Add NixOS guest support

plugins/guests/nixos/cap/change_host_name.rb

@@ -0,0 +1,41 @@
+require 'tempfile'
+
+require "vagrant/util/template_renderer"
+
+module VagrantPlugins
+  module GuestNixos
+    module Cap
+      class ChangeHostName
+        include Vagrant::Util
+
+        def self.change_host_name(machine, name)
+          # upload the config file
+          hostname_module = TemplateRenderer.render("guests/nixos/hostname", :name => name)
+          upload(machine, hostname_module, "/etc/nixos/vagrant-hostname.nix")
+        end
+
+        # Upload a file.
+        def self.upload(machine, content, remote_path)
+          local_temp = Tempfile.new("vagrant-upload")
+          local_temp.binmode
+          local_temp.write(content)
+          local_temp.close
+          remote_temp = mktemp(machine)
+          machine.communicate.upload(local_temp.path, "#{remote_temp}")
+          local_temp.delete
+          machine.communicate.sudo("mv #{remote_temp} #{remote_path}")
+        end
+
+        # Create a temp file.
+        def self.mktemp(machine)
+          path = nil
+
+          machine.communicate.execute("mktemp --suffix -vagrant-upload") do |type, result|
+            path = result.chomp if type == :stdout
+          end
+          path
+        end
+      end
+    end
+  end
+end

plugins/guests/nixos/cap/configure_networks.rb

@@ -0,0 +1,129 @@
+require 'tempfile'
+require 'ipaddr'
+
+require "vagrant/util/template_renderer"
+
+module VagrantPlugins
+  module GuestNixos
+    module Cap
+      class ConfigureNetworks
+        include Vagrant::Util
+
+        def self.configure_networks(machine, networks)
+          # set the prefix length.
+          networks.each do |network|
+            network[:prefix_length] = (network[:netmask] && netmask_to_cidr(network[:netmask]))
+          end
+
+          # set the device names.
+          assign_device_names(machine, networks)
+
+          # upload the config file
+          network_module = TemplateRenderer.render("guests/nixos/network", :networks => networks)
+          upload(machine, network_module, "/etc/nixos/vagrant-network.nix")
+        end
+
+        # Set :device on each network.
+        # Attempts to use biosdevname when available to detect interface names,
+        # and falls back to ifconfig otherwise.
+        def self.assign_device_names(machine, networks)
+          if machine.communicate.test("command -v biosdevname")
+            # use biosdevname to get info about the interfaces
+            interfaces = get_interfaces(machine)
+            if machine.provider.capability?(:nic_mac_addresses)
+              # find device name by MAC lookup.
+              mac_addresses = machine.provider.capability(:nic_mac_addresses)
+              networks.each do |network|
+                mac_address = mac_addresses[network[:interface]+1]
+                interface = interfaces.detect {|nic| nic[:mac_address].gsub(":","") == mac_address} if mac_address
+                network[:device] = interface[:kernel] if interface
+              end
+            else
+              # assume interface numbers correspond to (ethN+1).
+              networks.each do |network|
+                interface = interfaces.detect {|nic| nic[:ethn] == network[:interface]}
+                network[:device] = interface[:kernel] if interface
+              end
+            end
+          else
+            # assume interface numbers correspond to the order of interfaces.
+            interfaces = get_interface_names(machine)
+            networks.each do |network|
+              network[:device] = interfaces[network[:interface]]
+            end
+          end
+        end
+
+        def self.get_interface_names(machine)
+          output = nil
+          machine.communicate.execute("ifconfig -a") do |type, result|
+            output = result.chomp if type == :stdout
+          end
+          names = output.scan(/^[^:\s]+/).reject {|name| name =~ /^lo/ }
+          names
+        end
+
+        # Upload a file.
+        def self.upload(machine, content, remote_path)
+          local_temp = Tempfile.new("vagrant-upload")
+          local_temp.binmode
+          local_temp.write(content)
+          local_temp.close
+          remote_temp = mktemp(machine)
+          machine.communicate.upload(local_temp.path, "#{remote_temp}")
+          local_temp.delete
+          machine.communicate.sudo("mv #{remote_temp} #{remote_path}")
+        end
+
+        # Create a temp file.
+        def self.mktemp(machine)
+          path = nil
+
+          machine.communicate.execute("mktemp --suffix -vagrant-upload") do |type, result|
+            path = result.chomp if type == :stdout
+          end
+          path
+        end
+
+        # using biosdevname, get all interfaces as a list of hashes, where:
+        #   :kernel      - the kernel's name for the device,
+        #   :ethn        - the calculated ethN-style name converted to integer.
+        #   :mac_address - the permanent mac address. ethN-style name converted to integer.
+        def self.get_interfaces(machine)
+          interfaces = []
+
+          # get all adapters, as named by the kernel
+          output = nil
+          machine.communicate.sudo("biosdevname -d") do |type, result|
+            output = result if type == :stdout
+          end
+          kernel_if_names = output.scan(/Kernel name: ([^\n]+)/).flatten
+          mac_addresses   = output.scan(/Permanent MAC: ([^\n]+)/).flatten
+
+          # get ethN-style names
+          ethns = []
+          kernel_if_names.each do |name|
+            machine.communicate.sudo("biosdevname --policy=all_ethN -i #{name}") do |type, result|
+              ethns << result.gsub(/[^\d]/,'').to_i if type == :stdout
+            end
+          end
+
+          # populate the interface list
+          kernel_if_names.each_index do |i|
+            interfaces << {
+              :kernel      => kernel_if_names[i],
+              :ethn        => ethns[i],
+              :mac_address => mac_addresses[i]
+            }
+          end
+
+          interfaces
+        end
+
+        def self.netmask_to_cidr(mask)
+          IPAddr.new(mask).to_i.to_s(2).count("1")
+        end
+      end
+    end
+  end
+end

plugins/guests/nixos/guest.rb

@@ -0,0 +1,11 @@
+require "vagrant"
+
+module VagrantPlugins
+  module GuestNixos
+    class Guest < Vagrant.plugin("2", :guest)
+      def detect?(machine)
+        machine.communicate.test("test -f /run/current-system/nixos-version")
+      end
+    end
+  end
+end

plugins/guests/nixos/plugin.rb

@@ -0,0 +1,25 @@
+require "vagrant"
+
+module VagrantPlugins
+  module GuestNixos
+    class Plugin < Vagrant.plugin("2")
+      name "NixOS guest"
+      description "NixOS guest support."
+
+      guest("nixos", "linux") do
+        require File.expand_path("../guest", __FILE__)
+        Guest
+      end
+
+      guest_capability("nixos", "configure_networks") do
+        require_relative "cap/configure_networks"
+        Cap::ConfigureNetworks
+      end
+
+      guest_capability("nixos", "change_host_name") do
+        require_relative "cap/change_host_name"
+        Cap::ChangeHostName
+      end
+    end
+  end
+end

templates/guests/nixos/hostname.erb

@@ -0,0 +1,6 @@
+{ config, pkgs, ... }:
+{
+  <% if name %>
+  networking.hostName = "<%= name %>";
+  <% end %>
+}

templates/guests/nixos/network.erb

@@ -0,0 +1,16 @@
+{ config, pkgs, ... }:
+{
+  networking.interfaces = [
+    <% networks.select {|n| n[:device]}.each do |network| %>
+    { 
+      name         = "<%= network[:device] %>";
+      <% if network[:type] == :static %>
+      ipAddress    = "<%= network[:ip] %>";
+      <% end %>
+      <% if network[:prefix_length] %>
+      prefixLength = <%= network[:prefix_length] %>;
+      <% end %>
+    }
+    <% end %>
+  ];
+}