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https://github.com/kubernetes-sigs/prometheus-adapter.git
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Extract label-resource logic to separate package
This extracts the label-to-resource conversion to a separte "naming" package for use across different providers. Early versions of the commit were done by antoinne85 in #79.
This commit is contained in:
Solly Ross
parent
d02384477a
commit
7dd9e94aea
3 changed files with 292 additions and 237 deletions
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@ -5,17 +5,14 @@ import (
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"fmt"
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"regexp"
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"strings"
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"sync"
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"text/template"
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"github.com/golang/glog"
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"github.com/kubernetes-incubator/custom-metrics-apiserver/pkg/provider"
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apimeta "k8s.io/apimachinery/pkg/api/meta"
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"k8s.io/apimachinery/pkg/runtime/schema"
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prom "github.com/directxman12/k8s-prometheus-adapter/pkg/client"
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"github.com/directxman12/k8s-prometheus-adapter/pkg/config"
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pmodel "github.com/prometheus/common/model"
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"github.com/directxman12/k8s-prometheus-adapter/pkg/naming"
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)
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var nsGroupResource = schema.GroupResource{Resource: "namespaces"}
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@ -34,86 +31,13 @@ type MetricNamer interface {
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// constrains beyond the series query. It's assumed that the series given
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// already matche the series query.
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FilterSeries(series []prom.Series) []prom.Series
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// ResourcesForSeries returns the group-resources associated with the given series,
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// as well as whether or not the given series has the "namespace" resource).
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ResourcesForSeries(series prom.Series) (res []schema.GroupResource, namespaced bool)
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// LabelForResource returns the appropriate label for the given resource.
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LabelForResource(resource schema.GroupResource) (pmodel.LabelName, error)
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// MetricNameForSeries returns the name (as presented in the API) for a given series.
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MetricNameForSeries(series prom.Series) (string, error)
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// QueryForSeries returns the query for a given series (not API metric name), with
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// the given namespace name (if relevant), resource, and resource names.
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QueryForSeries(series string, resource schema.GroupResource, namespace string, names ...string) (prom.Selector, error)
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}
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// labelGroupResExtractor extracts schema.GroupResources from series labels.
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type labelGroupResExtractor struct {
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regex *regexp.Regexp
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resourceInd int
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groupInd *int
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mapper apimeta.RESTMapper
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}
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// newLabelGroupResExtractor creates a new labelGroupResExtractor for labels whose form
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// matches the given template. It does so by creating a regular expression from the template,
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// so anything in the template which limits resource or group name length will cause issues.
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func newLabelGroupResExtractor(labelTemplate *template.Template) (*labelGroupResExtractor, error) {
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labelRegexBuff := new(bytes.Buffer)
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if err := labelTemplate.Execute(labelRegexBuff, schema.GroupResource{"(?P<group>.+?)", "(?P<resource>.+?)"}); err != nil {
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return nil, fmt.Errorf("unable to convert label template to matcher: %v", err)
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}
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if labelRegexBuff.Len() == 0 {
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return nil, fmt.Errorf("unable to convert label template to matcher: empty template")
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}
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labelRegexRaw := "^" + labelRegexBuff.String() + "$"
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labelRegex, err := regexp.Compile(labelRegexRaw)
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if err != nil {
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return nil, fmt.Errorf("unable to convert label template to matcher: %v", err)
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}
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var groupInd *int
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var resInd *int
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for i, name := range labelRegex.SubexpNames() {
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switch name {
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case "group":
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ind := i // copy to avoid iteration variable reference
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groupInd = &ind
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case "resource":
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ind := i // copy to avoid iteration variable reference
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resInd = &ind
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}
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}
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if resInd == nil {
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return nil, fmt.Errorf("must include at least `{{.Resource}}` in the label template")
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}
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return &labelGroupResExtractor{
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regex: labelRegex,
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resourceInd: *resInd,
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groupInd: groupInd,
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}, nil
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}
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// GroupResourceForLabel extracts a schema.GroupResource from the given label, if possible.
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// The second argument indicates whether or not a potential group-resource was found in this label.
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func (e *labelGroupResExtractor) GroupResourceForLabel(lbl pmodel.LabelName) (schema.GroupResource, bool) {
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matchGroups := e.regex.FindStringSubmatch(string(lbl))
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if matchGroups != nil {
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group := ""
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if e.groupInd != nil {
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group = matchGroups[*e.groupInd]
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}
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return schema.GroupResource{
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Group: group,
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Resource: matchGroups[e.resourceInd],
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}, true
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}
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return schema.GroupResource{}, false
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naming.ResourceConverter
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}
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func (r *metricNamer) Selector() prom.Selector {
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@ -161,17 +85,12 @@ func (m *reMatcher) Matches(val string) bool {
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type metricNamer struct {
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seriesQuery prom.Selector
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labelTemplate *template.Template
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labelResExtractor *labelGroupResExtractor
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metricsQueryTemplate *template.Template
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nameMatches *regexp.Regexp
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nameAs string
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seriesMatchers []*reMatcher
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labelResourceMu sync.RWMutex
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labelToResource map[pmodel.LabelName]schema.GroupResource
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resourceToLabel map[schema.GroupResource]pmodel.LabelName
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mapper apimeta.RESTMapper
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naming.ResourceConverter
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}
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// queryTemplateArgs are the arguments for the metrics query template.
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@ -247,121 +166,6 @@ func (n *metricNamer) QueryForSeries(series string, resource schema.GroupResourc
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return prom.Selector(queryBuff.String()), nil
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}
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func (n *metricNamer) ResourcesForSeries(series prom.Series) ([]schema.GroupResource, bool) {
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// use an updates map to avoid having to drop the read lock to update the cache
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// until the end. Since we'll probably have few updates after the first run,
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// this should mean that we rarely have to hold the write lock.
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var resources []schema.GroupResource
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updates := make(map[pmodel.LabelName]schema.GroupResource)
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namespaced := false
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// use an anon func to get the right defer behavior
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func() {
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n.labelResourceMu.RLock()
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defer n.labelResourceMu.RUnlock()
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for lbl := range series.Labels {
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var groupRes schema.GroupResource
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var ok bool
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// check if we have an override
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if groupRes, ok = n.labelToResource[lbl]; ok {
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resources = append(resources, groupRes)
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} else if groupRes, ok = updates[lbl]; ok {
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resources = append(resources, groupRes)
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} else if n.labelResExtractor != nil {
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// if not, check if it matches the form we expect, and if so,
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// convert to a group-resource.
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if groupRes, ok = n.labelResExtractor.GroupResourceForLabel(lbl); ok {
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info, _, err := provider.CustomMetricInfo{GroupResource: groupRes}.Normalized(n.mapper)
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if err != nil {
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// this is likely to show up for a lot of labels, so make it a verbose info log
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glog.V(9).Infof("unable to normalize group-resource %s from label %q, skipping: %v", groupRes.String(), lbl, err)
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continue
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}
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groupRes = info.GroupResource
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resources = append(resources, groupRes)
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updates[lbl] = groupRes
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}
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}
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if groupRes == nsGroupResource {
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namespaced = true
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}
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}
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}()
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// update the cache for next time. This should only be called by discovery,
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// so we don't really have to worry about the grap between read and write locks
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// (plus, we don't care if someone else updates the cache first, since the results
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// are necessarily the same, so at most we've done extra work).
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if len(updates) > 0 {
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n.labelResourceMu.Lock()
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defer n.labelResourceMu.Unlock()
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for lbl, groupRes := range updates {
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n.labelToResource[lbl] = groupRes
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}
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}
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return resources, namespaced
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}
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func (n *metricNamer) LabelForResource(resource schema.GroupResource) (pmodel.LabelName, error) {
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n.labelResourceMu.RLock()
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// check if we have a cached copy or override
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lbl, ok := n.resourceToLabel[resource]
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n.labelResourceMu.RUnlock() // release before we call makeLabelForResource
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if ok {
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return lbl, nil
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}
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// NB: we don't actually care about the gap between releasing read lock
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// and acquiring the write lock -- if we do duplicate work sometimes, so be
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// it, as long as we're correct.
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// otherwise, use the template and save the result
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lbl, err := n.makeLabelForResource(resource)
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if err != nil {
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return "", fmt.Errorf("unable to convert resource %s into label: %v", resource.String(), err)
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}
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return lbl, nil
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}
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// makeLabelForResource constructs a label name for the given resource, and saves the result.
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// It must *not* be called under an existing lock.
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func (n *metricNamer) makeLabelForResource(resource schema.GroupResource) (pmodel.LabelName, error) {
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if n.labelTemplate == nil {
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return "", fmt.Errorf("no generic resource label form specified for this metric")
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}
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buff := new(bytes.Buffer)
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singularRes, err := n.mapper.ResourceSingularizer(resource.Resource)
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if err != nil {
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return "", fmt.Errorf("unable to singularize resource %s: %v", resource.String(), err)
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}
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convResource := schema.GroupResource{
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Group: groupNameSanitizer.Replace(resource.Group),
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Resource: singularRes,
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}
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if err := n.labelTemplate.Execute(buff, convResource); err != nil {
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return "", err
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}
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if buff.Len() == 0 {
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return "", fmt.Errorf("empty label produced by label template")
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}
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lbl := pmodel.LabelName(buff.String())
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n.labelResourceMu.Lock()
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defer n.labelResourceMu.Unlock()
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n.resourceToLabel[resource] = lbl
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n.labelToResource[lbl] = resource
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return lbl, nil
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}
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func (n *metricNamer) MetricNameForSeries(series prom.Series) (string, error) {
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matches := n.nameMatches.FindStringSubmatchIndex(series.Name)
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if matches == nil {
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@ -376,21 +180,6 @@ func NamersFromConfig(cfg *config.MetricsDiscoveryConfig, mapper apimeta.RESTMap
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namers := make([]MetricNamer, len(cfg.Rules))
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for i, rule := range cfg.Rules {
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var labelTemplate *template.Template
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var labelResExtractor *labelGroupResExtractor
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var err error
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if rule.Resources.Template != "" {
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labelTemplate, err = template.New("resource-label").Delims("<<", ">>").Parse(rule.Resources.Template)
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if err != nil {
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return nil, fmt.Errorf("unable to parse label template %q associated with series query %q: %v", rule.Resources.Template, rule.SeriesQuery, err)
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}
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labelResExtractor, err = newLabelGroupResExtractor(labelTemplate)
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if err != nil {
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return nil, fmt.Errorf("unable to generate label format from template %q associated with series query %q: %v", rule.Resources.Template, rule.SeriesQuery, err)
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}
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}
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metricsQueryTemplate, err := template.New("metrics-query").Delims("<<", ">>").Parse(rule.MetricsQuery)
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if err != nil {
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return nil, fmt.Errorf("unable to parse metrics query template %q associated with series query %q: %v", rule.MetricsQuery, rule.SeriesQuery, err)
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@ -437,35 +226,18 @@ func NamersFromConfig(cfg *config.MetricsDiscoveryConfig, mapper apimeta.RESTMap
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}
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}
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resConv, err := naming.NewResourceConverter(rule.Resources.Template, rule.Resources.Overrides, mapper)
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if err != nil {
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return nil, err
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}
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namer := &metricNamer{
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seriesQuery: prom.Selector(rule.SeriesQuery),
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labelTemplate: labelTemplate,
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labelResExtractor: labelResExtractor,
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metricsQueryTemplate: metricsQueryTemplate,
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mapper: mapper,
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nameMatches: nameMatches,
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nameAs: nameAs,
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seriesMatchers: seriesMatchers,
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labelToResource: make(map[pmodel.LabelName]schema.GroupResource),
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resourceToLabel: make(map[schema.GroupResource]pmodel.LabelName),
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}
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// invert the structure for consistency with the template
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for lbl, groupRes := range rule.Resources.Overrides {
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infoRaw := provider.CustomMetricInfo{
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GroupResource: schema.GroupResource{
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Group: groupRes.Group,
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Resource: groupRes.Resource,
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},
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}
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info, _, err := infoRaw.Normalized(mapper)
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if err != nil {
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return nil, fmt.Errorf("unable to normalize group-resource %v: %v", groupRes, err)
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}
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namer.labelToResource[pmodel.LabelName(lbl)] = info.GroupResource
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namer.resourceToLabel[info.GroupResource] = pmodel.LabelName(lbl)
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ResourceConverter: resConv,
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}
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namers[i] = namer
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