaves like prometheus.CounterVec.GetMetricWithLabelValues but with type-safe labels.
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func (c *CounterVecT1) GetMetricWithLabelValues(labelValue string) (prometheus.Counter, error) {
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return c.inner.GetMetricWithLabelValues(labelValue)
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}
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// GetMetricWith behaves like prometheus.CounterVec.GetMetricWith but with type-safe labels.
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func (c *CounterVecT1) GetMetricWith(labelValue string) (prometheus.Counter, error) {
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return c.inner.GetMetricWith(prometheus.Labels{c.labelName: labelValue})
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}
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// WithLabelValues behaves like prometheus.CounterVec.WithLabelValues but with type-safe labels.
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func (c *CounterVecT1) WithLabelValues(labelValue string) prometheus.Counter {
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return c.inner.WithLabelValues(labelValue)
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}
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// With behaves like prometheus.CounterVec.With but with type-safe labels.
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func (c *CounterVecT1) With(labelValue string) prometheus.Counter {
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return c.inner.With(prometheus.Labels{c.labelName: labelValue})
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}
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// CurryWith behaves like prometheus.CounterVec.CurryWith but with type-safe labels.
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// It still returns a CounterVecT, but it's inner prometheus.CounterVec is curried.
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func (c *CounterVecT1) CurryWith(labelValue string) (*CounterVecT1, error) {
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curriedInner, err := c.inner.CurryWith(prometheus.Labels{c.labelName: labelValue})
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if err != nil {
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return nil, err
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}
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c.inner = curriedInner
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return c, nil
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}
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// MustCurryWith behaves like prometheus.CounterVec.MustCurryWith but with type-safe labels.
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// It still returns a CounterVecT, but it's inner prometheus.CounterVec is curried.
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func (c *CounterVecT1) MustCurryWith(labelValue string) *CounterVecT1 {
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c.inner = c.inner.MustCurryWith(prometheus.Labels{c.labelName: labelValue})
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return c
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}
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// Unsafe returns the underlying prometheus.CounterVec
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// it's used to call any other method of prometheus.CounterVec that doesn't require type-safe labels
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func (c *CounterVecT1) Unsafe() *prometheus.CounterVec {
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return c.inner
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}
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//
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// Promauto compatibility
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//
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// Factory is a promauto-like factory that allows type-safe labels.
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// We have to duplicate promauto.Factory logic here, because promauto.Factory's registry is private.
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type Factory[T labelProviderMarker] struct {
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type Factory[T labelsProviderMarker] struct {
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r prometheus.Registerer
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}
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// WithAuto is a helper function that allows to use promauto.With with promsafe.With
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func WithAuto(r prometheus.Registerer) Factory[labelProviderMarker] {
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return Factory[labelProviderMarker]{r: r}
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func WithAuto[T labelsProviderMarker](r prometheus.Registerer) Factory[T] {
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return Factory[T]{r: r}
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}
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// NewCounterVecT works like promauto.NewCounterVec but with type-safe labels
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func (f Factory[T]) NewCounterVecT(opts prometheus.CounterOpts, labels T) *CounterVecT[T] {
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c := NewCounterVecT(opts, labels)
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func (f Factory[T]) NewCounterVecT(opts prometheus.CounterOpts) *CounterVecT[T] {
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c := NewCounterVecT[T](opts)
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if f.r != nil {
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f.r.MustRegister(c.inner)
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}
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@ -257,10 +281,50 @@ func (f Factory[T]) NewCounterFuncT(opts prometheus.CounterOpts, function func()
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return promauto.With(f.r).NewCounterFunc(opts, function)
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}
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// TODO: we can't use Factory with NewCounterT1. If we need, then we need a new type-less Factory
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//
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// Helpers
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//
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// extractLabelsWithValues extracts labels names+values from a given labelsProviderMarker (parent instance of a StructLabelProvider)
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func extractLabelsWithValues(labelProvider labelsProviderMarker) prometheus.Labels {
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if any(labelProvider) == nil {
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return nil
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}
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// TODO: let's handle defaults as well, why not?
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// Here, then, it can be only a struct, that is a parent of StructLabelProvider
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return extractLabelFromStruct(labelProvider)
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}
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// extractLabelValues extracts label string values from a given labelsProviderMarker (parent instance of aStructLabelProvider)
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func extractLabelValues(labelProvider labelsProviderMarker) []string {
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m := extractLabelsWithValues(labelProvider)
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labelValues := make([]string, 0, len(m))
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for _, v := range m {
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labelValues = append(labelValues, v)
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}
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return labelValues
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}
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// extractLabelNames extracts labels names from a given labelsProviderMarker (parent instance of aStructLabelProvider)
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func extractLabelNames(labelProvider labelsProviderMarker) []string {
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if any(labelProvider) == nil {
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return nil
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}
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// Here, then, it can be only a struct, that is a parent of StructLabelProvider
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labels := extractLabelFromStruct(labelProvider)
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labelNames := make([]string, 0, len(labels))
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for k := range labels {
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labelNames = append(labelNames, k)
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}
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return labelNames
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}
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// extractLabelFromStruct extracts labels names+values from a given StructLabelProvider
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func extractLabelFromStruct(structWithLabels any) prometheus.Labels {
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labels := prometheus.Labels{}
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@ -17,26 +17,10 @@ import (
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"log"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/client_golang/prometheus/promauto"
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"github.com/prometheus/client_golang/prometheus/promsafe"
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)
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func ExampleNewCounterVecT_single_label_manual() {
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// Manually registering with a single label
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c := promsafe.NewCounterVecT(prometheus.CounterOpts{
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Name: "items_counted_by_status",
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}, promsafe.SingleLabelProvider("status"))
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// Manually register the counter
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if err := prometheus.Register(c.Unsafe()); err != nil {
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log.Fatal("could not register: ", err.Error())
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}
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c.With("active").Inc()
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// Output:
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}
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func ExampleNewCounterVecT_multiple_labels_manual() {
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// Manually registering with multiple labels
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@ -49,17 +33,17 @@ func ExampleNewCounterVecT_multiple_labels_manual() {
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ShouldNotBeUsed string `promsafe:"-"`
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}
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c := promsafe.NewCounterVecT(prometheus.CounterOpts{
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c := promsafe.NewCounterVecT[MyCounterLabels](prometheus.CounterOpts{
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Name: "items_counted_detailed",
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}, new(MyCounterLabels))
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})
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// Manually register the counter
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if err := prometheus.Register(c.Unsafe()); err != nil {
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log.Fatal("could not register: ", err.Error())
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log.Fatal("could not register1: ", err.Error())
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}
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// and now, because of generics we can call Inc() with filled struct of labels:
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counter := c.With(&MyCounterLabels{
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counter := c.With(MyCounterLabels{
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EventType: "reservation", Success: true, Position: 1,
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})
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counter.Inc()
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@ -81,14 +65,14 @@ func ExampleNewCounterVecT_promauto_migrated() {
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// promauto.With(myReg).NewCounterVec(counterOpts, []string{"event_type", "source"})
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// becomes:
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type TicketReservationAttemptsLabels struct {
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type MyLabels struct {
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promsafe.StructLabelProvider
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EventType string
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Source string
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}
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c := promsafe.WithAuto(myReg).NewCounterVecT(counterOpts, new(TicketReservationAttemptsLabels))
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c := promsafe.WithAuto[MyLabels](myReg).NewCounterVecT(counterOpts)
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c.With(&TicketReservationAttemptsLabels{
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c.With(MyLabels{
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EventType: "reservation", Source: "source1",
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}).Inc()
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@ -103,6 +87,10 @@ func ExampleNewCounterVecT_promauto_global_migrated() {
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// like promauto does
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// Note: it actually accepts other registry to become a default one
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promsafe.SetupGlobalPromauto()
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defer func() {
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// cleanup for other examples
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promsafe.SetupGlobalPromauto(promauto.With(nil))
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}()
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counterOpts := prometheus.CounterOpts{
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Name: "items_counted_detailed_auto_global",
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@ -116,16 +104,34 @@ func ExampleNewCounterVecT_promauto_global_migrated() {
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//}).Inc()
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// becomes:
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type TicketReservationAttemptsLabels struct {
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type MyLabels struct {
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promsafe.StructLabelProvider
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Status string
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Source string
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}
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c := promsafe.NewCounterVecT(counterOpts, new(TicketReservationAttemptsLabels))
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c := promsafe.NewCounterVecT[*MyLabels](counterOpts)
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c.With(&TicketReservationAttemptsLabels{
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c.With(&MyLabels{
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Status: "active", Source: "source1",
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}).Inc()
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// Output:
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}
|
||||
|
||||
func ExampleNewCounterVecT_single_label_manual() {
|
||||
// Manually registering with a single label
|
||||
// Example of usage of shorthand: no structs no generics, but one string only
|
||||
|
||||
c := promsafe.NewCounterVecT1(prometheus.CounterOpts{
|
||||
Name: "items_counted_by_status",
|
||||
}, promsafe.SingleLabelProvider("status"))
|
||||
|
||||
// Manually register the counter
|
||||
if err := prometheus.Register(c.Unsafe()); err != nil {
|
||||
log.Fatal("could not register: ", err.Error())
|
||||
}
|
||||
|
||||
c.With("active").Inc()
|
||||
|
||||
// Output:
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue