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Implement deletion based on partially matching labels (#1013)
* WIP partial match Signed-off-by: Zach Stone <[email protected]> * Cleanup Signed-off-by: Zach Stone <[email protected]> * Comments Signed-off-by: Zach Stone <[email protected]> * Tests and comments Signed-off-by: Zach Stone <[email protected]> * Handle properly deleting multiple metrics, update tests Signed-off-by: Zach Stone <[email protected]> * Comments Signed-off-by: Zach Stone <[email protected]> * Try using curry values Signed-off-by: Zach Stone <[email protected]> * Skip curry value to demo Signed-off-by: Zach Stone <[email protected]> * Fix curry deletion, remove outdated comment. Signed-off-by: Zach Stone <[email protected]> * Fix logic for deletion of metrics from prior to currying Signed-off-by: Zach Stone <[email protected]> * Don't match curried values. Update tests. Signed-off-by: Zach Stone <[email protected]> * Remove unneccesasry helper and todo comments Signed-off-by: Zach Stone <[email protected]> * Comment about partial matching curried labels Signed-off-by: Zach Stone <[email protected]> * Simplify curried value check Signed-off-by: Zach Stone <[email protected]>
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‎prometheus/vec.go‎

Lines changed: 86 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -99,6 +99,16 @@ func (m *MetricVec) Delete(labels Labels) bool {
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return m.metricMap.deleteByHashWithLabels(h, labels, m.curry)
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}
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// DeletePartialMatch deletes all metrics where the variable labels contain all of those
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// passed in as labels. The order of the labels does not matter.
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// It returns the number of metrics deleted.
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//
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// Note that curried labels will never be matched if deleting from the curried vector.
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// To match curried labels with DeletePartialMatch, it must be called on the base vector.
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func (m *MetricVec) DeletePartialMatch(labels Labels) int {
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return m.metricMap.deleteByLabels(labels, m.curry)
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}
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// Without explicit forwarding of Describe, Collect, Reset, those methods won't
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// show up in GoDoc.
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@@ -381,6 +391,82 @@ func (m *metricMap) deleteByHashWithLabels(
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return true
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}
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// deleteByLabels deletes a metric if the given labels are present in the metric.
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func (m *metricMap) deleteByLabels(labels Labels, curry []curriedLabelValue) int {
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m.mtx.Lock()
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defer m.mtx.Unlock()
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var numDeleted int
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for h, metrics := range m.metrics {
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i := findMetricWithPartialLabels(m.desc, metrics, labels, curry)
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if i >= len(metrics) {
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// Didn't find matching labels in this metric slice.
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continue
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}
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delete(m.metrics, h)
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numDeleted++
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}
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return numDeleted
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}
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// findMetricWithPartialLabel returns the index of the matching metric or
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// len(metrics) if not found.
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func findMetricWithPartialLabels(
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desc *Desc, metrics []metricWithLabelValues, labels Labels, curry []curriedLabelValue,
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) int {
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for i, metric := range metrics {
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if matchPartialLabels(desc, metric.values, labels, curry) {
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return i
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}
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}
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return len(metrics)
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}
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// indexOf searches the given slice of strings for the target string and returns
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// the index or len(items) as well as a boolean whether the search succeeded.
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func indexOf(target string, items []string) (int, bool) {
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for i, l := range items {
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if l == target {
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return i, true
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}
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}
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return len(items), false
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}
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// valueMatchesVariableOrCurriedValue determines if a value was previously curried,
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// and returns whether it matches either the "base" value or the curried value accordingly.
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// It also indicates whether the match is against a curried or uncurried value.
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func valueMatchesVariableOrCurriedValue(targetValue string, index int, values []string, curry []curriedLabelValue) (bool, bool) {
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for _, curriedValue := range curry {
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if curriedValue.index == index {
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// This label was curried. See if the curried value matches our target.
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return curriedValue.value == targetValue, true
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}
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}
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// This label was not curried. See if the current value matches our target label.
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return values[index] == targetValue, false
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}
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// matchPartialLabels searches the current metric and returns whether all of the target label:value pairs are present.
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func matchPartialLabels(desc *Desc, values []string, labels Labels, curry []curriedLabelValue) bool {
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for l, v := range labels {
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// Check if the target label exists in our metrics and get the index.
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varLabelIndex, validLabel := indexOf(l, desc.variableLabels)
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if validLabel {
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// Check the value of that label against the target value.
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// We don't consider curried values in partial matches.
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matches, curried := valueMatchesVariableOrCurriedValue(v, varLabelIndex, values, curry)
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if matches && !curried {
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continue
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}
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}
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return false
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}
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return true
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}
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// getOrCreateMetricWithLabelValues retrieves the metric by hash and label value
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// or creates it and returns the new one.
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//

‎prometheus/vec_test.go‎

Lines changed: 87 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -125,6 +125,93 @@ func testDeleteLabelValues(t *testing.T, vec *GaugeVec) {
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}
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}
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func TestDeletePartialMatch(t *testing.T) {
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baseVec := NewGaugeVec(
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GaugeOpts{
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Name: "test",
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Help: "helpless",
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},
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[]string{"l1", "l2", "l3"},
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)
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assertNoMetric := func(t *testing.T) {
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if n := len(baseVec.metricMap.metrics); n != 0 {
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t.Error("expected no metrics, got", n)
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}
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}
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// No metric value is set.
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if got, want := baseVec.DeletePartialMatch(Labels{"l1": "v1", "l2": "v2"}), 0; got != want {
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t.Errorf("got %v, want %v", got, want)
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}
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baseVec.With(Labels{"l1": "baseValue1", "l2": "baseValue2", "l3": "baseValue3"}).Inc()
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baseVec.With(Labels{"l1": "multiDeleteV1", "l2": "diff1BaseValue2", "l3": "v3"}).(Gauge).Set(42)
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baseVec.With(Labels{"l1": "multiDeleteV1", "l2": "diff2BaseValue2", "l3": "v3"}).(Gauge).Set(84)
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baseVec.With(Labels{"l1": "multiDeleteV1", "l2": "diff3BaseValue2", "l3": "v3"}).(Gauge).Set(168)
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curriedVec := baseVec.MustCurryWith(Labels{"l2": "curriedValue2"})
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curriedVec.WithLabelValues("curriedValue1", "curriedValue3").Inc()
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curriedVec.WithLabelValues("curriedValue1", "differentCurriedValue3").Inc()
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curriedVec.WithLabelValues("differentCurriedValue1", "differentCurriedValue3").Inc()
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// Try to delete nonexistent label with existent value from curried vector.
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if got, want := curriedVec.DeletePartialMatch(Labels{"lx": "curriedValue1"}), 0; got != want {
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t.Errorf("got %v, want %v", got, want)
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}
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// Try to delete valid label with nonexistent value from curried vector.
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if got, want := curriedVec.DeletePartialMatch(Labels{"l1": "badValue1"}), 0; got != want {
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t.Errorf("got %v, want %v", got, want)
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}
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// Try to delete from a curried vector based on labels which were curried.
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// This operation succeeds when run against the base vector below.
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if got, want := curriedVec.DeletePartialMatch(Labels{"l2": "curriedValue2"}), 0; got != want {
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t.Errorf("got %v, want %v", got, want)
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}
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// Try to delete from a curried vector based on labels which were curried,
175+
// but the value actually exists in the base vector.
176+
if got, want := curriedVec.DeletePartialMatch(Labels{"l2": "baseValue2"}), 0; got != want {
177+
t.Errorf("got %v, want %v", got, want)
178+
}
179+
180+
// Delete multiple matching metrics from a curried vector based on partial values.
181+
if got, want := curriedVec.DeletePartialMatch(Labels{"l1": "curriedValue1"}), 2; got != want {
182+
t.Errorf("got %v, want %v", got, want)
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}
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// Try to delete nonexistent label with existent value from base vector.
186+
if got, want := baseVec.DeletePartialMatch(Labels{"lx": "curriedValue1"}), 0; got != want {
187+
t.Errorf("got %v, want %v", got, want)
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}
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// Try to delete partially invalid labels from base vector.
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if got, want := baseVec.DeletePartialMatch(Labels{"l1": "baseValue1", "l2": "badValue2"}), 0; got != want {
192+
t.Errorf("got %v, want %v", got, want)
193+
}
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195+
// Delete from the base vector based on values which were curried.
196+
// This operation fails when run against a curried vector above.
197+
if got, want := baseVec.DeletePartialMatch(Labels{"l2": "curriedValue2"}), 1; got != want {
198+
t.Errorf("got %v, want %v", got, want)
199+
}
200+
201+
// Delete multiple metrics from the base vector based on a single valid label.
202+
if got, want := baseVec.DeletePartialMatch(Labels{"l1": "multiDeleteV1"}), 3; got != want {
203+
t.Errorf("got %v, want %v", got, want)
204+
}
205+
206+
// Delete from the base vector based on values which were not curried.
207+
if got, want := baseVec.DeletePartialMatch(Labels{"l3": "baseValue3"}), 1; got != want {
208+
t.Errorf("got %v, want %v", got, want)
209+
}
210+
211+
// All metrics should have been deleted now.
212+
assertNoMetric(t)
213+
}
214+
128215
func TestMetricVec(t *testing.T) {
129216
vec := NewGaugeVec(
130217
GaugeOpts{

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