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What Is Nix?

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Re: What Is Nix?

#161

Post by dataflow »

takeda wrote: post #155
dataflow wrote: post #67

Earlier quoted context omitted.

"Just files" doesn't quite capture the complexity of the situation to me though. Say I happen to install package X via apt and Y via nix, and both of them depend on Z (in apt and nix respectively), and Z needs to bind to a port, then I imagine both will install but one of them will break, possibly including their dependents. Or if I install a package on Nix that expects a certain syscall that's not in the Ubuntu kern…

> Say I happen to install package X via apt and Y via nix, and both of them depend on Z (in apt and nix respectively) That actually is impossible, Nix will only depend on packages in nix, and nothing else. So whatever you have installed won't affect it. The important part of Nix on Linux is patchelf[1] basically binaries generated are processed by it, this rewrites elfs to link to libraries in the /nix/store Regardin…

>> Say I happen to install package X via apt and Y via nix, and both of them depend on Z (in apt and nix respectively)

> That actually is impossible, Nix will only depend on packages in nix, and nothing else. So whatever you have installed won't affect it.

You misunderstood the scenario. X, Y, Z are package names here. Like Z might be openssh, and it might have dependent X in apt, and Y in nix. You'd get an apt installation of Z and a nix installation of Z.

Re: What Is Nix?

#162

Post by joepie91_ »

yawaramin wrote: post #156
joepie91_ wrote: post #146

Earlier quoted context omitted.

Hi, JS developer here who uses Nix and who liberally makes use of single-responsibility modules. No, Nix does not need "hours" to build a modern JS project. Something else is going on here. Nix is slow, but not that slow. (With the limited information provided here, my first guess would be "someone turned off the binary cache because they don't trust prebuilt binaries, and now it recompiles the world from scratch bec…

I suspect that someone being the auditors who are suspicious of opaque binary caches and insist on building everything from scratch.

I don't know. If that were the case, I'd imagine they would know why their build was taking hours and that it wasn't a Nix problem.

Re: What Is Nix?

#163

Post by endgame »

ninetax wrote: post #63
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…

Unfortunately there's a pretty annoying bug with MacOS which resulted from Apple making /nix non-writable by default. And since /nix is hard coded in all the cached packages it's not easy to fix. This is one big thing that's preventing us from adopting nix https://github.com/NixOS/nix/issues/2925

Buried in that issue is a workaround, although GitHub's UI hides it from you: https://github.com/NixOS/nix/issues/2925#issuecomment-604501...

Re: What Is Nix?

#164

Post by derefr »

geofft wrote: post #68
ninetax wrote: post #63

Earlier quoted context omitted.

Unfortunately there's a pretty annoying bug with MacOS which resulted from Apple making /nix non-writable by default. And since /nix is hard coded in all the cached packages it's not easy to fix. This is one big thing that's preventing us from adopting nix https://github.com/NixOS/nix/issues/2925

I'm trying to understand why macOS can't use a different path (since it's a different OS anyway, and you can't run Linux Nix binaries on macOS). From the end of the thread, it sounds like > The main consequence of using a separate prefix for macOS is that you can't have Hydra jobsets anymore containing jobs for macOS and Linux. It would also make it harder to deploy from macOS to Linux. i.e., if the same package buil…

Perhaps they hardcode full paths into whatever Nix calls its formula files (which are then, if I understand correctly, referred to by their cryptographic hashes, meaning that a file with a different path would have a different hash, and so break the whole hierarchy of formula-to-formula dependency references above it.)

Re: What Is Nix?

#165

Post by johndoe42377 »

A messy pile of unnecessary, redundant abstractions which "solves" nonexistent problem.

Stable interfaces (the main principle behind literally everything in nature) and semantic versioning will do the job.

systemd-like cancer. And, of course, look, ma, I am so smart.

Re: What Is Nix?

#166

Post by joepie91_ »

somatic wrote: post #152
joepie91_ wrote: post #146

Earlier quoted context omitted.

Hi, JS developer here who uses Nix and who liberally makes use of single-responsibility modules. No, Nix does not need "hours" to build a modern JS project. Something else is going on here. Nix is slow, but not that slow. (With the limited information provided here, my first guess would be "someone turned off the binary cache because they don't trust prebuilt binaries, and now it recompiles the world from scratch bec…

“who liberally makes use of single-responsibility modules” If your aim is precision of language, you should call this “400MB of unaudited and unauditable mystery code from the [total clowns]( https://github.com/babel/babel/pull/3646 )* who run the npm ecosystem.” Imagine [this]( https://medium.com/s/silicon-satire/i-peeked-into-my-node-mo... )* but instead riddled with advertisers and intelligence agencies. Burn it d…

Please take your badly-informed language bashing elsewhere.

I actually audit dependencies for a living, and the dependency model that JS uses is far, far preferable for auditability over the "monolithic tightly-coupled framework and a mountain of custom badly-maintained copy-pasted business logic" approach that is widely used elsewhere.

Re: What Is Nix?

#167

Post by tbenst »

ironmagma wrote: post #150
nilkn wrote: post #129

This article is a good explanation of how nix works at a high level, and I'm excited to see nix getting some really prominent support, but for some reason it never tells you what the point of all of this is, so I think many folks might feel turned off by it. In other words, I don't believe it ever compellingly answers the question that constitutes its title. The word "package" doesn't even appear until near the end o…

Isn’t that the same goal as Docker? I’m surprised there’s still no Docker base image for NixOS...

Using nix, you typically build from scratch and only include binaries that are needed in the Docker container. It’s quite elegant, and uses the nix cache, too, so you aren’t dependent on order of layers

https://nixos.org/nixpkgs/manual/#sec-pkgs-dockerTools

Re: What Is Nix?

#168

Post by burke »

bradly wrote: post #137
burke wrote: post #89

Earlier quoted context omitted.

That's kind of the approach I took in this playlist: https://www.youtube.com/playlist?list=PLRGI9KQ3_HP_OFRG6R-p4... However, there is really an important and subtle set of concepts to grasp in order to actually understand Nix, and not just mess around with a package manager tool incidentally built with it. It's fine to not understand them, but they are what this article tries to explain.

FWIW... I read this article as someone who doesn't know what Nix is. Like no idea at all besides the name sounding familiar. After reading the first few paragraphs I feel I'm not the target audience for the article, which it totally fine, but based on the title of the post, I assumed I was.

Yeah, it was a last-minute title change that I now regret.

Re: What Is Nix?

#169

Post by takeda »

mehrdadn wrote: post #114
geofft wrote: post #107

Earlier quoted context omitted.

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 un…

It's not done that way.

If you install Nix on Linux or OS X, you just have packages installed but configuration (if any) you have to edit manually like you would in another Linux distro.

If you use NixOS in addition to packages it also uses modules. Modules take care of setting up services, adding users/groups etc and placing the configuration in right place. You use module configuration to configure the application, and Nix generates actual config.

Here[1] is example of how PostgreSQL is configured.

[1] https://github.com/NixOS/nixpkgs/blob/master/nixos/modules/s...

Re: What Is Nix?

#170

Post by tomberek »

mehrdadn wrote: post #114
geofft wrote: post #107

Earlier quoted context omitted.

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 un…

Interestingly, sshd WILL magically know to look at /nix/store/efgh5678-my-sshd-config-2.0/etc/ssh_config. Usually you would use sshd as a systemd service (possible to do and manage with Nix in Ubuntu, but why would you?). If so, you would write the systemd configuration using Nix and the service file deployed to NixOS (or Ubuntu, imagine deploying some custom/proprietary service you want isolated from whatever else the client has on the machine) would have all the long hashes auto-magically inserted to produce this (this is on my machine, all i had to write was "services.openssh.enable = true;" but additional configuration is available, see https://nixos.org/nixos/options.html#services.openssh.):

  [Unit]
  After=network.target
  Description=SSH Daemon
  X-Restart-Triggers=/nix/store/d4ys2c8kzzcp3g4fv3ivy7a5nkayg7w2-sshd.conf-validated

  [Service]
  Environment="LD_LIBRARY_PATH=/nix/store/71mr6yjmia7y8lw4g5ghk5ag9yq5ir2i-nss-mdns-0.10/lib:/nix/store/zbxfs37qjj6ddrfnzrdnxnkrvvm1ddsf-systemd-245.3/lib"
  Environment="LOCALE_ARCHIVE=/nix/store/9b725cly2a6a61vb8bgz7cyr0xr8y2av-glibc-locales-2.30/lib/locale/locale-archive"
  Environment="PATH=/nix/store/5yx7mv7md9c9nldj69inrnr7rjdkzqq3-openssh-8.2p1/bin:/nix/store/miwvn81sgbbcq5bfglr6v3pwchgsd00c-gawk-5.0.1/bin:/nix/store/ca9mkrf8sa8md8pv61jslhcnfk9mmg4p-coreutils-8.31/bin:/nix/store/hg3albf7g05ljfqrfjhd58rblimrp6ph-findutils-4.7.0/bin:/nix/store/8pajzfyqx1v7dz1znrnrc4pqj5rmnx24-gnugrep-3.4/bin:/nix/store/jpqlmf3wqg281j8fdz50kjl525pfsxjc-gnused-4.8/bin:/nix/store/zbxfs37qjj6ddrfnzrdnxnkrvvm1ddsf-systemd-245.3/bin:/nix/store/5yx7mv7md9c9nldj69inrnr7rjdkzqq3-openssh-8.2p1/sbin:/nix/store/miwvn81sgbbcq5bfglr6v3pwchgsd00c-gawk-5.0.1/sbin:/nix/store/ca9mkrf8sa8md8pv61jslhcnfk9mmg4p-coreutils-8.31/sbin:/nix/store/hg3albf7g05ljfqrfjhd58rblimrp6ph-findutils-4.7.0/sbin:/nix/store/8pajzfyqx1v7dz1znrnrc4pqj5rmnx24-gnugrep-3.4/sbin:/nix/store/jpqlmf3wqg281j8fdz50kjl525pfsxjc-gnused-4.8/sbin:/nix/store/zbxfs37qjj6ddrfnzrdnxnkrvvm1ddsf-systemd-245.3/sbin"
  Environment="TZDIR=/nix/store/wmry9mqmimq8ib8ijli4g1yx92gxjli5-tzdata-2019c/share/zoneinfo"
  
  
  X-StopIfChanged=false
  ExecStart=/nix/store/5yx7mv7md9c9nldj69inrnr7rjdkzqq3-openssh-8.2p1/bin/sshd -f /etc/ssh/sshd_config
  ExecStartPre=/nix/store/1mzzy0dwjzy6kcwad7q79pvc444yn288-unit-script-sshd-pre-start
  KillMode=process
  Restart=always
  Type=simple
No symlinks to /etc/sshd. This service would be independent from other software on the host system, other than PID1 managing it.
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