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What Is Nix?

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Re: What Is Nix?

#111

Post by takeda »

austinl wrote: post #102

We're using Nix where I work as well, and while I can say it was not the most user-friendly to set up, once we got it in place it has reliably worked for the last two years. We used to have a long and flaky shell script which set up the development environment for new engineers and CI machines (for iOS development on macOS, specifically). Now we have a very simple script which just installs nix and runs alls builds t…

You can use Nix on MacOS X and with nix you don't need brew.

I used it for few years that way.

If you use nix-darwin + home-manager you can also configure your mac the way you would NixOS.

Amazing tools that discovered not long ago (they aren't specific to os x) is:

niv - makes pinning to specific repos/versions in repos much easier which helps with reproducibility, especially pinning of nixpkgs version which is now controlled in your source code.

direnv + lorri - you no longer need to invoke nix-shell just cd the directory and all tooling you need for your project is suddenly available which is AWESOME.

Here's an example of using them together with packaging a python project[1] if you have lorri and direnv installed and cd to the directory, not only you have the right python version installed but also all dependencies and even the "hello" command becomes available, as if you installed it through `pip -e .`

[1] https://github.com/takeda/example_python_project

Re: What Is Nix?

#112

Post by smichel17 »

mzaccari wrote: post #106
WatchDog wrote: post #74

Earlier quoted context omitted.

I haven't used Nix, but I would have thought that builds would be fast, due to how cache-able the dependencies should be.

We've been using Nix for deploying a Rails app for an enterprise customer for quite a few years now. One area where it shines for us is the ability to build it on relatively recent version of Ubuntu and deploy to a (almost EOL) RHEL6 box. Bundling, assets and various other tasks take just a few minutes. We also have ~20 Go services that are also deployed via Nix, and building takes seconds. However, it can be quite c…

I'm having a hard time parsing -- you migrated everything from nix to containers (containers removed the need for nix) or to nix+containers (containers solved the "having to build for multiple platforms" issue)?

Re: What Is Nix?

#113

Post by microphone987 »

throwaway894345 wrote: post #98
maytc wrote: post #92

Earlier quoted context omitted.

That’s how nix guarantees reproducibility. The compiled artifacts can be cached but that didnt quite work out of the box

Nix guarantees reproducibility, which means anything can be rebuilt from scratch, but that's a very abnormal use case. If it didn't work out of the box, it's a problem with the package scripts (the "derivations"). That said, all of our software tends to bottom out in a bunch of shitty C libraries that are all delicately cobbled together with autotools and cmake, so anything that aspires to reproduce these things is g…

This comment is really, really confusing. If it builds once Nix, it will build again with Nix... If you can find a derivation that builds on one machine and not on the other there's usually a fundamental difference - either in CPU arch, your nixpkgs config differs (overlays), etc. Or I guess you could write a build script that non-deterministic ally fails, but that has nothing to do with Nix's maturity.

Nix ensures the tooling is called the same. I can understand having a non-autotools project that is more difficult to write a derivation for, but "Nix can't wrangle messy libraries" makes absolutely no sense, either from a "make compiling reliable" or anything at use-time.

Do you have a specific example in mind that is less hand-wavy?

Re: What Is Nix?

#114

Post by mehrdadn »

geofft wrote: post #107
mehrdadn wrote: post #85

Earlier quoted context omitted.

Thank you! Your comments are always great. :) Especially this bit was I think the insight I was looking for: > This does mean that the experience of using Nix is different from using a traditional package manager - you'll need to take care of starting the services you need, etc. I was trying to figure out where exactly the trade-offs would be -- so that's one of them: it seems like (in some sense, to simplify) Nix ta…

So, there is no /nix/etc - anything in /nix is immutable. I haven't done this and hopefully someone will correct me if I get the details wrong, but I think the way you'd make this work within nix is you'd make your own package, let's call it "my-sshd-config," and it depends on a certain version of sshd. Then you'd have /nix/store/abcd1234-my-sshd-config-1.0/etc/sshd_config. (where "abcd1234" is a hash of everything i…

Oh dear... so you have to write a Nix package (and learn how the language and package management work) just to modify global config files, instead of just editing them? That sounds like an absolute nightmare for a local machine, though possibly a great tool for automated systems.

Also, if there's no /nix/etc... then what is Nix modifying? sshd (or any other more common program; I'm just using sshd as an example to understand the rest of the system) won't magically know to look at /nix/store/efgh5678-my-sshd-config-2.0/etc/ssh_config, right? I thought you'd at least need a symlink like /nix/etc/ssh/sshd_config to link to it. Unless you're saying Nix modifies your system's /etc/ssh/sshd_config directly and makes it a symlink to the immutable Nix store? In which case, wouldn't it just trample everything your own distro's package manager does in that folder?

Re: What Is Nix?

#115

Post by mikepurvis »

tel wrote: post #20
dataflow wrote: post #2

I'm still confused. What is Nix? Is it an OS, or a package manager? From the looks of it it's a package manager that I should be able to use it on any POSIX system, but I doubt that's the case?

It's kind of a mess. Nix is a collection of tools and systems that together form a highly reproducible build system. Nix is also a declarative, largely pure and lazy programming language that you use to design and specify the different build outputs for the Nix build system. Nixpkgs is, more or less, the only project written using Nix (and a lot of shell). It's a collection of many thousands of "derivations", many of…

Thank you for this thoughtful comment. I was involved in establishing a bunch of build and deployment infrastructure at my org that's currently based around large (300mb+) "bundle" Debian packages, but that bundle package is composed of hundreds of small sub-packages, most of which don't change day to day (it's extremely convenient to ship them all as one big unit for versioning sanity and ABI consistency reasons).

Nix seems like it would be a great fit for this use case, but there are a number of things about it which give me pause, particularly when it may be possible to get at least some of its advantages by applying the lessons learned to a system built out of boring, old-school packaging tools.

Re: What Is Nix?

#116

Post by takeda »

WatchDog wrote: post #74
illumin8 wrote: post #70

Earlier quoted context omitted.

I've had the (dis)pleasure of working with several projects that have been built by developers that have religion around Nix. These projects were contract work where the client paid a significant amount of money, and the final product was really poor quality. One of them is a financial application that has strict security requirements, so having a reproducible build system and some of the other qualities of Nix sound…

I haven't used Nix, but I would have thought that builds would be fast, due to how cache-able the dependencies should be.

It is, perhaps they didn't use cache to store previously built packages and build everything from scratch. With no cache Nix will start with building compilers and glibc until it has everything to build the actual application.

Re: What Is Nix?

#117

Post by chpatrick »

mehrdadn wrote: post #33
tel wrote: post #20

Earlier quoted context omitted.

It's kind of a mess. Nix is a collection of tools and systems that together form a highly reproducible build system. Nix is also a declarative, largely pure and lazy programming language that you use to design and specify the different build outputs for the Nix build system. Nixpkgs is, more or less, the only project written using Nix (and a lot of shell). It's a collection of many thousands of "derivations", many of…

Thanks! So let's say I start installing Nix packages. What distro's packages would they end up most similar to? Say, maybe Arch (which mostly leaves things unmodified)? Does that mean you basically end up with Arch no matter which distro you're on?

In my experience, nixpkgs packages are modified with the bare minimum to get the upstream code to work.

Re: What Is Nix?

#118

Post by yawaramin »

lmickh wrote: post #7
dataflow wrote: post #2

I'm still confused. What is Nix? Is it an OS, or a package manager? From the looks of it it's a package manager that I should be able to use it on any POSIX system, but I doubt that's the case?

It is pretty easy to be confused. Especially since it is also a language yet all the other replies at the time have writing have failed to mention that. While I like the project as a whole, their naming is horrible. Just wait until you get into `nix-env` vs `nix-shell` etc...

> It is pretty easy to be confused. Especially since it is also a language yet all the other replies at the time have writing have failed to mention that.

The OP mentioned it. It helps to read the OP if one wants to avoid confusion.

Re: What Is Nix?

#119

Post by illumin8 »

WatchDog wrote: post #74
illumin8 wrote: post #70

Earlier quoted context omitted.

I've had the (dis)pleasure of working with several projects that have been built by developers that have religion around Nix. These projects were contract work where the client paid a significant amount of money, and the final product was really poor quality. One of them is a financial application that has strict security requirements, so having a reproducible build system and some of the other qualities of Nix sound…

I haven't used Nix, but I would have thought that builds would be fast, due to how cache-able the dependencies should be.

While this is true if you are building new versions of dependencies on an existing system, in many cases in high security environments you want to start with a clean build environment every time. Cached dependencies might be considered to be a security risk. Bootstrapping an entire Nix environment can take a lot of time.

Re: What Is Nix?

#120

Post by jariel »

I loathe to be so critical, but I have no idea what this is.

I'm sorry to say but this is a bad article - either that - or nix itself is a mishmash of things impossible to explain.

I just see red flags everywhere.

If it's 'A' - then maybe take some time to do a high-level introduction and some context.

- 'Everything depends on something else' - really? Most 'installed software' doesn't depend on a whole lot else. Does the author really mean server software? Development environment?

- "The easiest place to start is the Nix Store. Once you've installed Nix, you'll wind up with a directory at /nix/store,"

No! That's not easy, because what he&& is Nix, why and how would I install it, and what is the 'nix store'? Starting to explain something by introducing a whole bunch of other unknowns without description or context is going in the wrong direction.

- "This directory, /nix/store, is a kind of Graph Database. Each entry (each file or directory directly under /nix/store) is a Node in that Graph Database, and the relationships between them constitute Edges."

WHAT? We are now 3 layers deep in a rabbit hole of unexplained things.

- " Nix guarantees that the contents of a Node doesn't change after it's been created."

What is a Node?

If the issue is 'B' - i.e. the inherent overlap of technologies that Nix makes it hard to explain ... well maybe it could be broken up.

Take a minute to give some context for what Nix is, the kinds of people that use it, what problems it solves, and then have some exceedingly basic introductory examples so that people have a frame of reference for what you are talking about.

Then you can step by step, go into the weeds.

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