Fix canary's heap usage to avoid system crash (#46)

Retain cached environment

Co-authored-by: Meshwa Savalia <meshwas@amazon.com>

Author: meshwa19

src/Amazon.CloudWatch.EMF/Environment/EnvironmentProvider.cs

@@ -14,7 +14,7 @@ public class EnvironmentProvider : IEnvironmentProvider
         private readonly IResourceFetcher _resourceFetcher;
         private readonly ILoggerFactory _loggerFactory;
         private readonly ILogger<ECSEnvironment> _logger;
-        private IEnvironment _cachedEnvironment;
+        private static IEnvironment _cachedEnvironment;
 
         public EnvironmentProvider(IConfiguration configuration, IResourceFetcher resourceFetcher)
             : this(configuration, resourceFetcher, NullLoggerFactory.Instance)
@@ -58,6 +58,14 @@ public IEnvironment ResolveEnvironment()
             return new DefaultEnvironment(_configuration, _loggerFactory);
         }
 
+        /// <summary>
+        /// A helper method to clean the cached environment in tests.
+        /// </summary>
+        internal void CleanResolvedEnvironment()
+        {
+            _cachedEnvironment = null;
+        }
+
         private IEnvironment GetEnvironmentFromConfig()
         {
             switch (_configuration.EnvironmentOverride)

tests/Amazon.CloudWatch.EMF.Canary/Dockerfile

@@ -1,4 +1,4 @@
-FROM mcr.microsoft.com/dotnet/core/aspnet:3.1
-COPY bin/Release/netcoreapp3.1/publish/ App/
+FROM mcr.microsoft.com/dotnet/aspnet:6.0
+COPY bin/Release/net6.0/publish/ App/
 WORKDIR /App
 ENTRYPOINT ["dotnet", "Amazon.CloudWatch.EMF.Canary.dll"]

tests/Amazon.CloudWatch.EMF.Tests/Environment/EnvironmentProviderTests.cs

@@ -4,11 +4,19 @@
 using AutoFixture.AutoNSubstitute;
 using NSubstitute;
 using Xunit;
+using System;
 
 namespace Amazon.CloudWatch.EMF.Tests.Environment
 {
-    public class EnvironmentProviderTests
+    public class EnvironmentProviderTests: IDisposable
     {
+        
+        private EnvironmentProvider environmentProvider;
+
+        public void Dispose(){
+            environmentProvider.CleanResolvedEnvironment();
+        }
+
         [Fact]
         public void ResolveEnvironment_ReturnCachedEnv()
         {
@@ -17,8 +25,8 @@ public void ResolveEnvironment_ReturnCachedEnv()
             var configuration = fixture.Create<IConfiguration>();
             configuration.EnvironmentOverride.Returns(Environments.Local);
             var resourceFetcher = fixture.Create<IResourceFetcher>();
-            var environmentProvider = new EnvironmentProvider(configuration, resourceFetcher);
-
+            environmentProvider = new EnvironmentProvider(configuration, resourceFetcher);
+            
             //Act
             var environment = environmentProvider.ResolveEnvironment();
             var environmentCache = environmentProvider.ResolveEnvironment();
@@ -35,8 +43,8 @@ public void ResolveEnvironment_ReturnsLambdaEnvironment()
             var configuration = fixture.Create<IConfiguration>();
             configuration.EnvironmentOverride.Returns(Environments.Lambda);
             var resourceFetcher = fixture.Create<IResourceFetcher>();
-            var environmentProvider = new EnvironmentProvider(configuration, resourceFetcher);
-
+            environmentProvider = new EnvironmentProvider(configuration, resourceFetcher);
+            
             //Act
             var environment = environmentProvider.ResolveEnvironment();
 
@@ -52,8 +60,8 @@ public void ResolveEnvironment_ReturnsLocalEnvironment()
             var configuration = fixture.Create<IConfiguration>();
             configuration.EnvironmentOverride.Returns(Environments.Local);
             var resourceFetcher = fixture.Create<IResourceFetcher>();
-            var environmentProvider = new EnvironmentProvider(configuration, resourceFetcher);
-
+            environmentProvider = new EnvironmentProvider(configuration, resourceFetcher);
+            
             //Act
             var environment = environmentProvider.ResolveEnvironment();
 
@@ -69,8 +77,8 @@ public void ResolveEnvironment_ReturnsEC2Environment()
             var configuration = fixture.Create<IConfiguration>();
             configuration.EnvironmentOverride.Returns(Environments.EC2);
             var resourceFetcher = fixture.Create<IResourceFetcher>();
-            var environmentProvider = new EnvironmentProvider(configuration, resourceFetcher);
-
+            environmentProvider = new EnvironmentProvider(configuration, resourceFetcher);
+            
             //Act
             var environment = environmentProvider.ResolveEnvironment();
 
@@ -86,8 +94,8 @@ public void ResolveEnvironment_ReturnsECSEnvironment()
             var configuration = fixture.Create<IConfiguration>();
             configuration.EnvironmentOverride.Returns(Environments.ECS);
             var resourceFetcher = fixture.Create<IResourceFetcher>();
-            var environmentProvider = new EnvironmentProvider(configuration, resourceFetcher);
-
+            environmentProvider = new EnvironmentProvider(configuration, resourceFetcher);
+            
             //Act
             var environment = environmentProvider.ResolveEnvironment();