Capture The Flag 3: Distributed Systems

This edition of the Capture The Flag contest by @Stripe was about distributed systems and performance:

This Capture the Flag is all about distributed systems. There are five levels, each one focused on a different problem in the field. In each case, the problem is one you've likely read about many times but never had a chance to try out in practice.

This repository contains the source code of the original levels, without solutions. You can find solutions and write-ups by many participants on https://github.com/ctfs/write-ups/tree/master/stripe-ctf3.

The purpose of this repo is to make it easy to implement your own solutions and compare them against a benchmark.

Each level contains a README.md, which should get you started.

TODO

• level1:
  • sample output
  • minimum target score
• level3:
  • need to confirm build steps, in Linux and OSX
  • ready-to-open/import in Scala-IDE and/or IntelliJ
  • sample output
  • minimum target score
• level4:
  • need to confirm build steps, in Linux and OSX
  • ready-to-open/import in IntelliJ (or other IDE?)

level0

To test your implementation against the benchmark, simply run:

./test/harness

Example run:

No test case supplied. Randomly choosing among defaults.
About to run test case: level0-R5ez7L9mIu
Beginning run.
Finished run
Test case passed. Your time: 9.513440 seconds. Benchmark time: 0.621270 seconds. You/Benchmark: 15.312883

You/Benchmark: 15.312883 is very poor. Try to get that rate below 0.5

level1

TODO

level2

The sample implementation requires npm, the Node.js package manager. Build the sample implementation with:

./build.sh

To test your implementation against the benchmark, simply run:

./test/harness

Example run:

... (skipped)
Number of total responses 528
Number of good responses: 30
Number of responses less than ideal: 538.6666666666667
Finished run
Test case passed. Your score: 0.010000. Benchmark score: 124.791667. You/Benchmark: 0.000080.

You/Benchmark: 0.000080 is very poor. Try to get that rate below 2.0

level3

TODO: need more details here about installing sbt and scala, and the build process in general. (will test in a clean vanilla Ubuntu)

TODO: would be nice to have a ready-to-open project in Scala-IDE or IntelliJ

The sample implementation requires scala, the Scala compiler, and sbt, the Scala build tool. Build the sample implementation with:

./build.sh

To test your implementation against the benchmark, simply run:

./test/harness

Example run:

... (skipped)
TODO

level4

The sample implementation requires go, the Go compiler. You can download it from http://golang.org/doc/install

Build the sample implementation with:

./build.sh

To test your implementation against the benchmark, simply run:

./test/harness

Example run:

... (skipped)
Final stats (running with 5 nodes for 30s):
Bytes read: 44.88KB
Bytes written: 43.76KB
Connection attempts: 8
Correct queries: 5

Score breakdown:
50 points from queries
-151 points from network traffic

Total:
-101 points (canceled due to disqualification)
-------------------->8--------------------

That's worse than poor, the run got cancelled due to disqualification.

Another example:

... (skipped)
--------------------8<--------------------
Final stats (running with 5 nodes for 30s):
Bytes read: 97.94KB
Bytes written: 96.79KB
Connection attempts: 120
Correct queries: 67

Score breakdown:
670 points from queries
-223 points from network traffic

Total:
447 points
-------------------->8--------------------
Your normalized score works out to 74. (Our benchmark scored 1430 [queries] - 826 [network] = 603 points on this test case.)

Try to get consistently better score than the benchmark.