Replays Logfiles (especially Apache logfiles) against a given target host considering the original time delays between requests
How to run
Download the latest release, unzip it and run it:
wget https://github.com/paulwellnerbou/chronicreplay/releases/download/v1.5.0/chronicreplay-1.5.0.zip unzip chronicreplay*.zip ./chronicreplay-*/bin/chronicreplay --host=host.to.replay.against --logfile=/path/to/your/logfile --logparser=combined
Standard log level is set as environment variable, named
LOG_LEVEL, default value is
To change the log level, that environment variable needs to be altered. Available relevant
WARN. To disable logging completely, use
WARN (or higher).
LOG_LEVEL=warn ./chronicreplay-*/bin/chronicreplay --host=host.to.replay.against --logfile=/path/to/your/logfile --logparser=combined
How to build
How to run from source directory with gradle
./gradlew run -Pargs='--host=http://localhost --logfile=src/test/resources/combined-log-example.log --logparser=combined'
How to build a binary distribution
The distribution will be put into build/install. For more options about packaging and distribution, see http://www.gradle.org/docs/current/userguide/application_plugin.html.
To run the application, you will find the start scripts for Windows and Unix/Linux in build/install/chronicreplay/bin.
How to write a custom log line parser
The selection of the logfile reader (implementation of LogLineReader) is done using Java's ServiceLoader. See http://docs.oracle.com/javase/7/docs/api/java/util/ServiceLoader.html for more information.
The steps you have to follow:
- Create your own implementation of LogLineParser
- Add the classname to src/main/resources/META-INF/services/de.wellnerbou.chronic.logparser.LogLineParser
- Use --logparser=ID-OF-YOUR-IMPLEMENTATION starting the program
You don't have to modifiy the original services file for this purpose, you can create a separate project which depends on chronicreplay and add your services file in this project. Or, the other way round, you add a (runtime) dependency to your custom LogLineReader implementation project.
For a basic example, have a look at de.wellnerbou.chronic.logparser.CommonLogFormatLogLineParser.
How to get duration comparisons in your chronicreplayer's logfiles
Apache does not log the duration of the requests in the default log formats. To achieve this, you have to add '%D' to your LogFormat. See (http://httpd.apache.org/docs/current/mod/mod_log_config.html) for more information of customizing your LogFormat.
To parse the microseconds you will get then, you can use the code in
CombinedWithDurationLogLineParser or you
can extend from this class, overwriting the extractDuration method or/and the parseLine method.
Plotting the results with gnuplot
The CSV files created contain all data you will need to plot. The file is tab separated, which is the default data format for gnuplot.
In most cases you are mainly interested in the results containing the same status code. That's why the responses with the same status as
the original ones are logged additionally in another file, ending with
Plotting the durations over time with gnuplot:
gnuplot> set timefmt "%s" gnuplot> set format x "%H:%M:%S" gnuplot> set xdata time gnuplot> plot "chronicreplay-host_2015-08-21_08-48-42.csv" using 1:6
Overlaying results from different servers in one plot:
gnuplot> set timefmt "%s" gnuplot> set format x "%H:%M:%S" gnuplot> set xdata time gnuplot> plot "chronicreplay-host1_2015-08-21_08-48-42.csv" using 1:6, "chronicreplay-host2_2015-08-21_08-48-42.csv" using 1:6