This commit is contained in:
dsanz 2017-03-22 16:10:55 +01:00
commit dee6ea7342
6 changed files with 66 additions and 59 deletions

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@ -11,6 +11,6 @@ namespace Microsoft.eShopOnContainers.BuildingBlocks.EventBus.Events
Id = Guid.NewGuid(); Id = Guid.NewGuid();
} }
public Guid Id { get; private set; } public Guid Id { get; }
} }
} }

View File

@ -21,7 +21,8 @@ namespace Microsoft.eShopOnContainers.BuildingBlocks.EventBusRabbitMQ
private readonly Dictionary<string, List<IIntegrationEventHandler>> _handlers; private readonly Dictionary<string, List<IIntegrationEventHandler>> _handlers;
private readonly List<Type> _eventTypes; private readonly List<Type> _eventTypes;
private Tuple<IModel, IConnection> _connection; private IModel _model;
private IConnection _connection;
private string _queueName; private string _queueName;
@ -86,15 +87,15 @@ namespace Microsoft.eShopOnContainers.BuildingBlocks.EventBusRabbitMQ
_handlers.Remove(eventName); _handlers.Remove(eventName);
var eventType = _eventTypes.Single(e => e.Name == eventName); var eventType = _eventTypes.Single(e => e.Name == eventName);
_eventTypes.Remove(eventType); _eventTypes.Remove(eventType);
_connection.Item1.QueueUnbind(queue: _queueName, _model.QueueUnbind(queue: _queueName,
exchange: _brokerName, exchange: _brokerName,
routingKey: eventName); routingKey: eventName);
if (_handlers.Keys.Count == 0) if (_handlers.Keys.Count == 0)
{ {
_queueName = string.Empty; _queueName = string.Empty;
_connection.Item1.Dispose(); _model.Dispose();
_connection.Item2.Dispose(); _connection.Dispose();
} }
} }
@ -103,50 +104,53 @@ namespace Microsoft.eShopOnContainers.BuildingBlocks.EventBusRabbitMQ
public void Dispose() public void Dispose()
{ {
if (_connection != null) _handlers.Clear();
{ _model?.Dispose();
_handlers.Clear(); _connection?.Dispose();
_connection.Item1.Dispose();
_connection.Item2.Dispose();
}
} }
private IModel GetChannel() private IModel GetChannel()
{ {
if (_connection != null) if (_model != null)
{ {
return _connection.Item1; return _model;
} }
else else
{ {
var factory = new ConnectionFactory() { HostName = _connectionString }; (_model, _connection) = CreateConnection();
var connection = factory.CreateConnection(); return _model;
var channel = connection.CreateModel();
channel.ExchangeDeclare(exchange: _brokerName,
type: "direct");
if (string.IsNullOrEmpty(_queueName))
{
_queueName = channel.QueueDeclare().QueueName;
}
var consumer = new EventingBasicConsumer(channel);
consumer.Received += async (model, ea) =>
{
var eventName = ea.RoutingKey;
var message = Encoding.UTF8.GetString(ea.Body);
await ProcessEvent(eventName, message);
};
channel.BasicConsume(queue: _queueName,
noAck: true,
consumer: consumer);
_connection = new Tuple<IModel, IConnection>(channel, connection);
return _connection.Item1;
} }
} }
private (IModel model, IConnection connection) CreateConnection()
{
var factory = new ConnectionFactory() { HostName = _connectionString };
var con = factory.CreateConnection();
var channel = con.CreateModel();
channel.ExchangeDeclare(exchange: _brokerName,
type: "direct");
if (string.IsNullOrEmpty(_queueName))
{
_queueName = channel.QueueDeclare().QueueName;
}
var consumer = new EventingBasicConsumer(channel);
consumer.Received += async (model, ea) =>
{
var eventName = ea.RoutingKey;
var message = Encoding.UTF8.GetString(ea.Body);
await ProcessEvent(eventName, message);
};
channel.BasicConsume(queue: _queueName,
noAck: true,
consumer: consumer);
return (channel, con);
}
private async Task ProcessEvent(string eventName, string message) private async Task ProcessEvent(string eventName, string message)
{ {
if (_handlers.ContainsKey(eventName)) if (_handlers.ContainsKey(eventName))

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@ -9,6 +9,7 @@
<ItemGroup> <ItemGroup>
<PackageReference Include="Newtonsoft.Json" Version="9.0.1" /> <PackageReference Include="Newtonsoft.Json" Version="9.0.1" />
<PackageReference Include="RabbitMQ.Client" Version="4.1.1" /> <PackageReference Include="RabbitMQ.Client" Version="4.1.1" />
<PackageReference Include="System.ValueTuple" Version="4.3.0" />
</ItemGroup> </ItemGroup>
<ItemGroup> <ItemGroup>

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@ -8,6 +8,12 @@ using System.Threading.Tasks;
namespace WebMVC.Services.Utilities namespace WebMVC.Services.Utilities
{ {
/// <summary>
/// HttpClient wrapper that integrates Retry and Circuit
/// breaker policies when calling to Api services.
/// Currently is ONLY implemented for the ASP MVC
/// and Xamarin App
/// </summary>
public class HttpApiClientWrapper : IHttpClient public class HttpApiClientWrapper : IHttpClient
{ {
private HttpClient _client; private HttpClient _client;
@ -30,7 +36,7 @@ namespace WebMVC.Services.Utilities
Policy.Handle<HttpRequestException>() Policy.Handle<HttpRequestException>()
.CircuitBreakerAsync( .CircuitBreakerAsync(
// number of exceptions before breaking circuit // number of exceptions before breaking circuit
3, 5,
// time circuit opened before retry // time circuit opened before retry
TimeSpan.FromMinutes(1), TimeSpan.FromMinutes(1),
(exception, duration) => (exception, duration) =>
@ -49,11 +55,11 @@ namespace WebMVC.Services.Utilities
Policy.Handle<HttpRequestException>() Policy.Handle<HttpRequestException>()
.WaitAndRetryAsync( .WaitAndRetryAsync(
// number of retries // number of retries
3, 5,
// exponential backofff // exponential backofff
retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)), retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)),
// on retry // on retry
(exception, timeSpan, retryCount, context) => (exception, timeSpan, retryCount, context) =>
{ {
_logger.LogTrace($"Retry {retryCount} " + _logger.LogTrace($"Retry {retryCount} " +
$"of {context.PolicyKey} " + $"of {context.PolicyKey} " +
@ -62,27 +68,21 @@ namespace WebMVC.Services.Utilities
} }
); );
// Notice that these (and other methods below) are Task
// returning asynchronous methods. But, they do not
// have the 'async' modifier, and do not contain
// any 'await statements. In each of these methods,
// the only asynchronous call is the last (or only)
// statement of the method. In those instances,
// a Task returning method that does not use the
// async modifier is preferred. The compiler generates
// synchronous code for this method, but returns the
// task from the underlying asynchronous method. The
// generated code does not contain the state machine
// generated for asynchronous methods.
public Task<string> GetStringAsync(string uri) => public Task<string> GetStringAsync(string uri) =>
HttpInvoker(() => _client.GetStringAsync(uri)); HttpInvoker(() =>
_client.GetStringAsync(uri));
public Task<HttpResponseMessage> PostAsync<T>(string uri, T item) => public Task<HttpResponseMessage> PostAsync<T>(string uri, T item) =>
// a new StringContent must be created for each retry // a new StringContent must be created for each retry
// as it is disposed after each call // as it is disposed after each call
HttpInvoker(() =>_client.PostAsync(uri, HttpInvoker(() =>
new StringContent(JsonConvert.SerializeObject(item), {
System.Text.Encoding.UTF8, "application/json"))); var response = _client.PostAsync(uri, new StringContent(JsonConvert.SerializeObject(item), System.Text.Encoding.UTF8, "application/json"));
// raise exception if not success response
// needed for circuit breaker to track fails
response.Result.EnsureSuccessStatusCode();
return response;
});
public Task<HttpResponseMessage> DeleteAsync(string uri) => public Task<HttpResponseMessage> DeleteAsync(string uri) =>
HttpInvoker(() => _client.DeleteAsync(uri)); HttpInvoker(() => _client.DeleteAsync(uri));

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@ -54,11 +54,11 @@ namespace Microsoft.eShopOnContainers.WebMVC
if(Configuration.GetValue<string>("ActivateCircuitBreaker") == bool.TrueString) if(Configuration.GetValue<string>("ActivateCircuitBreaker") == bool.TrueString)
{ {
services.AddSingleton<IHttpClient, HttpApiClientWrapper>(); services.AddTransient<IHttpClient, HttpApiClientWrapper>();
} }
else else
{ {
services.AddSingleton<IHttpClient, HttpApiClient>(); services.AddTransient<IHttpClient, HttpApiClient>();
} }
} }

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@ -11,6 +11,8 @@ import 'rxjs/add/operator/catch';
import { SecurityService } from './security.service'; import { SecurityService } from './security.service';
import { Guid } from '../../../guid'; import { Guid } from '../../../guid';
// Implementing a Retry-Circuit breaker policy
// is pending to do for the SPA app
@Injectable() @Injectable()
export class DataService { export class DataService {
constructor(private http: Http, private securityService: SecurityService) { } constructor(private http: Http, private securityService: SecurityService) { }