[Backport 2.x] Eliminate Google Guava dependency (#383)

build.gradle

@@ -146,7 +146,6 @@ configurations {
 dependencies {
     implementation "org.opensearch:opensearch:${opensearch_version}"
     implementation 'org.junit.jupiter:junit-jupiter:5.10.1'
-    implementation "com.google.guava:guava:33.0.0-jre"
     api group: 'org.opensearch', name:'opensearch-ml-client', version: "${opensearch_build}"
     api group: 'org.opensearch.client', name: 'opensearch-rest-client', version: "${opensearch_version}"
     implementation group: 'org.apache.commons', name: 'commons-lang3', version: '3.14.0'
@@ -159,7 +158,7 @@ dependencies {
 
     configurations.all {
         resolutionStrategy {
-            force("com.google.guava:guava:33.0.0-jre") // CVE for 31.1
+            force("com.google.guava:guava:33.0.0-jre") // CVE for 31.1, keep to force transitive dependencies
             force("org.eclipse.platform:org.eclipse.core.runtime:3.30.0") // CVE for < 3.29.0
             force("com.fasterxml.jackson.core:jackson-core:2.16.1") // Dependency Jar Hell
         }

src/main/java/org/opensearch/flowframework/indices/FlowFrameworkIndicesHandler.java

@@ -8,7 +8,6 @@
  */
 package org.opensearch.flowframework.indices;
 
-import com.google.common.io.Resources;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.ExceptionsHelper;
@@ -39,12 +38,11 @@
 import org.opensearch.flowframework.model.Template;
 import org.opensearch.flowframework.model.WorkflowState;
 import org.opensearch.flowframework.util.EncryptorUtils;
+import org.opensearch.flowframework.util.ParseUtils;
 import org.opensearch.script.Script;
 import org.opensearch.script.ScriptType;
 
 import java.io.IOException;
-import java.net.URL;
-import java.nio.charset.StandardCharsets;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
@@ -292,8 +290,7 @@ private void shouldUpdateIndex(String indexName, Integer newVersion, ActionListe
      * @throws IOException IOException if mapping file can't be read correctly
      */
     public static String getIndexMappings(String mapping) throws IOException {
-        URL url = FlowFrameworkIndicesHandler.class.getClassLoader().getResource(mapping);
-        return Resources.toString(url, StandardCharsets.UTF_8);
+        return ParseUtils.resourceToString("/" + mapping);
     }
 
     /**

src/main/java/org/opensearch/flowframework/model/WorkflowValidator.java

@@ -8,13 +8,10 @@
  */
 package org.opensearch.flowframework.model;
 
-import com.google.common.io.Resources;
 import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.flowframework.util.ParseUtils;
 
 import java.io.IOException;
-import java.net.URL;
-import java.nio.charset.StandardCharsets;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -62,8 +59,7 @@ public static WorkflowValidator parse(XContentParser parser) throws IOException
      * @throws IOException on failure to read and parse the json file
      */
     public static WorkflowValidator parse(String file) throws IOException {
-        URL url = WorkflowValidator.class.getClassLoader().getResource(file);
-        String json = Resources.toString(url, StandardCharsets.UTF_8);
+        String json = ParseUtils.resourceToString("/" + file);
         return parse(ParseUtils.jsonToParser(json));
     }
 

src/main/java/org/opensearch/flowframework/util/ParseUtils.java

@@ -11,6 +11,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.client.Client;
+import org.opensearch.common.io.Streams;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.common.xcontent.XContentType;
@@ -26,7 +27,9 @@
 import org.opensearch.flowframework.workflow.WorkflowData;
 import org.opensearch.ml.common.agent.LLMSpec;
 
+import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.io.InputStream;
 import java.time.Instant;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -71,6 +74,25 @@
         return parser;
     }
 
+    /**
+     * Reads a file from the classpath into a String. Useful for reading JSON mapping files.
+     *
+     * @param path A string identifying the resource on the class path
+     * @return A string containing the contents of the file as UTF-8
+     * @throws IOException if file is not found or error reading
+     */
+    public static String resourceToString(String path) throws IOException {
+        try (InputStream is = ParseUtils.class.getResourceAsStream(path)) {
+            if (is == null) {
+                throw new FileNotFoundException("Resource [" + path + "] not found in classpath");
+            }
+            final StringBuilder sb = new StringBuilder();
+            // Read as UTF-8
+            Streams.readAllLines(is, sb::append);
+            return sb.toString();
+        }
+    }
+
     /**
      * Builds an XContent object representing a map of String keys to String values.
      *

src/test/java/org/opensearch/flowframework/TestHelpers.java

@@ -8,7 +8,6 @@
  */
 package org.opensearch.flowframework;
 
-import com.google.common.io.Resources;
 import org.apache.http.Header;
 import org.apache.http.HttpEntity;
 import org.apache.http.nio.entity.NStringEntity;
@@ -31,13 +30,12 @@
 import org.opensearch.core.xcontent.ToXContentObject;
 import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.flowframework.model.Template;
+import org.opensearch.flowframework.util.ParseUtils;
 
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
-import java.net.URL;
-import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
@@ -51,8 +49,7 @@
 public class TestHelpers {
 
     public static Template createTemplateFromFile(String fileName) throws IOException {
-        URL url = TestHelpers.class.getClassLoader().getResource("template/" + fileName);
-        String json = Resources.toString(url, StandardCharsets.UTF_8);
+        String json = ParseUtils.resourceToString("/template/" + fileName);
         return Template.parse(json);
     }
 

src/test/java/org/opensearch/flowframework/util/ParseUtilsTests.java

@@ -12,6 +12,7 @@
 import org.opensearch.core.rest.RestStatus;
 import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.core.xcontent.XContentParser;
+import org.opensearch.core.xcontent.XContentParser.Token;
 import org.opensearch.flowframework.exception.FlowFrameworkException;
 import org.opensearch.flowframework.workflow.WorkflowData;
 import org.opensearch.test.OpenSearchTestCase;
@@ -23,6 +24,16 @@
 import java.util.Set;
 
 public class ParseUtilsTests extends OpenSearchTestCase {
+    public void testResourceToStringToJson() throws IOException {
+        String json = ParseUtils.resourceToString("/template/finaltemplate.json");
+        assertTrue(json.startsWith("{"));
+        assertTrue(json.contains("name"));
+        try (XContentParser parser = ParseUtils.jsonToParser(json)) {
+            assertEquals(Token.FIELD_NAME, parser.nextToken());
+            assertEquals("name", parser.currentName());
+        }
+    }
+
     public void testToInstant() throws IOException {
         long epochMilli = Instant.now().toEpochMilli();
         XContentBuilder builder = XContentFactory.jsonBuilder().value(epochMilli);