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Last pushed: 23 days ago
Short Description
A test container with various purposes.
Full Description


A simple little Flask app which computes pi to the nth number to simulate CPU load to test autoscaling on the cloud provider.

Testing the flask app locally


(of course flask has to be installed, so you should do it in a virtualenv)

Environment variables

FLASK_PORT=5000             # port flask listens on
FLASK_DEBUG=0               # whether flask is put in debug mode
FLASK_THREADED=1            # whether flask is being run multi-threaded

LOADUMMY_NEXT=http:/...     # optional, for the /distrib/... endpoint

Data encoding

The app will return HTML data (Content-type: text/html), unless otherwise specified in the Accept: header. If it finds the string yaml in that header, YAML data is returned (Content-type: application/x-yaml, like rails), if it finds the string json it returns JSON data (Content-type: application/json).



Returns "OK" with a HTTP status code of 200.


Computes the number pi with the number of digits given. So ...


... will compute pi until 5000 digits. On a MacBook Air 2012 100.000 digits will take about 20 seconds.


Displays all environment variables in the docker container.


Displays all environment variables starting with VAR_START_STR



To simulate a controller / worker type of structure you can use the /distrib/<a>/<b> endpoint. To use this endpoint variable LOADUMMY_DISTRIB must be set.


If you call http://host:port/distrib/5/250 now, what happens then is ...

  • it will create NUM requests for calculation of pi with
  • (on average) DIGITS digits.

Or better: if you call it with /5/250, it might query those urls:

  • http://next_host:nextport/pi/267 (1st request)
  • http://next_host:nextport/pi/229 (2nd request)
  • http://next_host:nextport/pi/244 (...)
  • http://next_host:nextport/pi/231
  • http://next_host:nextport/pi/276 (5th request)

... where the numbers are made up randomly around the 250 digits marker (plus minus 10%).

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