in_tail: Implement long line truncation

plugins/in_tail/tail.c

@@ -719,6 +719,12 @@ static struct flb_config_map config_map[] = {
      0, FLB_TRUE, offsetof(struct flb_tail_config, skip_empty_lines),
      "Allows to skip empty lines."
     },
+
+    {
+      FLB_CONFIG_MAP_BOOL, "truncate_long_lines", "false",
+      0, FLB_TRUE, offsetof(struct flb_tail_config, truncate_long_lines),
+      "Truncate overlong lines after input encoding to UTF-8"
+    },
 #ifdef __linux__
     {
      FLB_CONFIG_MAP_BOOL, "file_cache_advise", "true",

plugins/in_tail/tail_config.c

@@ -170,7 +170,7 @@ struct flb_tail_config *flb_tail_config_create(struct flb_input_instance *ins,
             if (sec == 0 && nsec == 0) {
                 flb_plg_error(ctx->ins, "invalid 'refresh_interval' config "
                               "value (%s)", tmp);
-                flb_free(ctx);
+                flb_tail_config_destroy(ctx);
                 return NULL;
             }
 
@@ -192,7 +192,7 @@ struct flb_tail_config *flb_tail_config_create(struct flb_input_instance *ins,
     /* Config: seconds interval to monitor file after rotation */
     if (ctx->rotate_wait <= 0) {
         flb_plg_error(ctx->ins, "invalid 'rotate_wait' config value");
-        flb_free(ctx);
+        flb_tail_config_destroy(ctx);
         return NULL;
     }
 
@@ -215,7 +215,7 @@ struct flb_tail_config *flb_tail_config_create(struct flb_input_instance *ins,
         }
         else {
             flb_plg_error(ctx->ins, "invalid encoding 'unicode.encoding' value");
-            flb_free(ctx);
+            flb_tail_config_destroy(ctx);
             return NULL;
         }
     }
@@ -230,11 +230,20 @@ struct flb_tail_config *flb_tail_config_create(struct flb_input_instance *ins,
         }
         else {
             flb_plg_error(ctx->ins, "invalid encoding 'generic.encoding' value %s", tmp);
-            flb_free(ctx);
+            flb_tail_config_destroy(ctx);
             return NULL;
         }
     }
 
+#ifdef FLB_HAVE_UNICODE_ENCODER
+    if (ctx->preferred_input_encoding != FLB_UNICODE_ENCODING_UNSPECIFIED &&
+        ctx->generic_input_encoding_type != FLB_GENERIC_UNSPECIFIED) {
+        flb_plg_error(ctx->ins,
+                      "'unicode.encoding' and 'generic.encoding' cannot be specified at the same time");
+        flb_tail_config_destroy(ctx);
+        return NULL;
+    }
+#endif
 #ifdef FLB_HAVE_PARSER
     /* Config: multi-line support */
     if (ctx->multiline == FLB_TRUE) {
@@ -258,7 +267,7 @@ struct flb_tail_config *flb_tail_config_create(struct flb_input_instance *ins,
     /* Validate buffer limit */
     if (ctx->buf_chunk_size > ctx->buf_max_size) {
         flb_plg_error(ctx->ins, "buffer_max_size must be >= buffer_chunk");
-        flb_free(ctx);
+        flb_tail_config_destroy(ctx);
         return NULL;
     }
 
@@ -485,6 +494,13 @@ struct flb_tail_config *flb_tail_config_create(struct flb_input_instance *ins,
                                "multiline_truncated_total",
                                "Total number of truncated occurences for multilines",
                                1, (char *[]) {"name"});
+    ctx->cmt_long_line_truncated = \
+            cmt_counter_create(ins->cmt,
+                               "fluentbit", "input",
+                               "long_line_truncated_total",
+                               "Total number of truncated occurences for long lines",
+                               1, (char *[]) {"name"});
+
     /* OLD metrics */
     flb_metrics_add(FLB_TAIL_METRIC_F_OPENED,
                     "files_opened", ctx->ins->metrics);
@@ -494,6 +510,8 @@ struct flb_tail_config *flb_tail_config_create(struct flb_input_instance *ins,
                     "files_rotated", ctx->ins->metrics);
     flb_metrics_add(FLB_TAIL_METRIC_M_TRUNCATED,
                     "multiline_truncated", ctx->ins->metrics);
+    flb_metrics_add(FLB_TAIL_METRIC_L_TRUNCATED,
+                    "long_line_truncated", ctx->ins->metrics);
 #endif
 
     return ctx;

plugins/in_tail/tail_config.h

@@ -42,6 +42,7 @@
 #define FLB_TAIL_METRIC_F_CLOSED  101  /* number of closed files  */
 #define FLB_TAIL_METRIC_F_ROTATED 102  /* number of rotated files */
 #define FLB_TAIL_METRIC_M_TRUNCATED 103  /* number of truncated occurrences of multiline */
+#define FLB_TAIL_METRIC_L_TRUNCATED 104  /* number of truncated occurrences of long lines */
 #endif
 
 struct flb_tail_config {
@@ -54,6 +55,7 @@ struct flb_tail_config {
     /* Buffer Config */
     size_t buf_chunk_size;     /* allocation chunks        */
     size_t buf_max_size;       /* max size of a buffer     */
+    int    truncate_long_lines; /* truncate long lines after re-encode */
 
     /* Static files processor */
     size_t static_batch_size;
@@ -169,6 +171,7 @@ struct flb_tail_config {
     struct cmt_counter *cmt_files_closed;
     struct cmt_counter *cmt_files_rotated;
     struct cmt_counter *cmt_multiline_truncated;
+    struct cmt_counter *cmt_long_line_truncated;
 
     /* Hash: hash tables for quick acess to registered files */
     struct flb_hash_table *static_hash;

plugins/in_tail/tail_file.c

@@ -457,6 +457,26 @@ static FLB_INLINE const char *flb_skip_leading_zeros_simd(const char *data, cons
     return data;
 }
 
+/* Return a UTF-8 safe cut position <= max */
+static size_t utf8_safe_truncate_pos(const char *s, size_t len, size_t max)
+{
+    size_t cut = 0;
+
+    cut = (len <= max) ? len : max;
+    if (cut == len) {
+        return cut;
+    }
+
+   /* backtrack over continuation bytes 10xxxxxx
+    * NOTE: check the last INCLUDED byte => s[cut-1], not s[cut].
+    */
+    while (cut > 0 && ((unsigned char)s[cut - 1] & 0xC0) == 0x80) {
+        cut--;
+    }
+
+    return cut;
+}
+
 static int process_content(struct flb_tail_file *file, size_t *bytes)
 {
     size_t len;
@@ -481,6 +501,14 @@ static int process_content(struct flb_tail_file *file, size_t *bytes)
 #ifdef FLB_HAVE_UNICODE_ENCODER
     size_t decoded_len;
 #endif
+    size_t cut = 0;
+    size_t eff_max = 0;
+    size_t cur_cap = 0;
+    size_t dec_len = 0;
+    size_t window = 0;
+    int truncation_happened = FLB_FALSE;
+    size_t bytes_override = 0;
+    void *nl = NULL;
 #ifdef FLB_HAVE_METRICS
     uint64_t ts;
     char *name;
@@ -530,7 +558,8 @@ static int process_content(struct flb_tail_file *file, size_t *bytes)
                                                   end - data);
         if (ret > 0) {
             data = decoded;
-            end  = data + strlen(decoded);
+            /* Generic encoding conversion returns decoded length precisely with ret. */
+            end  = data + (size_t) ret;
         }
         else {
             flb_plg_error(ctx->ins, "encoding failed '%.*s' with status %d", end - data, data, ret);
@@ -542,6 +571,76 @@ static int process_content(struct flb_tail_file *file, size_t *bytes)
         data = (char *)flb_skip_leading_zeros_simd(data, end, &processed_bytes);
     }
 
+    if (ctx->truncate_long_lines == FLB_TRUE) {
+        /* Determine the effective truncation threshold (eff_max) */
+        /* Use the smaller of buf_max_size or the current buf_size */
+        if (ctx->buf_max_size > 0) {
+            eff_max = ctx->buf_max_size - 1;
+        }
+        else {
+            eff_max = 0;
+        }
+        if (file->buf_size > 0) {
+            cur_cap = file->buf_size - 1;
+        }
+        else {
+            cur_cap = 0;
+        }
+        if (cur_cap > 0 && (eff_max == 0 || cur_cap < eff_max)) {
+            eff_max = cur_cap;
+        }
+
+        /* Set the search window for memchr. Add 1 because memchr is (ptr, char, size) */
+        if (eff_max > 0) {
+            window = eff_max + 1;
+        }
+        else {
+            window = 0;
+        }
+        dec_len = (size_t)(end - data);
+        window = ctx->buf_max_size + 1;
+        if (window > dec_len) {
+            window = dec_len;
+        }
+
+        nl = memchr(data, '\n', window);
+        if (file->buf_size >= ctx->buf_max_size &&
+            nl == NULL && eff_max > 0 && dec_len >= eff_max) {
+            if (file->skip_next == FLB_TRUE) {
+                bytes_override = (original_len > 0) ? original_len : file->buf_len;
+                goto truncation_end;
+            }
+            cut = utf8_safe_truncate_pos(data, dec_len, eff_max);
+
+            if (cut > 0) {
+                if (ctx->multiline == FLB_TRUE) {
+                    flb_tail_mult_flush(file, ctx);
+                }
+
+                flb_tail_file_pack_line(NULL, data, cut, file, processed_bytes);
+                file->skip_next = FLB_TRUE;
+
+    #ifdef FLB_HAVE_METRICS
+                cmt_counter_inc(ctx->cmt_long_line_truncated,
+                                cfl_time_now(), 1,
+                                (char*[]){ (char*) flb_input_name(ctx->ins) });
+                /* Old api */
+                flb_metrics_sum(FLB_TAIL_METRIC_L_TRUNCATED, 1, ctx->ins->metrics);
+    #endif
+                if (original_len > 0) {
+                    bytes_override = original_len;
+                }
+                else {
+                    bytes_override = file->buf_len;
+                }
+                truncation_happened = FLB_TRUE;
+
+                lines++;
+                goto truncation_end;
+            }
+        }
+    }
+
     while (data < end && (p = memchr(data, '\n', end - data))) {
         len = (p - data);
         crlf = 0;
@@ -700,6 +799,7 @@ static int process_content(struct flb_tail_file *file, size_t *bytes)
         file->last_processed_bytes = processed_bytes;
     }
 
+truncation_end:
     if (decoded) {
         flb_free(decoded);
         decoded = NULL;
@@ -709,9 +809,13 @@ static int process_content(struct flb_tail_file *file, size_t *bytes)
 
     if (lines > 0) {
         /* Append buffer content to a chunk */
-        if (original_len > 0) {
+        if (truncation_happened) {
+            *bytes = bytes_override;
+        }
+        else if (original_len > 0) {
             *bytes = original_len;
-        } else {
+        }
+        else {
             *bytes = processed_bytes;
         }
 
@@ -1506,12 +1610,13 @@ int flb_tail_file_chunk(struct flb_tail_file *file)
     size_t                  file_buffer_capacity;
     size_t                  stream_data_length;
     ssize_t                 raw_data_length;
-    size_t                  processed_bytes;
+    size_t                  processed_bytes = 0;
     uint8_t                *read_buffer;
     size_t                  read_size;
     size_t                  size;
     char                   *tmp;
     int                     ret;
+    int                     lines;
     struct flb_tail_config *ctx;
 
     /* Check if we the engine issued a pause */
@@ -1529,6 +1634,29 @@ int flb_tail_file_chunk(struct flb_tail_file *file)
          * If there is no more room for more data, try to increase the
          * buffer under the limit of buffer_max_size.
          */
+        if (ctx->truncate_long_lines == FLB_TRUE) {
+            lines = process_content(file, &processed_bytes);
+            if (lines < 0) {
+                flb_plg_debug(ctx->ins, "inode=%"PRIu64" file=%s process content ERROR",
+                              file->inode, file->name);
+                return FLB_TAIL_ERROR;
+            }
+
+            if (lines > 0) {
+                file->stream_offset += processed_bytes;
+                file->last_processed_bytes = 0;
+                consume_bytes(file->buf_data, processed_bytes, file->buf_len);
+                file->buf_len -= processed_bytes;
+                file->buf_data[file->buf_len] = '\0';
+
+#ifdef FLB_HAVE_SQLDB
+                if (file->config->db) {
+                    flb_tail_db_file_offset(file, file->config);
+                }
+#endif
+                return adjust_counters(ctx, file);
+            }
+        }
         if (file->buf_size >= ctx->buf_max_size) {
             if (ctx->skip_long_lines == FLB_FALSE) {
                 flb_plg_error(ctx->ins, "file=%s requires a larger buffer size, "