From 4b200a22d9327484fb71d9af9c38d9c6f13eff70 Mon Sep 17 00:00:00 2001
From: Ruben Bartelink <ruben@bartelink.com>
Date: Tue, 31 May 2022 12:49:08 +0100
Subject: [PATCH] Use net6.0 Lambda hosting

---
 src/Propulsion.DynamoStore.Lambda/Function.fs | 31 ++++++++++++++++---
 .../Propulsion.DynamoStore.Lambda.fsproj      |  4 ++-
 .../aws-lambda-tools-defaults.json            |  2 +-
 3 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/src/Propulsion.DynamoStore.Lambda/Function.fs b/src/Propulsion.DynamoStore.Lambda/Function.fs
index 5f9373b9..0d5e7bce 100644
--- a/src/Propulsion.DynamoStore.Lambda/Function.fs
+++ b/src/Propulsion.DynamoStore.Lambda/Function.fs
@@ -1,7 +1,7 @@
-namespace Propulsion.DynamoStore.Lambda
+module Propulsion.DynamoStore.Lambda.Program
 
-open Amazon.Lambda.Core
 open Amazon.Lambda.DynamoDBEvents
+open Amazon.Lambda.RuntimeSupport
 open Equinox.DynamoStore
 open Propulsion.DynamoStore
 open Serilog
@@ -67,5 +67,28 @@ type Function() =
             .CreateLogger()
     let service = DynamoStoreIndexer(log, conn.Context, cache, epochBytesCutoff = epochCutoffMiB * 1024 * 1024) //
 
-    member _.FunctionHandler(dynamoEvent : DynamoDBEvent, _context : ILambdaContext) =
-        DynamoStreamsLambda.ingest log service dynamoEvent |> Async.StartImmediateAsTask
+    // Warm up (pending https://github.com/aws/aws-lambda-dotnet/pull/1091)
+    member _.InitAsync() =
+        service.IngestWithoutConcurrency(AppendsTrancheId.wellKnownId, Array.empty)
+
+    member _.Handle(dynamoEvent : DynamoDBEvent) =
+        DynamoStreamsLambda.ingest log service dynamoEvent
+
+let adaptInit f () =
+    async {
+        do! f ()
+        return true
+    } |> Async.StartImmediateAsTask
+let adaptHandler h x =
+    h x
+    |> Async.StartImmediateAsTask
+    :> System.Threading.Tasks.Task
+
+[<EntryPoint>]
+let main _ =
+    let f = Function()
+    let serializer = Amazon.Lambda.Serialization.SystemTextJson.DefaultLambdaJsonSerializer()
+    let t = LambdaBootstrapBuilder.Create<_>(adaptHandler f.Handle, serializer)
+                .UseBootstrapHandler(adaptInit f.InitAsync)
+                .Build().RunAsync().GetAwaiter()
+    let () = t.GetResult() in 0
diff --git a/src/Propulsion.DynamoStore.Lambda/Propulsion.DynamoStore.Lambda.fsproj b/src/Propulsion.DynamoStore.Lambda/Propulsion.DynamoStore.Lambda.fsproj
index 433410ca..9241f519 100644
--- a/src/Propulsion.DynamoStore.Lambda/Propulsion.DynamoStore.Lambda.fsproj
+++ b/src/Propulsion.DynamoStore.Lambda/Propulsion.DynamoStore.Lambda.fsproj
@@ -23,8 +23,10 @@
       <PackageReference Include="MinVer" Version="4.0.0" PrivateAssets="All" />
         
       <PackageReference Include="Amazon.Lambda.Core" Version="2.1.0" />
-      <PackageReference Include="Amazon.Lambda.DynamoDBEvents" Version="2.1.0" />
+      <PackageReference Include="Amazon.Lambda.DynamoDBEvents" Version="2.1.1" />
+      <PackageReference Include="Amazon.Lambda.RuntimeSupport" Version="1.8.1" />
       <PackageReference Include="Amazon.Lambda.Serialization.SystemTextJson" Version="2.3.0" />
+      <PackageReference Include="Serilog.Formatting.Compact" Version="1.1.0" />
       <PackageReference Include="Serilog.Sinks.Console" Version="4.0.1" />
       <ProjectReference Include="..\Propulsion.DynamoStore\Propulsion.DynamoStore.fsproj" />
     </ItemGroup>
diff --git a/src/Propulsion.DynamoStore.Lambda/aws-lambda-tools-defaults.json b/src/Propulsion.DynamoStore.Lambda/aws-lambda-tools-defaults.json
index 21daed22..0448e7a2 100644
--- a/src/Propulsion.DynamoStore.Lambda/aws-lambda-tools-defaults.json
+++ b/src/Propulsion.DynamoStore.Lambda/aws-lambda-tools-defaults.json
@@ -12,5 +12,5 @@
   "function-memory-size": 128,
   "function-timeout": 180,
   "function-architecture": "arm64",
-  "function-handler": "Propulsion.DynamoStore.Lambda::Propulsion.DynamoStore.Lambda.Function::FunctionHandler"
+  "function-handler": "Propulsion.DynamoStore.Lambda"
 }