WIP: Reproducer for bug with Custom 3 log line prefix when app contains brackets

[lfittl]

This needs more investigation, but parking this here to document the issue.

[msakrejda]

This change (allowing the app name regex to match brackets but making it non-greedy) fixes the problem and does not break the tests in the existing suite, but it needs more validation:

diff --git a/logs/parse.go b/logs/parse.go
index 15328926..28075b0c 100644
--- a/logs/parse.go
+++ b/logs/parse.go
@@ -60,7 +60,7 @@ var DbRegexp = `(\S*)`                                                       //
 var AppBeforeSpaceRegexp = `(\S*)`                                           // %a
 var AppBeforeCommaRegexp = `([^,]*)`                                         // %a
 var AppBeforeQuoteRegexp = `([^"]*)`                                         // %a
-var AppInsideBracketsRegexp = `(\[unknown\]|[^,\]]*)`                        // %a
+var AppInsideBracketsRegexp = `(\[unknown\]|.+?)`                            // %a
 var HostRegexp = `(\S*)`                                                     // %h
 var VirtualTxRegexp = `(\d+/\d+)?`                                           // %v
 var LogLineCounterRegexp = `(\d+)` 

[msakrejda]

Also, it looks like we're currently matching empty app names. I don't think that can actually happen: if you set your application_name to an empty string, the prefix lists '[unknown'] (which we're already handling). We're also matching empty database names, host names, and user names (which I'm guessing also can't happen). I don't think that's causing problems here, but it may lead to other parsing issues. We should maybe change those *s to +?s...