Support provider URI per machine definition (#1363)

Save the variables on the instance to allow for different connection
settings to be specified on a per machine basis.

Provide some rudimentary tests that ensure that the different URIs are
used when constructing connections, and additionally the connection is
created only once, no matter how many times it is subsequently called.

Fixes: #1358

lib/vagrant-libvirt/driver.rb

@@ -8,13 +8,15 @@ require 'json'
 module VagrantPlugins
   module ProviderLibvirt
     class Driver
-      # store the connection at the process level
+      # store the connection at the instance level as this will be per
+      # thread and allows for individual machines to use different
+      # connection settings.
       #
       # possibly this should be a connection pool using the connection
-      # settings as a key to allow per machine connection attributes
-      # to be used.
-      @@connection = nil
-      @@system_connection = nil
+      # settings as a key to allow identical connections to be reused
+      # across machines.
+      @connection = nil
+      @system_connection = nil
 
       def initialize(machine)
         @logger = Log4r::Logger.new('vagrant_libvirt::driver')
@@ -24,7 +26,7 @@ module VagrantPlugins
       def connection
         # If already connected to Libvirt, just use it and don't connect
         # again.
-        return @@connection if @@connection
+        return @connection if @connection
 
         # Get config options for Libvirt provider.
         config = @machine.provider_config
@@ -43,24 +45,24 @@ module VagrantPlugins
 
         @logger.info("Connecting to Libvirt (#{uri}) ...")
         begin
-          @@connection = Fog::Compute.new(conn_attr)
+          @connection = Fog::Compute.new(conn_attr)
         rescue Fog::Errors::Error => e
           raise Errors::FogLibvirtConnectionError,
                 error_message: e.message
         end
 
-        @@connection
+        @connection
       end
 
       def system_connection
         # If already connected to Libvirt, just use it and don't connect
         # again.
-        return @@system_connection if @@system_connection
+        return @system_connection if @system_connection
 
         config = @machine.provider_config
 
-        @@system_connection = Libvirt::open(config.system_uri)
-        @@system_connection
+        @system_connection = Libvirt::open(config.system_uri)
+        @system_connection
       end
 
       def get_domain(machine)

spec/unit/driver_spec.rb

@@ -0,0 +1,83 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'support/sharedcontext'
+
+require 'vagrant-libvirt/driver'
+
+describe VagrantPlugins::ProviderLibvirt::Driver do
+  include_context 'unit'
+
+  let(:vagrantfile) do
+    <<-EOF
+    Vagrant.configure('2') do |config|
+      config.vm.define :test1 do |node|
+        node.vm.provider :libvirt do |domain|
+          domain.uri = "qemu+ssh://user@remote1/system"
+        end
+      end
+      config.vm.define :test2 do |node|
+        node.vm.provider :libvirt do |domain|
+          domain.uri = "qemu+ssh://vms@remote2/system"
+        end
+      end
+    end
+    EOF
+  end
+  # need to override the default package iso_env as using a different
+  # name for the test machines above.
+  let(:machine)    { iso_env.machine(:test1, :libvirt) }
+  let(:machine2)   { iso_env.machine(:test2, :libvirt) }
+  let(:connection1) { double("connection 1") } 
+  let(:connection2) { double("connection 2") } 
+  let(:system_connection1) { double("system connection 1") } 
+  let(:system_connection2) { double("system connection 2") } 
+
+  describe '#connection' do
+    it 'should configure a separate connection per machine' do
+      expect(Fog::Compute).to receive(:new).with(
+        hash_including({:libvirt_uri => 'qemu+ssh://user@remote1/system'})).and_return(connection1)
+      expect(Fog::Compute).to receive(:new).with(
+        hash_including({:libvirt_uri => 'qemu+ssh://vms@remote2/system'})).and_return(connection2)
+
+      expect(machine.provider.driver.connection).to eq(connection1)
+      expect(machine2.provider.driver.connection).to eq(connection2)
+    end
+
+    it 'should configure the connection once' do
+      expect(Fog::Compute).to receive(:new).once().and_return(connection1)
+
+      expect(machine.provider.driver.connection).to eq(connection1)
+      expect(machine.provider.driver.connection).to eq(connection1)
+      expect(machine.provider.driver.connection).to eq(connection1)
+    end
+  end
+
+  describe '#system_connection' do
+    # note that the urls for the two tests are currently
+    # incorrect here as they should be the following:
+    #   qemu+ssh://user@remote1/system
+    #   qemu+ssh://vms@remote2/system
+    #
+    # In that the system uri should be resolved based on
+    # the provider uri so that for:
+    #   uri => qemu+ssh://user@remote1/session
+    # system_uri should be 'qemu+ssh://user@remote1/system'
+    # and not 'qemu:///system'.
+    it 'should configure a separate connection per machine' do
+      expect(Libvirt).to receive(:open).with('qemu:///system').and_return(system_connection1)
+      expect(Libvirt).to receive(:open).with('qemu:///system').and_return(system_connection2)
+
+      expect(machine.provider.driver.system_connection).to eq(system_connection1)
+      expect(machine2.provider.driver.system_connection).to eq(system_connection2)
+    end
+
+    it 'should configure the connection once' do
+      expect(Libvirt).to receive(:open).with('qemu:///system').and_return(system_connection1)
+
+      expect(machine.provider.driver.system_connection).to eq(system_connection1)
+      expect(machine.provider.driver.system_connection).to eq(system_connection1)
+      expect(machine.provider.driver.system_connection).to eq(system_connection1)
+    end
+  end
+end