~cbehrens/openstack-guest-agents/lp764221

using System;

using Rackspace.Cloud.Server.Agent.Configuration;

using Rackspace.Cloud.Server.Agent.Interfaces;

using Rackspace.Cloud.Server.Agent.Utilities;

using Rackspace.Cloud.Server.Common.Logging;

 

namespace Rackspace.Cloud.Server.Agent {

    public interface ICommandQueue {

        void Work();

    }

 

    public class CommandQueue : ICommandQueue {

        private readonly IXenStore _store;

        private readonly ICommandFactory _factory;

        private readonly ILogger _logger;

 

        public CommandQueue(IXenStore store, ICommandFactory factory, ILogger logger) {

            _store = store;

            _factory = factory;

            _logger = logger;

        }

 

        public void Work() {

            var commands = _store.GetCommands();

            if (commands.Count == 0) {

                LogManager.ShouldBeLogging = false;

                return;

            }

 

            LogManager.ShouldBeLogging = true;

            foreach (var command in commands) {

                ProcessCommand(command);

            }

        }

 

        private void ProcessCommand(Command command) {

            var removeMessageFromXenStore = true;

 

            try {

                var executableResult = _factory.CreateCommand(command.name).Execute(command.value);

                _store.Write(command.key, new Json<object>().Serialize(new { returncode = executableResult.ExitCode, message = executableResult.Output.Value() }));

            } catch (InvalidCommandException exception) {

                _store.Write(command.key, new Json<object>().Serialize(new { returncode = "1", message = exception.Message }));

            } catch (UnsuccessfulCommandExecutionException exception) {

                var result = (ExecutableResult) exception.Data["result"];

                var output = "";

                var error = "";

                if (result.Output != null && !string.IsNullOrEmpty(result.Output.Value()))

                    output = ", Output:" + result.Output.Value();

                if (result.Error != null && !string.IsNullOrEmpty(result.Error.Value()))

                    error = ", Error:" + result.Error.Value();

                _store.Write(command.key, new Json<object>().Serialize(new

                                                                           {

                                                                               returncode = result.ExitCode, 

                                                                               message = exception.Message + 

                                                                               output + error

                                                                           }));

            } catch(Exception ex) {

                removeMessageFromXenStore = false;

                _logger.Log(String.Format("Exception was : {0}\nStackTrace Was: {1}", ex.Message, ex.StackTrace));

            } finally {

                if (removeMessageFromXenStore) _store.Remove(command.key);

            }

        }

    }

}