Support filtering label allowlist by "all"

Support filtering label allowlist by "all", which will expand to the
enabled resources, while infering their values based on its value(s).

Signed-off-by: Pranshu Srivastava <[email protected]>

.gitignore

@@ -37,6 +37,7 @@ _testmain.go
 
 *.iml
 .idea/
+.run/
 
 # Generated CLI help file
 help.txt

internal/store/builder.go

@@ -202,7 +202,16 @@ func (b *Builder) WithAllowAnnotations(annotations map[string][]string) {
 // WithAllowLabels configures which labels can be returned for metrics
 func (b *Builder) WithAllowLabels(labels map[string][]string) {
 	if len(labels) > 0 {
-		b.allowLabelsList = labels
+		// "all" takes precedence over other specifications
+		if allowedLabels, ok := labels["all"]; ok {
+			m := make(map[string][]string)
+			for _, resource := range b.enabledResources {
+				m[resource] = allowedLabels
+			}
+			b.allowLabelsList = m
+		} else {
+			b.allowLabelsList = labels
+		}
 	}
 }