lib/promrelabel: add support for keep_if_equal and drop_if_equal actions to relabel configs

These actions may be useful for filtering out unneeded targets and/or metrics if they contain equal label values.
For example, the following rule would leave the target only if __meta_kubernetes_annotation_prometheus_io_port
equals __meta_kubernetes_pod_container_port_number:

  - action: keep_if_equal
    source_labels: [__meta_kubernetes_annotation_prometheus_io_port, __meta_kubernetes_pod_container_port_number]
This commit is contained in:
Aliaksandr Valialkin 2020-06-23 17:17:58 +03:00
parent de7e585ac8
commit 3a444bb7bb
7 changed files with 189 additions and 2 deletions

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@ -170,6 +170,8 @@ Additionally it provides the following extra actions:
* `replace_all`: replaces all the occurences of `regex` in the values of `source_labels` with the `replacement` and stores the result in the `target_label`.
* `labelmap_all`: replaces all the occurences of `regex` in all the label names with the `replacement`.
* `keep_if_equal`: keeps the entry if all label values from `source_labels` are equal.
* `drop_if_equal`: drops the entry if all the label values from `source_labels` are equal.
The relabeling can be defined in the following places:
@ -210,6 +212,14 @@ either via `vmagent` itself or via Prometheus, so the exported metrics could be
The directory can grow large when remote storage is unavailable for extended periods of time and if `-remoteWrite.maxDiskUsagePerURL` isn't set.
If you don't want to send all the data from the directory to remote storage, simply stop `vmagent` and delete the directory.
* If you see `skipping duplicate scrape target with identical labels` errors when scraping Kubernetes pods, then it is likely these pods listen multiple ports.
Just add the following relabeling rule to `relabel_configs` section in order to filter out targets with unneeded ports:
```yml
- action: keep_if_equal
source_labels: [__meta_kubernetes_pod_annotation_prometheus_io_port, __meta_kubernetes_pod_container_port_number]
```
### How to build from sources

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@ -170,6 +170,8 @@ Additionally it provides the following extra actions:
* `replace_all`: replaces all the occurences of `regex` in the values of `source_labels` with the `replacement` and stores the result in the `target_label`.
* `labelmap_all`: replaces all the occurences of `regex` in all the label names with the `replacement`.
* `keep_if_equal`: keeps the entry if all label values from `source_labels` are equal.
* `drop_if_equal`: drops the entry if all the label values from `source_labels` are equal.
The relabeling can be defined in the following places:
@ -210,6 +212,14 @@ either via `vmagent` itself or via Prometheus, so the exported metrics could be
The directory can grow large when remote storage is unavailable for extended periods of time and if `-remoteWrite.maxDiskUsagePerURL` isn't set.
If you don't want to send all the data from the directory to remote storage, simply stop `vmagent` and delete the directory.
* If you see `skipping duplicate scrape target with identical labels` errors when scraping Kubernetes pods, then it is likely these pods listen multiple ports.
Just add the following relabeling rule to `relabel_configs` section in order to filter out targets with unneeded ports:
```yml
- action: keep_if_equal
source_labels: [__meta_kubernetes_pod_annotation_prometheus_io_port, __meta_kubernetes_pod_container_port_number]
```
### How to build from sources

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@ -92,6 +92,14 @@ func parseRelabelConfig(dst []ParsedRelabelConfig, rc *RelabelConfig) ([]ParsedR
if targetLabel == "" {
return dst, fmt.Errorf("missing `target_label` for `action=replace`")
}
case "keep_if_equal":
if len(sourceLabels) < 2 {
return dst, fmt.Errorf("`source_labels` must contain at least two entries for `action=keep_if_equal`; got %q", sourceLabels)
}
case "drop_if_equal":
if len(sourceLabels) < 2 {
return dst, fmt.Errorf("`source_labels` must contain at least two entries for `action=drop_if_equal`; got %q", sourceLabels)
}
case "keep":
if len(sourceLabels) == 0 {
return dst, fmt.Errorf("missing `source_labels` for `action=keep`")

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@ -11,8 +11,8 @@ func TestLoadRelabelConfigsSuccess(t *testing.T) {
if err != nil {
t.Fatalf("cannot load relabel configs from %q: %s", path, err)
}
if len(prcs) != 7 {
t.Fatalf("unexpected number of relabel configs loaded from %q; got %d; want %d", path, len(prcs), 7)
if len(prcs) != 9 {
t.Fatalf("unexpected number of relabel configs loaded from %q; got %d; want %d", path, len(prcs), 9)
}
}
@ -117,6 +117,36 @@ func TestParseRelabelConfigsFailure(t *testing.T) {
},
})
})
t.Run("keep_if_equal-missing-source-labels", func(t *testing.T) {
f([]RelabelConfig{
{
Action: "keep_if_equal",
},
})
})
t.Run("keep_if_equal-single-source-label", func(t *testing.T) {
f([]RelabelConfig{
{
Action: "keep_if_equal",
SourceLabels: []string{"foo"},
},
})
})
t.Run("drop_if_equal-missing-source-labels", func(t *testing.T) {
f([]RelabelConfig{
{
Action: "drop_if_equal",
},
})
})
t.Run("drop_if_equal-single-source-label", func(t *testing.T) {
f([]RelabelConfig{
{
Action: "drop_if_equal",
SourceLabels: []string{"foo"},
},
})
})
t.Run("drop-missing-source-labels", func(t *testing.T) {
f([]RelabelConfig{
{

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@ -148,6 +148,30 @@ func applyRelabelConfig(labels []prompbmarshal.Label, labelsOffset int, prc *Par
relabelBufPool.Put(bb)
valueStr := prc.Regex.ReplaceAllString(sourceStr, prc.Replacement)
return setLabelValue(labels, labelsOffset, prc.TargetLabel, valueStr)
case "keep_if_equal":
// Keep the entry if all the label values in source_labels are equal.
// For example:
//
// - source_labels: [foo, bar]
// action: keep_if_equal
//
// Would leave the entry if `foo` value equals `bar` value
if areEqualLabelValues(src, prc.SourceLabels) {
return labels
}
return labels[:labelsOffset]
case "drop_if_equal":
// Drop the entry if all the label values in source_labels are equal.
// For example:
//
// - source_labels: [foo, bar]
// action: drop_if_equal
//
// Would drop the entry if `foo` value equals `bar` value.
if areEqualLabelValues(src, prc.SourceLabels) {
return labels[:labelsOffset]
}
return labels
case "keep":
bb := relabelBufPool.Get()
bb.B = concatLabelValues(bb.B[:0], src, prc.SourceLabels, prc.Separator)
@ -249,6 +273,21 @@ func (prc *ParsedRelabelConfig) expandCaptureGroups(template, source string, mat
var relabelBufPool bytesutil.ByteBufferPool
func areEqualLabelValues(labels []prompbmarshal.Label, labelNames []string) bool {
if len(labelNames) < 2 {
logger.Panicf("BUG: expecting at least 2 labelNames; got %d", len(labelNames))
return false
}
labelValue := GetLabelValueByName(labels, labelNames[0])
for _, labelName := range labelNames[1:] {
v := GetLabelValueByName(labels, labelName)
if v != labelValue {
return false
}
}
return true
}
func concatLabelValues(dst []byte, labels []prompbmarshal.Label, labelNames []string, separator string) []byte {
if len(labelNames) == 0 {
return dst

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@ -336,6 +336,92 @@ func TestApplyRelabelConfigs(t *testing.T) {
},
})
})
t.Run("keep_if_equal-miss", func(t *testing.T) {
f([]ParsedRelabelConfig{
{
Action: "keep_if_equal",
SourceLabels: []string{"foo", "bar"},
},
}, nil, true, nil)
f([]ParsedRelabelConfig{
{
Action: "keep_if_equal",
SourceLabels: []string{"xxx", "bar"},
},
}, []prompbmarshal.Label{
{
Name: "xxx",
Value: "yyy",
},
}, true, []prompbmarshal.Label{})
})
t.Run("keep_if_equal-hit", func(t *testing.T) {
f([]ParsedRelabelConfig{
{
Action: "keep_if_equal",
SourceLabels: []string{"xxx", "bar"},
},
}, []prompbmarshal.Label{
{
Name: "xxx",
Value: "yyy",
},
{
Name: "bar",
Value: "yyy",
},
}, true, []prompbmarshal.Label{
{
Name: "bar",
Value: "yyy",
},
{
Name: "xxx",
Value: "yyy",
},
})
})
t.Run("drop_if_equal-miss", func(t *testing.T) {
f([]ParsedRelabelConfig{
{
Action: "drop_if_equal",
SourceLabels: []string{"foo", "bar"},
},
}, nil, true, nil)
f([]ParsedRelabelConfig{
{
Action: "drop_if_equal",
SourceLabels: []string{"xxx", "bar"},
},
}, []prompbmarshal.Label{
{
Name: "xxx",
Value: "yyy",
},
}, true, []prompbmarshal.Label{
{
Name: "xxx",
Value: "yyy",
},
})
})
t.Run("drop_if_equal-hit", func(t *testing.T) {
f([]ParsedRelabelConfig{
{
Action: "drop_if_equal",
SourceLabels: []string{"xxx", "bar"},
},
}, []prompbmarshal.Label{
{
Name: "xxx",
Value: "yyy",
},
{
Name: "bar",
Value: "yyy",
},
}, true, []prompbmarshal.Label{})
})
t.Run("keep-miss", func(t *testing.T) {
f([]ParsedRelabelConfig{
{

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@ -18,3 +18,7 @@
- action: labelmap_all
regex: "\\."
replacement: ":"
- action: keep_if_equal
source_labels: [foo, bar]
- action: drop_if_equal
source_labels: [foo, bar]