参数 close_older
close_older:
# This has different implications depending on if a file is being tailed or read.
# If tailing, and there is a large time gap in incoming data the file can be closed (allowing other files to be opened)
# but will be queued for reopening when new data is detected.
# If reading, the file will be closed after closed_older seconds from when the last bytes were read.
# The default is 1 hour
# 当有大量新文件需要监控的时候，该值需要设置得适当小一些。
# 因为该 plugin 默认是最大打开4095 个文件，如果短时间内有超过这个数量的文档需要处理，将导致不会响应新的 event 。
参数 ignore_older
ignore_older:
# 如果你有一些老文件的内容需要处理（该文件又不会新增内容，只是要处理已有内容），那么该值需要设置得较大才行，否则这些文件将会被 ignore 。
# 比如你有一年前的数据，那么该值必须大于一年的秒数 31557600 ,,,
参数 start_position
start_position:
# Choose where Logstash starts initially reading files: at the beginning or
# at the end. The default behavior treats files like live streams and thus
# starts at the end. If you have old data you want to import, set this to 'beginning'
#如果有老文件需要处理，需要设置为 beginning ，否则将不会处理。