As an exercise, let us build a Python web application using the Flask web framework.
+ +Create a new file default.nix. This file is conventionally used for specifying packages:
+{ pkgs ? import <nixpkgs> {} }:
+
+pkgs.python3Packages.buildPythonApplication {
+ pname = "myapp";
+ src = ./.;
+ version = "0.1";
+ propagatedBuildInputs = [ pkgs.python3Packages.flask ];
+}
+
+
+You will also need a simple Flask app as main.py:
+#! /usr/bin/env python
+
+from flask import Flask
+
+app = Flask(__name__)
+
+@app.route("/")
+def hello():
+ return "Hello, Nix!"
+
+def run():
+ app.run(host='0.0.0.0')
+
+
+and a setup.py script:
+from setuptools import setup
+
+setup(
+ name='myapp',
+ version='0.1',
+ py_modules=['myapp'],
+ entry_points={
+ 'console_scripts': ['myapp = myapp:run']
+ },
+)
+
+
+Now build the package with:
+ ++nix-build ++ +
This will create a symbolic link result to our package's path in the Nix store, which looks like /nix/store/6i4l781jwk5vbia8as32637207kgkllj-myapp-0.1. Look around to see what is inside.
You may notice we can run the application from the package like ./result/bin/main.py. We can still use the default.nix as a shell environment to get the same result:
+nix-shell default.nix +python3 main.py ++ +
In this context, Nix takes on the role that you would otherwise use pip or virtualenv for. Nix installs required dependencies and separates the environment from others on your system.
+ +You can check this Nix configuration into version control and share it with others to make sure you are all running the same software. Especially with many dependencies this is a great way to prevent configuration drift between different team members & contributors.
+ +[% END %] diff --git a/guides/docker-image.tt b/guides/docker-image.tt new file mode 100644 index 0000000000..a630e55371 --- /dev/null +++ b/guides/docker-image.tt @@ -0,0 +1,47 @@ +[% WRAPPER layout.tt hideTitle=1 title="Guide: Install Nix" menu='nixos' %] + +For this section we assume you have Docker installed.
+ +When you set up the development environment, you created a package of a Flask app. Now you may want to deploy it. One way to do this is to package it as a Docker container that can be hosted on a container hosting platform.
+ +Nix comes with tools for building Docker containers. To turn our Python app into a Docker container, we only have to specify what command to run. Nix will take care of building a minimal image required to make that happen.
+ +Create a file docker.nix:
+{ pkgs ? import <nixpkgs> {} }:
+
+let
+ app = pkgs.callPackage ./default.nix {
+ inherit pkgs;
+ };
+
+in pkgs.dockerTools.buildImage {
+ name = "myapp";
+ tag = "latest";
+ config = {
+ Cmd = [ "${app}/bin/myapp" ];
+ };
+}
+
+
+We are calling the expression under ./default.nix and pass it our own pkgs. Under Cmd we use the variable appto retrieve the path to the executable Python app.
Now we can build the Docker image and load it into Docker:
+ ++nix-build docker.nix +docker load --input result ++ +
Now Docker has an image tagged myapp:latest. Run the Docker image and make sure to forward port 5000, so you can access the app in the browser:
+docker run -it -p 5000:5000 myapp:latest ++ +
Now you can see the site on http://localhost:5000.
Nix can create reproducible environments given a declarative configuration called a Nix expression. Reproducible means you can share the configuration with others and guarantee that they are using the same software as you.
+ +To get started, make a new folder and create a file called shell.nix with the following contents:
+{ pkgs ? import <nixpkgs> {} }:
+
+pkgs.mkShell {
+ buildInputs = [
+ pkgs.which
+ pkgs.htop
+ ];
+}
+
+
+Basically we import our package channel nixpkgs and make a shell with which and htop as inputs. To enter this environment, type in:
+nix-shell ++ +
The command will start downloading the missing packages from the cache. This may take a few moments. When it is done, you are dropped into a new shell. This shell provides the packages specified in shell.nix.
Run htop to confirm it is present. Quit the program again by hitting Q.
Now try which htop to check where the htop command is on-disk. You should see something similar to this:
+/nix/store/y3w2i8kfdbfj9rx287ad52rahjpgv423-htop-2.2.0/bin/htop ++ +
This is the path to the binary in the Nix store. Nix installs all packages into the store using a combination of its hash, name and version.
+ +You can search for available packages using nix-env -qa, for example:
+nix-env -qa python3 +nix-env -qa nodejs +nix-env -qa ghc +nix-env -qa cargo ++ +[% END %] diff --git a/guides/install-nix.tt b/guides/install-nix.tt new file mode 100644 index 0000000000..ba8754aaab --- /dev/null +++ b/guides/install-nix.tt @@ -0,0 +1,21 @@ +[% WRAPPER layout.tt hideTitle=1 title="Guide: Install Nix" menu='nixos' %] + +
While NixOS is a Linux distribution based on Nix, you can install Nix on other Linux distributions, MacOS and Windows via WSL using the install script from our website:
+ ++curl -L https://nixos.org/nix/install | sh ++ +
(For security, you may want to verify the script using our GPG signatures.)
+ +Check that the installation was successful by running
+ ++nix-channel --list ++ +
This command displays the package distribution channel used by Nix. By default, this is https://nixos.org/channels/nixpkgs-unstable
This quickstart guide will get you started with the Nix package manager.
- -You will learn how to…
- -While NixOS is a Linux distribution based on Nix, you can install Nix on other Linux distributions, MacOS and Windows via WSL using the install script from our website:
- --curl -L https://nixos.org/nix/install | sh -- -
(For security, you may want to verify the script using our GPG signatures.)
- -Check that the installation was successful by running
- --nix-channel --list -- -
This command displays the package distribution channel used by Nix. By default, this is https://nixos.org/channels/nixpkgs-unstable
Nix can create reproducible environments given a declarative configuration called a Nix expression. Reproducible means you can share the configuration with others and guarantee that they are using the same software as you.
- -To get started, make a new folder and create a file called shell.nix with the following contents:
-{ pkgs ? import <nixpkgs> {} }:
-
-pkgs.mkShell {
- buildInputs = [
- pkgs.which
- pkgs.htop
- ];
-}
-
-
-Basically we import our package channel nixpkgs and make a shell with which and htop as inputs. To enter this environment, type in:
-nix-shell -- -
The command will start downloading the missing packages from the cache. This may take a few moments. When it is done, you are dropped into a new shell. This shell provides the packages specified in shell.nix.
Run htop to confirm it is present. Quit the program again by hitting Q.
Now try which htop to check where the htop command is on-disk. You should see something similar to this:
-/nix/store/y3w2i8kfdbfj9rx287ad52rahjpgv423-htop-2.2.0/bin/htop -- -
This is the path to the binary in the Nix store. Nix installs all packages into the store using a combination of its hash, name and version.
- -You can search for available packages using nix-env -qa, for example:
-nix-env -qa python3 -nix-env -qa nodejs -nix-env -qa ghc -nix-env -qa cargo -- - -
As an exercise, let us build a Python web application using the Flask web framework.
- -Create a new file default.nix. This file is conventionally used for specifying packages:
-{ pkgs ? import <nixpkgs> {} }:
-
-pkgs.python3Packages.buildPythonApplication {
- pname = "myapp";
- src = ./.;
- version = "0.1";
- propagatedBuildInputs = [ pkgs.python3Packages.flask ];
-}
-
-
-You will also need a simple Flask app as main.py:
-#! /usr/bin/env python
-
-from flask import Flask
-
-app = Flask(__name__)
-
-@app.route("/")
-def hello():
- return "Hello, Nix!"
-
-def run():
- app.run(host='0.0.0.0')
-
-
-and a setup.py script:
-from setuptools import setup
-
-setup(
- name='myapp',
- version='0.1',
- py_modules=['myapp'],
- entry_points={
- 'console_scripts': ['myapp = myapp:run']
- },
-)
-
-
-Now build the package with:
- --nix-build -- -
This will create a symbolic link result to our package's path in the Nix store, which looks like /nix/store/6i4l781jwk5vbia8as32637207kgkllj-myapp-0.1. Look around to see what is inside.
You may notice we can run the application from the package like ./result/bin/main.py. We can still use the default.nix as a shell environment to get the same result:
-nix-shell default.nix -python3 main.py -- -
In this context, Nix takes on the role that you would otherwise use pip or virtualenv for. Nix installs required dependencies and separates the environment from others on your system.
- -You can check this Nix configuration into version control and share it with others to make sure you are all running the same software. Especially with many dependencies this is a great way to prevent configuration drift between different team members & contributors.
- - -For this section we assume you have Docker installed.
- -Now that you have package a Flask app, you may want to deploy it. One way to do this is to package it as a Docker container that can be hosted on a container hosting platform.
- -Nix comes with tools for building Docker containers. To turn our Python app into a Docker container, we only have to specify what command to run. Nix will take care of building a minimal image required to make that happen.
- -Create a file docker.nix:
-{ pkgs ? import <nixpkgs> {} }:
-
-let
- app = pkgs.callPackage ./default.nix {
- inherit pkgs;
- };
-
-in pkgs.dockerTools.buildImage {
- name = "myapp";
- tag = "latest";
- config = {
- Cmd = [ "${app}/bin/myapp" ];
- };
-}
-
-
-We are calling the expression under ./default.nix and pass it our own pkgs. Under Cmd we use the variable appto retrieve the path to the executable Python app.
Now we can build the Docker image and load it into Docker:
- --nix-build docker.nix -docker load --input result -- -
Now Docker has an image tagged myapp:latest. Run the Docker image and make sure to forward port 5000, so you can access the app in the browser:
-docker run -it -p 5000:5000 myapp:latest -- -
Now you can see the site on http://localhost:5000.