Limit MinIO folder depth to 2 (#2715)

Avoids creating tons of intermediate folders thus reduces inode pressure while still on disk splitting objects in 4.000 slots

Co-authored-by: Benoit TELLIER <[email protected]>

Author: quantranhong1999

server/blob/blob-s3/src/test/java/org/apache/james/blob/objectstorage/aws/S3WithMinIOGenerationAwareBlobIdTest.java

@@ -126,7 +126,7 @@ void saveShouldReturnBlobIdOfString(BlobStore.StoragePolicy storagePolicy) {
         String blobIdString = blobId.asString();
 
         // Then: BlobId string and parsed BlobId should match expectations
-        assertThat(blobIdString).isEqualTo("1/628/M/f/e/m/XjFVhqwZi9eYtmKc5JA9CJlHbVdBqfMuLlIbamY=");
+        assertThat(blobIdString).isEqualTo("1/628/M/f/emXjFVhqwZi9eYtmKc5JA9CJlHbVdBqfMuLlIbamY=");
         assertThat(blobId).isEqualTo(blobIdFactory().parse(blobIdString));
     }
 

server/blob/blob-storage-strategy/src/main/java/org/apache/james/server/blob/deduplication/MinIOGenerationAwareBlobId.java

@@ -74,13 +74,11 @@ public BlobId parse(String id) {
         }
 
         private static String injectFoldersInBlobId(String blobIdPart) {
-            int folderDepthToCreate = 4;
+            int folderDepthToCreate = 2;
             if (blobIdPart.length() > folderDepthToCreate) {
                 return blobIdPart.charAt(0) + "/" +
                     blobIdPart.charAt(1) + "/" +
-                    blobIdPart.charAt(2) + "/" +
-                    blobIdPart.charAt(3) + "/" +
-                    blobIdPart.substring(4);
+                    blobIdPart.substring(2);
             }
             return blobIdPart;
         }

server/blob/blob-storage-strategy/src/test/java/org/apache/james/server/blob/deduplication/MinIOGenerationAwareBlobIdTest.java

@@ -62,7 +62,7 @@ void ofShouldGenerateABlobIdOfTheRightGeneration() {
             SoftAssertions.assertSoftly(soft -> {
                 soft.assertThat(actual.getFamily()).isEqualTo(GenerationAwareBlobId.Configuration.DEFAULT.getFamily());
                 soft.assertThat(actual.getGeneration()).isEqualTo(628L);
-                soft.assertThat(actual.getDelegate()).isEqualTo(delegate.of("4/c/c/b/692e-3efb-40e9-8876-4ecfd51ffd4d"));
+                soft.assertThat(actual.getDelegate()).isEqualTo(delegate.of("4/c/cb692e-3efb-40e9-8876-4ecfd51ffd4d"));
             });
         }
     }
@@ -94,6 +94,22 @@ void previousBlobIdsShouldBeParsable() {
                 });
         }
 
+        @Test
+        void previousFourFolderDepthBlobIdsShouldBeParsedAsMinIOGenerationAwareBlobId() {
+            String fourDepthBlobIdString = delegate.of("1/628/3/6/8/2/5033-d835-4490-9f5a-eef120b1e85c").asString();
+
+            BlobId actual = testee.parse(fourDepthBlobIdString);
+            assertThat(actual)
+                .isInstanceOfSatisfying(MinIOGenerationAwareBlobId.class, actualBlobId -> {
+                    SoftAssertions.assertSoftly(soft -> {
+                        soft.assertThat(actualBlobId.getFamily()).isEqualTo(1);
+                        soft.assertThat(actualBlobId.getGeneration()).isEqualTo(628L);
+                        soft.assertThat(actualBlobId.getDelegate().asString()).isEqualTo("3/6/8/2/5033-d835-4490-9f5a-eef120b1e85c");
+                        soft.assertThat(actualBlobId.asString()).isEqualTo("1/628/3/6/8/2/5033-d835-4490-9f5a-eef120b1e85c");
+                    });
+                });
+        }
+
         @Test
         void noFamilyShouldBeParsable() {
             String originalBlobId = "abcdef";
@@ -206,7 +222,7 @@ void shouldMatchPojoContract() {
         void asStringShouldIntegrateFamilyAndGeneration() {
             BlobId blobId = testee.of("36825033-d835-4490-9f5a-eef120b1e85c");
 
-            assertThat(blobId.asString()).isEqualTo("1/628/3/6/8/2/5033-d835-4490-9f5a-eef120b1e85c");
+            assertThat(blobId.asString()).isEqualTo("1/628/3/6/825033-d835-4490-9f5a-eef120b1e85c");
         }
 
         @Test
@@ -220,7 +236,8 @@ void asStringShouldReturnDelegateForZeroFamily() {
         @ValueSource(strings = {
             "1/2/a/b/c/d/efgh",
             "abc",
-            "1/2/abc"
+            "1/2/abc",
+            "1/628/3/6/8/2/5033-d835-4490-9f5a-eef120b1e85c"
         })
         void asStringShouldRevertFromString(String blobIdString) {
             BlobId blobId = testee.parse(blobIdString);