core: support query matching using tags function (#1743)

Add `Query.matches` overload that takes a function to supply
the tags. This can be used for cases like `LwcEvent` to do
matching where the data structure for the tags may not be
known.

atlas-core/src/main/scala/com/netflix/atlas/core/model/Query.scala

@@ -21,6 +21,9 @@ import com.netflix.spectator.impl.PatternMatcher
 
 sealed trait Query extends Expr {
 
+  /** Returns true if the query expression matches the tags provided by the function. */
+  def matches(tags: String => String): Boolean
+
   /** Returns true if the query expression matches the tags. */
   def matches(tags: Map[String, String]): Boolean
 
@@ -238,6 +241,8 @@ object Query {
 
   case object True extends Query {
 
+    def matches(tags: String => String): Boolean = true
+
     def matches(tags: Map[String, String]): Boolean = true
 
     def matchesAny(tags: Map[String, List[String]]): Boolean = true
@@ -259,6 +264,8 @@ object Query {
 
   case object False extends Query {
 
+    def matches(tags: String => String): Boolean = false
+
     def matches(tags: Map[String, String]): Boolean = false
 
     def matchesAny(tags: Map[String, List[String]]): Boolean = false
@@ -287,6 +294,11 @@ object Query {
 
     def check(s: String): Boolean
 
+    def matches(tags: String => String): Boolean = {
+      val v = tags(k)
+      v != null && check(v)
+    }
+
     def matches(tags: Map[String, String]): Boolean = {
       tags match {
         case ts: SortedTagMap =>
@@ -314,6 +326,8 @@ object Query {
 
   case class HasKey(k: String) extends KeyQuery {
 
+    def matches(tags: String => String): Boolean = tags(k) != null
+
     def matches(tags: Map[String, String]): Boolean = tags.contains(k)
 
     def matchesAny(tags: Map[String, List[String]]): Boolean = tags.contains(k)
@@ -436,6 +450,8 @@ object Query {
 
   case class And(q1: Query, q2: Query) extends Query {
 
+    def matches(tags: String => String): Boolean = q1.matches(tags) && q2.matches(tags)
+
     def matches(tags: Map[String, String]): Boolean = q1.matches(tags) && q2.matches(tags)
 
     def matchesAny(tags: Map[String, List[String]]): Boolean =
@@ -452,6 +468,8 @@ object Query {
 
   case class Or(q1: Query, q2: Query) extends Query {
 
+    def matches(tags: String => String): Boolean = q1.matches(tags) || q2.matches(tags)
+
     def matches(tags: Map[String, String]): Boolean = q1.matches(tags) || q2.matches(tags)
 
     def matchesAny(tags: Map[String, List[String]]): Boolean =
@@ -468,6 +486,8 @@ object Query {
 
   case class Not(q: Query) extends Query {
 
+    def matches(tags: String => String): Boolean = !q.matches(tags)
+
     def matches(tags: Map[String, String]): Boolean = !q.matches(tags)
 
     def matchesAny(tags: Map[String, List[String]]): Boolean = !q.matchesAny(tags)

atlas-core/src/test/scala/com/netflix/atlas/core/model/QuerySuite.scala

@@ -25,6 +25,7 @@ class QuerySuite extends FunSuite {
   def matches(q: Query, tags: Map[String, String]): Boolean = {
     val result = q.matches(tags)
     assertEquals(result, q.matches(SortedTagMap(tags)))
+    assertEquals(result, q.matches(SortedTagMap(tags).getOrNull _))
     result
   }
 

atlas-lwc-events/src/test/scala/com/netflix/atlas/lwc/events/LwcEventClientSuite.scala

@@ -15,6 +15,7 @@
  */
 package com.netflix.atlas.lwc.events
 
+import com.netflix.atlas.core.model.Query
 import com.netflix.atlas.core.util.SortedTagMap
 import com.netflix.atlas.json.Json
 import com.netflix.spectator.api.Clock
@@ -218,6 +219,13 @@ class LwcEventClientSuite extends FunSuite {
     assert(vs.forall(_.contains(""""tags":{"value":"duration"}""")))
     assert(vs.forall(_.contains(""""value":8.4""")))
   }
+
+  test("check if event matches query") {
+    val matching = Query.And(Query.Equal("app", "www"), Query.Equal("node", "i-123"))
+    val nonMatching = Query.And(Query.Equal("app", "www"), Query.Equal("node", "i-124"))
+    assert(matching.matches(sampleLwcEvent.tagValue _))
+    assert(!nonMatching.matches(sampleLwcEvent.tagValue _))
+  }
 }
 
 object LwcEventClientSuite {