Add LabelQuerier.LabelValuesSet method

Signed-off-by: Arve Knudsen <[email protected]>

storage/fanout_test.go

@@ -237,6 +237,10 @@ func (errQuerier) LabelValues(string, ...*labels.Matcher) ([]string, storage.War
 	return nil, nil, errors.New("label values error")
 }
 
+func (errQuerier) LabelValuesStream(string, ...*labels.Matcher) (LabelValuesSet, error) {
+	return nil, errors.New("label values set error")
+}
+
 func (errQuerier) LabelNames(...*labels.Matcher) ([]string, storage.Warnings, error) {
 	return nil, nil, errors.New("label names error")
 }

storage/interface.go

@@ -122,6 +122,10 @@ func (q *MockQuerier) LabelValues(string, ...*labels.Matcher) ([]string, Warning
 	return nil, nil, nil
 }
 
+func (q *MockQuerier) LabelValuesStream(string, ...*labels.Matcher) (LabelValuesSet, error) {
+	return nil, nil
+}
+
 func (q *MockQuerier) LabelNames(...*labels.Matcher) ([]string, Warnings, error) {
 	return nil, nil, nil
 }
@@ -159,6 +163,12 @@ type LabelQuerier interface {
 	// to label values of metrics matching the matchers.
 	LabelValues(name string, matchers ...*labels.Matcher) ([]string, Warnings, error)
 
+	// LabelValuesSet returns an iterator over all potential values for a label name.
+	// It is not safe to use the strings beyond the lifetime of the querier.
+	// If matchers are specified the returned result set is reduced
+	// to label values of metrics matching the matchers.
+	LabelValuesSet(name string, matchers ...*labels.Matcher) (LabelValuesSet, error)
+
 	// LabelNames returns all the unique label names present in the block in sorted order.
 	// If matchers are specified the returned result set is reduced
 	// to label names of metrics matching the matchers.
@@ -444,3 +454,16 @@ type ChunkIterable interface {
 }
 
 type Warnings []error
+
+// LabelValuesSet contains a set of label values.
+type LabelValuesSet interface {
+	Next() bool
+	// At returns a label value.
+	At() string
+	// The error that iteration as failed with.
+	// When an error occurs, set cannot continue to iterate.
+	Err() error
+	// A collection of warnings for the whole set.
+	// Warnings could be return even iteration has not failed with error.
+	Warnings() Warnings
+}

storage/merge_test.go

@@ -1014,6 +1014,16 @@ func (m *mockGenericQuerier) LabelValues(name string, matchers ...*labels.Matche
 	return m.resp, m.warnings, m.err
 }
 
+func (m *mockGenericQuerier) LabelValuesSet(name string, matchers ...*labels.Matcher) (LabelValuesSet, error) {
+	m.mtx.Lock()
+	m.labelNamesRequested = append(m.labelNamesRequested, labelNameRequest{
+		name:     name,
+		matchers: matchers,
+	})
+	m.mtx.Unlock()
+	return m.resp, m.warnings, m.err
+}
+
 func (m *mockGenericQuerier) LabelNames(...*labels.Matcher) ([]string, Warnings, error) {
 	m.mtx.Lock()
 	m.labelNamesCalls++

storage/noop.go

@@ -32,6 +32,10 @@ func (noopQuerier) LabelValues(string, ...*labels.Matcher) ([]string, Warnings,
 	return nil, nil, nil
 }
 
+func (noopQuerier) LabelValuesSet(string, ...*labels.Matcher) (LabelValuesSet, error) {
+	return nil, nil
+}
+
 func (noopQuerier) LabelNames(...*labels.Matcher) ([]string, Warnings, error) {
 	return nil, nil, nil
 }
@@ -55,6 +59,13 @@ func (noopChunkQuerier) LabelValues(string, ...*labels.Matcher) ([]string, Warni
 	return nil, nil, nil
 }
 
+func (noopChunkQuerier) LabelValuesSet(string, ...*labels.Matcher) (LabelValuesSet, Warnings, error) {
+	return nil, nil
+}
+func (noopChunkQuerier) LabelValues(string, ...*labels.Matcher) ([]string, Warnings, error) {
+	return nil, nil, nil
+}
+
 func (noopChunkQuerier) LabelNames(...*labels.Matcher) ([]string, Warnings, error) {
 	return nil, nil, nil
 }

storage/remote/read.go

@@ -217,6 +217,12 @@ func (q *querier) LabelValues(string, ...*labels.Matcher) ([]string, storage.War
 	return nil, nil, errors.New("not implemented")
 }
 
+// LabelValuesStream implements storage.Querier and is a noop.
+func (q *querier) LabelValuesStream(string, ...*labels.Matcher) ([]string, error) {
+	// TODO: Implement: https://github.com/prometheus/prometheus/issues/3351
+	return nil, errors.New("not implemented")
+}
+
 // LabelNames implements storage.Querier and is a noop.
 func (q *querier) LabelNames(...*labels.Matcher) ([]string, storage.Warnings, error) {
 	// TODO: Implement: https://github.com/prometheus/prometheus/issues/3351

storage/secondary.go

@@ -55,6 +55,11 @@ func (s *secondaryQuerier) LabelValues(name string, matchers ...*labels.Matcher)
 	return vals, w, nil
 }
 
+func (s *secondaryQuerier) LabelValuesSet(name string, matchers ...*labels.Matcher) (LabelValuesSet, error) {
+	vals, err := s.genericQuerier.LabelValuesStream(name, matchers...)
+	return vals, err
+}
+
 func (s *secondaryQuerier) LabelNames(matchers ...*labels.Matcher) ([]string, Warnings, error) {
 	names, w, err := s.genericQuerier.LabelNames(matchers...)
 	if err != nil {