ml: tests: Detect truncation ocurrence in multiline testcase.

Signed-off-by: Hiroshi Hatake <[email protected]>

Author: cosmo0920

include/fluent-bit/multiline/flb_ml.h

@@ -57,6 +57,7 @@
 
 /* Return codes */
 #define FLB_MULTILINE_OK         0
+#define FLB_MULTILINE_PROCESSED  1 /* Reserved */
 #define FLB_MULTILINE_TRUNCATED  2
 
 /* Maximum number of groups per stream */

src/multiline/flb_ml.c

@@ -491,7 +491,7 @@ static int process_append(struct flb_ml_parser_ins *parser_i,
     if (ret == FLB_FALSE) {
         return -1;
     }
-    return 0;
+    return ret;
 }
 
 static int ml_append_try_parser_type_text(struct flb_ml_parser_ins *parser,

src/multiline/flb_ml_rule.c

@@ -417,8 +417,6 @@ int flb_ml_rule_process(struct flb_ml_parser *ml_parser,
 
             /* Copy full map content in stream buffer */
             flb_ml_register_context(group, tm, full_map);
-
-            return 0;
         }
     }
 

tests/internal/multiline.c

@@ -1466,24 +1466,65 @@ static void test_buffer_limit_truncation()
     uint64_t stream_id;
     struct flb_config *config;
     struct flb_ml *ml;
+    struct flb_ml_parser *mlp;
     struct flb_ml_parser_ins *mlp_i;
+    struct flb_parser *p;
     struct flb_time tm;
 
+    /*
+     * A realistic Docker log where the content of the "log" field will be
+     * concatenated, and that concatenated buffer is what should be truncated.
+     */
+    char *line1 = "{\"log\": \"12345678901234567890\", \"stream\": \"stdout\"}";
+    char *line2 = "{\"log\": \"abcdefghijklmnopqrstuvwxyz\", \"stream\": \"stdout\"}";
+
     config = flb_config_init();
-    config->multiline_buffer_limit = 32;
+    /* The buffer limit is for the concatenated 'log' content, not the full JSON */
+    config->multiline_buffer_limit = 80;
+
+    /* Use the dummy 'docker' parser for JSON extraction */
+    p = flb_parser_get("docker", config);
 
+    /* This parser will trigger on any content, ensuring concatenation. */
     ml = flb_ml_create(config, "limit-test");
     TEST_CHECK(ml != NULL);
 
-    mlp_i = flb_ml_parser_instance_create(ml, "docker");
+    mlp = flb_ml_parser_create(config, "test-concat", FLB_ML_REGEX,
+                               NULL, FLB_FALSE, 1000,
+                               "log", NULL, NULL,
+                               p, "docker");
+    TEST_CHECK(mlp != NULL);
+
+    /* Define rules that will always match the test data */
+    ret = flb_ml_rule_create(mlp, "start_state", "/./", "cont", NULL);
+    TEST_CHECK(ret == 0);
+    ret = flb_ml_rule_create(mlp, "cont", "/./", "cont", NULL);
+    TEST_CHECK(ret == 0);
+
+    /* Finalize parser initialization */
+    ret = flb_ml_parser_init(mlp);
+    TEST_CHECK(ret == 0);
+
+    mlp_i = flb_ml_parser_instance_create(ml, "test-concat");
     TEST_CHECK(mlp_i != NULL);
 
     ret = flb_ml_stream_create(ml, "test", -1, flush_callback, NULL, &stream_id);
     TEST_CHECK(ret == 0);
 
     flb_time_get(&tm);
-    ret = flb_ml_append_text(ml, stream_id, &tm,
-                             "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ", 36);
+
+    /* Append the first line. It will match the 'start_state' and start a block. */
+    ret = flb_ml_append_text(ml, stream_id, &tm, line1, strlen(line1));
+    printf("ret (line 1) = %d\n", ret);
+    TEST_CHECK(ret == FLB_MULTILINE_OK);
+
+    /*
+     * Append the second line. This will match the 'cont' state and concatenate.
+     * The concatenation (20 + 1 + 26 bytes) will exceed the 32-byte limit
+     * and correctly trigger the truncation logic.
+     */
+    ret = flb_ml_append_text(ml, stream_id, &tm, line2, strlen(line2));
+    printf("ret (line 2) = %d\n", ret);
     TEST_CHECK(ret == FLB_MULTILINE_TRUNCATED);
 
     flb_ml_destroy(ml);