I'm working on an application that uses Log4J for logging. Occasionally, the application creates log messages that are very long, > 10000 characters. This causes performance problems when the log is displayed in a Console window in Eclipse.
I want to limit the maximum message length, truncating long messages to the maximum length. How can I do that with Log4J?
You can use a PatternLayout with a ConversionPattern that has a 'maximum width' format modifier on the message conversion character.
Example:
%r [%t] %-5p %c %x - %.10000m%n
limits message size to 10000 characters.
If someone is looking for a maximum width, that is removing the last characters and not the first (like i did) here is an example:
%r [%t] %-5p %c %x - %-0.-10000m%n
limits the message size to 10000 characters and removes everything on the end that is longer.
source: https://issues.apache.org/jira/browse/LOG4J2-926
Related
I have to log in different-2 file. So I have created two appender. One for basic log which would log little bit information.
Second appender will be dynamic and depending on the one parameter log file name will be different. Both scenario are working fine.
Now just found the log statement are getting added.
Means first time it write once, second time tow lines and third time three and so on.. My program runs on every 20 seconds. If I close the program and run again it will not repeat but if continuous runs every 20 second then it start repeat log.
I have used log4j.Create to logger and adding appender in this. Every thing I am doing by code. Not using any log file. Below is one of them.
static Logger loggerCustom = Logger.getLogger("CustomLog");
PatternLayout plt = new PatternLayout();
plt.setConversionPattern("%-7p %d [%t] %c %x - %m%n");
fh = new FileAppender(plt, "logs\\" + strDate + "\\CustomLog.log");
loggerCustom.addAppender(fh);
loggerCustom.setAdditivity(false);
Dear All above issue has been resolve by adding below line before appending appender.
.removeAllAppenders()
I have the below entry in the log4j config xml. What is the significant of '%p', '%C;%L', '%m'. What is stands for those characters? What other characters, we can use in log4j? Explain their usage..
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern"
value="INSERT INTO LOGS (user_id, dated, msg_level, class, message)
VALUES ( '%X{MESSAGE_ID}','%d{ISO8601}','%p', '%C;%L', '%m' )" />
</layout>
Some of the main conversion characters are
p --- Used to output the priority of the logging event.
C --- Used to output the fully qualified class name of the caller issuing the logging request.
L --- Used to output the line number from where the logging request was issued.
m --- Used to output the application supplied message associated with the logging event.
Using number with any conversion character, for example %4p means
the priority of the logging event should be left justified to a width of four characters.
Besides this conversions , there are other patterns also .
You can see detail about them here.
I am facing some problem regarding log message.
When I generate log report, the first line was not shown in proper alignment but rest of the log message was in proper order.
I checked log patterns, but didn't find any clue to the issue.
Can anybody suggest me the how I can resolve this issue?
Output:
INFO|------------------------------- Start Control Information --------------------------
INFO|***********
INFO|**********************
INFO|***** ************************
INFO|Doc***** Version : 6.7.0004.0217 Win64.SQLServer
INFO|------------------------------ End Control Information -----------------------------
INFO|
INFO|******************
INFO|*************** :
INFO|Version identifiers :
INFO|***********
here , first line(INFO|------------------------------- Start Control Information --------------------------
Only the first line is not properly aligned.
Logger messages are generated based on the pattern layout of log4j.properties. If you wanted to do alignmnet of your logger message, you have use pattern layout as follows.
log4j.rootLogger=DEBUG, CA
log4j.appender.CA=org.apache.log4j.ConsoleAppender
log4j.appender.CA.layout=org.apache.log4j.PatternLayout
log4j.appender.CA.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n
I am using the latest ChainSaw developer snapshot
I'm trying get logs from a file with logs in pattern :
[%d] [%t] [%c] [%m]%n
and I don't know why it doesn't work - whole log is read as %m. When I use pattern without %c every log is displayed correctly.
Try this pattern instead
[TIMESTAMP] [THREAD] [LOGGER] [MESSAGE]
(I'm assuming your logs also have those "[]", otherwise remove them)
i am trying to use a log viewer (doesn't matter which one) to parse my log files.
my log4j pattern is this.
%p [%t] (%C{1}:%M():%L) %d{dd/MM/yyyy-HH:mm:ss,SSS} S:%X{serviceType} N:%X{requestID}- %m%n
the log viewers (at least the open source ones) need you to implement a pattern so they will be able to read the file.
for example:
for the log4j pattern: %p [%t] (%C{1}:%M():%L) %d{dd/MM/yyyy-HH:mm:ss,SSS} - %m%n
the log viewer pattern would be:
pattern= pattern=LEVEL [THREAD] (CLASS:METHOD():LINE) TIMESTAMP - MESSAGE
the example works well.
but i have not been able to parse the %X property in any way. i have seen there are property types NDC and PROP(key) but i seem to either miss use them or they are not related to the %X
so the question is how to implement the pattern so it will read the %X parameter.
thanks.
Ok, i think i see the problem.
Your application use the log4J MDC since it use the %X in the pattern layout. Your log viewer seems to support only NDC.
log4j pattern layout for NDC is %x (lowercase).
If you have control on the application, you have to change MDC -> NDC and modifiy the log4j.xml to use %x instead of %X. That may be a big task if the app is huge...
Another solution would be to find a log viewer that support MDC(%X)
I tried to look around for the PROP(key), but there is not much doc on it ;-(
Good luck