Add a KeyName argument to LabelFilter::should_include_label (metr…

…ics-rs#342)

metrics-tracing-context/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "metrics-tracing-context"
-version = "0.12.0"
+version = "0.13.0"
 authors = ["MOZGIII <mike-n@narod.ru>"]
 edition = "2018"
 rust-version = "1.56.1"

metrics-tracing-context/src/label_filter.rs

@@ -2,21 +2,22 @@
 
 use std::collections::HashSet;
 
-use metrics::Label;
+use metrics::{KeyName, Label};
 
 /// [`LabelFilter`] trait encapsulates the ability to filter labels, i.e.
 /// determining whether a particular span field should be included as a label or not.
 pub trait LabelFilter {
-    /// Returns `true` if the passed label should be included in the key.
-    fn should_include_label(&self, label: &Label) -> bool;
+    /// Returns `true` if the passed `label` of the metric named `name` should
+    /// be included in the key.
+    fn should_include_label(&self, name: &KeyName, label: &Label) -> bool;
 }
 
 /// A [`LabelFilter`] that allows all labels.
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 pub struct IncludeAll;
 
 impl LabelFilter for IncludeAll {
-    fn should_include_label(&self, _label: &Label) -> bool {
+    fn should_include_label(&self, _name: &KeyName, _label: &Label) -> bool {
         true
     }
 }
@@ -40,7 +41,7 @@ impl Allowlist {
 }
 
 impl LabelFilter for Allowlist {
-    fn should_include_label(&self, label: &Label) -> bool {
+    fn should_include_label(&self, _name: &KeyName, label: &Label) -> bool {
         self.label_names.contains(label.key())
     }
 }

metrics-tracing-context/src/lib.rs

@@ -178,7 +178,9 @@ where
 
                             let filtered_labels = new_labels
                                 .iter()
-                                .filter(|label| self.label_filter.should_include_label(label))
+                                .filter(|label| {
+                                    self.label_filter.should_include_label(&name, label)
+                                })
                                 .cloned();
                             labels.extend(filtered_labels);
 

metrics-tracing-context/tests/integration.rs

@@ -1,4 +1,4 @@
-use metrics::{counter, Key, Label};
+use metrics::{counter, Key, KeyName, Label};
 use metrics_tracing_context::{LabelFilter, MetricsLayer, TracingContextLayer};
 use metrics_util::debugging::{DebugValue, DebuggingRecorder, Snapshotter};
 use metrics_util::{layers::Layer, CompositeKey, MetricKind};
@@ -317,7 +317,7 @@ fn test_nested_spans() {
 struct OnlyUser;
 
 impl LabelFilter for OnlyUser {
-    fn should_include_label(&self, label: &Label) -> bool {
+    fn should_include_label(&self, _name: &KeyName, label: &Label) -> bool {
         label.key() == "user"
     }
 }