109 lines
2.9 KiB
Go
109 lines
2.9 KiB
Go
package web
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import (
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"io"
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"net/http"
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"bitbucket.org/ww/goautoneg"
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"github.com/golang/protobuf/proto"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/client_golang/text"
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"github.com/prometheus/prometheus/promql"
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"github.com/prometheus/prometheus/storage/local"
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clientmodel "github.com/prometheus/client_golang/model"
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dto "github.com/prometheus/client_model/go"
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)
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type Federation struct {
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Storage local.Storage
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}
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func (fed *Federation) ServeHTTP(w http.ResponseWriter, req *http.Request) {
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req.ParseForm()
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metrics := map[clientmodel.Fingerprint]clientmodel.COWMetric{}
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for _, s := range req.Form["match[]"] {
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matchers, err := promql.ParseMetricSelector(s)
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if err != nil {
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http.Error(w, err.Error(), http.StatusBadRequest)
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return
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}
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for fp, met := range fed.Storage.MetricsForLabelMatchers(matchers...) {
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metrics[fp] = met
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}
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}
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enc, contentType := chooseEncoder(req)
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w.Header().Set("Content-Type", contentType)
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protMetric := &dto.Metric{
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Label: []*dto.LabelPair{},
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Untyped: &dto.Untyped{},
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}
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protMetricFam := &dto.MetricFamily{
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Metric: []*dto.Metric{protMetric},
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Type: dto.MetricType_UNTYPED.Enum(),
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}
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for fp, met := range metrics {
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sp := fed.Storage.LastSamplePairForFingerprint(fp)
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if sp == nil {
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continue
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}
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// Reset label slice.
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protMetric.Label = protMetric.Label[:0]
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for ln, lv := range met.Metric {
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if ln == clientmodel.MetricNameLabel {
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protMetricFam.Name = proto.String(string(lv))
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continue
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}
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protMetric.Label = append(protMetric.Label, &dto.LabelPair{
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Name: proto.String(string(ln)),
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Value: proto.String(string(lv)),
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})
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}
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protMetric.TimestampMs = (*int64)(&sp.Timestamp)
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protMetric.Untyped.Value = (*float64)(&sp.Value)
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if _, err := enc(w, protMetricFam); err != nil {
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http.Error(w, err.Error(), http.StatusInternalServerError)
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return
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}
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}
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}
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type encoder func(w io.Writer, p *dto.MetricFamily) (int, error)
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func chooseEncoder(req *http.Request) (encoder, string) {
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accepts := goautoneg.ParseAccept(req.Header.Get("Accept"))
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for _, accept := range accepts {
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switch {
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case accept.Type == "application" &&
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accept.SubType == "vnd.google.protobuf" &&
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accept.Params["proto"] == "io.prometheus.client.MetricFamily":
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switch accept.Params["encoding"] {
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case "delimited":
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return text.WriteProtoDelimited, prometheus.DelimitedTelemetryContentType
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case "text":
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return text.WriteProtoText, prometheus.ProtoTextTelemetryContentType
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case "compact-text":
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return text.WriteProtoCompactText, prometheus.ProtoCompactTextTelemetryContentType
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default:
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continue
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}
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case accept.Type == "text" &&
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accept.SubType == "plain" &&
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(accept.Params["version"] == "0.0.4" || accept.Params["version"] == ""):
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return text.MetricFamilyToText, prometheus.TextTelemetryContentType
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default:
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continue
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}
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}
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return text.MetricFamilyToText, prometheus.TextTelemetryContentType
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}
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