77 lines
1.6 KiB
Go
77 lines
1.6 KiB
Go
package merger
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import (
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"context"
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"fmt"
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"io"
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"sort"
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"sync"
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"github.com/pkg/errors"
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prom "github.com/prometheus/client_model/go"
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"github.com/prometheus/common/expfmt"
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"golang.org/x/sync/errgroup"
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)
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func (m *merger) merge(ctx context.Context, w io.Writer) error {
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mu := &sync.Mutex{}
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result := map[string]*prom.MetricFamily{}
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g, ctx := errgroup.WithContext(ctx)
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for _, source := range m.sources {
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source := source
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g.Go(func() error {
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resp, err := m.client.Get(source.url)
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if err != nil {
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return errors.Wrap(err, fmt.Sprintf("get url: %s", source.url))
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}
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defer resp.Body.Close()
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tp := new(expfmt.TextParser)
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out, err := tp.TextToMetricFamilies(resp.Body)
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if err != nil {
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return errors.Wrap(err, fmt.Sprintf("parse url: %s", source.url))
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}
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mu.Lock()
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defer mu.Unlock()
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for name, metricFamily := range out {
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// append labels
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if len(source.labels) > 0 {
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for _, metric := range metricFamily.Metric {
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metric.Label = append(metric.Label, source.labels...)
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}
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}
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// append metrics
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if mfResult, ok := result[name]; ok {
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mfResult.Metric = append(mfResult.Metric, metricFamily.Metric...)
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} else {
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result[name] = metricFamily
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}
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}
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return nil
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})
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}
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// wait to process all routines
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if err := g.Wait(); err != nil {
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return err
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}
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// sort names
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var names []string
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for n := range result {
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names = append(names, n)
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}
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sort.Strings(names)
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// write result
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enc := expfmt.NewEncoder(w, expfmt.FmtText)
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for _, n := range names {
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err := enc.Encode(result[n])
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if err != nil {
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return err
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}
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}
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return nil
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}
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