Control output on empty virtual properties values

[rfoltyns]

Control output on empty virtual properties values

[rfoltyns]

I'll release it in 1.4.3. Enjoy! :)

[rfoltyns]

No, it's not possible. But, if you're not using Markers yet, you can achieve that with mixins:

One for LogEvent to stop ignoring Marker field:

@JsonSerialize(as = LogEvent.class)
public abstract class CustomLogEventMixIn extends LogEventJacksonJsonMixIn {

    @JsonUnwrapped
    @JsonProperty(value = "event.category")
    @JsonIgnore(false)
    @JsonInclude(value = JsonInclude.Include.NON_NULL)
    @Override
    public abstract Marker getMarker();

}

Second one for Marker (package-private):

package org.apache.logging.log4j.core.jackson;

import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonValue;
import org.apache.logging.log4j.Marker;

public abstract class CustomMarkerMixIn extends MarkerMixIn {

    CustomMarkerMixIn() {
        super(null);
    }

    @JsonValue
    @Override
    public abstract String getName();

    @JsonIgnore
    @Override
    public abstract Marker[] getParents();

}

JacksonJsonLayout config:

    <JacksonMixIn mixInClass="foo.bar.CustomLogEventMixIn"
                             targetClass="org.apache.logging.log4j.core.LogEvent" />
    <JacksonMixIn mixInClass="org.apache.logging.log4j.core.jackson.CustomMarkerMixIn"
                             targetClass="org.apache.logging.log4j.Marker" />

and then simply:

Marker category = MarkerManager.getMarker("custom category");
logger.info(category, "Hello, World!");

Do you think it could be an acceptable solution? It will for for event.category. Other fields can also be extracted from LogEvent to conform to ECS.

Context data can also be serialized as described here

[dysan54]

Yes, it could do the trick for event.category but not for the others.

I would imagined an additional attribute in virtual properties that can control generation of json output, maybe like this in VirtualPropertiesWriter :

  @Override
  public void serializeAsField(Object bean, JsonGenerator gen, SerializerProvider prov) throws Exception {
    if (virtualProperties.length > 0) {
      for (int i = 0; i < virtualProperties.length; i++) {
        String val = valueResolver.resolve(virtualProperties[i]);
        if (!val.isEmpty()) {
          gen.writeFieldName(virtualProperties[i].getName());
          gen.writeString(val);
        }
      }
    }
  }

[rfoltyns]

Yeah, it will work, but I need to think it through. Initially I didn't want to pack too many flags there.

Ideally, value based inclusion should be done with Jackson's Include, but it's not applicable to this field.

Maybe I'll just add a configurable filters as an alternative so you can choose what you'd like to do (including writing your own ones). What do you think?

String val = valueResolver.resolve(virtualProperties[i]);
if (!filter.test(val)) {
    return;
}
gen.writeFieldName(virtualProperties[i].getName());
gen.writeString(val);

[dysan54]

Yes it would work because in my case i don't have to apply different rules between virtual properties, just a general rule to filter blank values.
Choosing virtual properties to which apply this filter would be a plus.

[rfoltyns]

Ok, I'll add the configurable filters and NonBlankFilter it in 1.4.3.

Choosing properties might be useful, but it should be possible to achieve with custom filters and default values. It might look a bit awkward, but actually allows maximum functionality with minimum amount of changes to VirtualProperty and the writer.

<JacksonJsonLayout>
    <VirtualProperty name="field1" value="$${ctx:val1:-someDefaultValue}"/><!-- included, default behaviour -->
    <VirtualProperty name="field2" value="$${ctx:val2:-}"/><!-- excluded by NonBlankFilter -->
    <VirtualProperty name="field3" value="$${ctx:val3:-filter2}"/><!-- excluded by UserProvidedFilter2 -->
    <VirtualProperty name="field4" value="$${ctx:val4:-filter1}"/><!-- excluded by UserProvidedFilter1 -->
    <VirtualProperty name="field5" value="$${ctx:val5:-someDefaultValue}"/><!-- excluded by UserProvidedFieldFilter -->
    <VirtualProperty name="field6" value="$${ctx:val6:-someOtherValue}"/><!-- included, default behaviour -->
    <UserProvidedFilter1/>
    <UserProvidedFilter2/>
    <NonBlankFilter/><!-- available out-of-the-box -->
    <UserProvidedFieldFilter fields="field5,field6" condition="eq someDefaultValue" />
    
</JacksonJsonLayout>

[dysan54]

It's perfect, many thanks !

[rfoltyns]

Released in 1.4.3.