add metadata (#186)

kayenta-core/src/main/java/com/netflix/kayenta/canary/CanaryExecutionRequest.java

@@ -20,6 +20,7 @@
 import javax.validation.constraints.NotNull;
 import java.time.Duration;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
@@ -30,6 +31,8 @@ public class CanaryExecutionRequest {
 
   protected CanaryClassifierThresholdsConfig thresholds;
 
+  protected List<Metadata> metadata;
+
   public Duration calculateDuration() {
     Set<Duration> durationsFound = new HashSet<>();
 

kayenta-core/src/main/java/com/netflix/kayenta/canary/Metadata.java

@@ -0,0 +1,23 @@
+package com.netflix.kayenta.canary;
+
+import lombok.Builder;
+import lombok.Data;
+import lombok.Getter;
+import lombok.NonNull;
+
+@Data
+public class Metadata {
+  @Getter
+  @NonNull
+  protected String name;
+
+  @Getter
+  @NonNull
+  protected String value;
+
+  // 'hidden' is a UI-hint to show or not show this value by default in the UI,
+  // likely in a generic way.
+  @Getter
+  @Builder.Default
+  protected Boolean hidden = false;
+}