Fix metric comparison for empty labels

reflect.DeepEqual is not suitable for zero occurrences of repeated
proto messages. This changes the comparison to act on the string
representation of proto messages.

Signed-off-by: beorn7 <beorn@soundcloud.com>
This commit is contained in:
beorn7 2018-11-13 16:16:43 +01:00
parent 1db43792db
commit 86702ea6b4
1 changed files with 32 additions and 25 deletions

View File

@ -37,7 +37,6 @@ import (
"bytes"
"fmt"
"io"
"reflect"
"github.com/prometheus/common/expfmt"
@ -125,39 +124,49 @@ func CollectAndCompare(c prometheus.Collector, expected io.Reader, metricNames .
// exposition format. If any metricNames are provided, only metrics with those
// names are compared.
func GatherAndCompare(g prometheus.Gatherer, expected io.Reader, metricNames ...string) error {
metrics, err := g.Gather()
got, err := g.Gather()
if err != nil {
return fmt.Errorf("gathering metrics failed: %s", err)
}
if metricNames != nil {
metrics = filterMetrics(metrics, metricNames)
got = filterMetrics(got, metricNames)
}
var tp expfmt.TextParser
expectedMetrics, err := tp.TextToMetricFamilies(expected)
wantRaw, err := tp.TextToMetricFamilies(expected)
if err != nil {
return fmt.Errorf("parsing expected metrics failed: %s", err)
}
want := internal.NormalizeMetricFamilies(wantRaw)
if !reflect.DeepEqual(metrics, internal.NormalizeMetricFamilies(expectedMetrics)) {
// Encode the gathered output to the readable text format for comparison.
var buf1 bytes.Buffer
enc := expfmt.NewEncoder(&buf1, expfmt.FmtText)
for _, mf := range metrics {
if err := enc.Encode(mf); err != nil {
return fmt.Errorf("encoding result failed: %s", err)
}
}
// Encode normalized expected metrics again to generate them in the same ordering
// the registry does to spot differences more easily.
var buf2 bytes.Buffer
enc = expfmt.NewEncoder(&buf2, expfmt.FmtText)
for _, mf := range internal.NormalizeMetricFamilies(expectedMetrics) {
if err := enc.Encode(mf); err != nil {
return fmt.Errorf("encoding result failed: %s", err)
}
if len(got) != len(want) {
return notMatchingError(got, want)
}
for i := range got {
if got[i].String() != want[i].String() {
return notMatchingError(got, want)
}
}
return nil
}
return fmt.Errorf(`
// notMatchingError encodes both provided slices of metric families into the
// text format and creates a readable error message from the result.
func notMatchingError(got, want []*dto.MetricFamily) error {
var gotBuf, wantBuf bytes.Buffer
enc := expfmt.NewEncoder(&gotBuf, expfmt.FmtText)
for _, mf := range got {
if err := enc.Encode(mf); err != nil {
return fmt.Errorf("encoding gathered metrics failed: %s", err)
}
}
enc = expfmt.NewEncoder(&wantBuf, expfmt.FmtText)
for _, mf := range want {
if err := enc.Encode(mf); err != nil {
return fmt.Errorf("encoding expected metrics failed: %s", err)
}
}
return fmt.Errorf(`
metric output does not match expectation; want:
%s
@ -165,9 +174,7 @@ metric output does not match expectation; want:
got:
%s
`, buf2.String(), buf1.String())
}
return nil
`, wantBuf.String(), gotBuf.String())
}
func filterMetrics(metrics []*dto.MetricFamily, names []string) []*dto.MetricFamily {