Functional, Declarative and Modular System Environment with Nix and NixOS

身為長年的 Linux 使用者，你是否覺得維護作業系統環境是一大困擾？無論是那些套件服務的組態相依、或者那堆針對各個程式打的 patch，這些散落各處、無法被管理或重現的設定是否讓你徹夜難眠：哪天要搬系統怎麼辦？環境壞了是不是很難修？會不會有人偷偷動了我的設定？

又或者你是開發者，常常苦於為新機器設定開發環境都要花上近一整天、或是不同專案倚賴於不同系統套件不知道該如何解決。

Nix 或許可以解決你的煩惱！本議程將簡單介紹 Nix 套件管理工具以及 NixOS 的基本概念：Nix Store、Nix Language、Nix Derivation、Nixpkgs、NixOS、nix-env，來看看 "Purely Functional"、"Declarative" 的 Nix 套件管理工具以及 NixOS 如何解決系統環境問題吧！

個人套件集與 NixOS 設定檔：

- https://github.com/zetavg/nix-packages
- https://github.com/zetavg/nixos-configs

## 參考資料

- [Nix Pills](https://nixos.org/nixos/nix-pills/)
個人最推薦的入門指南，共有 20 篇短篇文章，從安裝、基本使用、原理，一路涵蓋到語言、如何寫套件、一些架構和設計模式，不僅教你如何用 Nix，讀完之後還能任意暴改你的系統以及包裝你自己的 package。
- [Continuous integration for iOS with Nix and Buildkite - Pinterest Engineering](https://medium.com/@Pinterest_Engineering/continuous-integration-for-ios-with-nix-and-buildkite-ef5b36c5292d)
Pinterest 的工程師分享他們如何用 Nix 來統一他們 mobile app 在開發者的機器以及 CI 上的環境，並用 [Buildkite](https://buildkite.com/) 這套 CI Interface as a Service 來打造他們的 CI 環境。
- [Nix: Haskell Concepts for Package Management - HackerNoon.com](https://hackernoon.com/nix-haskell-concepts-for-package-management-65830ac89659)
介紹 Nix 如何利用 Functional、Declarative 的特性，解決傳統系統環境容易被污染、無法版本控管等問題，也提出了每次都要從原始碼編譯很耗時（但我想 binary cache 可以解決這個問題，現在也有很方便的 binary cache as a service，CI 也可以用 Hydra 來獨立測試每個單元，因此除了像是 node 的 npm 一個程式 depend on 數千個 package 會造成就算有 cache 但用正常的方式 handle 數千個 deps 的計算量就很大會慢之外，不算太大的問題）的問題。
- [Eelco Dolstra 在荷蘭烏特勒支大學的博士論文](https://nixos.org/~eelco/pubs/phd-thesis.pdf)
是 Nix 套件管理工具的前身 ([Nix Community - Academia - NixOS Wiki](https://nixos.wiki/wiki/Nix_Community#Academia)) 。
- [Cheatsheet - NixOS Wiki](https://nixos.wiki/index.php?title=Cheatsheet&useskin=vector)
- [How we use Nix at IOHK - Input Output](https://iohk.io/blog/how-we-use-nix-at-iohk/)

## 社群

- [r/NixOS on Reddit](https://www.reddit.com/r/NixOS/)

Transcript

1. ! # @zetavg

   fb.me/pokaichang72
   Functional, Declarative and
   Modular System Environment 

   with Nix and NixOS
   

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2. Hi !
   

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3. ! # @zetavg

   fb.me/pokaichang72

   皰玡㳓 Pokai Chang
   

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4. ! # @zetavg

   fb.me/pokaichang72

   speakerdeck.com/zetavg
   皰玡㳓 Pokai Chang
   

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5. Functional Programming
   

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6. 礍ᒊ
   

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9. /ๅ碝懿袅.txt
   

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10. /ๅ碝懿袅.txt
    

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11. VPS
    

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12. apt-get install blablabla
    vi /etc/nginx/conf.d/default.conf
    patch and recompile nginx
    独
    独
    

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13. /ๅ碝懿袅.txt
    ݈憎ᶎЎ聲๏݋
    

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14. Software Development
    

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15. Develop Environment
    ▪ Your project still have some system dependencies.
    
    ▪ How to write instructions for setting up the develop environment?
    
    ▪ Write automated scripts instead of instructions.
    
    ▪ The script can act as documentation.

    (A kind of doc that you can get benefit from without reading it.)
    
    ▪ Forgot to check/install something...

    (Especially when you added or updated some dependencies)
    
    ▪ Script broken on a different OS distribution or package
    manager.
    
    ▪ Spend three days to onboard a new member with a working
    development environment.
    

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16. Your Desktop/NB
    

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19. Hidden Dependencies
    e.g. 

    Key Mapping Tool
    ↓
    Window Manager
    ↓

    App Scripting
    

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20. Patches Everywhere
    

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21. ???
    

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22. Software Deployment
    Problems
    

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23. Software Deployment
    Problems
    

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24. Global Library Dependencies
    Libraries
    LibA
    Applications
    App1 App2 App3
    LibB
    

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25. Libraries
    Applications
    LibA
    App2
    Global Library Dependencies
    Upgrade of App2
    App1 App2' App3
    LibB
    LibA'
    $
    

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26. Global Library Dependencies
    Libraries
    LibA
    Applications
    App1 App2 App3
    LibB
    

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27. Global Library Dependencies
    Removal of App3
    Libraries
    LibA
    Applications
    App1 App2 App3
    LibB
    $
    

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28. View Slide

29. #PurelyFunctional
    #Immutable 

    #Declarative #Lazy

    #GarbageCollection

    #PersistedCache
    

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30. Nix Store
    Nix Language / Derivation
    
    NixOS / nix-env /nix-shell
    

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31. Nix Store
    Nix Language / Derivation
    
    NixOS / nix-env /nix-shell
    {
    च๜禊盢

    膏戔懯߽䋊
    䋿褬ֵአ
    {
    

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32. Nix Store
    

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33. Nix Store
    Nix Store
    glibc-2.27
    bash-4.4
    zsh-5.7.1
    ncurses-6.1
    readline-7.0
    pcre-8.42
    ghc-8.4.4
    nodejs-8.15.1
    ruby-2.5.4 python-2.7.15
    

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34. Nix Store
    Packages should not depend on global system stuff
    /usr/lib
    libssl.so
    App
    ruby-2.5.4
    Global Variables Are Evil!
    

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35. Nix Store
    Packages can depend on other packages in the Nix Store
    /usr/lib
    libssl.so
    App
    ruby-2.5.4
    Nix Store
    ruby-2.5.4
    openssl-1.0.2
    

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36. Nix Store
    Example: bash
    bash-interactive-4.4
    glibc-2.27
    bash-4.4 readline-7.0
    ncurses-6.1
    

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37. Nix Store
    Example: wget
    wget-1.19.5
    glibc-2.27
    zlib-1.2.11
    openssl-1.0.2
    util-linux-2.32.1
    libunistring-0.9.10
    pcre-8.42
    libidn2-2.0.5
    

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38. Generated using: nix-store -q --graph $(which bash)
    Nix Store
    Real Dependency Graph Generated by Nix: bash
    

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39. Generated using: nix-store -q --graph $(which gcc)
    Nix Store
    Real Dependency Graph Generated by Nix: gcc
    

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40. Generated using: nix-store -q --graph $(which ghc)
    Nix Store
    Real Dependency Graph Generated by Nix: ghc
    

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41. Nix Store
    Nix Store
    Packages Are Read-only upon Build
    glibc-2.27
    bash-4.4
    zsh-5.7.1
    ncurses-6.1
    readline-7.0
    pcre-8.42
    ghc-8.4.4
    nodejs-8.15.1
    ruby-2.5.4 python-2.7.15
    

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42. Nix Store
    Reusable Packages
    bash-interactive-4.4
    glibc-2.27
    bash-4.4 readline-7.0
    ncurses-6.1
    

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43. Nix Store
    Reusable Packages
    bash-interactive-4.4
    glibc-2.27
    bash-4.4
    zsh-5.6.2
    ncurses-6.1
    readline-7.0 pcre-8.42
    

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44. Nix Store
    Reusable Packages
    bash-interactive-4.4
    glibc-2.27
    bash-4.4
    zsh-5.6.2
    zsh-5.7.1
    ncurses-6.1
    readline-7.0
    pcre-8.42
    pcre-8.43
    

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45. Nix Store
    Reusable Packages
    bash-interactive-4.4
    glibc-2.27
    bash-4.4
    zsh-5.6.2
    zsh-5.7.1
    ncurses-6.1
    readline-7.0
    pcre-8.42
    pcre-8.43
    #Immutable
    

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46. Nix Store
    Package Removal
    bash-interactive-4.4
    glibc-2.27
    bash-4.4
    zsh-5.6.2
    zsh-5.7.1
    ncurses-6.1
    readline-7.0
    pcre-8.42
    pcre-8.43
    

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47. Nix Store
    Package Removal
    bash-interactive-4.4
    glibc-2.27
    bash-4.4
    zsh-5.6.2
    zsh-5.7.1
    ncurses-6.1
    readline-7.0
    pcre-8.42
    pcre-8.43
    Unused
    

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48. Nix Store
    Package Removal
    bash-interactive-4.4
    glibc-2.27
    bash-4.4
    zsh-5.6.2
    zsh-5.7.1
    ncurses-6.1
    readline-7.0
    pcre-8.42
    pcre-8.43
    Unused
    #GarbageCollection
    

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49. Nix Store
    Package Removal
    bash-interactive-4.4
    glibc-2.27
    bash-4.4
    zsh-5.6.2
    zsh-5.7.1
    ncurses-6.1
    readline-7.0
    pcre-8.42
    pcre-8.43
    GC Roots
    GC Roots
    

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50. Nix Store
    Package Removal
    bash-interactive-4.4
    glibc-2.27
    bash-4.4
    zsh-5.6.2
    zsh-5.7.1
    ncurses-6.1
    readline-7.0
    pcre-8.42
    pcre-8.43
    GC Roots
    GC Roots
    

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51. Nix Store
    Package Removal
    bash-interactive-4.4
    glibc-2.27
    bash-4.4
    zsh-5.7.1
    ncurses-6.1
    readline-7.0
    pcre-8.43
    GC Roots
    GC Roots
    

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52. Q: How to modify a package?
    

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53. Q: How to modify a package?
    A: You don't. You create a new one.
    

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54. Nix Store: Cryptographic Hash
    Hash

    Function
    Source Code
    Dependencies
    Build Script Build Arguments
    Environment Variables
    Build Shell
    Package Name
    mn4jdnhkz12a6yd6jg6wvb4mqpxf8q1f
    Cryptographic Hash
    

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56. Cryptographic Hash
    

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57. Nix Store
    This is Possible
    Same Package Name And "Version"
    bash-4.4 bash-4.4
    With Patches
    

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58. Nix Store
    This is Possible
    Same Package Name And "Version"
    bash-4.4 bash-4.4
    Cryptographic Hashes are different
    With Patches
    

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59. Nix Store: Cryptographic Hash
    Hash

    Function
    Source Code
    Dependencies
    Build Script Build Arguments
    Environment Variables
    Build Shell
    Package Name
    mn4jdnhkz12a6yd6jg6wvb4mqpxf8q1f
    {
    Build Inputs
    Cryptographic Hash
    

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60. Nix Store: Cryptographic Hash
    Hash

    Function
    Source Code
    Dependencies
    Build Script Build Arguments
    Environment Variables
    Build Shell
    Package Name
    mn4jdnhkz12a6yd6jg6wvb4mqpxf8q1f
    {
    Build Inputs
    Cryptographic Hash
    #PurelyFunctional
    

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61. Nix Language
    

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62. Nix Language
    A pure, lazy, functional language
    

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63. Nix Language
    The Language used to write expressions 

    that produce derivations
    

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64. Derivation
    Nix-speak for a package build action, which derives the
    package from its inputs.
    

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65. Packages are (special)
    variables in the Nix
    Language
    

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66. Your whole software and its
    dependencies are declared as data
    structure in a programming
    language
    

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    default.nix
    let
    pkgs = import { };
    in
    derivation {
    name = "hello";
    system = "x86_64-linux";
    builder = "${pkgs.bash}/bin/bash";
    args = [
    "-c"
    ''
    export PATH="${pkgs.coreutils}/bin:${pkgs.gcc}/bin"
    mkdir $out
    gcc "${./hello.c}" -o "$out/hello"
    ''
    ];
    }
    

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    default.nix
    let
    pkgs = import { };
    in
    derivation {
    name = "hello";
    system = "x86_64-linux";
    builder = "${pkgs.bash}/bin/bash";
    args = [
    "-c"
    ''
    export PATH="${pkgs.coreutils}/bin:${pkgs.gcc}/bin"
    mkdir $out
    gcc "${./hello.c}" -o "$out/hello"
    ''
    ];
    }
    

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    default.nix
    let
    pkgs = import { };
    in
    derivation {
    name = "hello";
    system = "x86_64-linux";
    builder = "${pkgs.bash}/bin/bash";
    args = [
    "-c"
    ''
    export PATH="${pkgs.coreutils}/bin:${pkgs.gcc}/bin"
    mkdir $out
    gcc "${./hello.c}" -o "$out/hello"
    ''
    ];
    }
    Build Inputs
    

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70. Nixpkgs
    

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71. ~= stdlib
    For Nix Language
    

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    default.nix
    let
    pkgs = import { };
    in
    derivation {
    name = "hello";
    system = "x86_64-linux";
    builder = "${pkgs.bash}/bin/bash";
    args = [
    "-c"
    ''
    export PATH="${pkgs.coreutils}/bin:${pkgs.gcc}/bin"
    mkdir $out
    gcc "${./hello.c}" -o "$out/hello"
    ''
    ];
    }
    bash from Nixpkgs
    gcc from Nixpkgs
    

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    default.nix
    let
    pkgs = import { };
    in
    derivation {
    name = "hello";
    system = "x86_64-linux";
    builder = "${pkgs.bash}/bin/bash";
    args = [
    "-c"
    ''
    export PATH="${pkgs.coreutils}/bin:${pkgs.gcc}/bin"
    mkdir $out
    gcc "${./hello.c}" -o "$out/hello"
    ''
    ];
    }
    bash from Nixpkgs
    gcc from Nixpkgs
    #Lazy
    

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74. ~= Channel
    For Nix Package Manager
    

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75. You can create a custom
    package collection that adds or
    overrides packages in Nixpkgs
    https://github.com/zetavg/nix-packages
    

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76. NixOS
    

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77. NixOS
    Linux distribution, build via Nix
    

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78. NixOS
    Packages, Kernal, Configurations... are built by Nix
    

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    configuration.nix
    { config, pkgs, lib, ... }:
    {
    fileSystems."/home" = {
    device = "/dev/disk/by-label/home";
    };
    environment.systemPackages = [ pkgs.git pkgs.vim ];
    services.nginx = {
    enable = true;
    package = pkgs.nginx.overrideAttrs (oldAttrs: {
    patches = [ (builtins.toFile "patch" ''
    --- ./src/core/ngx_conf_file.c
    +++ ./src/core/ngx_conf_file.c
    @@ -2,10 +2,10 @@
    -#define NGX_CONF_BUFFER 4096
    +#define NGX_CONF_BUFFER 131072
    '') ];
    });
    virtualHosts."example.com" = {
    serverAliases = [ "www.example.com" ];
    enableACME = true;
    forceSSL = true;
    root = someSitePackage.root;
    };
    };
    }
    

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    configuration.nix
    { config, pkgs, lib, ... }:
    {
    fileSystems."/home" = {
    device = "/dev/disk/by-label/home";
    };
    environment.systemPackages = [ pkgs.git pkgs.vim ];
    services.nginx = {
    enable = true;
    package = pkgs.nginx.overrideAttrs (oldAttrs: {
    patches = [ (builtins.toFile "patch" ''
    --- ./src/core/ngx_conf_file.c
    +++ ./src/core/ngx_conf_file.c
    @@ -2,10 +2,10 @@
    -#define NGX_CONF_BUFFER 4096
    +#define NGX_CONF_BUFFER 131072
    '') ];
    });
    virtualHosts."example.com" = {
    serverAliases = [ "www.example.com" ];
    enableACME = true;
    forceSSL = true;
    root = someSitePackage.root;
    };
    };
    }
    #Declarative
    

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81. NixOS
    Whole System in the Nix Store
    Nix Store
    nixos-system
    bash-interactive-4.4
    glibc-2.27
    bash-4.4
    zsh-5.6.2
    pcre-8.42
    openssl-1.1.1
    libxslt-1.1.33
    libxml2-2.9.9
    nginx-1.14.2
    ncurses-6.1
    readline-7.0
    zlib-1.2.11
    etc
    etc-user.conf
    nginx.service
    ...
    *Lots of stuff are omitted or simplified to fit in this limited space.
    nginx.conf
    

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82. NixOS
    Switch Between System Versions: Update
    Nix Store
    nixos-system-xxx-1 nixos-system-xxx-2 nixos-system-xxx-3
    bash-interactive-4.4
    glibc-2.27
    bash-4.4
    zsh-5.6.2 zsh-5.7.1
    pcre-8.42
    nginx-1.14.2
    passenger-6.0.2
    pcre-8.43
    openssl-1.1.1
    libxslt-1.1.33
    libxml2-2.9.9
    nginx-1.14.2
    ncurses-6.1
    readline-7.0
    zlib-1.2.11
    *Lots of stuff are omitted or simplified to fit in this limited space.
    nixos rebuild --switch
    

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83. NixOS
    Switch Between System Versions
    Nix Store
    nixos-system-xxx-1 nixos-system-xxx-2 nixos-system-xxx-3
    bash-interactive-4.4
    glibc-2.27
    bash-4.4
    zsh-5.6.2 zsh-5.7.1
    pcre-8.42
    nginx-1.14.2
    passenger-6.0.2
    pcre-8.43
    openssl-1.1.1
    libxslt-1.1.33
    libxml2-2.9.9
    nginx-1.14.2
    ncurses-6.1
    readline-7.0
    zlib-1.2.11
    *Lots of stuff are omitted or simplified to fit in this limited space.
    

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84. NixOS
    Switch Between System Versions
    Nix Store
    nixos-system-xxx-1 nixos-system-xxx-2 nixos-system-xxx-3
    bash-interactive-4.4
    glibc-2.27
    bash-4.4
    zsh-5.6.2 zsh-5.7.1
    pcre-8.42
    nginx-1.14.2
    passenger-6.0.2
    pcre-8.43
    openssl-1.1.1
    libxslt-1.1.33
    libxml2-2.9.9
    nginx-1.14.2
    ncurses-6.1
    readline-7.0
    zlib-1.2.11
    *Lots of stuff are omitted or simplified to fit in this limited space.
    

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85. NixOS
    Switch Between System Versions
    Nix Store
    nixos-system-xxx-1 nixos-system-xxx-2 nixos-system-xxx-3
    bash-interactive-4.4
    glibc-2.27
    bash-4.4
    zsh-5.6.2 zsh-5.7.1
    pcre-8.42
    nginx-1.14.2
    passenger-6.0.2
    pcre-8.43
    openssl-1.1.1
    libxslt-1.1.33
    libxml2-2.9.9
    nginx-1.14.2
    ncurses-6.1
    readline-7.0
    zlib-1.2.11
    *Lots of stuff are omitted or simplified to fit in this limited space.
    

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86. NixOS
    Multiple Systems Coexist
    Nix Store
    nixos-system-xxx-1 nixos-system-xxx-2 nixos-system-xxx-3
    bash-interactive-4.4
    glibc-2.27
    bash-4.4
    zsh-5.6.2 zsh-5.7.1
    pcre-8.42
    nginx-1.14.2
    passenger-6.0.2
    pcre-8.43
    openssl-1.1.1
    libxslt-1.1.33
    libxml2-2.9.9
    nginx-1.14.2
    ncurses-6.1
    readline-7.0
    zlib-1.2.11
    *Lots of stuff are omitted or simplified to fit in this limited space.
    

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87. Boot Into a Specific Version
    

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88. nix-env
    

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89. Your Shell Environment
    

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90. View Slide

91. View Slide

92. Generations
    Switch between different nix-env generations
    

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93. NixOS
    Switch Between System Versions
    Nix Store
    nixos-system-xxx-1 nixos-system-xxx-2 nixos-system-xxx-3
    bash-interactive-4.4
    glibc-2.27
    bash-4.4
    zsh-5.6.2 zsh-5.7.1
    pcre-8.42
    nginx-1.14.2
    passenger-6.0.2
    pcre-8.43
    openssl-1.1.1
    libxslt-1.1.33
    libxml2-2.9.9
    nginx-1.14.2
    ncurses-6.1
    readline-7.0
    zlib-1.2.11
    *Lots of stuff are omitted or simplified to fit in this limited space.
    

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94. NixOS
    Switch Between System Versions
    Nix Store
    nixos-system-xxx-1 nixos-system-xxx-2 nixos-system-xxx-3
    bash-interactive-4.4
    glibc-2.27
    bash-4.4
    zsh-5.6.2 zsh-5.7.1
    pcre-8.42
    nginx-1.14.2
    passenger-6.0.2
    pcre-8.43
    openssl-1.1.1
    libxslt-1.1.33
    libxml2-2.9.9
    nginx-1.14.2
    ncurses-6.1
    readline-7.0
    zlib-1.2.11
    *Lots of stuff are omitted or simplified to fit in this limited space.
    

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95. View Slide

96. nix-shell
    

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97. For

    Software Development
    

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98. 1. Get into the shell
    environment that builds a
    specific package
    

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99. 2. Write Nix expressions to
    declare a shell environment
    and jump into it
    

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100. 2. Write Nix expressions to
     declare a shell environment
     and jump into it
     #Declarative
     

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101. Wrap Up
     

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102. Nix Store: Cryptographic Hash
     Hash

     Function
     Source Code
     Dependencies
     Build Script Build Arguments
     Environment Variables
     Build Shell
     Package Name
     mn4jdnhkz12a6yd6jg6wvb4mqpxf8q1f
     {
     Build Inputs
     Cryptographic Hash
     #PurelyFunctional
     

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103. Nix Store
     Reusable Packages
     bash-interactive-4.4
     glibc-2.27
     bash-4.4
     zsh-5.6.2
     zsh-5.7.1
     ncurses-6.1
     readline-7.0
     pcre-8.42
     pcre-8.43
     #Immutable
     

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104. NixOS
     Whole System in the Nix Store
     nixos-system
     42
     penssl-1.1.1
     libxslt-1.1.33
     libxml2-2.9.9
     nginx-1.14.2
     zlib-1.2.11
     etc
     etc-user.conf
     nginx.service
     ...
     *Lots of stuff are omitted or simplified to fit in this limited space.
     nginx.conf
     1
     2
     3
     4
     5
     6
     7
     8
     9
     10
     11
     12
     13
     14
     15
     16
     17
     18
     19
     20
     21
     22
     23
     24
     configuration.nix
     { config, pkgs, lib, ... }:
     {
     fileSystems."/home" = {
     device = "/dev/disk/by-label/home";
     };
     environment.systemPackages = [ pkgs.git
     services.nginx = {
     enable = true;
     package = pkgs.nginx.overrideAttrs (o
     patches = [ (builtins.toFile "patch
     --- ./src/core/ngx_conf_file.c
     +++ ./src/core/ngx_conf_file.c
     @@ -2,10 +2,10 @@
     -#define NGX_CONF_BUFFER 4096
     +#define NGX_CONF_BUFFER 131072
     '') ];
     });
     virtualHosts."example.com" = {
     serverAliases = [ "www.example.com"
     #Declarative
     

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105. NixOS
     Whole System in the Nix Store
     nixos-system
     42
     penssl-1.1.1
     libxslt-1.1.33
     libxml2-2.9.9
     nginx-1.14.2
     zlib-1.2.11
     etc
     etc-user.conf
     nginx.service
     ...
     *Lots of stuff are omitted or simplified to fit in this limited space.
     nginx.conf
     1
     2
     3
     4
     5
     6
     7
     8
     9
     10
     11
     12
     13
     14
     15
     16
     17
     18
     19
     20
     21
     22
     23
     24
     configuration.nix
     { config, pkgs, lib, ... }:
     {
     fileSystems."/home" = {
     device = "/dev/disk/by-label/home";
     };
     environment.systemPackages = [ pkgs.git
     services.nginx = {
     enable = true;
     package = pkgs.nginx.overrideAttrs (o
     patches = [ (builtins.toFile "patch
     --- ./src/core/ngx_conf_file.c
     +++ ./src/core/ngx_conf_file.c
     @@ -2,10 +2,10 @@
     -#define NGX_CONF_BUFFER 4096
     +#define NGX_CONF_BUFFER 131072
     '') ];
     });
     virtualHosts."example.com" = {
     serverAliases = [ "www.example.com"
     #Lazy
     #Declarative
     

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106. Nix Store
     Package Removal
     bash-interactive-4.4
     glibc-2.27
     bash-4.4
     zsh-5.6.2
     zsh-5.7.1
     ncurses-6.1
     readline-7.0
     pcre-8.42
     pcre-8.43
     GC Roots
     GC Roots
     #GarbageCollection
     

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107. More
     ▪ Cachix: Nix binary cache as a service
     
     ▪ Hydra: A Nix build farm
     
     ▪ NixOps: Use Nix to declaratively deploy infrastructures
     

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108. Stuff I Done
     ▪ NixOS on GCP
     
     ▪ https://github.com/zetavg/nixos-configs
     
     ▪ https://github.com/zetavg/nix-packages
     
     ▪ Phusion Passenger and nginx-mod-passenger
     
     ▪ "NPM" implemented with Nix
     
     ▪ Patched version of some programms
     

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109. Recommend Materials
     ▪ Functional Thursday: Nix and NixOS牧9/5 at Mozilla מ嬝玟旰獍ਰ牐
     
     ▪ Nix Pills: https://nixos.org/nixos/nix-pills/

     㮆Ո磧വ萃ጱ獈槹瞲ܖ牧و磪 20 缰Ꭸ缰෈ᒍ牧ℂਞ蕕牏च๜ֵአ牏ܻቘ牧Ӟ
     ᪠窩荠ک承᥺牏ই֜䌃ॺկ牏Ӟ犚礍䯤޾戔懯秇ୗ牧犋㰍硽֦ই֜አ Nix牧捝
     ਠԏ盅螭胼犨఺ู硬֦ጱ羬翄犥现۱蕕֦ᛔ૩ጱ package牐
     
     ▪ Continuous integration for iOS with Nix and Buildkite - Pinterest
     Engineering

     Pinterest ጱૡ纷䒍獤Ձ犢㮉ই֜አ Nix 㬵翄Ӟ犢㮉 mobile app ࣁ樄咳ᘏጱ秚
     瑊犥现 CI Ӥጱ絑ह牧㪔አ Buildkite 蝡ॺ CI Interface as a Service 㬵಑蝨犢
     㮉ጱ CI 絑ह牐
     
     ▪ Nix: Haskell Concepts for Package Management - HackerNoon.com

     Օ奧 Nix ই֜ڥአ Functional牏Declarative ጱ粬௔牧薹究㯽翄羬翄絑ह਻ฃ
     ᤩ࿱礕牏篷ဩ粚๜矒ᓕ缛㺔氂牐
     
     ▪ Eelco Dolstra ࣁ艰葦僂粬ۦඪय़䋊ጱ玡ॊ抷෈

     ฎ Nix ॺկᓕቘૡٍጱ獮蛪牐
     

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