Multiple markers not handled correctly

[danjo133]

Hi,

I'm having some problems with the gelf output, if I understand correctly, this line should loop over related markers and add them as properties like Mdc does.

logback-gelf/src/main/java/de/siegmar/logbackgelf/GelfEncoder.java

Line 337 in 97a14b7

additionalFields.put("marker", marker.getName());

With multiple markers I get a _marker="LS_APPEND_OBJECT" in my json output.

For example logstash logback adds the various markers as separate properties

Best regards,
Daniel

[osiegmar]

Indeed, multiple markers are not yet supported. Could you give an example of logstash handles multiple markers / properties?

[danjo133]

When you add multiple markers with and, they get added as a reference, from
https://github.com/logstash/logstash-logback-encoder/blob/master/src/main/java/net/logstash/logback/marker/LogstashMarker.java

    /**
     * Adds the given marker as a reference, and returns this marker.
     * <p>
     * This can be used to chain markers together fluently on a log line. For example:
     * 
     * <pre>
     * {@code
     * import static net.logstash.logback.marker.Markers.*
     *     
     * logger.info(append("name1", "value1).and(append("name2", "value2")), "log message");
     * }
     * </pre>
     * 
     * @param <T> subtype of LogstashMarker
     * @param reference The marker to add
     * @return A marker with this marker and the given marker
     */
    @SuppressWarnings("unchecked")
    public <T extends LogstashMarker> T and(Marker reference) {
        add(reference);
        return (T) this;
    }

Then they can be added as a string as they are in that file

public String toString() {
     String self = toStringSelf();
     if (!hasReferences()) {
         return self;
     }

     StringBuilder sb = new StringBuilder(self);
     boolean appendSeparator = !self.isEmpty();
     for (Marker marker : this) {
         if (appendSeparator) {
             sb.append(", ");
         }
         String referenceToString = marker.toString();
         sb.append(referenceToString);
         appendSeparator = !referenceToString.isEmpty();
     }

     return sb.toString();
 }

or as json properties as in:

https://github.com/logstash/logstash-logback-encoder/blob/master/src/main/java/net/logstash/logback/marker/MapEntriesAppendingMarker.java

    @Override
    public void writeTo(JsonGenerator generator) throws IOException {
        if (map != null) {
            for (Map.Entry<?, ?> entry : map.entrySet()) {
                generator.writeFieldName(String.valueOf(entry.getKey()));
                generator.writeObject(entry.getValue());
            }
        }
    }

Which is then added the same way as mdc properties.

[osiegmar]

I've added support for multiple markers in the bugfix/multiple-markers branch. Could you please check and confirm, that this also fixes your issue? I'm not sure where your LS_APPEND_OBJECT comes from.

[osiegmar]

Fix released in 2.2.0.