Pattern parser does not support messages including [] characters

[donatelloOo]

Hello,

Here is a recurrent issue we encounter when our message contains square brackets like in the example below:

Log parser:

type=log4j
pattern=[TIMESTAMP][LEVEL][THREAD][LOGGER][LINE]MESSAGE
dateFormat=yyyy-MM-dd HH:mm:ss,SSS
name=Standard Parser
charset=UTF-8

Log file:

[2019-06-18 14:46:53,522][TRACE][T-X][com.company.product.TheClass][ 257]a message
[2019-06-18 14:46:54,087][TRACE][T-Y][com.company.product.TheClass][ 558]another mesage with output: [MyObject][7714][20190611.0]
[2019-06-18 14:46:55,568][TRACE][T-X][com.company.product.TheClass][ 257]a last message

The result is invalid mapping as below:

Date:    2019-06-18 14:46:54.087
Class:   ?
Method:  ?
Level:     DEBUG
Thread:  558]another mesage with output: [MyObject
File:    ?:20190611.0
Logger:  7714

Message: com.company.product.TheClass

This is very inconvenient as filters obviously won't work for these messages.