Correct and tune equinox-sync template progress management

CHANGELOG.md

@@ -14,11 +14,12 @@ The `Unreleased` section name is replaced by the expected version of next releas
 - `dotnet new eqxetl` is now `dotnet new eqxsync`
 - `dotnet new eqxsync` now supports command-line category white/blacklist [#18](https://github.com/jet/dotnet-templates/pull/18)
 - `dotnet new eqxsync` now supports command-line selection of an `aux` collection in either the `source` or destination collections [#18](https://github.com/jet/dotnet-templates/pull/18)
+- `dotnet new eqxsync` has separated processing for progress computation, progress writing and batch loading (this also happens to be the only way in which to balance throughput with correctness in the context of a ChangeFeedProcessor) [#19](https://github.com/jet/dotnet-templates/pull/19)
 - Targets `Equinox`.* v `2.0.0-preview5`
 - `dotnet new eqxprojector` now uses `Jet.ConfluentKafka.FSharp 1.0.0-rc2` (which uses `Confluent.Kafka 1.0.0-RC3`, `librdkafka 1.0.0`)
 
 ### Removed
-### Fixed555
+### Fixed
 
 <a name="2.0.0"></a>
 ## [2.0.0] - 2019-03-26

equinox-sync/Sync.Tests/Tests.fs → equinox-sync/Sync.Tests/CosmosIngesterTests.fs

@@ -1,6 +1,6 @@
-module SyncTemplate.Tests.IngesterTests
+module SyncTemplate.Tests.CosmosIngesterTests
 
-open SyncTemplate.Program.Ingester
+open SyncTemplate.Program.CosmosIngester
 open Swensen.Unquote
 open Xunit
 

equinox-sync/Sync.Tests/ProgressTests.fs

@@ -0,0 +1,38 @@
+module ProgressTests
+
+open SyncTemplate.Program
+
+open Swensen.Unquote
+open Xunit
+
+let [<Fact>] ``Empty has zero streams pending or progress to write`` () =
+    let sut = Progress.State<_>()
+    let validatedPos, batches = sut.Validate(fun _ -> None)
+    None =! validatedPos
+    0 =! batches
+
+let [<Fact>] ``Can add multiple batches`` () =
+    let sut = Progress.State<_>()
+    sut.AppendBatch(0,["a",1L; "b",2L])
+    sut.AppendBatch(1,["b",2L; "c",3L])
+    let validatedPos, batches = sut.Validate(fun _ -> None)
+    None =! validatedPos
+    2 =! batches
+
+let [<Fact>] ``Marking Progress Removes batches and updates progress`` () =
+    let sut = Progress.State<_>()
+    sut.AppendBatch(0,["a",1L; "b",2L])
+    sut.MarkStreamProgress("a",1L)
+    sut.MarkStreamProgress("b",1L)
+    let validatedPos, batches = sut.Validate(fun _ -> None)
+    None =! validatedPos
+    1 =! batches
+
+let [<Fact>] ``Marking progress is not persistent`` () =
+    let sut = Progress.State<_>()
+    sut.AppendBatch(0,["a",1L])
+    sut.MarkStreamProgress("a",2L)
+    sut.AppendBatch(1,["a",1L; "b",2L])
+    let validatedPos, batches = sut.Validate(fun _ -> None)
+    Some 0 =! validatedPos
+    1 =! batches

equinox-sync/Sync.Tests/Sync.Tests.fsproj

@@ -7,7 +7,8 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <Compile Include="Tests.fs" />
+    <Compile Include="CosmosIngesterTests.fs" />
+    <Compile Include="ProgressTests.fs" />
   </ItemGroup>
 
   <ItemGroup>

equinox-sync/Sync/Infrastructure.fs

@@ -18,6 +18,17 @@ type Async with
             and d : IDisposable = Console.CancelKeyPress.Subscribe callback
             in ())
 
+module Queue =
+    let tryDequeue (x : System.Collections.Generic.Queue<'T>) =
+#if NET461
+        if x.Count = 0 then None
+        else x.Dequeue() |> Some
+#else
+        match x.TryDequeue() with
+        | false, _ -> None
+        | true, res -> Some res
+#endif
+
 open Equinox.Store // AwaitTaskCorrect
 
 type SemaphoreSlim with

equinox-sync/Sync/Sync.fsproj

@@ -17,6 +17,7 @@
     <PackageReference Include="Equinox.Cosmos.Projection" Version="2.0.0-preview5" />
     <PackageReference Include="Microsoft.Azure.DocumentDB.ChangeFeedProcessor" Version="2.2.6" />
     <PackageReference Include="Serilog.Sinks.Console" Version="3.1.1" />
+    <PackageReference Include="Serilog.Sinks.Seq" Version="4.0.0" />
   </ItemGroup>
 
 </Project>