[Story] Replace LabelSelectorMatcher with MatchExpression

[andrewazores]

diff --git a/src/main/java/io/cryostat/graphql/RootNode.java b/src/main/java/io/cryostat/graphql/RootNode.java
index 4af6eef..c2facb6 100644
--- a/src/main/java/io/cryostat/graphql/RootNode.java
+++ b/src/main/java/io/cryostat/graphql/RootNode.java
@@ -21,6 +21,8 @@ import java.util.Set;
 import java.util.function.Predicate;
 
 import io.cryostat.discovery.DiscoveryNode;
+import io.cryostat.expressions.MatchExpression;
+import io.cryostat.expressions.MatchExpressionEvaluator;
 import io.cryostat.graphql.matchers.LabelSelectorMatcher;
 
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
@@ -30,6 +32,7 @@ import org.eclipse.microprofile.graphql.Description;
 import org.eclipse.microprofile.graphql.GraphQLApi;
 import org.eclipse.microprofile.graphql.Query;
 import org.eclipse.microprofile.graphql.Source;
+import org.projectnessie.cel.tools.ScriptException;
 
 @GraphQLApi
 public class RootNode {
@@ -77,6 +80,7 @@ public class RootNode {
         public @Nullable List<String> nodeTypes;
         public @Nullable List<String> labels;
         public @Nullable List<String> annotations;
+        public @Nullable List<String> matchExpressions;
 
         @Override
         public boolean test(DiscoveryNode t) {
@@ -114,6 +118,24 @@ public class RootNode {
                                                                                             .annotations
                                                                                             .merged())));
 
+            MatchExpressionEvaluator evaluator = new MatchExpressionEvaluator(); // WRONG
+            Predicate<DiscoveryNode> matchesExpression =
+                    n ->
+                            matchExpressions == null
+                                    || (n.target != null
+                                            && matchExpressions.stream()
+                                                    .map(MatchExpression::new)
+                                                    .allMatch(
+                                                            expr -> {
+                                                                try {
+                                                                    return evaluator.applies(
+                                                                            expr, n.target);
+                                                                } catch (ScriptException e) {
+                                                                    // FIXME log this
+                                                                    return false;
+                                                                }
+                                                            }));
+
             return List.of(
                             matchesId,
                             matchesIds,
@@ -122,7 +144,8 @@ public class RootNode {
                             matchesNames,
                             matchesNodeTypes,
                             matchesLabels,
-                            matchesAnnotations)
+                            matchesAnnotations,
+                            matchesExpression)
                     .stream()
                     .reduce(x -> true, Predicate::and)
                     .test(t);
diff --git a/src/test/java/itest/GraphQLTest.java b/src/test/java/itest/GraphQLTest.java
index 3d28654..15d1b69 100644
--- a/src/test/java/itest/GraphQLTest.java
+++ b/src/test/java/itest/GraphQLTest.java
@@ -307,8 +307,8 @@ class GraphQLTest extends StandardSelfTest {
         JsonObject query2 = new JsonObject();
         query2.put(
                 "query",
-                "mutation { createRecording( nodes:{annotations: ["
-                        + "\"REALM = Custom Targets\""
+                "mutation { createRecording( nodes:{matchExpressions: ["
+                        + "\"target.annotations[\"REALM\"] == \"Custom Targets\"\""
                         + "]}, recording: { name: \"test\", template:"
                         + " \"Profiling\", templateType: \"TARGET\", duration: 30, continuous:"
                         + " false, archiveOnStop: true, toDisk: true }) { name state duration"

Rough prototype of the idea. The LabelSelectorMatcher has a very limited syntax and is only used for matching on maps of labels and annotations. This could easily be a MatchExpression instead and use CEL syntax that is also already used for Automated Rules and Stored Credentials, instead of its own k8s-inspired syntax that only appears in GraphQL query filters.