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POJava: How to log raw JSON as JSON and avoid escaping during logging with logback / slf4j
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  1. POJava: How to log raw JSON as JSON and avoid escaping during logging with logback / slf4j
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    copied!<p>I'm using SLF4J with Logback in a JAX-RS application... I want to log to JSON in such a way that my message is not encoded again but printed raw into the logfile: </p> <p>At the moment it looks like this:</p> <pre><code>{"@timestamp":1363834123012,"@message":"{\"text\":\"From MLK to Barack Ob...\n\"}" </code></pre> <p>But I want to have this: </p> <pre><code> {"@timestamp":1363834123012,"@message": { "text ": "From MLK to Barack Ob...\n\} </code></pre> <p>The reason is I want to parse the JSON again and want to avoid the unescaping of the data. </p> <p>I've written a custom logback encoder but I found no way to avoid the escaping. Can I pass a object to logback and change the settings based on the type of the object? </p> <p>Edit: I've found a way - not exactly elegant - as requested a SSCE: </p> <p>In my Application</p> <pre><code>// SLF4J Logger private static Logger logger = LoggerFactory.getLogger(MyClass.class); // A logback? Marker private Marker foo = MarkerFactory.getMarker("foo"); // Jackson ObjectMapper() ObjectMapper mapper = new ObjectMapper(); // Log something... logger.info(foo, mapper.writeValueAsString(json)); </code></pre> <p>I've used a variation of the Logstash-Encoder found here: <a href="https://github.com/logstash/logstash-logback-encoder">https://github.com/logstash/logstash-logback-encoder</a></p> <pre><code>package my.package; import static org.apache.commons.io.IOUtils.*; import java.io.IOException; import java.util.Map; import java.util.Map.Entry; import org.codehaus.jackson.JsonGenerator.Feature; import org.codehaus.jackson.JsonNode; import org.codehaus.jackson.map.ObjectMapper; import org.codehaus.jackson.node.ObjectNode; import org.slf4j.Marker; import ch.qos.logback.classic.spi.ILoggingEvent; import ch.qos.logback.classic.spi.IThrowableProxy; import ch.qos.logback.classic.spi.ThrowableProxyUtil; import ch.qos.logback.core.CoreConstants; import ch.qos.logback.core.encoder.EncoderBase; public class JsonEncoder extends EncoderBase&lt;ILoggingEvent&gt; { private static final ObjectMapper MAPPER = new ObjectMapper().configure( Feature.ESCAPE_NON_ASCII, true); private static Marker M; private boolean immediateFlush = true; @Override public void doEncode(ILoggingEvent event) throws IOException { M = event.getMarker(); ObjectNode eventNode = MAPPER.createObjectNode(); eventNode.put("@timestamp", event.getTimeStamp()); // if (M != null) { if (M.getName().equals("foo")) { JsonNode j = MAPPER.readTree(event.getFormattedMessage()); eventNode.put("@foo", j); } } else { eventNode.put("@message", event.getFormattedMessage()); } eventNode.put("@fields", createFields(event)); write(MAPPER.writeValueAsBytes(eventNode), outputStream); write(CoreConstants.LINE_SEPARATOR, outputStream); if (immediateFlush) { outputStream.flush(); } } private ObjectNode createFields(ILoggingEvent event) { // not important here return fieldsNode; } @Override public void close() throws IOException { write(LINE_SEPARATOR, outputStream); } public boolean isImmediateFlush() { return immediateFlush; } public void setImmediateFlush(boolean immediateFlush) { this.immediateFlush = immediateFlush; } } </code></pre> <p>It's works now! Yeah! But I guess it's not the best way to do it (serialize, deserialize the JSON...) </p>
 

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