fix: Remove 'Dns.GetHostName' from the message source resolution chai…

…n and set '/aws/messaging' as the fallback source

src/AWS.Messaging/Configuration/MessageBusBuilder.cs

@@ -276,7 +276,6 @@ internal void Build(IServiceCollection services)
  services.TryAddSingleton<IAWSClientProvider, AWSClientProvider>();
  services.TryAddSingleton<IMessageSourceHandler, MessageSourceHandler>();
  services.TryAddSingleton<IEnvironmentManager, EnvironmentManager>();
- services.TryAddSingleton<IDnsManager, DnsManager>();
  services.TryAddSingleton<IEC2InstanceMetadataManager, EC2InstanceMetadataManager>();
  services.TryAddSingleton<IECSContainerMetadataManager, ECSContainerMetadataManager>();
  services.AddHttpClient("ECSMetadataClient");

src/AWS.Messaging/Services/MessageSourceHandler.cs

@@ -15,22 +15,19 @@ namespace AWS.Messaging.Services;
 internal class MessageSourceHandler : IMessageSourceHandler
 {
  private readonly IEnvironmentManager _environmentManager;
- private readonly IDnsManager _dnsManager;
  private readonly IECSContainerMetadataManager _ecsContainerMetadataManager;
  private readonly IEC2InstanceMetadataManager _ec2InstanceMetadataHandler;
  private readonly IMessageConfiguration _messageConfiguration;
  private readonly ILogger<MessageSourceHandler> _logger;
 
  public MessageSourceHandler(
  IEnvironmentManager environmentManager,
- IDnsManager dnsManager,
  IECSContainerMetadataManager ecsContainerMetadataManager,
  IEC2InstanceMetadataManager ec2InstanceMetadataHandler,
  IMessageConfiguration messageConfiguration,
  ILogger<MessageSourceHandler> logger)
  {
  _environmentManager = environmentManager;
- _dnsManager = dnsManager;
  _ecsContainerMetadataManager = ecsContainerMetadataManager;
  _ec2InstanceMetadataHandler = ec2InstanceMetadataHandler;
  _messageConfiguration = messageConfiguration;
@@ -56,7 +53,7 @@ public MessageSourceHandler(
  /// </item>
  /// <item>
  /// <description>If the source cannot be resolved from the compute environment,
- /// we fallback to using <see cref="Dns.GetHostName"/></description>
+ /// we fallback to using "/aws/messaging" as the source identifier</description>
  /// </item>
  /// </list>
  /// After a source is computed, the message source suffix is appended if one is set.
@@ -68,7 +65,7 @@ public async Task<Uri> ComputeMessageSource()
  return GetFullSourceUri(_messageConfiguration.Source, _messageConfiguration.SourceSuffix);
 
  _logger.LogTrace("Attempting to compute message source based on the current environment...");
- string? messageSource = GetSourceFromLambda();
+ var messageSource = GetSourceFromLambda();
  if (string.IsNullOrEmpty(messageSource))
  {
  messageSource = await GetSourceFromECS();
@@ -78,10 +75,6 @@ public async Task<Uri> ComputeMessageSource()
  messageSource = GetSourceFromEC2();
  }
  if (string.IsNullOrEmpty(messageSource))
- {
- messageSource = GetSourceFromDnsHostName();
- }
- if (string.IsNullOrEmpty(messageSource))
  {
  messageSource = "/aws/messaging";
  }
@@ -172,23 +165,4 @@ private Uri GetFullSourceUri(string source, string? suffix)
  $"/AmazonEC2/{instanceID}" :
  null;
  }
-
- /// <summary>
- /// Retrieve the DNS host name using <see cref="Dns.GetHostName"/>.
- /// </summary>
- /// <returns>Message source from DNS host name</returns>
- private string? GetSourceFromDnsHostName()
- {
- _logger.LogTrace("Retrieving the DNS host name...");
-
- try
- {
- return $"/DNSHostName/{_dnsManager.GetHostName()}";
- }
- catch (Exception ex)
- {
- _logger.LogError(ex, "Unable to retrieve the DNS host name.");
- return null;
- }
- }
 }

test/AWS.Messaging.UnitTests/MessageSourceHandlerTests.cs

@@ -15,7 +15,6 @@ namespace AWS.Messaging.UnitTests;
 public class MessageSourceHandlerTests
 {
  private readonly Mock<IEnvironmentManager> _environmentManager;
- private readonly Mock<IDnsManager> _dnsManager;
  private readonly Mock<IEC2InstanceMetadataManager> _ec2InstanceMetadataManager;
  private readonly Mock<IECSContainerMetadataManager> _ecsContainerMetadataManager;
  private readonly IMessageConfiguration _messageConfiguration;
@@ -24,7 +23,6 @@ public class MessageSourceHandlerTests
  public MessageSourceHandlerTests()
  {
  _environmentManager = new Mock<IEnvironmentManager>();
- _dnsManager = new Mock<IDnsManager>();
  _ec2InstanceMetadataManager = new Mock<IEC2InstanceMetadataManager>();
  _ecsContainerMetadataManager = new Mock<IECSContainerMetadataManager>();
  _messageConfiguration = new MessageConfiguration();
@@ -36,14 +34,7 @@ public async Task MessageSourceIsSet()
  {
  _messageConfiguration.Source = "/aws/messaging";
 
- var messageSourceHandler = new MessageSourceHandler(
- _environmentManager.Object,
- _dnsManager.Object,
- _ecsContainerMetadataManager.Object,
- _ec2InstanceMetadataManager.Object,
- _messageConfiguration,
- _logger.Object
- );
+ var messageSourceHandler = GetMessageSourceHandler();
 
  var messageSource = await messageSourceHandler.ComputeMessageSource();
 
@@ -56,14 +47,7 @@ public async Task MessageSourceAndSuffixIsSet()
  _messageConfiguration.Source = "/aws/messaging";
  _messageConfiguration.SourceSuffix = "/suffix";
 
- var messageSourceHandler = new MessageSourceHandler(
- _environmentManager.Object,
- _dnsManager.Object,
- _ecsContainerMetadataManager.Object,
- _ec2InstanceMetadataManager.Object,
- _messageConfiguration,
- _logger.Object
- );
+ var messageSourceHandler = GetMessageSourceHandler();
 
  var messageSource = await messageSourceHandler.ComputeMessageSource();
 
@@ -76,14 +60,7 @@ public async Task MessageSourceAndSuffixIsSet_SourceDoesntEndInSlash_SuffixDoesn
  _messageConfiguration.Source = "/aws/messaging";
  _messageConfiguration.SourceSuffix = "suffix";
 
- var messageSourceHandler = new MessageSourceHandler(
- _environmentManager.Object,
- _dnsManager.Object,
- _ecsContainerMetadataManager.Object,
- _ec2InstanceMetadataManager.Object,
- _messageConfiguration,
- _logger.Object
- );
+ var messageSourceHandler = GetMessageSourceHandler();
 
  var messageSource = await messageSourceHandler.ComputeMessageSource();
 
@@ -96,14 +73,7 @@ public async Task MessageSourceAndSuffixIsSet_SourceEndsInSlash_SuffixStartsWith
  _messageConfiguration.Source = "/aws/messaging/";
  _messageConfiguration.SourceSuffix = "/suffix";
 
- var messageSourceHandler = new MessageSourceHandler(
- _environmentManager.Object,
- _dnsManager.Object,
- _ecsContainerMetadataManager.Object,
- _ec2InstanceMetadataManager.Object,
- _messageConfiguration,
- _logger.Object
- );
+ var messageSourceHandler = GetMessageSourceHandler();
 
  var messageSource = await messageSourceHandler.ComputeMessageSource();
 
@@ -116,14 +86,7 @@ public async Task MessageSourceAndSuffixIsSet_SourceAndSuffixHaveWhitespace()
  _messageConfiguration.Source = " /aws/messaging/ ";
  _messageConfiguration.SourceSuffix = " /suffix ";
 
- var messageSourceHandler = new MessageSourceHandler(
- _environmentManager.Object,
- _dnsManager.Object,
- _ecsContainerMetadataManager.Object,
- _ec2InstanceMetadataManager.Object,
- _messageConfiguration,
- _logger.Object
- );
+ var messageSourceHandler = GetMessageSourceHandler();
 
  var messageSource = await messageSourceHandler.ComputeMessageSource();
 
@@ -134,56 +97,33 @@ public async Task MessageSourceAndSuffixIsSet_SourceAndSuffixHaveWhitespace()
  public async Task MessageSourceNotSet_RunningLocally()
  {
  _ecsContainerMetadataManager.Setup(x => x.GetContainerTaskMetadata()).ReturnsAsync(new Dictionary<string, object>());
- _dnsManager.Setup(x => x.GetHostName()).Returns("local");
 
- var messageSourceHandler = new MessageSourceHandler(
- _environmentManager.Object,
- _dnsManager.Object,
- _ecsContainerMetadataManager.Object,
- _ec2InstanceMetadataManager.Object,
- _messageConfiguration,
- _logger.Object
- );
+ var messageSourceHandler = GetMessageSourceHandler();
 
  var messageSource = await messageSourceHandler.ComputeMessageSource();
 
- Assert.Equal("/DNSHostName/local", messageSource.ToString());
+ Assert.Equal("/aws/messaging", messageSource.ToString());
  }
 
  [Fact]
  public async Task MessageSourceNotSet_SuffixSet_RunningLocally()
  {
  _messageConfiguration.SourceSuffix = "/suffix";
  _ecsContainerMetadataManager.Setup(x => x.GetContainerTaskMetadata()).ReturnsAsync(new Dictionary<string, object>());
- _dnsManager.Setup(x => x.GetHostName()).Returns("local");
 
- var messageSourceHandler = new MessageSourceHandler(
- _environmentManager.Object,
- _dnsManager.Object,
- _ecsContainerMetadataManager.Object,
- _ec2InstanceMetadataManager.Object,
- _messageConfiguration,
- _logger.Object
- );
+ var messageSourceHandler = GetMessageSourceHandler();
 
  var messageSource = await messageSourceHandler.ComputeMessageSource();
 
- Assert.Equal("/DNSHostName/local/suffix", messageSource.ToString());
+ Assert.Equal("/aws/messaging/suffix", messageSource.ToString());
  }
 
  [Fact]
  public async Task MessageSourceNotSet_RunningInLambda()
  {
  _environmentManager.Setup(x => x.GetEnvironmentVariable("AWS_LAMBDA_FUNCTION_NAME")).Returns("lambda");
 
- var messageSourceHandler = new MessageSourceHandler(
- _environmentManager.Object,
- _dnsManager.Object,
- _ecsContainerMetadataManager.Object,
- _ec2InstanceMetadataManager.Object,
- _messageConfiguration,
- _logger.Object
- );
+ var messageSourceHandler = GetMessageSourceHandler();
 
  var messageSource = await messageSourceHandler.ComputeMessageSource();
 
@@ -199,14 +139,7 @@ public async Task MessageSourceNotSet_RunningInECS()
  { "TaskARN", "taskArn" }
  });
 
- var messageSourceHandler = new MessageSourceHandler(
- _environmentManager.Object,
- _dnsManager.Object,
- _ecsContainerMetadataManager.Object,
- _ec2InstanceMetadataManager.Object,
- _messageConfiguration,
- _logger.Object
- );
+ var messageSourceHandler = GetMessageSourceHandler();
 
  var messageSource = await messageSourceHandler.ComputeMessageSource();
 
@@ -219,37 +152,23 @@ public async Task MessageSourceNotSet_RunningInEC2()
  _ecsContainerMetadataManager.Setup(x => x.GetContainerTaskMetadata()).ReturnsAsync(new Dictionary<string, object>());
  _ec2InstanceMetadataManager.Setup(x => x.InstanceId).Returns("instanceId");
 
- var messageSourceHandler = new MessageSourceHandler(
- _environmentManager.Object,
- _dnsManager.Object,
- _ecsContainerMetadataManager.Object,
- _ec2InstanceMetadataManager.Object,
- _messageConfiguration,
- _logger.Object
- );
+ var messageSourceHandler = GetMessageSourceHandler();
 
  var messageSource = await messageSourceHandler.ComputeMessageSource();
 
  Assert.Equal("/AmazonEC2/instanceId", messageSource.ToString());
  }
 
- [Fact]
- public async Task MessageSourceNotSet_DnsThrowsException()
+ private IMessageSourceHandler GetMessageSourceHandler()
  {
- _ecsContainerMetadataManager.Setup(x => x.GetContainerTaskMetadata()).ReturnsAsync(new Dictionary<string, object>());
- _dnsManager.Setup(x => x.GetHostName()).Throws<Exception>();
-
  var messageSourceHandler = new MessageSourceHandler(
- _environmentManager.Object,
- _dnsManager.Object,
- _ecsContainerMetadataManager.Object,
- _ec2InstanceMetadataManager.Object,
- _messageConfiguration,
- _logger.Object
- );
-
- var messageSource = await messageSourceHandler.ComputeMessageSource();
-
- Assert.Equal("/aws/messaging", messageSource.ToString());
+ _environmentManager.Object,
+ _ecsContainerMetadataManager.Object,
+ _ec2InstanceMetadataManager.Object,
+ _messageConfiguration,
+ _logger.Object
+ );
+
+ return messageSourceHandler;
  }
 }