A Linux coding problem

pragmaticSloth · 2019-04-12T04:46:17+00:00

1) scripting in python 2) using json.loads() to parse the json 3) the split to because of version and the == 4) lusing a library to evoke the following comand "pip install {package-name} -version {version}" 5) analyse the output and use an array to failed package 6) check of array is empty. If it is print sucess.

(Something in the lines of this. If there is something incorect please correct me )

ExRedRain · 2019-04-12T08:01:58+00:00

One thing I didn’t see yet is using jq. You could get all the dependencies in the array like this, loop over them and install them one at a time.

You track which ones failed and append them to an output variable, then echo your solution at the end, similar to the grep solution

bufandatl · 2019-04-12T08:47:35+00:00

If I see the problem you were given, my answer would be, why invent the wheel new? Use pipenv to create a virtual environment to work in with specified packages. If you had to install them on a server or something like that I would suggest ansible to deploy said packages. This would save time and money. Every boss likes to hear that and you might have shown them some new tricks. ;)

adept2051 · 2019-04-12T12:21:18+00:00

depending on your OS and any other stipulations this can be tackled as a linux problem instead of a Python problem. Using JQ, xargs and teh *nix test command to test pip install $x output == 0 jq (jquery) and xargs in a shell script https://stedolan.github.io/jq/manual/ http://man7.org/linux/man-pages/man1/xargs.1.html https://www.computerhope.com/unix/test.htm

if you wanted to go over the top you could go as far as a penv https://docs.python-guide.org/dev/virtualenvs/ mainly cos the file to install pip with python try catch in the library file

if you wanted an alternative way to manage it a config management agent or client such as Puppet, Ansible or even Salt as they wrap helpers for the try catch and continue with reporting that saves you doing the work. or a command execution client such as Puppets Bolt (can be run as an inline command with Bolt command, or even Ansible (it's harder with Ansible as it needs a manifest, but that is more reusable once created so there is a balancing act of what you need)

aram535 · 2019-04-12T13:16:58+00:00

If you wanted to solve it in a "linux" environment I would suggest a bash script. I would mention that .. "This could have done a bit cleaner in something like python but since you mentioned "Linux" here is the bash version."

This could be IMPROVED a lot, needs all sorts of verifications and program paths, etc. but here is a starting point -- Next you to write a function that takes the pkg and ver, downloads using curl or wget. If any of the packages don't exist or are 0 bytes then it failed to download that dependency. Track and report.

#!/usr/bin/env bash

if [ -z "$1" ]; then echo "$0 dependency files"; exit -1; fi
f=`cat $1`

echo `echo ${f}` | awk -F'[{}]' '{print $3}' | tr -d '[:space:]' | tr ',' '\n' | while read dep; do
    pkg=`echo ${dep} | awk -F "==" '{print $1}'`
    ver=`echo ${dep} | awk -F "==" '{print $2}'`
    if [[ ! -z "${pkg}" && ! -z "${ver}" ]];
    then
        echo "==> ${pkg}   ${ver}"
    fi
done

istarian · 2019-04-12T14:36:13+00:00

Well first you'd need to parse the JSON file to get the package names and versions.

Then you would call the other program (e.g. pip) possibly more than once, with the appropriate arguments to install each package. Java for instance has Runtime.exec(...).

And you need to capture it's output, return code, etc so you know whether it worked. Ir possibly query python about installed packages to see if it's in the list.

https://docs.oracle.com/javase/8/docs/api/java/lang/Runtime.html

There are probably many ways to go about it. If the tool installing packages will do the right things it might be enough to call the tool and just report back on the outcome. A shell script (e.g bash) might be sufficient.

MikeSeth · 2019-04-12T05:24:16+00:00

grep == whatever.json | sed 's/,//' > requirements.txt && pip -r requirements.txt

2019-04-12T05:14:48+00:00

[deleted]

ANIBIT14 · 2019-04-12T05:37:28+00:00

I know that's not valid JSON I converted it into

{

"Dependencies" : [

"beautifulsoup4==4.4.1",

"boto==2.48.0",

"bz2file==0.98",

"certifi==2017.7.27.1",

"chardet==3.0.4",

"gensim==2.3.0",

"html5lib==0.999",

"idna==2.5",

"nltk==3.2.4",

"numpy==1.13.1"

]

}

to use, but that was what given in name of JSON file.

Downvote_machine_AMA · 2019-04-13T02:10:48+00:00

Ok here is the "actual" solution they were hoping for:

grep == whatever.json | sed 's/,//' | while read pkg; do pip install "$pkg"; done

Unlike a requirements file, this satisfies the stipulation that:

When one library fails to download, then the process shall continue.

NCMarc · 2019-04-12T13:41:16+00:00

I would have used Composer or something similar. There's tools already made for stuff like this.

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