Why we’re writing machine learning infrastructure in Go, not Python
towardsdatascience.com
towardsdatascience.com
But why pass up the opportunity to use a buzzword to get on the front page of HN?
It does things like prediction monitoring, and it supports models exported by ONNX and TF Serving. We also have designed Cortex to prioritize infrastructure needs specific to inference workloads (inference workloads are read only and memory hungry, for example). This is why we’ve prioritized things like GPU spot instances.
Our long-term plan includes more end-to-end ML workflows, including things like training, but for now we’re focused on getting model serving right.
On my team we use Python and Scala. For network critical I/O stuff in Python, asyncio has worked out just fine for our needs. For massive CPU parallelism needs (at least in sporadic bursts), we've actually found that AWS/Lambda does pretty well.
Golang seems to be really polarizing. Most engineers on my team have tried Golang in the past, but haven't liked it, which is why we would never consider building anything on top of it. Everyone likes Python well-enough that it has kind of become the lingua franca for us.
Deployment is all based around containers or serverless/lambda, and we have a pretty standardized way of deploying these things by now. Just because a bunch of k8s tooling is written in Golang doesn't mean I need to rush out and write my stuff in Golang too.
I've worked with hundreds of Data Scientists, many new to the industry and they all know that R and Scala are important and popular languages for ML.
Majority of Data Engineering today is using Spark, which is written in Scala and even when you write Python code using it you can't escape Java/Scala internals being exposed.
How would you write an article about moving to a hipster language then? :-)
Zero downtime model updates can be done using a redis cache to persist models.
In any case, that's a solved problem using haproxy and kubernetes.
Not sure why go has these advantages
> Implementing all of this functionality in Python may be doable with recent tools like asyncio, but the fact that Go is designed with this use case in mind makes our lives much easier.
This just makes me think about Armin Ronacher's article on back pressure but, sure, whatever.
> Building a cross-platform CLI is easier in Go
No, it isn't.
> The performance benefits of a compiled Go binary versus an interpreted language are also significant
Ah, yes, because performance is such a key feature of command line interfaces, as evidenced by bash and its outstanding performance in every benchmark.
> The Go ecosystem is great for infrastructure projects
And the reality discussed in this point would be different if docker wasn't written in Go. Had the docker developers chose anything else, this point would apply to that hypothetical language, so it isn't an inherent advantage of Go as a language.
> Go is just a pleasure to work with
No, it really, really isn't, but that's not the point.
This is ultimately the real reason they chose go: whoever made the original decision liked it and everything else is post-hoc rationalization.
Which is fine, most of this tends to be subjective.
Golang is probably a step up from Python, but it's just that. There are a lot of issues with Golang. From the top of my head, lack of decent error handling (if err !=nil { return nil,err} ) or lack of decent polymorphism are the most annoying. There's a github repo dedicated to what's bugging people:
https://github.com/ksimka/go-is-not-goodIn day to day work it's really not an issue.
>In day to day work it's really not an issue.
Polymorphism and error handling, these are issues, address them. Go's a fine language, but don't dismiss actual real issues that have been addressed in other languages for 40+? years.
A bigger issue, IMO, is that people coming to Go from other languages expect it to have similar features to what they're used to. Go is small and conceptually simple, but its ideas and philosophy are pretty different from most mainstream languages.
Go has its benefits and reasons to use it (especially the network effects around it). But when it comes to the three things I mention, Go is truly pathetic compared to a language like Haskell. It's amazing how much effort is wasted on those activities. I can see why a corporation would not care, but as an engineer I can do better with my time and effort for my personally-owned endeavors.
Go is made to treat people as Resources. Full stop. That explains everything about it's benefits.
Go only appeared about 10 years ago. The industry standard is 50 lines of production code a day. 50/day * 250 working days a year = 12.5k loc/year. So it would take you how many continuous years to write 200k LOC?
The industry standard is probably very heavily biased by big corporate code bases where refactoring / architecture takes a lot more time than implementing the actual changes afterwards. Doesn't seem like a very useful calculation you are trying to do there to proof the previous poster wrong.
I have a lot of time playing ms flight sim and so obviously I know how to design airplanes is his argument.
Writing "greenfield" applications that no one (comparatively) is using is relatively easy. Creating systems that have four+ 9's availability, integrate with various disparate APIs, don't lose data, and,and etc is where, IMO, the learning is.
Once one has this experience, watching this micro services "movement" is, in my mind, related to global warming - like watching someone jump out of a plane with no parachute, smiling.
No, they aren't. They are the same as languages from 40 years ago: We have had channels, coroutines, and good garbage collectors from long, long ago. Plus the syntax is directly borrowed from Algol 68 (from 1968).
Go looks nice because it fills a niche (a high performance garbage collected language that is easier to learn than Java and provides faster compilation times than C++), but there's absolutely nothing different here.
For "pretty different from mainstream" see Forth, Prolog, Erlang, etc.
Surely you see that other people value other things than you do?
If you value simplicity check out the programming language zig.
I value simplicity, that's what i use Brainfuck. Far simpler than Go and Zig.
* no generics
* null pointers
* no compile time checked enums or sum types
* The golang time package is garbage
* golang interfaces are garbage, can't tag types with an interface without implementing a dummy method and hope that no other type implements it. Can't find what interfaces a type implements without an IDE
* profiling and debugging tools are nothing in front of JVM and .NET tools
* no const/immutablility
* no ternary operator, need to write 6 lines instead of a single line if it existed
* error handling is error prone and verbose
* no default method implementation in interfaces
* unit testing frameworks are sucky and rely on code gen, can't mock arbitrary types, but only by defining an interface
* that unnused variables and imports are compile time errors, makes it very annoying and time consuming to prototype or when debugging
* no private/public/etc modifier. if you want to change the visibility of a type, you need to rename it in all files it's listed in
* no incremental compilation (yes Java compiles faster in large projects where I only modify a handful of files, or even more)
* pervasive use of single letter identifiers in golang code bases
* pervasive use of int, which has a platform dependent size
* pervasive instantiation of structs by calling them structFoo { Field1: field1, Field2: field2, ... FieldN: fieldN }, which makes it easy to miss when a new field gets added. Rust and Zig solve this by making it required to specify all fields and values.
* defer works on the function scope, not the current scope
* defer doesn't handle functions that return errors, meaning many errors are missed
* no struct or file private, only package private
* the global scope is polluted with special functions like len, copy, delete, make, new, append, for no good reason
* golang imports don't support cyclic imports
* golang doesn't allow you to import a a specific function or struct from a package. You have you always qualify anything with the package name, which makes things verbose and awkward.
Not true, unless you're using an esoteric definition of "incremental".
> imports don't support cyclic imports
Why on earth would you consider this bad?
I think this was why Python was able to overtake Perl, for example.
> lack of decent error handling (if err !=nil { return nil,err} )
Errors are in your face, instead of having exceptions performing invisible gotos to somewhere far up in call tree. Implicit error handling is more code, but your error handling is going to be much more robust.
> or lack of decent polymorphism...
Lack of polymorphism also means you don't have to guess about concrete types when reading code. When troubleshooting, you can see what's going on without going through whole inheritance tree.
Go encourages composition instead of inheritance. That's something I wish more C++ codebases would do as well. Composition makes code inherently more maintainable and easier to refactor.
Go tends to be easy to read and maintain. It does come with some cost. It's just a matter where your priorities lie. Software projects spend majority of their life as legacy, something that needs to be maintained.
My understanding of composition comes from interfaces in C#. In my experience composition is actually more difficult to code and refactor, because it leads to bloat from repeated code as you cannot simply inherit. Refactoring then can become tedious as you may need to manually edit every repeated code block. Whereas with inheritance I define a function once and override it where necessary.
Am I misunderstanding something?
Over time your whole inheritance model often turns out to be no longer viable, when the basic assumptions made years ago are no longer valid.
Worse, because of all of the accumulated cruft, you might not even be able to change the shape of the monster.
So you can get some of the conveniences of inheritance. The behaviour is of course different, because the composed member has no way of knowing the identity of the including struct.
Errors as values is a great idea. Errors as values without sum types or pattern matching, though, gives you twice the tedium and a tenth of the benefit, so once again Golang's slavish adherence to "worse is better" really just makes things...worse. The real problem here, though, is that those invisible gotos still exist: because of how limited Go's type system is, it's very easy to cause a panic with e.g. a nil pointer. Of course, the answer is to rigorously check the cases where a pointer could be nillable, but that trivially contradicts the idea that, when reading Go code, you can feel confident reasoning locally about its resilience if it handles all potential error values appropriately. IMO, this false sense of safety is even worse than just making exceptions first class citizens of the language, and it belies the notion that Go is especially maintainable.
The cost of simpler tools is you need to target better, simpler designs and refactor. This requires more from programmers but produces better code.
Parametric polymorphism would mean you never have to even consider the type of the code. It's a freeing abstraction with plenty of very simple reference implementations. And it lends itself to composition over inheritance.
And sadly I doubt Go will ever manage to get it.
Concurrency in Swift is not yet a solved problem, but libdispatch is quite workable (although not "elegant, out of the box" per the article).
With the work being done in Swift for TensorFlow [0], I'd imagine in a year or two both the infrastructure and the ML portions of a product like Cortex could be written in a single language.
We looked at Go early on but quickly dismissed it because with the move from Python to Go, it didn't seem like we were getting enough benefits to warrant the amount of work that would be required.
To do large scale data preparation and engineering which necessitates clustering you would need to reinvent Spark. And then how about for the more common algorithms like boosted trees etc. Those algorithms are provided by Apple for iOS/MacOS but not sure if they exist for everyone else.
Pythons asyncio is pretty hard to beat. For non-cpu intensive tasks, I find it a pleasure to work with. Goroutines can still have race conditions.
> Originally, we wrote the CLI in Python, but trying to distribute it across platforms proved to be too difficult
Sure, I get that go can cross-compile. But what makes python hard? Python works on every platform, and distributing is just a "pip install" and "pip install -u" Surely thats easier than "Download the correct binary for the platform, unzip it, change permissions, add it to your path, then do it all over again for every update"
I was the original author of the awseb cli and we found that pip install was significantly less of a hurdle than a go binary and decided to do it in Python instead. If a user on windows has a hard time installing python and pip, telling them to drop a binary and change their path isnt going to be any easier.
I was yelled at a few times for not using package and environment management tools (Conda, etc). So, when working with Python it is not just a "pip install" anymore
You ever tried setting up Python on a new machine? https://xkcd.com/1987/
apt install python3 python3-pip python3-virtualenv
Also, when we had the Python CLI, some of our users complained that in their CI systems which ran `cortex deploy`, they didn’t need Python/Pip in their images, and installing them was inconvenient
Until you have a dependency which has a C dependency (like a crypto framework, SQL connector, etc). Suddenly you need an entire compiler toolchain, dev dependencies, all the library headers, and a decent amount of time. Also the errors thrown when these compile steps fail are anything but helpful for new users. If you are lucky there is already a wheel for your platform/arch.
> Surely thats easier than "Download the correct binary for the platform, unzip it, change permissions, add it to your path, then do it all over again for every update"
This is trivial to automate using a script and has a ton less failure modes to deal with than Pip would have (do you have the correct Python version?, is there a compiler installed for C modules?, etc).
but... that's not a python problem.
every time people say they are having a hard time installing a python module, it's almost always a non-pure python module. it has an extension in c or c++. if that tells us anything, it's that mixing c and c++ makes software hard to install...
a fairer comparison with go here is with a go package that has extensions or bindings written in another language.
A fairer comparison would be comparing the ease of how to create and install a cross platform Go binary compared to how to distribute a Python application as a single package/pseudo-binary (I've been down that rabbithole and many others with Python packages in the past 15 years).