From 71032ce900500f45361065ec6164e6cc905f5cd1 Mon Sep 17 00:00:00 2001
From: Boris Yakhno <boris.yakhno@jetbrains.com>
Date: Thu, 24 Aug 2023 06:57:15 +0000
Subject: [PATCH] Added an option of creating a service message writer that
 doesn't set a top-level flowId attribute on messages

---
 .../ServiceMessageParserPerformanceTest.cs    |  3 +-
 .../TeamCity.ServiceMessages.Tests.csproj     | 19 +++----
 .../FlowAwareServiceMessageWriterTest.cs      | 49 +++++++++++++++++++
 .../Specials/TeamCityFlowWriterBaseTest.cs    |  7 +--
 .../Write/Specials/TeamCityFlowWriterTest.cs  | 25 +++++++++-
 .../Write/Specials/TeamCityTestsWriterTest.cs |  2 +-
 .../Write/Specials/TeamCityWriterBaseTest.cs  |  2 +-
 .../TeamCity.ServiceMessages.csproj           |  3 +-
 ...s => IFlowAwareServiceMessageProcessor.cs} |  6 +--
 .../Write/Special/ITeamCityServiceMessages.cs | 14 ++----
 ...er.cs => FlowAwareServiceMessageWriter.cs} | 35 ++++++++-----
 .../Write/Special/Impl/TeamCityWriterImpl.cs  |  4 +-
 .../Impl/Updater/FlowMessageUpdater.cs        | 18 ++-----
 .../Special/Impl/Writer/TeamCityFlowWriter.cs | 34 +++++++------
 .../Impl/Writer/TeamCityTestSuiteBlock.cs     |  4 +-
 .../Write/Special/TeamCityServiceMessages.cs  | 18 ++++---
 build.proj                                    |  2 +-
 17 files changed, 164 insertions(+), 81 deletions(-)
 create mode 100644 TeamCity.ServiceMessages.Tests/Write/Specials/FlowAwareServiceMessageWriterTest.cs
 rename TeamCity.ServiceMessages/Write/Special/{IFlowServiceMessageProcessor.cs => IFlowAwareServiceMessageProcessor.cs} (88%)
 rename TeamCity.ServiceMessages/Write/Special/Impl/{FlowServiceMessageWriter.cs => FlowAwareServiceMessageWriter.cs} (69%)

diff --git a/TeamCity.ServiceMessages.Tests/Read/ServiceMessageParserPerformanceTest.cs b/TeamCity.ServiceMessages.Tests/Read/ServiceMessageParserPerformanceTest.cs
index 81ffcad..f10bcdf 100644
--- a/TeamCity.ServiceMessages.Tests/Read/ServiceMessageParserPerformanceTest.cs
+++ b/TeamCity.ServiceMessages.Tests/Read/ServiceMessageParserPerformanceTest.cs
@@ -25,6 +25,7 @@ namespace JetBrains.TeamCity.ServiceMessages.Tests.Read
     using ServiceMessages.Read;
 
     [TestFixture]
+    [Explicit]
     public class ServiceMessageParserPerformanceTest
     {
         private static string GenerateTestData(int sz)
@@ -77,4 +78,4 @@ public void Parse10000()
             Console.Out.WriteLine(trash);
         }
     }
-}
\ No newline at end of file
+}
diff --git a/TeamCity.ServiceMessages.Tests/TeamCity.ServiceMessages.Tests.csproj b/TeamCity.ServiceMessages.Tests/TeamCity.ServiceMessages.Tests.csproj
index e522243..e27cb11 100644
--- a/TeamCity.ServiceMessages.Tests/TeamCity.ServiceMessages.Tests.csproj
+++ b/TeamCity.ServiceMessages.Tests/TeamCity.ServiceMessages.Tests.csproj
@@ -1,5 +1,5 @@
-<Project Sdk="Microsoft.NET.Sdk">
-
+<Project Sdk="Microsoft.NET.Sdk">
+
   <PropertyGroup>
     <TargetFrameworks>netstandard1.6;net45;netcoreapp1.0;netcoreapp2.0;netcoreapp3.0</TargetFrameworks>
     <AssemblyName>TeamCity.ServiceMessages.Tests</AssemblyName>
@@ -14,16 +14,17 @@
     <SignAssembly>True</SignAssembly>
     <AssemblyOriginatorKeyFile>TeamCity.ServiceMessages.snk</AssemblyOriginatorKeyFile>
     <DelaySign>False</DelaySign>
-  </PropertyGroup>
-
+  </PropertyGroup>
+
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.4.0" />
+    <PackageReference Include="Moq" Version="4.10.1" />
     <PackageReference Include="NUnit3TestAdapter" Version="3.15.1" />
     <PackageReference Include="NUnit"><Version>3.12.0</Version></PackageReference>
-  </ItemGroup>
-
+  </ItemGroup>
+
   <ItemGroup>
     <ProjectReference Include="..\TeamCity.ServiceMessages\TeamCity.ServiceMessages.csproj" />
-  </ItemGroup>
-
-</Project>
+  </ItemGroup>
+
+</Project>
diff --git a/TeamCity.ServiceMessages.Tests/Write/Specials/FlowAwareServiceMessageWriterTest.cs b/TeamCity.ServiceMessages.Tests/Write/Specials/FlowAwareServiceMessageWriterTest.cs
new file mode 100644
index 0000000..fa3a381
--- /dev/null
+++ b/TeamCity.ServiceMessages.Tests/Write/Specials/FlowAwareServiceMessageWriterTest.cs
@@ -0,0 +1,49 @@
+namespace JetBrains.TeamCity.ServiceMessages.Tests.Write.Specials
+{
+    using System.Collections.Generic;
+    using System.Linq;
+    using Moq;
+    using NUnit.Framework;
+    using ServiceMessages.Write;
+    using ServiceMessages.Write.Special;
+    using ServiceMessages.Write.Special.Impl;
+
+    [TestFixture]
+    public class FlowAwareServiceMessageWriterTest
+    {
+        [Test]
+        public void ShouldNotAddFlowIdAttributeToServiceMessageWhenFlowIdIsNotSet()
+        {
+            var processorMock = new Mock<IServiceMessageProcessor>();
+            var flowAwareWriter = new FlowAwareServiceMessageWriter(
+                null,
+                processorMock.Object,
+                Mock.Of<IFlowIdGenerator>(),
+                new List<IServiceMessageUpdater>());
+
+            var serviceMessage = new ServiceMessage("foo");
+            flowAwareWriter.AddServiceMessage(serviceMessage);
+
+            processorMock.Verify(x => x.AddServiceMessage(
+                It.Is<IServiceMessage>(m => m.Keys.All(k => k != "flowId"))));
+        }
+
+        [Test]
+        public void ShouldAddFlowIdAttributeToServiceMessageWhenFlowIdIsSet()
+        {
+            string flowId = "123";
+            var processorMock = new Mock<IServiceMessageProcessor>();
+            var flowAwareWriter = new FlowAwareServiceMessageWriter(
+                flowId,
+                processorMock.Object,
+                Mock.Of<IFlowIdGenerator>(),
+                new List<IServiceMessageUpdater>());
+
+            var serviceMessage = new ServiceMessage("foo");
+            flowAwareWriter.AddServiceMessage(serviceMessage);
+
+            processorMock.Verify(x => x.AddServiceMessage(
+                It.Is<IServiceMessage>(m => m.GetValue("flowId") == flowId)));
+        }
+    }
+}
diff --git a/TeamCity.ServiceMessages.Tests/Write/Specials/TeamCityFlowWriterBaseTest.cs b/TeamCity.ServiceMessages.Tests/Write/Specials/TeamCityFlowWriterBaseTest.cs
index a830d73..036bb38 100644
--- a/TeamCity.ServiceMessages.Tests/Write/Specials/TeamCityFlowWriterBaseTest.cs
+++ b/TeamCity.ServiceMessages.Tests/Write/Specials/TeamCityFlowWriterBaseTest.cs
@@ -24,11 +24,12 @@ namespace JetBrains.TeamCity.ServiceMessages.Tests.Write.Specials
 
     public abstract class TeamCityFlowWriterBaseTest<T> : TeamCityWriterBaseTest<T>
     {
-        protected abstract T Create(IFlowServiceMessageProcessor proc);
+        protected abstract T Create(IFlowAwareServiceMessageProcessor proc);
 
         protected sealed override T Create(IServiceMessageProcessor proc)
         {
-            return Create(new FlowServiceMessageWriter(proc, new DefaultFlowIdGenerator(), Enumerable.Empty<IServiceMessageUpdater>()));
+            var flowIdGenerator = new DefaultFlowIdGenerator();
+            return Create(new FlowAwareServiceMessageWriter(flowIdGenerator.NewFlowId(), proc, flowIdGenerator, Enumerable.Empty<IServiceMessageUpdater>()));
         }
 
         protected override ToStringProcessor CreateProcessor()
@@ -70,4 +71,4 @@ private string FlowToString(string flowId)
             }
         }
     }
-}
\ No newline at end of file
+}
diff --git a/TeamCity.ServiceMessages.Tests/Write/Specials/TeamCityFlowWriterTest.cs b/TeamCity.ServiceMessages.Tests/Write/Specials/TeamCityFlowWriterTest.cs
index 8548a6e..ed8e4d8 100644
--- a/TeamCity.ServiceMessages.Tests/Write/Specials/TeamCityFlowWriterTest.cs
+++ b/TeamCity.ServiceMessages.Tests/Write/Specials/TeamCityFlowWriterTest.cs
@@ -17,6 +17,8 @@
 namespace JetBrains.TeamCity.ServiceMessages.Tests.Write.Specials
 {
     using System;
+    using System.Linq;
+    using Moq;
     using NUnit.Framework;
     using ServiceMessages.Write.Special;
     using ServiceMessages.Write.Special.Impl;
@@ -25,7 +27,7 @@ namespace JetBrains.TeamCity.ServiceMessages.Tests.Write.Specials
     [TestFixture]
     public class TeamCityFlowWriterTest : TeamCityFlowWriterBaseTest<TeamCityFlowWriter<IDisposable>>
     {
-        protected override TeamCityFlowWriter<IDisposable> Create(IFlowServiceMessageProcessor proc)
+        protected override TeamCityFlowWriter<IDisposable> Create(IFlowAwareServiceMessageProcessor proc)
         {
             return new TeamCityFlowWriter<IDisposable>(proc, (x, _) => x, DisposableDelegate.Empty);
         }
@@ -43,5 +45,24 @@ public void TestOpenCloseBlock()
                 "##teamcity[flowStarted parent='1' flowId='2']",
                 "##teamcity[flowFinished flowId='2']");
         }
+
+        [Test]
+        public void ShouldNotAddParentFlowAttributeToMessageAfterOpeningNewFlowIfThereIsNoParentFlow()
+        {
+            var parentFlowAwareProcessorMock = new Mock<IFlowAwareServiceMessageProcessor>();
+            var childFlowAwareProcessorMock = new Mock<IFlowAwareServiceMessageProcessor>();
+            parentFlowAwareProcessorMock.SetupGet(x => x.FlowId).Returns((string)null);
+            parentFlowAwareProcessorMock.Setup(x => x.ForNewFlow()).Returns(childFlowAwareProcessorMock.Object);
+            var teamCityFlowWriter = new TeamCityFlowWriter<IDisposable>(
+                parentFlowAwareProcessorMock.Object,
+                (handler, processor) => Mock.Of<IDisposable>(),
+                Mock.Of<IDisposable>());
+
+            teamCityFlowWriter.OpenFlow();
+
+            childFlowAwareProcessorMock.Verify(
+                x => x.AddServiceMessage(
+                    It.Is<IServiceMessage>(m => m.Keys.All(k => k != "parent"))));
+        }
     }
-}
\ No newline at end of file
+}
diff --git a/TeamCity.ServiceMessages.Tests/Write/Specials/TeamCityTestsWriterTest.cs b/TeamCity.ServiceMessages.Tests/Write/Specials/TeamCityTestsWriterTest.cs
index 37b98f0..0fe76d7 100644
--- a/TeamCity.ServiceMessages.Tests/Write/Specials/TeamCityTestsWriterTest.cs
+++ b/TeamCity.ServiceMessages.Tests/Write/Specials/TeamCityTestsWriterTest.cs
@@ -26,7 +26,7 @@ namespace JetBrains.TeamCity.ServiceMessages.Tests.Write.Specials
     [TestFixture]
     public class TeamCityTestsWriterTest : TeamCityFlowWriterBaseTest<ITeamCityTestsWriter>
     {
-        protected override ITeamCityTestsWriter Create(IFlowServiceMessageProcessor proc)
+        protected override ITeamCityTestsWriter Create(IFlowAwareServiceMessageProcessor proc)
         {
             return new TeamCityTestSuiteBlock(proc, DisposableDelegate.Empty);
         }
diff --git a/TeamCity.ServiceMessages.Tests/Write/Specials/TeamCityWriterBaseTest.cs b/TeamCity.ServiceMessages.Tests/Write/Specials/TeamCityWriterBaseTest.cs
index d9f2d08..2bc68dd 100644
--- a/TeamCity.ServiceMessages.Tests/Write/Specials/TeamCityWriterBaseTest.cs
+++ b/TeamCity.ServiceMessages.Tests/Write/Specials/TeamCityWriterBaseTest.cs
@@ -86,7 +86,7 @@ public virtual void AddServiceMessage(IServiceMessage serviceMessage)
 
     public abstract class TeamCityWriterBaseTest : TeamCityFlowWriterBaseTest<ITeamCityWriter>
     {
-        protected override ITeamCityWriter Create(IFlowServiceMessageProcessor proc)
+        protected override ITeamCityWriter Create(IFlowAwareServiceMessageProcessor proc)
         {
             return new TeamCityWriterImpl(proc, DisposableDelegate.Empty);
         }
diff --git a/TeamCity.ServiceMessages/TeamCity.ServiceMessages.csproj b/TeamCity.ServiceMessages/TeamCity.ServiceMessages.csproj
index 6b6e312..2dc16d9 100644
--- a/TeamCity.ServiceMessages/TeamCity.ServiceMessages.csproj
+++ b/TeamCity.ServiceMessages/TeamCity.ServiceMessages.csproj
@@ -21,10 +21,11 @@
     <DelaySign>False</DelaySign>
     <Authors>JetBrains</Authors>
     <Title>TeamCity Service Messages read/write access</Title>
-    <Description>This library provides read/write access to TeamCity Service messages. Take a look at the description of service messages at http://confluence.jetbrains.net/display/TCDL/Build+Script+Interaction+with+TeamCity#BuildScriptInteractionwithTeamCity-ServiceMessages</Description>
+    <Description>This library provides read/write access to TeamCity Service messages. The documentation on service messages can be found at https://www.jetbrains.com/help/teamcity/service-messages.html</Description>
     <PackageLicenseUrl>https://github.com/JetBrains/TeamCity.ServiceMessages/raw/master/LICENSE.txt</PackageLicenseUrl>
     <PackageProjectUrl>https://github.com/JetBrains/TeamCity.ServiceMessages</PackageProjectUrl>
     <PackageIconUrl>https://github.com/JetBrains/TeamCity.ServiceMessages/raw/master/icon.png</PackageIconUrl>
+    <PackageReleaseNotes>Release descriptions are available at https://github.com/JetBrains/TeamCity.ServiceMessages/releases</PackageReleaseNotes>
     <RepositoryUrl>https://github.com/JetBrains/TeamCity.ServiceMessages.git</RepositoryUrl>
     <RepositoryType>git</RepositoryType>
     <PackageTags>TeamCity ServiceMessage ServiceMessages</PackageTags>
diff --git a/TeamCity.ServiceMessages/Write/Special/IFlowServiceMessageProcessor.cs b/TeamCity.ServiceMessages/Write/Special/IFlowAwareServiceMessageProcessor.cs
similarity index 88%
rename from TeamCity.ServiceMessages/Write/Special/IFlowServiceMessageProcessor.cs
rename to TeamCity.ServiceMessages/Write/Special/IFlowAwareServiceMessageProcessor.cs
index e3f47e4..691c198 100644
--- a/TeamCity.ServiceMessages/Write/Special/IFlowServiceMessageProcessor.cs
+++ b/TeamCity.ServiceMessages/Write/Special/IFlowAwareServiceMessageProcessor.cs
@@ -19,7 +19,7 @@ namespace JetBrains.TeamCity.ServiceMessages.Write.Special
     /// <summary>
     /// FlowId aware implementation of ServiceMessagesProcessor
     /// </summary>
-    public interface IFlowServiceMessageProcessor : IServiceMessageProcessor
+    public interface IFlowAwareServiceMessageProcessor : IServiceMessageProcessor
     {
         /// <summary>
         /// Current flow Id
@@ -31,6 +31,6 @@ public interface IFlowServiceMessageProcessor : IServiceMessageProcessor
         /// </summary>
         /// <returns></returns>
         [NotNull]
-        IFlowServiceMessageProcessor ForNewFlow();
+        IFlowAwareServiceMessageProcessor ForNewFlow();
     }
-}
\ No newline at end of file
+}
diff --git a/TeamCity.ServiceMessages/Write/Special/ITeamCityServiceMessages.cs b/TeamCity.ServiceMessages/Write/Special/ITeamCityServiceMessages.cs
index e682dcc..9440bf0 100644
--- a/TeamCity.ServiceMessages/Write/Special/ITeamCityServiceMessages.cs
+++ b/TeamCity.ServiceMessages/Write/Special/ITeamCityServiceMessages.cs
@@ -25,24 +25,20 @@ namespace JetBrains.TeamCity.ServiceMessages.Write.Special
     public interface ITeamCityServiceMessages
     {
         /// <summary>
-        /// Created writer that generates service messages to a Console.Out
+        /// Creates a writer that outputs service messages to Console.Out
         /// </summary>
-        /// <remarks>
-        /// Implementation does not support multiple-threads.
-        /// If you need to log more me
-        /// </remarks>
         /// <returns></returns>
         [NotNull]
         ITeamCityWriter CreateWriter();
 
         /// <summary>
-        /// Creates writer that translates service messages to the given
-        /// delegate.
+        /// Creates a writer that uses the provided delegate to output service messages
         /// </summary>
         /// <param name="destination">generated service messages processor</param>
+        /// <param name="addFlowIdsOnTopLevelMessages">specifies whether messages written without explicitly opening a flow should be marked with a common flow id</param>
         /// <returns></returns>
         [NotNull]
-        ITeamCityWriter CreateWriter(Action<string> destination);
+        ITeamCityWriter CreateWriter(Action<string> destination, bool addFlowIdsOnTopLevelMessages = true);
 
         /// <summary>
         /// Adds user-specific service message updater to the list of service message updaters.
@@ -50,4 +46,4 @@ public interface ITeamCityServiceMessages
         /// <param name="updater">updater instance</param>
         void AddServiceMessageUpdater([NotNull] IServiceMessageUpdater updater);
     }
-}
\ No newline at end of file
+}
diff --git a/TeamCity.ServiceMessages/Write/Special/Impl/FlowServiceMessageWriter.cs b/TeamCity.ServiceMessages/Write/Special/Impl/FlowAwareServiceMessageWriter.cs
similarity index 69%
rename from TeamCity.ServiceMessages/Write/Special/Impl/FlowServiceMessageWriter.cs
rename to TeamCity.ServiceMessages/Write/Special/Impl/FlowAwareServiceMessageWriter.cs
index 242b78e..5d3fe36 100644
--- a/TeamCity.ServiceMessages/Write/Special/Impl/FlowServiceMessageWriter.cs
+++ b/TeamCity.ServiceMessages/Write/Special/Impl/FlowAwareServiceMessageWriter.cs
@@ -22,30 +22,35 @@ namespace JetBrains.TeamCity.ServiceMessages.Write.Special.Impl
     using Updater;
 
     /// <summary>
-    /// Servivce message acceptor implementation with support of IServiceMessageUpdater chains
+    /// Service message acceptor implementation that is aware of service message flows and supports IServiceMessageUpdater chains
     /// </summary>
-    public class FlowServiceMessageWriter : IFlowServiceMessageProcessor
+    public class FlowAwareServiceMessageWriter : IFlowAwareServiceMessageProcessor
     {
         private readonly IFlowIdGenerator _generator;
         private readonly IServiceMessageProcessor _processor;
         private readonly List<IServiceMessageUpdater> _updaters;
 
         /// <summary>
-        /// Creates generic processor that calls messages updaters and sends output to provided deledate.
+        /// Creates generic processor that calls messages updaters and sends output to provided delegate.
         /// </summary>
+        /// <param name="serviceMessageFlowId">id of the flow assigned to messages written through this processor, can be null</param>
         /// <param name="processor">writer of service messages objects</param>
         /// <param name="generator">flow id generator that is called to create next flowId</param>
         /// <param name="updaters">service message updaters, i.e. timestamp updater</param>
-        public FlowServiceMessageWriter([NotNull] IServiceMessageProcessor processor,
+        public FlowAwareServiceMessageWriter(
+            string serviceMessageFlowId,
+            [NotNull] IServiceMessageProcessor processor,
             [NotNull] IFlowIdGenerator generator,
             [NotNull] IEnumerable<IServiceMessageUpdater> updaters)
         {
             if (processor == null) throw new ArgumentNullException(nameof(processor));
             if (generator == null) throw new ArgumentNullException(nameof(generator));
             if (updaters == null) throw new ArgumentNullException(nameof(updaters));
+
+            FlowId = serviceMessageFlowId;
             _processor = processor;
             _generator = generator;
-            _updaters = IncludeFlowId(updaters);
+            _updaters = AddFlowIdUpdater(updaters.ToList());
         }
 
         public void AddServiceMessage(IServiceMessage serviceMessage)
@@ -54,26 +59,32 @@ public void AddServiceMessage(IServiceMessage serviceMessage)
             _processor.AddServiceMessage(_updaters.Aggregate(serviceMessage, (current, updater) => updater.UpdateServiceMessage(current)));
         }
 
-        public string FlowId => _updaters.OfType<FlowMessageUpdater>().First().FlowId;
+        public string FlowId { get; }
 
         /// <summary>
         /// Creates new ServiceMessage updater that uses specified FlowId
         /// </summary>
-        public IFlowServiceMessageProcessor ForNewFlow()
+        public IFlowAwareServiceMessageProcessor ForNewFlow()
         {
-            return new FlowServiceMessageWriter(
+            return new FlowAwareServiceMessageWriter(
+                _generator.NewFlowId(),
                 _processor,
                 _generator,
-                IncludeFlowId(_updaters)
+                _updaters
             );
         }
 
         [NotNull]
-        private List<IServiceMessageUpdater> IncludeFlowId([NotNull] IEnumerable<IServiceMessageUpdater> updaters)
+        private List<IServiceMessageUpdater> AddFlowIdUpdater([NotNull] List<IServiceMessageUpdater> updaters)
         {
+            if (FlowId == null)
+            {
+                return updaters;
+            }
+
             return updaters.Where(x => !(x is FlowMessageUpdater))
-                .Union(new[] {new FlowMessageUpdater(_generator)})
+                .Union(new[] {new FlowMessageUpdater(FlowId)})
                 .ToList();
         }
     }
-}
\ No newline at end of file
+}
diff --git a/TeamCity.ServiceMessages/Write/Special/Impl/TeamCityWriterImpl.cs b/TeamCity.ServiceMessages/Write/Special/Impl/TeamCityWriterImpl.cs
index f43af2a..b5eafc8 100644
--- a/TeamCity.ServiceMessages/Write/Special/Impl/TeamCityWriterImpl.cs
+++ b/TeamCity.ServiceMessages/Write/Special/Impl/TeamCityWriterImpl.cs
@@ -25,7 +25,7 @@ public class TeamCityWriterImpl : TeamCityWriterFacade, ISubWriter
         private readonly IEnumerable<ISubWriter> _writeCheck;
 
         public TeamCityWriterImpl(
-            [NotNull] IFlowServiceMessageProcessor processor,
+            [NotNull] IFlowAwareServiceMessageProcessor processor,
             [NotNull] IDisposable dispose)
             : this(processor,
                 new TeamCityFlowWriter<ITeamCityWriter>(processor, (handler, writer) => new TeamCityWriterImpl(writer, handler), DisposableDelegate.Empty),
@@ -89,4 +89,4 @@ protected override void CheckConsistency()
             AssertNoChildOpened();
         }
     }
-}
\ No newline at end of file
+}
diff --git a/TeamCity.ServiceMessages/Write/Special/Impl/Updater/FlowMessageUpdater.cs b/TeamCity.ServiceMessages/Write/Special/Impl/Updater/FlowMessageUpdater.cs
index 66f2428..77b528d 100644
--- a/TeamCity.ServiceMessages/Write/Special/Impl/Updater/FlowMessageUpdater.cs
+++ b/TeamCity.ServiceMessages/Write/Special/Impl/Updater/FlowMessageUpdater.cs
@@ -24,28 +24,20 @@ namespace JetBrains.TeamCity.ServiceMessages.Write.Special.Impl.Updater
     /// </summary>
     public class FlowMessageUpdater : IServiceMessageUpdater
     {
+        [NotNull] private readonly string _flowId;
+
         /// <summary>
         /// Constructs updater
         /// </summary>
         /// <param name="flowId">flowId set to all messages</param>
         public FlowMessageUpdater([NotNull] string flowId)
         {
-            FlowId = flowId ?? throw new ArgumentNullException(nameof(flowId));
+            _flowId = flowId ?? throw new ArgumentNullException(nameof(flowId));
         }
 
-        /// <summary>
-        /// Creates flow id from given generator instance
-        /// </summary>
-        /// <param name="flowId"></param>
-        public FlowMessageUpdater([NotNull] IFlowIdGenerator flowId) : this(flowId.NewFlowId())
-        {
-        }
-
-        public string FlowId { [NotNull] get; }
-
         public IServiceMessage UpdateServiceMessage(IServiceMessage message)
         {
-            return message.DefaultValue != null || message.GetValue("flowId") != null ? message : new PatchedServiceMessage(message) { { "flowId", FlowId } };
+            return message.DefaultValue != null || message.GetValue("flowId") != null ? message : new PatchedServiceMessage(message) { { "flowId", _flowId } };
         }
     }
-}
\ No newline at end of file
+}
diff --git a/TeamCity.ServiceMessages/Write/Special/Impl/Writer/TeamCityFlowWriter.cs b/TeamCity.ServiceMessages/Write/Special/Impl/Writer/TeamCityFlowWriter.cs
index 216f68b..f5d6240 100644
--- a/TeamCity.ServiceMessages/Write/Special/Impl/Writer/TeamCityFlowWriter.cs
+++ b/TeamCity.ServiceMessages/Write/Special/Impl/Writer/TeamCityFlowWriter.cs
@@ -19,20 +19,20 @@ namespace JetBrains.TeamCity.ServiceMessages.Write.Special.Impl.Writer
     using System;
     using System.Threading;
 
-    public class TeamCityFlowWriter<TCloseBlock> : BaseDisposableWriter<IFlowServiceMessageProcessor>, ITeamCityFlowWriter<TCloseBlock>, ISubWriter
+    public class TeamCityFlowWriter<TCloseBlock> : BaseDisposableWriter<IFlowAwareServiceMessageProcessor>, ITeamCityFlowWriter<TCloseBlock>, ISubWriter
         where TCloseBlock : IDisposable
     {
-        public delegate TCloseBlock CreateWriter([NotNull] IDisposable disposeHandler, [NotNull] IFlowServiceMessageProcessor writer);
+        public delegate TCloseBlock CreateWriter([NotNull] IDisposable disposeHandler, [NotNull] IFlowAwareServiceMessageProcessor writer);
 
         private readonly CreateWriter _closeBlock;
-        private int _isChildFlowOpenned;
+        private int _isChildFlowOpened;
 
-        public TeamCityFlowWriter([NotNull] IFlowServiceMessageProcessor target, [NotNull] CreateWriter closeBlock, [NotNull] IDisposable disposableHander)
-            : base(target, disposableHander)
+        public TeamCityFlowWriter([NotNull] IFlowAwareServiceMessageProcessor target, [NotNull] CreateWriter closeBlock, [NotNull] IDisposable disposableHandler)
+            : base(target, disposableHandler)
         {
             if (target == null) throw new ArgumentNullException(nameof(target));
             if (closeBlock == null) throw new ArgumentNullException(nameof(closeBlock));
-            if (disposableHander == null) throw new ArgumentNullException(nameof(disposableHander));
+            if (disposableHandler == null) throw new ArgumentNullException(nameof(disposableHandler));
             _closeBlock = closeBlock;
         }
 
@@ -52,23 +52,29 @@ public TCloseBlock OpenFlow()
             );
 
             //##teamcity[flowStarted flowId='%lt;new flow id>' parent='current flow id']
-            processor.AddServiceMessage(new ServiceMessage("flowStarted") {{"parent", myTarget.FlowId}});
-            Interlocked.Increment(ref _isChildFlowOpenned);
+            var flowStartedMessage = new ServiceMessage("flowStarted");
+            if (myTarget.FlowId != null)
+            {
+                flowStartedMessage.Add("parent", myTarget.FlowId);
+            }
+            processor.AddServiceMessage(flowStartedMessage);
+
+            Interlocked.Increment(ref _isChildFlowOpened);
             return block;
         }
 
         protected override void DisposeImpl()
         {
-            if (_isChildFlowOpenned != 0)
+            if (_isChildFlowOpened != 0)
                 throw new InvalidOperationException("Some of child block writers were not disposed");
         }
 
-        private void CloseBlock([NotNull] IFlowServiceMessageProcessor flowId)
+        private void CloseBlock([NotNull] IFlowAwareServiceMessageProcessor flowAwareServiceMessageProcessor)
         {
-            if (flowId == null) throw new ArgumentNullException(nameof(flowId));
-            Interlocked.Decrement(ref _isChildFlowOpenned);
+            if (flowAwareServiceMessageProcessor == null) throw new ArgumentNullException(nameof(flowAwareServiceMessageProcessor));
+            Interlocked.Decrement(ref _isChildFlowOpened);
             //##teamcity[flowFinished flowId='%lt;new flow id>']
-            flowId.AddServiceMessage(new ServiceMessage("flowFinished"));
+            flowAwareServiceMessageProcessor.AddServiceMessage(new ServiceMessage("flowFinished"));
         }
     }
-}
\ No newline at end of file
+}
diff --git a/TeamCity.ServiceMessages/Write/Special/Impl/Writer/TeamCityTestSuiteBlock.cs b/TeamCity.ServiceMessages/Write/Special/Impl/Writer/TeamCityTestSuiteBlock.cs
index 1ad8501..3b9b487 100644
--- a/TeamCity.ServiceMessages/Write/Special/Impl/Writer/TeamCityTestSuiteBlock.cs
+++ b/TeamCity.ServiceMessages/Write/Special/Impl/Writer/TeamCityTestSuiteBlock.cs
@@ -18,13 +18,13 @@ namespace JetBrains.TeamCity.ServiceMessages.Write.Special.Impl.Writer
 {
     using System;
 
-    public class TeamCityTestSuiteBlock : BaseDisposableWriter<IFlowServiceMessageProcessor>, ITeamCityTestsSubWriter, ISubWriter
+    public class TeamCityTestSuiteBlock : BaseDisposableWriter<IFlowAwareServiceMessageProcessor>, ITeamCityTestsSubWriter, ISubWriter
     {
         private readonly TeamCityFlowWriter<ITeamCityTestsSubWriter> _flows;
         private int _isChildSuiteOpened;
         private int _isChildTestOpened;
 
-        public TeamCityTestSuiteBlock([NotNull] IFlowServiceMessageProcessor target, [NotNull] IDisposable disposableHandler)
+        public TeamCityTestSuiteBlock([NotNull] IFlowAwareServiceMessageProcessor target, [NotNull] IDisposable disposableHandler)
             : base(target, disposableHandler)
         {
             if (target == null) throw new ArgumentNullException(nameof(target));
diff --git a/TeamCity.ServiceMessages/Write/Special/TeamCityServiceMessages.cs b/TeamCity.ServiceMessages/Write/Special/TeamCityServiceMessages.cs
index bbc8464..29defbf 100644
--- a/TeamCity.ServiceMessages/Write/Special/TeamCityServiceMessages.cs
+++ b/TeamCity.ServiceMessages/Write/Special/TeamCityServiceMessages.cs
@@ -65,19 +65,23 @@ public void AddServiceMessageUpdater(IServiceMessageUpdater updater)
             Updaters = Updaters.Union(new[] {updater}).ToArray();
         }
 
-        public ITeamCityWriter CreateWriter()
-        {
-            return CreateWriter(Console.WriteLine);
-        }
+        public ITeamCityWriter CreateWriter() => CreateWriter(Console.WriteLine, true);
 
-        public ITeamCityWriter CreateWriter(Action<string> destination)
+        public ITeamCityWriter CreateWriter(Action<string> destination, bool addFlowIdsOnTopLevelMessages = true)
         {
             if (destination == null) throw new ArgumentNullException(nameof(destination));
-            var processor = new FlowServiceMessageWriter(new ServiceMessagesWriter(Formatter, destination), FlowIdGenerator, Updaters.ToList());
+
+            var rootServiceMessageFlowId = addFlowIdsOnTopLevelMessages ? FlowIdGenerator.NewFlowId() : null;
+            var processor = new FlowAwareServiceMessageWriter(
+                rootServiceMessageFlowId,
+                new ServiceMessagesWriter(Formatter, destination),
+                FlowIdGenerator,
+                Updaters.ToList());
+
             return new TeamCityWriterImpl(
                 processor,
                 DisposableDelegate.Empty
             );
         }
     }
-}
\ No newline at end of file
+}
diff --git a/build.proj b/build.proj
index 09a0962..3792c93 100644
--- a/build.proj
+++ b/build.proj
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="15.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
     <PropertyGroup>
-        <Version Condition=" '$(Version)' == '' ">3.0.0-dev</Version>
+        <Version Condition=" '$(Version)' == '' ">4.0.0-dev</Version>
         <Configuration Condition=" '$(Configuration)' == '' ">Release</Configuration>
         <PackagesDirectory>packages</PackagesDirectory>
     </PropertyGroup>