Transformation improvements.

I've added all of the transformer jars to the runtime closure of the replayer since it's going to be a challenge for users using a cloud-deployment shrink-wrap solution to add addition jarfiles.
Change the syntax/rules for Transformer configs.
* If no argument was specified for the transformer config, no transformer used, regardless of what's in the classpath.
* To use multiple transformers, you’ll need to specify the transformer-config as a json array (of json transformer configs)
* To use one transformer with default settings, you can JUST put the name of the transformer in the arg.  e.g. --transformer-config JsonTransformerForOpenSearch23PlusTargetTransformerProvider.

I've also updated the key name to only use the short, simple name of a class rather than the fully qualified one with the namespace.
Add a NoopTransformer, which makes unit and sanity testing a lot simpler.

Signed-off-by: Greg Schohn <greg.schohn@gmail.com>

TrafficCapture/replayerPlugins/jsonMessageTransformers/jsonJoltMessageTransformerProvider/src/test/java/org/opensearch/migrations/replay/MultipleJoltScriptsTest.java

@@ -22,7 +22,7 @@ private static Map<String,Object> parseAsMap(String contents) throws Exception {
     @Test
     public void testAddGzip() throws Exception {
         final var addGzip =
-                "[{\"org.opensearch.migrations.transform.JsonJoltTransformerProvider\": { \"canned\": \"ADD_GZIP\" }}]";
+                "[{\"JsonJoltTransformerProvider\": { \"canned\": \"ADD_GZIP\" }}]";
         var toNewHostTransformer = new TransformationLoader().getTransformerFactoryLoader("testhostname",
                 addGzip);
         var origDocStr = SampleContents.loadSampleJsonRequestAsString();
@@ -37,8 +37,8 @@ public void testAddGzip() throws Exception {
     @Test
     public void testAddGzipAndCustom() throws Exception {
         final var addGzip = "[" +
-                "{\"org.opensearch.migrations.transform.JsonJoltTransformerProvider\": { \"canned\": \"ADD_GZIP\" }}," +
-                "{ \"org.opensearch.migrations.transform.JsonJoltTransformerProvider\":" +
+                "{\"JsonJoltTransformerProvider\": { \"canned\": \"ADD_GZIP\" }}," +
+                "{ \"JsonJoltTransformerProvider\":" +
                 "  {\"script\": \n" +
                 "    { \"operation\": \"modify-overwrite-beta\", \"spec\": " +
                 "      { \"headers\": {\"newHeader\": \"newValue\"}}}}}" +

TrafficCapture/replayerPlugins/jsonMessageTransformers/jsonMessageTransformerInterface/src/main/java/org/opensearch/migrations/transform/NoopTransformerProvider.java

@@ -0,0 +1,17 @@
+package org.opensearch.migrations.transform;
+
+import java.util.Map;
+
+public class NoopTransformerProvider implements IJsonTransformerProvider {
+    private static class NoopTransformer implements IJsonTransformer {
+        @Override
+        public Map<String, Object> transformJson(Map<String, Object> incomingJson) {
+            return incomingJson;
+        }
+    }
+
+    @Override
+    public IJsonTransformer createTransformer(Object jsonConfig) {
+        return new NoopTransformer();
+    }
+}

TrafficCapture/replayerPlugins/jsonMessageTransformers/jsonMessageTransformerInterface/src/main/resources/META-INF.services/org.opensearch.migrations.transform.IJsonTransformerProvider

@@ -0,0 +1 @@
+org.opensearch.migrations.transform.NoopTransformerProvider

TrafficCapture/trafficReplayer/build.gradle

@@ -40,7 +40,9 @@ dependencies {
     implementation project(':captureProtobufs')
     implementation project(':coreUtilities')
     implementation project(':replayerPlugins:jsonMessageTransformers:jsonMessageTransformerInterface')
-    implementation project(':replayerPlugins:jsonMessageTransformers:openSearch23PlusTargetTransformerProvider')
+    runtimeOnly project(':replayerPlugins:jsonMessageTransformers:jsonJMESPathMessageTransformerProvider')
+    runtimeOnly project(':replayerPlugins:jsonMessageTransformers:jsonJoltMessageTransformerProvider')
+    runtimeOnly project(':replayerPlugins:jsonMessageTransformers:openSearch23PlusTargetTransformerProvider')
 
     implementation group: 'com.beust', name: 'jcommander', version: '1.82'
     implementation group: 'com.fasterxml.jackson.core', name: 'jackson-databind', version: '2.15.0'
@@ -73,6 +75,9 @@ dependencies {
     testImplementation project(':captureOffloader')
     testImplementation testFixtures(project(path: ':captureOffloader'))
     testImplementation testFixtures(project(path: ':testUtilities'))
+    testImplementation project(':replayerPlugins:jsonMessageTransformers:jsonJMESPathMessageTransformerProvider')
+    testImplementation project(':replayerPlugins:jsonMessageTransformers:jsonJoltMessageTransformerProvider')
+    testImplementation project(':replayerPlugins:jsonMessageTransformers:openSearch23PlusTargetTransformerProvider')
 
     testImplementation group: 'org.apache.httpcomponents.client5', name: 'httpclient5', version: '5.2.1'
     testImplementation group: 'org.junit.jupiter', name:'junit-jupiter-api', version:'5.x.x'

TrafficCapture/trafficReplayer/src/main/java/org/opensearch/migrations/replay/TransformationLoader.java

@@ -16,13 +16,15 @@
 import java.util.Map;
 import java.util.Optional;
 import java.util.ServiceLoader;
+import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 @Slf4j
 public class TransformationLoader {
     public static final String WRONG_JSON_STRUCTURE_MESSAGE = "Must specify the top-level configuration list with a sequence of " +
             "maps that have only one key each, where the key is the name of the transformer to be configured.";
+    public static final Pattern CLASS_NAME_PATTERN = Pattern.compile("^[a-zA-Z_$][a-zA-Z\\d_$]*$");
     private final List<IJsonTransformerProvider> providers;
     ObjectMapper objMapper = new ObjectMapper();
 
@@ -40,23 +42,22 @@ public TransformationLoader() {
     }
 
     List<Map<String, Object>> parseFullConfig(String fullConfig) throws JsonProcessingException {
-        return objMapper.readValue(fullConfig, new TypeReference<>() {});
+        if (CLASS_NAME_PATTERN.matcher(fullConfig).matches()) {
+            return List.of(Collections.singletonMap(fullConfig, null));
+        } else {
+            return objMapper.readValue(fullConfig, new TypeReference<>() {
+            });
+        }
     }
 
     protected Stream<IJsonTransformer> getTransformerFactoryFromServiceLoader(String fullConfig)
             throws JsonProcessingException {
         var configList = fullConfig == null ? List.of() : parseFullConfig(fullConfig);
-        if (providers.size() > 1 && configList.isEmpty()) {
-            throw new IllegalArgumentException("Must provide a configuration when multiple IJsonTransformerProvider " +
-                    "are loaded (" + providers.stream().map(p -> p.getClass().toString())
-                    .collect(Collectors.joining(",")) + ")");
-        } else if (providers.isEmpty()) {
+        if (configList.isEmpty() || providers.isEmpty()) {
+            log.warn("No transformer configuration specified.  No custom transformations will be performed");
             return Stream.of();
-        } else if (!configList.isEmpty()) {
+        }else {
             return configList.stream().map(c -> configureTransformerFromConfig((Map<String, Object>) c));
-        } else {
-            // send in Optional.empty because we would have hit the other case in the previous branch
-            return Stream.of(providers.get(0).createTransformer(Optional.empty()));
         }
     }
 
@@ -69,7 +70,7 @@ private IJsonTransformer configureTransformerFromConfig(Map<String, Object> c) {
         var key = keys.stream().findFirst()
                 .orElseThrow(()->new IllegalArgumentException(WRONG_JSON_STRUCTURE_MESSAGE));
         for (var p : providers) {
-            var className = p.getClass().getName();
+            var className = p.getClass().getSimpleName();
             if (className.equals(key)) {
                 var configuration = c.get(key);
                 log.atInfo().setMessage(()->"Creating a transformer with configuration="+configuration).log();

TrafficCapture/trafficReplayer/src/test/java/org/opensearch/migrations/replay/HeaderTransformerTest.java

@@ -113,7 +113,7 @@ public void testMalformedPayload_andTypeMappingUri_IsPassedThrough() throws Exce
 
         var transformingHandler = new HttpJsonTransformingConsumer(
                 new TransformationLoader().getTransformerFactoryLoader(SILLY_TARGET_CLUSTER_NAME,
-                        "[{\"org.opensearch.migrations.transform.JsonTransformerForOpenSearch23PlusTargetTransformerProvider\":\"\"}]"),
+                        "[{\"JsonTransformerForOpenSearch23PlusTargetTransformerProvider\":\"\"}]"),
                 null, testPacketCapture, "TEST", TestRequestKey.getTestConnectionRequestId(0));
 
         Random r = new Random(2);

TrafficCapture/trafficReplayer/src/test/java/org/opensearch/migrations/replay/TransformationLoaderTest.java

@@ -28,4 +28,13 @@ public void testTransformationLoader() throws Exception {
         Assertions.assertNotEquals(origDocStr, docWithNewHostnameStr);
     }
 
+    @Test
+    public void testThatSimpleNoopTransformerLoads() throws Exception {
+        var noopTransformer = new TransformationLoader()
+                .getTransformerFactoryLoader("localhost", "NoopTransformerProvider");
+        var origDoc = parseAsMap(SampleContents.loadSampleJsonRequestAsString());
+        var output = noopTransformer.transformJson(origDoc);
+        Assertions.assertEquals(mapper.writeValueAsString(origDoc), mapper.writeValueAsString(output));
+
+    }
 }