[LOG4J2-3074] Add replacement parameter to mdc resolver

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.14.1
• Fix Version/s: 2.15.0
• Component/s: JsonTemplateLayout
• Assignee: Unassigned
• Reporter: Paul Rubin
• Created: 16/Apr/21 14:52
• Updated: 09/Jul/21 13:38
• Resolved: 07/Jul/21 13:12

Description

This story aims to add a replacement parameter to ReadOnlyStringMapResolver (which is used by ThreadContextDataResolver and MapResolver) for modifying the keys of the map before resolving them. That is, given the following JSON template

{
  "user": {
    "$resolver": "mdc",
    "pattern": "user:(.*)",
    "replacement": "$1"
  }
}

A LogEvent with an MDC map composed of user:name, user:role, sessionId entries will generate the following JSON:

{
  "user": {
    "name": "Paul Rubin",
    "role": "ADMIN"
  }
}

Issue Links

• relates to: LOG4J2-3073 Issues using Lookup Plugin in Json Template Logging