Catch exceptions when opening files for plugin options serialization (#412)

* Catch exceptions when opening files for plugin options serialization

* Cleanup

Author: mslukebo

src/Microsoft.Performance.SDK.Runtime.Tests/Options/StreamPluginOptionsLoaderTests.cs

@@ -87,6 +87,9 @@ public async Task DoNotCloseStreamOnRead_DoesNotCloseStream()
         Assert.IsTrue(stream.CanWrite);
     }
 
+    /// <summary>
+    ///     Asserts that an empty <see cref="Stream"/> returns an empty <see cref="PluginOptionsDto"/>.
+    /// </summary>
     [TestMethod]
     public async Task EmptyStream_ReturnsEmptyDto()
     {
@@ -99,6 +102,69 @@ public async Task EmptyStream_ReturnsEmptyDto()
         Assert.IsTrue(loadedDto.IsEmpty());
     }
 
+    /// <summary>
+    ///     Asserts that <see cref="StreamPluginOptionsLoader{T}.TryLoadAsync"/> returns <c>null</c> if an exception is thrown
+    ///     when getting the <see cref="Stream"/> to load from.
+    /// </summary>
+    [TestMethod]
+    public async Task GetStreamThrows_ReturnsNull()
+    {
+        var sut = new ThrowingStreamPluginOptionsLoader(true, false);
+
+        var loadedDto = await sut.TryLoadAsync();
+
+        Assert.IsNull(loadedDto);
+    }
+
+    /// <summary>
+    ///     Asserts that <see cref="StreamPluginOptionsLoader{T}.TryLoadAsync"/> returns <c>null</c> if an exception is thrown
+    ///     when checking if the <see cref="Stream"/> to load from has content.
+    /// </summary>
+    [TestMethod]
+    public async Task HasContentThrows_ReturnsNull()
+    {
+        using MemoryStream stream = new MemoryStream();
+        var sut = new ThrowingStreamPluginOptionsLoader(false, true);
+
+        var loadedDto = await sut.TryLoadAsync();
+
+        Assert.IsNull(loadedDto);
+    }
+
+    private sealed class ThrowingStreamPluginOptionsLoader
+        : StreamPluginOptionsLoader<MemoryStream>
+    {
+        private readonly bool throwInGetStream;
+        private readonly bool throwInHasContent;
+
+        public ThrowingStreamPluginOptionsLoader(bool throwInGetStream, bool throwInHasContent)
+            : base(true, Logger.Null)
+        {
+            this.throwInGetStream = throwInGetStream;
+            this.throwInHasContent = throwInHasContent;
+        }
+
+        protected override MemoryStream GetStream()
+        {
+            if (this.throwInGetStream)
+            {
+                throw new InvalidOperationException();
+            }
+
+            return new MemoryStream();
+        }
+
+        protected override bool HasContent(MemoryStream stream)
+        {
+            if (this.throwInHasContent)
+            {
+                throw new InvalidOperationException();
+            }
+
+            return true;
+        }
+    }
+
     private sealed class TestStreamPluginOptionsLoader
         : StreamPluginOptionsLoader<MemoryStream>
     {

src/Microsoft.Performance.SDK.Runtime.Tests/Options/StreamPluginOptionsSaverTests.cs

@@ -82,6 +82,42 @@ public async Task DoNotCloseStreamOnWrite_DoesNotCloseStream()
         Assert.IsTrue(stream.CanWrite);
     }
 
+    /// <summary>
+    ///     Asserts that <see cref="StreamPluginOptionsSaver.TrySaveAsync"/> returns <c>false</c> if an exception is thrown
+    ///     when getting the <see cref="Stream"/> to save to.
+    /// </summary>
+    [TestMethod]
+    public async Task GetStreamThrows_ReturnsFalse()
+    {
+        var sut = new ThrowingStreamPluginOptionsSaver(true);
+
+        var saved = await sut.TrySaveAsync(TestPluginOptionDto.PluginOptionsDto());
+
+        Assert.IsFalse(saved);
+    }
+
+    private sealed class ThrowingStreamPluginOptionsSaver
+        : StreamPluginOptionsSaver
+    {
+        private readonly bool throwOnGetStream;
+
+        public ThrowingStreamPluginOptionsSaver(bool throwOnGetStream)
+            : base(true, Logger.Null)
+        {
+            this.throwOnGetStream = throwOnGetStream;
+        }
+
+        protected override Stream GetStream()
+        {
+            if (this.throwOnGetStream)
+            {
+                throw new InvalidOperationException();
+            }
+
+            return new MemoryStream();
+        }
+    }
+
     private sealed class TestPluginOptionsSaver
         : StreamPluginOptionsSaver
     {

src/Microsoft.Performance.SDK.Runtime/Options/Serialization/Loading/StreamPluginOptionsLoader.cs

@@ -46,7 +46,17 @@ public async Task<PluginOptionsDto> TryLoadAsync()
     {
         var jsonSerializerOptions = PluginOptionsDtoJsonSerialization.GetJsonSerializerOptions();
 
-        var stream = GetStream();
+        T stream;
+        try
+        {
+            stream = GetStream();
+        }
+        catch (Exception e)
+        {
+            this.logger?.Error(e, "Failed to get stream to load plugin options from.");
+            return null;
+        }
+
         try
         {
             if (!HasContent(stream))
@@ -77,6 +87,8 @@ private protected virtual string GetDeserializeErrorMessage(Exception exception)
 
     /// <summary>
     ///     Gets the <see cref="Stream"/> from which to load the <see cref="PluginOptionsDto"/>.
+    ///     If this method throws an exception, the call to <see cref="TryLoadAsync"/> will be considered
+    ///     as cleanly failed and return <c>null</c>.
     /// </summary>
     /// <returns>
     ///     The <see cref="Stream"/> from which to load the <see cref="PluginOptionsDto"/>.
@@ -85,6 +97,8 @@ private protected virtual string GetDeserializeErrorMessage(Exception exception)
 
     /// <summary>
     ///     Determines whether <paramref name="stream"/> has content.
+    ///     If this method throws an exception, the call to <see cref="TryLoadAsync"/> will be considered
+    ///     as cleanly failed and return <c>null</c>.
     /// </summary>
     /// <param name="stream">
     ///     The <see cref="Stream"/> of type <typeparamref name="T"/> to check.

src/Microsoft.Performance.SDK.Runtime/Options/Serialization/Saving/StreamPluginOptionsSaver.cs

@@ -40,7 +40,17 @@ public async Task<bool> TrySaveAsync(PluginOptionsDto optionsDto)
     {
         var jsonSerializerOptions = PluginOptionsDtoJsonSerialization.GetJsonSerializerOptions();
 
-        var stream = GetStream();
+        Stream stream;
+        try
+        {
+            stream = GetStream();
+        }
+        catch (Exception e)
+        {
+            this.logger?.Error(e, "Failed to get stream to save plugin options to.");
+            return false;
+        }
+
         try
         {
             await JsonSerializer.SerializeAsync(stream, optionsDto, jsonSerializerOptions);
@@ -67,6 +77,8 @@ private protected virtual string GetSerializeErrorMessage(Exception exception)
 
     /// <summary>
     ///     Gets the <see cref="Stream"/> to save to.
+    ///     If this method throws an exception, the call to <see cref="TrySaveAsync"/> will be considered
+    ///     as cleanly failed and return <c>false</c>.
     /// </summary>
     /// <returns>
     ///     The <see cref="Stream"/> to save to.