CHN256234

CHN256234 - Programming request from a customer for a new project for bridgingIT GmbH.

see also: Coding Task

Abstract

This small example in golang will process integer intervals. This intervals needs to be in a json format as described below.

Json input format

The input needs to be in a json format, consists of an array representation in depth of 2. The main array collect the different intervals:

[
      <interval1>,
      <interval2>,
      <interval3>,
      ...
      <intervalN>
]

Every interval is also an array of 2 integer values. The lower- and the upper-end of the interval:

   [<lower>, <upper>]

Example

[
      [25,30],
      [2,19],
      [14,23],
      [4,8]
]

or without spaces and newline characters:

[[25,30],[2,19],[14,23],[4,8]]

Build the tool from source

c:\go\bin\go.exe build -a -installsuffix cgo -o interval_merger.exe .\src\interval_merger

Execution

usage

interval_merger.exe -h
Usage of interval_merger.exe:
  -file string
        The json file that contains the intervals
  -i string
        A json string that contains the intervals

example

interval_merger.exe -i "[[25,30],[2,19],[14,23],[4,8]]"
[[2,23],[25,30]]

Build and runtime alternatives

Docker

You will have a Dockerfile inside this repo to build a docker image out of the golang source.

Example:

git clone https://github.com/cybcon/CHN256234.git
docker build -t interval_merger:latest ./CHN256234/

After building the image, you can run the image example:

docker run --rm interval_merger -i "[[25,30],[2,19],[14,23],[4,8]]"
[[2,23],[25,30]]

A ready to use docker image can be pulled from Docker Hub: https://hub.docker.com/r/oitc/chn256234

docker run --rm oitc/chn256234:latest -i "[[25,30],[2,19],[14,23],[4,8]]"
[[2,23],[25,30]]

Azure DevOps CI/CD pipeline script

Inside this repo, there is also an Azure DevOps CI/CD build pipeline definition: azure-pipelines.yml. This can also be used to build the docker container and automatically push to a docker repository.

FAQ

• Raw coding time of this solution: ~4h
• Resilience:
  • Map input parameters to a struct, invalid values will be ignored
  • Large input parameters over command line will not be processed due to bash input limitations
  • Large input via input file: due to the static linked, compiled and small solution, large files up to 1 mio intervals can be processed without any issues
• Runtime metrics:
  • Azure VM parameters:
    • Region: West Europe
    • Image: Ubuntu Server 18.04 LTS - Gen 1
    • Size: Standard_D4as_v4 - 4 vcpus, 16 GiB memory
    • OS disk type: Premium SSD
  • runtime measurement with the build-in Linux command: time
  • memory consumption measurement with the Linux tool: /usr/bin/time
  • Data in subfolder: loadtest

intervals	runtime	memory consumption (max rss in kbytes)
5	0m0.002s	7.820
50	0m0.002s	5.904
100	0m0.002s	5.800
500	0m0.003s	5.836
1.000	0m0.003s	9.896
5.000	0m0.008s	7.956
10.000	0m0.014s	12.296
50.000	0m0.065s	17.220
100.000	0m0.131s	27.176
500.000	0m0.651s	90.724
1.000.000	0m1.297s	204.096

other solutions

• Christian Will, implemented in C#: https://github.com/dnkh/MergeIntervals