remove unused etag

Signed-off-by: Eric Wei <mengwei.eric@gmail.com>

Author: mengweieric

plugin/src/main/java/org/opensearch/sql/plugin/rest/RestPPLGrammarAction.java

@@ -34,31 +34,6 @@
  *   <li>Channel and mode names
  * </ul>
  *
- * <p>The bundle is cached in memory and versioned via ETag (grammar hash). Clients should cache
- * locally and only refetch when ETag changes.
- *
- * <p>Example request:
- *
- * <pre>
- * GET /_plugins/_ppl/_grammar
- * If-None-Match: "sha256:abc123..."
- * </pre>
- *
- * <p>Response headers:
- *
- * <pre>
- * HTTP/1.1 200 OK
- * ETag: "sha256:abc123..."
- * Cache-Control: public, max-age=3600
- * Content-Type: application/json
- * </pre>
- *
- * <p>Or if client has latest:
- *
- * <pre>
- * HTTP/1.1 304 Not Modified
- * ETag: "sha256:abc123..."
- * </pre>
  */
 @Log4j2
 public class RestPPLGrammarAction extends BaseRestHandler {
@@ -90,37 +65,10 @@ protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient cli
         // Get or build artifact (lazy initialization)
         AutocompleteArtifact artifact = getOrBuildArtifact();
 
-        String grammarHash = artifact.getGrammarHash();
-        String ifNoneMatch = request.header("If-None-Match");
-
-        // Strip quotes from ETag if present ("sha256:..." → sha256:...)
-        if (ifNoneMatch != null && ifNoneMatch.startsWith("\"") && ifNoneMatch.endsWith("\"")) {
-          ifNoneMatch = ifNoneMatch.substring(1, ifNoneMatch.length() - 1);
-        }
-
-        // Return 304 Not Modified if client has latest version
-        if (grammarHash.equals(ifNoneMatch)) {
-          log.debug("Client has latest grammar (ETag match), returning 304");
-          BytesRestResponse response =
-              new BytesRestResponse(RestStatus.NOT_MODIFIED, "application/json", "");
-          response.addHeader("ETag", "\"" + grammarHash + "\"");
-          response.addHeader("Cache-Control", "public, max-age=3600");
-          channel.sendResponse(response);
-          return;
-        }
-
-        // Serialize artifact to JSON
-        log.debug("Serializing grammar to JSON (hash: {})", grammarHash);
         XContentBuilder builder = channel.newBuilder();
         serializeArtifact(builder, artifact);
 
         BytesRestResponse response = new BytesRestResponse(RestStatus.OK, builder);
-
-        // Add caching headers
-        response.addHeader("ETag", "\"" + grammarHash + "\"");
-        response.addHeader("Cache-Control", "public, max-age=3600");
-        response.addHeader("Content-Type", "application/json; charset=UTF-8");
-
         log.info("Returning PPL grammar (size: {} bytes)", response.content().length());
         channel.sendResponse(response);
 

plugin/src/test/java/org/opensearch/sql/plugin/rest/RestPPLGrammarActionTest.java

@@ -12,7 +12,6 @@
 
 import java.io.ByteArrayOutputStream;
 import java.nio.charset.StandardCharsets;
-import java.util.Collections;
 import org.junit.Before;
 import org.junit.Test;
 import org.opensearch.core.rest.RestStatus;
@@ -31,7 +30,6 @@
  *
  * <ul>
  *   <li>200 OK response with grammar bundle
- *   <li>304 Not Modified when ETag matches
  *   <li>Grammar structure validation
  *   <li>Cache behavior
  * </ul>
@@ -62,36 +60,19 @@ public void testRoutes() {
 
   @Test
   public void testGetGrammar_ReturnsBundle() throws Exception {
-    // Create request without ETag
     FakeRestRequest request =
         new FakeRestRequest.Builder(NamedXContentRegistry.EMPTY)
             .withMethod(RestRequest.Method.GET)
             .withPath("/_plugins/_ppl/_grammar")
-            .withHeaders(Collections.emptyMap())
             .build();
 
-    // Create mock channel to capture response
     MockRestChannel channel = new MockRestChannel(request, true);
-
-    // Execute request
     action.prepareRequest(request, client).accept(channel);
 
-    // Verify response
     RestResponse response = channel.getResponse();
     assertNotNull("Response should not be null", response);
     assertEquals("Should return 200 OK", RestStatus.OK, response.status());
 
-    // Verify ETag header present
-    String etag = response.getHeaders().get("ETag").get(0);
-    assertNotNull("ETag header should be present", etag);
-    assertTrue("ETag should start with sha256:", etag.contains("sha256:"));
-
-    // Verify Cache-Control header
-    String cacheControl = response.getHeaders().get("Cache-Control").get(0);
-    assertNotNull("Cache-Control header should be present", cacheControl);
-    assertTrue("Should allow caching", cacheControl.contains("max-age=3600"));
-
-    // Verify response content
     String content = new String(response.content().array(), StandardCharsets.UTF_8);
     assertTrue("Should contain bundleVersion", content.contains("\"bundleVersion\":"));
     assertTrue("Should contain grammarHash", content.contains("\"grammarHash\":"));
@@ -101,39 +82,6 @@ public void testGetGrammar_ReturnsBundle() throws Exception {
     assertTrue("Should contain symbolicNames", content.contains("\"symbolicNames\":"));
   }
 
-  @Test
-  public void testGetGrammar_Returns304WhenETagMatches() throws Exception {
-    // First request to get ETag
-    FakeRestRequest firstRequest =
-        new FakeRestRequest.Builder(NamedXContentRegistry.EMPTY)
-            .withMethod(RestRequest.Method.GET)
-            .withPath("/_plugins/_ppl/_grammar")
-            .build();
-
-    MockRestChannel firstChannel = new MockRestChannel(firstRequest, true);
-    action.prepareRequest(firstRequest, client).accept(firstChannel);
-
-    RestResponse firstResponse = firstChannel.getResponse();
-    String etag = firstResponse.getHeaders().get("ETag").get(0);
-
-    // Second request with matching ETag
-    FakeRestRequest secondRequest =
-        new FakeRestRequest.Builder(NamedXContentRegistry.EMPTY)
-            .withMethod(RestRequest.Method.GET)
-            .withPath("/_plugins/_ppl/_grammar")
-            .withHeaders(Collections.singletonMap("If-None-Match", Collections.singletonList(etag)))
-            .build();
-
-    MockRestChannel secondChannel = new MockRestChannel(secondRequest, true);
-    action.prepareRequest(secondRequest, client).accept(secondChannel);
-
-    RestResponse secondResponse = secondChannel.getResponse();
-    assertEquals(
-        "Should return 304 Not Modified when ETag matches",
-        RestStatus.NOT_MODIFIED,
-        secondResponse.status());
-  }
-
   @Test
   public void testGetGrammar_ArtifactIsCached() throws Exception {
     // Make two requests
@@ -160,11 +108,6 @@ public void testGetGrammar_ArtifactIsCached() throws Exception {
     action.prepareRequest(request2, client).accept(channel2);
     long elapsed2 = System.currentTimeMillis() - startTime2;
 
-    // Both should return same ETag
-    String etag1 = channel1.getResponse().getHeaders().get("ETag").get(0);
-    String etag2 = channel2.getResponse().getHeaders().get("ETag").get(0);
-    assertEquals("ETags should match", etag1, etag2);
-
     // Second request should be faster (artifact cached)
     assertTrue(
         "Second request should be faster due to caching (elapsed1="
@@ -186,12 +129,12 @@ public void testInvalidateCache() throws Exception {
 
     MockRestChannel channel1 = new MockRestChannel(request1, true);
     action.prepareRequest(request1, client).accept(channel1);
-    String etag1 = channel1.getResponse().getHeaders().get("ETag").get(0);
+    assertEquals(RestStatus.OK, channel1.getResponse().status());
 
     // Invalidate cache
     action.invalidateCache();
 
-    // Get grammar again
+    // Get grammar again — should still return 200 OK with same content
     FakeRestRequest request2 =
         new FakeRestRequest.Builder(NamedXContentRegistry.EMPTY)
             .withMethod(RestRequest.Method.GET)
@@ -200,10 +143,7 @@ public void testInvalidateCache() throws Exception {
 
     MockRestChannel channel2 = new MockRestChannel(request2, true);
     action.prepareRequest(request2, client).accept(channel2);
-    String etag2 = channel2.getResponse().getHeaders().get("ETag").get(0);
-
-    // ETags should still match (same grammar)
-    assertEquals("ETags should match after cache invalidation", etag1, etag2);
+    assertEquals(RestStatus.OK, channel2.getResponse().status());
   }
 
   /** Mock RestChannel to capture responses */