Tsung - Instant gratification¶
Tsung is a tool for load testing web applications and databases.
The tsung command that we will look into now are
1. tsung-recorder, is a tool that can act as a proxy and record network track and record network requests to a live client. These recordings can be played back, on a much larger scale, by the real tsung program.
2. tsung, which is the actual program that reads from a configuration file that includes one or more “sessions”. These sessions can be ones that are created by the tsung-recorder, or handcoded.
3. tsung-stats.pl, is a tool that will generate html reports with graphs that presents all the metrics collected by the test session.
Tsung recorder¶
Tsung recorder is started so,
tsung-recorder start
It will print out something like
“Record file: /home/vagrant/.tsung/tsung_recorder20161130-0627.xml”
Which means that the recorded sessions will be stored at that path.
The proxy will be listening on port 8090. So now you can go change the proxy settings in your browser and start using the app.
After you are done, stop the recording using
tsung-stop
Tsung¶
The tsung uses a configuration file to do the test. Let us start with the very basic test. Let us test couple of json end points.
<?xml version="1.0"?>
<!DOCTYPE tsung SYSTEM "/opt/local/share/tsung/tsung-1.0.dtd">
<tsung loglevel="warning">
<clients>
<client host="localhost" cpu="1" maxusers="3000" use_controller_vm="true"/>
</clients>
<servers>
<server host="192.168.33.5" port="8080" type="tcp"/>
</servers>
<load>
<arrivalphase phase="1" duration="1" unit="minute">
<users arrivalrate="5" unit="second"/>
</arrivalphase>
</load>
<sessions>
<session name='rec20161129-1447' probability='100' type='ts_http'>
<setdynvars sourcetype="random_string" length="20">
<var name="booffice"/>
</setdynvars>
<request><http url='/tenants' version='1.1' method='GET'></http></request>
<thinktime random='true' value='32'/>
<request subst="true"><http url='/tenants/new' version='1.1' contents="{"id": 532, "name": "Tewvrewer", "firstname": "TenantwerweFtern", "lastname" : "TenaewrwntLn", "email": "TenantEweqweqerwrml2", "phone": "TenawerwerntPhone", "userId": null, "backofficeDomain": "%%_booffice%%"}" content_type='application/json; charset=utf-8' method='POST'></http></request>
</session>
</sessions>
</tsung>
Let us take a look at relavent sections.
- The host attribute of localhost means that we need the requests to be sent from this machine itself.
- The use_controller_vm attribute means that you don’t want to tsung to connect to another machine, and run tests from there, and instead run the test from the parent process itself. if you omit this attribute, tsung will try to ssh into localmachine and will often result in permission denied errors.
<servers>
<server host="192.168.33.5" port="8080" type="tcp"/>
</servers>
The host and port are pretty self explanatory.
<setdynvars sourcetype="random_string" length="20">
<var name="booffice"/>
</setdynvars>
This is where we set up a string which will get randomly generated for every request. We are using this variable here, which, by the way represents a single request.
<request subst="true"><http url='/tenants/new' version='1.1' contents="{"id": 532, "name": "Tewvrewer", "firstname": "TenantwerweFtern", "lastname" : "TenaewrwntLn", "email": "TenantEweqweqerwrml2", "phone": "TenawerwerntPhone", "userId": null, "backofficeDomain": "%%_booffice%%"}" content_type='application/json; charset=utf-8' method='POST'></http></request>
Here, the subst attribute is important. Without it, variable substitutions will not happen. Take a look at the content attribute. You can see that it is a double quoted string, which is required for variable substitution to happen. You can see that we are using the booffice variable as %%_booffice%%.
tsung-stats.pl¶
This is a perl script that can genenrate html reports with a lot of graphs and stuff. This is how you use it.
/usr/lib/tsung/bin/tsung_stats.pl --dygraph -stats ~/.tsung/log/20161129-1705/tsung.log chromium graph.html