basic cel-java integration/test

Author: sergiitk

gradle/libs.versions.toml

@@ -27,6 +27,7 @@ commons-math3 = "org.apache.commons:commons-math3:3.6.1"
 conscrypt = "org.conscrypt:conscrypt-openjdk-uber:2.5.2"
 cronet-api = "org.chromium.net:cronet-api:119.6045.31"
 cronet-embedded = "org.chromium.net:cronet-embedded:119.6045.31"
+dev-cel = "dev.cel:cel:0.6.0"
 errorprone-annotations = "com.google.errorprone:error_prone_annotations:2.28.0"
 errorprone-core = "com.google.errorprone:error_prone_core:2.28.0"
 google-api-protos = "com.google.api.grpc:proto-google-common-protos:2.41.0"

xds/build.gradle

@@ -52,6 +52,7 @@ dependencies {
             project(':grpc-services'),
             project(':grpc-auth'),
             project(path: ':grpc-alts', configuration: 'shadow'),
+            libraries.dev.cel,
             libraries.guava,
             libraries.gson,
             libraries.re2j,

xds/src/main/java/io/grpc/xds/internal/matchers/CelMatcher.java

@@ -16,27 +16,52 @@
 
 package io.grpc.xds.internal.matchers;
 
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import com.google.common.collect.ImmutableMap;
+import dev.cel.common.CelAbstractSyntaxTree;
+import dev.cel.runtime.CelEvaluationException;
+import dev.cel.runtime.CelRuntime;
+import dev.cel.runtime.CelRuntimeFactory;
 import java.util.function.Predicate;
 
 /** Unified Matcher API: xds.type.matcher.v3.CelMatcher. */
 public class CelMatcher implements Predicate<HttpMatchInput> {
+  private static final CelRuntime CEL_RUNTIME =
+      CelRuntimeFactory.standardCelRuntimeBuilder().build();
+
+  private final CelRuntime.Program program;
   private final String description;
 
-  public CelMatcher(String description) {
-    // TODO(sergiitk): cache parsed CEL expressions
+  private CelMatcher(CelAbstractSyntaxTree ast, String description) throws CelEvaluationException {
+    this.program = CEL_RUNTIME.createProgram(checkNotNull(ast));
     this.description = description != null ? description : "";
   }
 
+  public static CelMatcher create(CelAbstractSyntaxTree ast) throws CelEvaluationException {
+    return new CelMatcher(ast, null);
+  }
+
+  public static CelMatcher create(CelAbstractSyntaxTree ast, String description)
+      throws CelEvaluationException {
+    return new CelMatcher(ast, description);
+  }
+
   public String description() {
     return description;
   }
 
   @Override
   public boolean test(HttpMatchInput httpMatchInput) {
-    if (httpMatchInput.headers().keys().isEmpty()) {
+    // if (httpMatchInput.headers().keys().isEmpty()) {
+    //   return false;
+    // }
+    // TODO(sergiitk): [IMPL] convert headers to cel args
+    try {
+      return (boolean) program.eval(ImmutableMap.of("my_var", "Hello World"));
+    } catch (CelEvaluationException e) {
+      // TODO(sergiitk): [IMPL] log cel error?
       return false;
     }
-    // TODO(sergiitk): [IMPL] convert headers to cel args
-    return true;
   }
 }

xds/src/test/java/io/grpc/xds/internal/matchers/CelMatcherTest.java

@@ -18,20 +18,54 @@
 
 import static com.google.common.truth.Truth.assertThat;
 
+import dev.cel.common.CelAbstractSyntaxTree;
+import dev.cel.common.CelValidationResult;
+import dev.cel.common.types.SimpleType;
+import dev.cel.compiler.CelCompiler;
+import dev.cel.compiler.CelCompilerFactory;
+import dev.cel.runtime.CelEvaluationException;
+import io.grpc.Metadata;
+import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
 
 @RunWith(JUnit4.class)
 public class CelMatcherTest {
+  // Construct the compilation and runtime environments.
+  // These instances are immutable and thus trivially thread-safe and amenable to caching.
+  private static final CelCompiler CEL_COMPILER =
+      CelCompilerFactory.standardCelCompilerBuilder().addVar("my_var", SimpleType.STRING).build();
+  private static final CelValidationResult celProg1 =
+      CEL_COMPILER.compile("type(my_var) == string");
+
+  CelAbstractSyntaxTree ast1;
+  CelMatcher matcher1;
+
+  private static final HttpMatchInput fakeInput = new HttpMatchInput() {
+    @Override
+    public Metadata headers() {
+      return new Metadata();
+    }
+  };
+
+  @Before
+  public void setUp() throws Exception {
+    ast1 = celProg1.getAst();
+    matcher1 = CelMatcher.create(ast1);
+  }
 
   @Test
-  public void construct() {
+  public void construct() throws CelEvaluationException {
+    assertThat(matcher1.description()).isEqualTo("");
+
     String description = "Optional description";
-    CelMatcher matcher = new CelMatcher(description);
+    CelMatcher matcher = CelMatcher.create(ast1, description);
     assertThat(matcher.description()).isEqualTo(description);
+  }
 
-    matcher = new CelMatcher(null);
-    assertThat(matcher.description()).isEqualTo("");
+  @Test
+  public void testProgTrue() {
+    assertThat(matcher1.test(fakeInput)).isTrue();
   }
 }