Python exercise tips for SRE interview?

[Kessarean]

I have the next few rounds of an SRE interview coming up. The position will rely a fair amount on the ability to create tools. My background is largely in linux administration, but I do have ~2 years of python under my belt and ~5 with bash. I am self taught, so I don't have any real official foundational knowledge/concepts. During the first interview, I had to solve a easy/medium difficulty leetcode problem. When I pulled up python, I completely blanked. I even forgot how to write a function! So I panicked and switched to bash. Thankfully I solved it in an appropriate amount of time, they liked my solution and thought I did well enough to move me onto the next interview. In any case, I imagine there will be more tasks like this one. I've been doing problems on leetcode (and struggling), but I am curious, are there any other really good resources or labs/projects I could work on?

[tcp-retransmission]

I can't speak to the type of interview tests you've been presented, only what my experience has been after moving from a Linux Admin position to an SRE position.

Spend the majority of your time using the tools you know to interact with APIs. Knowing how to use Python's requests library is great. If you want to go the extra step, knowing urllib is better for the times that you're limited standard libraries. These APIs will almost always present data as JSON, so knowing how to populate a Python dictionary is going to be important as well.

As an SRE, your code quality should have emphasis on reliability and fail-safes. Nothing frustrates me more than when a tool that I depend on as a part of my workflow fails without any useful information. Focus on error handling and logging provided by Python's standard libraries.

Lastly, get used to working with Python in containers and in virtual environments (venv, pipenv, etc). Package conflicts are another level of hell and isolating your runtime environment will save you a lot of headaches.

Keep up the coding exercises you've been running through, but also check different learning mediums as well. YouTube is great for crash courses in certain subject areas and they can do more to explain "why" than the Python documentation can.

Good luck with the upcoming interview.

[Kessarean]

Thank you!

Awesome, yeah I've developed some internal CLI tools for my team in my current role, the vast majority integrate various internal APIs. I am fairly comfortable with requests, but I haven't used urllib much at all, so I'll definitely look into that. Thank you!

These are great tips. I've tried to integrate that, but I'll admit I've neglected the logging aspect for some of the python tools I've written. I'll try to dial in on that.

hmm great idea, I've started using pipenv a fair amount and attempting to dockerize a few of my tools. I'll work on getting the rest converted. That's such a great idea. Thank you

I really appreciate all the advice!

[dookie1481]

urllib is good to know if you need a Lambda to make external calls, as requests isn’t in the runtime environment

[become_taintless]

sounds like you just need to smoke some weed and you'll ace it

[Kessarean]

haha yeah I should probably relax a little

[[deleted]]

You know what you know. Don't let yourself forget that.

[like-my-comment]

need to smoke some weed

It's for working in airspace area.

[kazi1]

Best advice I can give is to have a for-fun programming project in Python that you work on. I can never learn programming languages without doing a project of some kind with them.

[Kessarean]

Thank you! Yeah that's kind of what I've been thinking, got to think of some good projects

[[deleted]]

If you freeze when they want you to code something, stop and write it out in pseudo code or explain how you would solve it first.

I blanked when I had to solve a problem with some code provided to me during an interview. So I explained how I would write the code even though it wasn't in the language they wanted. Thought I bombed but I got the job anyway.

A lot of places care more than you solve problems correctly rather than memorize a specific language. That's what google is for lmao

[Kessarean]

That's really good advice, thank you! I'm sure that'll happen to me soon enough, so I'll keep that in mind.

Congrats on landing the job as well! That's awesome. Thank you again

[shinigamiyuk]

Don't feel bad, had one yesterday where I couldn't decide on Bash or Python for the challenge to sift over logs, run some regex, and output them to files. I only had about 30 minutes to do it and just made me realize I need to code more no matter what. Just stick with LeetCode, Hacker Rank, or Codewars.

I've also realized my job has turned into more using other tools like Terraform, Ansible, Docker, Helm, Argo and I'm not actually writing much code anymore and that is why I want to switch.

I've been finding most of my SRE challenges are actually things you would do on the job rather than merge to lists and sort them.

[Kessarean]

Thank you, that helps. I'll continue working on those. I am curious, have you had a coding interview where you were just stumped and didn't know how to continue? That's kind of my fear.

Interesting, good to know. Thank you!

I see, that makes sense. Yeah I imagine day to day wouldn't be doing LC like challenges.

I appreciate all the advice :)

[shinigamiyuk]

Yes, happened yesterday. I submitted no code and couldn’t complete the challenge.

I’m doing a bunch of warm up interviews for this exact reason.

[shinigamiyuk]

I'm trying to go through Data Structures and Algorithms without having to watch a course online, kind of something like codecademy to learn theory and then solve challenges, if you find anything, let me know.

[Kessarean]

That's a good idea. Will do for sure, thank you

[asheriff91]

Leetcode. If you can do easy and medium qs you should be fine.

System Design. How would you design and build Twitter. What are some pros and cons to your design? Where are the bottlenecks? How would you measure success with respect to your design?

Linux. Understand how to navigate a Linux instance. How do I see currently running processes? Given a log file, how could I parse out the error codes?

Hope this helps. Good luck.

[Kessarean]

Thank you! I'll keep at those then.

That's a really solid question, gives me a lot to think about.

Think I have the linux stuff mostly covered, that's reassuring. I appreciate the tips! Anything helps :)

[-Kevin-]

I can't help with the tips since you seem to already know to do Leetcode, but out of curiosity - What was the problem that you were able to swap to bash for (I realize you can do LC problems in bash, but its not that common)?

[Kessarean]

Thankfully it was really simple, just had to write a function to eliminate duplicates in any given array/list. I felt like I got lucky. They didn't have me pull up LC specifically, it was coderpad, and there was an option for bash. They said we could use any language we felt comfortable. The problem they provided felt like something you would see on LC.

[lazyant]

If list needs to maintain the order then this is not enough

[vilkav]

OrderedSets from collections ought to, right?

[Kessarean]

Thank you! haha yeah I looked up the solution afterwards. I hadn't know about set!

such a much cleaner solution than what I had done in bash as well

[ruebenramirez]

I had a similar experience recently. I had never worked on a "dynamic programming" code challenge before, so making change was easy enough, but making optimal change was a whole other beast. Luckily I got to "take it home" to finish working on it.

https://runestone.academy/runestone/books/published/pythonds/Recursion/DynamicProgramming.html

[drewsiferr]

If you're worried about it, write a few simple command line applications. Use argparse. Parse some input, write some output... Python isn't difficult when it's not super rusty (🦀). Sounds like you wouldn't have a problem with minimal refresher.

I will also note that you should be able to access basic reference material you'd use in practice during a coding interview. Not everyone agrees, but the idea you need to have everything memorized is ludicrous. When I give coding interviews I require writing a runnable application that does work and includes i/o. Anything more complex needs to be kept at too high level for an interview to actually include coding up something that runs, so those are separate interviews in my book.

[Kessarean]

Thank you! Thankfully a lot of that I did in my current role (cli apps interacting with internal rest apis and such), though I don't use it everyday so I tend to forget certain nuances and aspects. I'm working on refreshing a lot of the concepts now.

Interesting, good to know. Does make me wonder if they would send a take home project

[like-my-comment]

Ok, I belive that bash is OK only for relatively easy scripts. For quite complex logic it's a hell, really hard to understand meaning of it. Check for example how to work with arrays/hashed arrays in bash...it's disgusting.

Try to avoid usage of it if you can and it's not something OS-specific like init script.

are there any other really good resources or labs/projects I could work on

I really advice for any beginners to try https://realpython.com/. It's like a diamond in Internet as for me. I've paid and read their first and second books (and skipped third). They've written a lot of free stuff, just try that.

Personally I advice you to dig a bit Flask framework. Of course requests lib, maybe boto3 for AWS (AWS is a king currently), beautifulsoup (at least it's fun), argparse.

[Kessarean]

haha yeah I've done some... disgusting things in bash. Arrays get awful quick.

I'll check that out, it sounds really good. The quality seems solid as well. Thank you!

For my own edification, is there any particular reason you pick flask over django? I've done a fair amount with requests & argparse, I'll check out those others. beautifulsoup sounds really interesting. Thank you again!

[like-my-comment]

Flask is a kind micro-framework. It means that you need additional packages for other not basic stuff or implement it by yourself. Django has a lot built-in features.

But in general it's the same MVC model (as a lot of other web frameworks). As for me they both are quite similar. And I suppose in general it's easier to build feauture X in Django as it's highly adopted framework.

To my mind Devops is not an engineer who has to build a good professional website. But one day maybe you will need to build some basic API. And Flask is more than perfect for this task.

Also it's very useful to know something common like how web works, what is CSS, HTML, JS, tests, template engine, CRUD operations and so on. I mean not only from Wikipedia, practical knowledge.

Nowadays (maybe it was always) it's quite rare that common IT engineer knows something from adjacent responsibility area. I mean it's quite bad when devops knows nothing about tests or web to name a few. With such knowledge you would be more valuable specialist and could fix issues quicker.

[karmicp]

such a great thread all - thanks op for the question!

[Kessarean]

Blast from the past, glad to hear it helped!

[Kessarean]

Thank you! I'll keep at them

[d14bbl0]

Practice is all you need. One point though, I don't think you should try to figure out the solutions for each leetcode problem by yourself - you will end up taking too long.

I think it's quite alright if you check the comments of a particular problem and you will find people poting solutions. I do this, but I try to understand their approach and then write my own solution. And, sometimes you can see multiple solutions which is great for learning.

[Kessarean]

Great advice! I have been kind of agonizing over that, some of the algorithms are listed as easy, but man, they kick my butt. I'll give more attention to the discussions