fix, simplify and add tests for lxd backend

Rakefile

@@ -18,7 +18,7 @@ if defined?(RSpec)
 
     task :backend => 'backend:all'
     namespace :backend do
-      backends = %w[exec ssh]
+      backends = Dir.glob("spec/backend/*").map { |path| File.basename(path) }
 
       task :all => backends
 

lib/specinfra/backend/lxd.rb

@@ -9,56 +9,30 @@ module Specinfra
   module Backend
     # LXD transport
     class Lxd < Exec
-      def initialize(config = {})
-        super
-
-        raise 'Please specify lxd_instance' unless (@instance = get_config(:lxd_instance))
-        raise 'Please specify lxd_remote' unless (@remote = get_config(:lxd_remote))
-
-        @remote_instance = [@remote, @instance].compact.join(':')
+      def build_command(cmd)
+        lxc_cmd = %W[lxc exec #{instance}]
+        lxc_cmd << '-t' if get_config(:interactive_shell)
+        lxc_cmd << '--'
+        (lxc_cmd << super(cmd)).join(' ')
       end
 
-      class << self
-        protected
-
-        def run_command(cmd, opts = {})
-          cmd = build_command(cmd)
-          run_pre_command(opts)
-          stdout, stderr, exit_status = with_env do
-            spawn_command(cmd)
-          end
-
-          if @example
-            @example.metadata[:command] = cmd
-            @example.metadata[:stdout]  = stdout
-          end
-
-          CommandResult.new :stdout => stdout, :stderr => stderr, :exit_status => exit_status
-        end
-
-        def build_command(cmd)
-          cmd = super(cmd)
-          "lxc exec #{@remote_instance} -- #{cmd}"
-        end
-
-        def send_file(source, destination)
-          flags = %w[--create-dirs]
-          if File.directory?(source)
-            flags << '--recursive'
-            destination = Pathname.new(destination).dirname.to_s
-          end
-          cmd = %W[lxc file push #{source} #{@remote_instance}#{destination}] + flags
-          spawn_command(cmd.join(' '))
+      def send_file(source, destination)
+        flags = %w[--create-dirs]
+        if File.directory?(source)
+          flags << '--recursive'
+          destination = Pathname.new(destination).dirname.to_s
         end
+        cmd = %W[lxc file push #{source} #{instance}#{destination}] + flags
+        spawn_command(cmd.join(' '))
+      end
 
-        private
+      private
 
-        def run_pre_command(_opts)
-          return unless get_config(:pre_command)
+      def instance
+        raise 'Please specify lxd_instance' unless (instance = get_config(:lxd_instance))
+        raise 'Please specify lxd_remote' unless (remote = get_config(:lxd_remote))
 
-          cmd = build_command(get_config(:pre_command))
-          spawn_command(cmd)
-        end
+        [remote, instance].compact.join(':')
       end
     end
   end

spec/backend/lxd/build_command_spec.rb

@@ -0,0 +1,113 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Specinfra::Backend::Lxd do
+  let(:lxd_instance) { 'instance' }
+  let(:lxd_remote) { 'remote' }
+  let(:lxc_exec) { "lxc exec #{lxd_remote}:#{lxd_instance}" }
+
+  before(:each) do
+    set :backend, :lxd
+    RSpec.configure do |c|
+      c.lxd_instance = lxd_instance
+      c.lxd_remote = lxd_remote
+    end
+  end
+
+  after(:each) do
+    Specinfra::Backend::Lxd.clear
+  end
+
+  describe '#build_command' do
+    context 'without required lxd_instance set' do
+      let(:lxd_instance) { nil }
+      it {
+        expect { subject.build_command('true') }.to raise_error(RuntimeError, /lxd_instance/)
+      }
+    end
+
+    context 'without required lxd_remote set' do
+      let(:lxd_remote) { nil }
+      it {
+        expect { subject.build_command('true') }.to raise_error(RuntimeError, /lxd_remote/)
+      }
+    end
+
+    context 'with simple command' do
+      it 'should escape spaces' do
+        expect(subject.build_command('test -f /etc/passwd')).to eq "#{lxc_exec} -- /bin/sh -c test\\ -f\\ /etc/passwd"
+      end
+    end
+
+    context 'with complex command' do
+      it 'should escape special chars' do
+        expect(subject.build_command('test ! -f /etc/selinux/config || (getenforce | grep -i -- disabled && grep -i -- ^SELINUX=disabled$ /etc/selinux/config)'))
+          .to eq "lxc exec #{lxd_remote}:#{lxd_instance} -- /bin/sh -c test\\ \\!\\ -f\\ /etc/selinux/config\\ \\|\\|\\ \\(getenforce\\ \\|\\ grep\\ -i\\ --\\ disabled\\ \\&\\&\\ grep\\ -i\\ --\\ \\^SELINUX\\=disabled\\$\\ /etc/selinux/config\\)"
+      end
+
+      it 'should escape quotes' do
+        if Gem::Version.new(RUBY_VERSION.dup) < Gem::Version.new('2.7')
+          expect(subject.build_command(%Q(find /etc/apt/ -name \*.list | xargs grep -o -E "^deb +[\\"']?http://ppa.launchpad.net/gluster/glusterfs-3.7"))).to eq("#{lxc_exec} -- /bin/sh -c find\\ /etc/apt/\\ -name\\ \\*.list\\ \\|\\ xargs\\ grep\\ -o\\ -E\\ \\\"\\^deb\\ \\+\\[\\\\\\\"\\'\\]\\?http://ppa.launchpad.net/gluster/glusterfs-3.7\\\"")
+        else
+          # Since Ruby 2.7, `+` is not escaped.
+          expect(subject.build_command(%Q(find /etc/apt/ -name \*.list | xargs grep -o -E "^deb +[\\"']?http://ppa.launchpad.net/gluster/glusterfs-3.7"))).to eq("#{lxc_exec} -- /bin/sh -c find\\ /etc/apt/\\ -name\\ \\*.list\\ \\|\\ xargs\\ grep\\ -o\\ -E\\ \\\"\\^deb\\ +\\[\\\\\\\"\\'\\]\\?http://ppa.launchpad.net/gluster/glusterfs-3.7\\\"")
+        end
+      end
+    end
+
+    context 'with custom shell' do
+      before { RSpec.configure { |c| c.shell = '/usr/local/bin/tcsh' } }
+      after { RSpec.configure { |c| c.shell = nil } }
+
+      it 'should use custom shell' do
+        expect(subject.build_command('test -f /etc/passwd')).to eq "#{lxc_exec} -- /usr/local/bin/tcsh -c test\\ -f\\ /etc/passwd"
+      end
+    end
+
+    context 'with custom shell that needs escaping' do
+      before { RSpec.configure { |c| c.shell = '/usr/test & spec/bin/sh' } }
+      after { RSpec.configure { |c| c.shell = nil } }
+
+      it 'should use custom shell' do
+        expect(subject.build_command('test -f /etc/passwd')).to eq "#{lxc_exec} -- /usr/test\\ \\&\\ spec/bin/sh -c test\\ -f\\ /etc/passwd"
+      end
+    end
+
+    context 'with an interactive shell' do
+      before { RSpec.configure { |c| c.interactive_shell = true } }
+      after { RSpec.configure { |c| c.interactive_shell = nil } }
+
+      it 'should emulate an interactive shell' do
+        expect(subject.build_command('test -f /etc/passwd')).to eq "#{lxc_exec} -t -- /bin/sh -i -c test\\ -f\\ /etc/passwd"
+      end
+    end
+
+    context 'with an login shell' do
+      before { RSpec.configure { |c| c.login_shell = true } }
+      after { RSpec.configure { |c| c.login_shell = nil } }
+
+      it 'should emulate an login shell' do
+        expect(subject.build_command('test -f /etc/passwd')).to eq "#{lxc_exec} -- /bin/sh -l -c test\\ -f\\ /etc/passwd"
+      end
+    end
+
+    context 'with custom path' do
+      before { RSpec.configure { |c| c.path = '/opt/bin:/opt/foo/bin:$PATH' } }
+      after { RSpec.configure { |c| c.path = nil } }
+
+      it 'should use custom path' do
+        expect(subject.build_command('test -f /etc/passwd')).to eq "#{lxc_exec} -- env PATH=\"/opt/bin:/opt/foo/bin:$PATH\" /bin/sh -c test\\ -f\\ /etc/passwd"
+      end
+    end
+
+    context 'with custom path that needs escaping' do
+      before { RSpec.configure { |c| c.path = '/opt/bin:/opt/test & spec/bin:$PATH' } }
+      after { RSpec.configure { |c| c.path = nil } }
+
+      it 'should use custom path' do
+        expect(subject.build_command('test -f /etc/passwd')).to eq "#{lxc_exec} -- env PATH=\"/opt/bin:/opt/test & spec/bin:$PATH\" /bin/sh -c test\\ -f\\ /etc/passwd"
+      end
+    end
+  end
+end