in_tail: reintroduced the old ignore_older behavior as opt-in

plugins/in_tail/tail.c

@@ -655,6 +655,12 @@ static struct flb_config_map config_map[] = {
      "only available when a Parser is specified and it can parse the time "
      "of a record."
     },
+    {
+     FLB_CONFIG_MAP_BOOL, "ignore_active_older_files", "false",
+     0, FLB_TRUE, offsetof(struct flb_tail_config, ignore_active_older_files),
+     "ignore files that are older than the value set in ignore_older even "
+     "if the file is being ingested."
+    },
     {
      FLB_CONFIG_MAP_SIZE, "buffer_chunk_size", FLB_TAIL_CHUNK,
      0, FLB_TRUE, offsetof(struct flb_tail_config, buf_chunk_size),

plugins/in_tail/tail_config.h

@@ -85,7 +85,10 @@ struct flb_tail_config {
     int read_from_head;        /* read new files from head     */
     int rotate_wait;           /* sec to wait on rotated files */
     int watcher_interval;      /* watcher interval             */
-    int ignore_older;          /* ignore fields older than X seconds        */
+    int ignore_older;          /* ignore fields older than X seconds */
+    int ignore_active_older_files; /* ignore files that exceed the ignore
+                                    * older limit even if they are already
+                                    * being ingested */
     time_t last_pending;       /* last time a 'pending signal' was emitted' */
     struct mk_list *path_list; /* list of paths to scan (glob) */
     flb_sds_t path_key;        /* key name of file path        */

plugins/in_tail/tail_file.c

@@ -1914,6 +1914,7 @@ static int check_purge_deleted_file(struct flb_tail_config *ctx,
                                     struct flb_tail_file *file, time_t ts)
 {
     int ret;
+    int64_t mtime;
     struct stat st;
 
     ret = fstat(file->fd, &st);
@@ -1937,6 +1938,18 @@ static int check_purge_deleted_file(struct flb_tail_config *ctx,
         return FLB_TRUE;
     }
 
+    if (ctx->ignore_older > 0 && ctx->ignore_active_older_files) {
+        mtime = flb_tail_stat_mtime(&st);
+        if (mtime > 0) {
+            if ((ts - ctx->ignore_older) > mtime) {
+                flb_plg_debug(ctx->ins, "purge: monitored file (ignore older): %s",
+                              file->name);
+                flb_tail_file_remove(file);
+                return FLB_TRUE;
+            }
+        }
+    }
+
     return FLB_FALSE;
 }