[LOG4J2-3358] 2.17.1: JsonLayout Context no longer working.

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.17.1
• Fix Version/s: 2.17.2
• Component/s: Layouts

Language

Java

• Assignee: Carter Kozak
• Reporter: Markus Duft
• Created: 21/Jan/22 09:59
• Updated: 24/Jan/22 07:00
• Resolved: 22/Jan/22 01:11

Description

We're creating a RollingFileAppender programmatically using a JsonLayout. This uses fields using ${ctx:...} expansion. This stopped working when upgrading from 2.17.0 to 2.17.1.

The code is as follows:

/**
     * Creates a rolling file appender that write audit entries to a programmatically readable JSON file.
     */
    private RollingFileAppender createJsonAppender(Path logDir) {
        List<KeyValuePair> fields = new ArrayList<>();
        fields.add(KeyValuePair.newBuilder().setKey("who").setValue("${ctx:WHO}").build());
        fields.add(KeyValuePair.newBuilder().setKey("what").setValue("${ctx:WHAT}").build());
        fields.add(KeyValuePair.newBuilder().setKey("method").setValue("${ctx:METHOD}").build());
        fields.add(KeyValuePair.newBuilder().setKey("parameters").setValue("${ctx:PARAMETERS}").build());        
        RollingFileAppender.Builder<?> builder = RollingFileAppender.newBuilder();
        builder.setName("auditJsonLogger");
        builder.withFileName(logDir.resolve(LOG_JSON_FILENAME).toString());
        builder.withFilePattern(logDir.resolve(LOG_JSON_FILEPATTERN).toString());
        builder.withPolicy(SizeBasedTriggeringPolicy.createPolicy("10M"));
        builder.setLayout(JsonLayout.newBuilder().setCompact(true).setEventEol(true).setConfiguration(new DefaultConfiguration())
                .setAdditionalFields(fields.toArray(new KeyValuePair[0])).build());
        builder.withStrategy(
                DefaultRolloverStrategy.newBuilder().withCompressionLevelStr(String.valueOf(Deflater.DEFAULT_COMPRESSION))
                        .withMax(Integer.toString(LOG_MAX_INDEX)).withFileIndex("min").build());
        return builder.build();
    } 

We also tried to use %X{...} as well as $${ctx:...} expansions instead to no avail. The log file always contains the literal string we use in .setValue(), i.e. lines like this:

{"instant":{"epochSecond":1642756242,"nanoOfSecond":271091900},"thread":"hive/fsck","level":"INFO","message":"Execute","endOfBatch":false,"threadId":65,"threadPriority":5,"who":"${ctx:WHO}","what":"${ctx:WHAT}","method":"${ctx:METHOD}","parameters":"${ctx:PARAMETERS}"}

Reverting to 2.17.0 will correctly give lines like this in the JSON file:

{"instant":{"epochSecond":1642756430,"nanoOfSecond":923210700},"thread":"hive/fsck","level":"INFO","message":"Execute","endOfBatch":false,"threadId":62,"threadPriority":5,"who":"marku","what":"ObjectConsistencyCheckOperation","method":"-","parameters":"{dryRun=false, roots=[io.bdeploy/demo/client-app/linux:1.0.0, io.bdeploy/demo/client-app/linux:2.0.0, io.bdeploy/demo/client-app/windows:1.0.0, ...]}"}

Issue Links

• links to: GitHub Pull Request #726