diff options
Diffstat (limited to 'vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_server.go')
| -rw-r--r-- | vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_server.go | 155 |
1 files changed, 81 insertions, 74 deletions
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_server.go b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_server.go index 3d145ad..9db2438 100644 --- a/vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_server.go +++ b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_server.go @@ -14,6 +14,7 @@ package promhttp import ( + "errors" "net/http" "strconv" "strings" @@ -42,10 +43,10 @@ func InstrumentHandlerInFlight(g prometheus.Gauge, next http.Handler) http.Handl // InstrumentHandlerDuration is a middleware that wraps the provided // http.Handler to observe the request duration with the provided ObserverVec. -// The ObserverVec must have zero, one, or two labels. The only allowed label -// names are "code" and "method". The function panics if any other instance -// labels are provided. The Observe method of the Observer in the ObserverVec -// is called with the request duration in seconds. Partitioning happens by HTTP +// The ObserverVec must have zero, one, or two non-const non-curried labels. For +// those, the only allowed label names are "code" and "method". The function +// panics otherwise. The Observe method of the Observer in the ObserverVec is +// called with the request duration in seconds. Partitioning happens by HTTP // status code and/or HTTP method if the respective instance label names are // present in the ObserverVec. For unpartitioned observations, use an // ObserverVec with zero labels. Note that partitioning of Histograms is @@ -77,14 +78,13 @@ func InstrumentHandlerDuration(obs prometheus.ObserverVec, next http.Handler) ht }) } -// InstrumentHandlerCounter is a middleware that wraps the provided -// http.Handler to observe the request result with the provided CounterVec. -// The CounterVec must have zero, one, or two labels. The only allowed label -// names are "code" and "method". The function panics if any other instance -// labels are provided. Partitioning of the CounterVec happens by HTTP status -// code and/or HTTP method if the respective instance label names are present -// in the CounterVec. For unpartitioned counting, use a CounterVec with -// zero labels. +// InstrumentHandlerCounter is a middleware that wraps the provided http.Handler +// to observe the request result with the provided CounterVec. The CounterVec +// must have zero, one, or two non-const non-curried labels. For those, the only +// allowed label names are "code" and "method". The function panics +// otherwise. Partitioning of the CounterVec happens by HTTP status code and/or +// HTTP method if the respective instance label names are present in the +// CounterVec. For unpartitioned counting, use a CounterVec with zero labels. // // If the wrapped Handler does not set a status code, a status code of 200 is assumed. // @@ -111,14 +111,13 @@ func InstrumentHandlerCounter(counter *prometheus.CounterVec, next http.Handler) // InstrumentHandlerTimeToWriteHeader is a middleware that wraps the provided // http.Handler to observe with the provided ObserverVec the request duration // until the response headers are written. The ObserverVec must have zero, one, -// or two labels. The only allowed label names are "code" and "method". The -// function panics if any other instance labels are provided. The Observe -// method of the Observer in the ObserverVec is called with the request -// duration in seconds. Partitioning happens by HTTP status code and/or HTTP -// method if the respective instance label names are present in the -// ObserverVec. For unpartitioned observations, use an ObserverVec with zero -// labels. Note that partitioning of Histograms is expensive and should be used -// judiciously. +// or two non-const non-curried labels. For those, the only allowed label names +// are "code" and "method". The function panics otherwise. The Observe method of +// the Observer in the ObserverVec is called with the request duration in +// seconds. Partitioning happens by HTTP status code and/or HTTP method if the +// respective instance label names are present in the ObserverVec. For +// unpartitioned observations, use an ObserverVec with zero labels. Note that +// partitioning of Histograms is expensive and should be used judiciously. // // If the wrapped Handler panics before calling WriteHeader, no value is // reported. @@ -140,15 +139,15 @@ func InstrumentHandlerTimeToWriteHeader(obs prometheus.ObserverVec, next http.Ha } // InstrumentHandlerRequestSize is a middleware that wraps the provided -// http.Handler to observe the request size with the provided ObserverVec. -// The ObserverVec must have zero, one, or two labels. The only allowed label -// names are "code" and "method". The function panics if any other instance -// labels are provided. The Observe method of the Observer in the ObserverVec -// is called with the request size in bytes. Partitioning happens by HTTP -// status code and/or HTTP method if the respective instance label names are -// present in the ObserverVec. For unpartitioned observations, use an -// ObserverVec with zero labels. Note that partitioning of Histograms is -// expensive and should be used judiciously. +// http.Handler to observe the request size with the provided ObserverVec. The +// ObserverVec must have zero, one, or two non-const non-curried labels. For +// those, the only allowed label names are "code" and "method". The function +// panics otherwise. The Observe method of the Observer in the ObserverVec is +// called with the request size in bytes. Partitioning happens by HTTP status +// code and/or HTTP method if the respective instance label names are present in +// the ObserverVec. For unpartitioned observations, use an ObserverVec with zero +// labels. Note that partitioning of Histograms is expensive and should be used +// judiciously. // // If the wrapped Handler does not set a status code, a status code of 200 is assumed. // @@ -175,15 +174,15 @@ func InstrumentHandlerRequestSize(obs prometheus.ObserverVec, next http.Handler) } // InstrumentHandlerResponseSize is a middleware that wraps the provided -// http.Handler to observe the response size with the provided ObserverVec. -// The ObserverVec must have zero, one, or two labels. The only allowed label -// names are "code" and "method". The function panics if any other instance -// labels are provided. The Observe method of the Observer in the ObserverVec -// is called with the response size in bytes. Partitioning happens by HTTP -// status code and/or HTTP method if the respective instance label names are -// present in the ObserverVec. For unpartitioned observations, use an -// ObserverVec with zero labels. Note that partitioning of Histograms is -// expensive and should be used judiciously. +// http.Handler to observe the response size with the provided ObserverVec. The +// ObserverVec must have zero, one, or two non-const non-curried labels. For +// those, the only allowed label names are "code" and "method". The function +// panics otherwise. The Observe method of the Observer in the ObserverVec is +// called with the response size in bytes. Partitioning happens by HTTP status +// code and/or HTTP method if the respective instance label names are present in +// the ObserverVec. For unpartitioned observations, use an ObserverVec with zero +// labels. Note that partitioning of Histograms is expensive and should be used +// judiciously. // // If the wrapped Handler does not set a status code, a status code of 200 is assumed. // @@ -204,9 +203,12 @@ func checkLabels(c prometheus.Collector) (code bool, method bool) { // once Descriptors can have their dimensionality queried. var ( desc *prometheus.Desc + m prometheus.Metric pm dto.Metric + lvs []string ) + // Get the Desc from the Collector. descc := make(chan *prometheus.Desc, 1) c.Describe(descc) @@ -223,49 +225,54 @@ func checkLabels(c prometheus.Collector) (code bool, method bool) { close(descc) - if _, err := prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0); err == nil { - return + // Create a ConstMetric with the Desc. Since we don't know how many + // variable labels there are, try for as long as it needs. + for err := errors.New("dummy"); err != nil; lvs = append(lvs, magicString) { + m, err = prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0, lvs...) + } + + // Write out the metric into a proto message and look at the labels. + // If the value is not the magicString, it is a constLabel, which doesn't interest us. + // If the label is curried, it doesn't interest us. + // In all other cases, only "code" or "method" is allowed. + if err := m.Write(&pm); err != nil { + panic("error checking metric for labels") } - if m, err := prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0, magicString); err == nil { - if err := m.Write(&pm); err != nil { - panic("error checking metric for labels") + for _, label := range pm.Label { + name, value := label.GetName(), label.GetValue() + if value != magicString || isLabelCurried(c, name) { + continue } - for _, label := range pm.Label { - name, value := label.GetName(), label.GetValue() - if value != magicString { - continue - } - switch name { - case "code": - code = true - case "method": - method = true - default: - panic("metric partitioned with non-supported labels") - } - return + switch name { + case "code": + code = true + case "method": + method = true + default: + panic("metric partitioned with non-supported labels") } - panic("previously set label not found – this must never happen") } - if m, err := prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0, magicString, magicString); err == nil { - if err := m.Write(&pm); err != nil { - panic("error checking metric for labels") + return +} + +func isLabelCurried(c prometheus.Collector, label string) bool { + // This is even hackier than the label test above. + // We essentially try to curry again and see if it works. + // But for that, we need to type-convert to the two + // types we use here, ObserverVec or *CounterVec. + switch v := c.(type) { + case *prometheus.CounterVec: + if _, err := v.CurryWith(prometheus.Labels{label: "dummy"}); err == nil { + return false } - for _, label := range pm.Label { - name, value := label.GetName(), label.GetValue() - if value != magicString { - continue - } - if name == "code" || name == "method" { - continue - } - panic("metric partitioned with non-supported labels") + case prometheus.ObserverVec: + if _, err := v.CurryWith(prometheus.Labels{label: "dummy"}); err == nil { + return false } - code = true - method = true - return + default: + panic("unsupported metric vec type") } - panic("metric partitioned with non-supported labels") + return true } // emptyLabels is a one-time allocation for non-partitioned metrics to avoid |