Add Lambda-Runtime-Deadline-Ms response header (#1998)

Author: normj

.autover/changes/cec1c49e-0a82-4cb0-bc2e-76d702ea3209.json

@@ -0,0 +1,11 @@
+{
+  "Projects": [
+    {
+      "Name": "Amazon.Lambda.TestTool",
+      "Type": "Patch",
+      "ChangelogMessages": [
+        "Add Lambda-Runtime-Deadline-Ms response header"
+      ]
+    }
+  ]
+}

Tools/LambdaTestTool-v2/src/Amazon.Lambda.TestTool/Services/LambdaRuntimeAPI.cs

@@ -145,6 +145,9 @@ public async Task GetNextInvocation(HttpContext ctx, string functionName)
         Console.WriteLine(HeaderBreak);
         Console.WriteLine($"Next invocation returned: {activeEvent.AwsRequestId}");
 
+        // Set the deadline to the Lambda max length of 15 minutes. Formatted as Epoch MS.
+        long deadline = ((long)(DateTime.UtcNow.AddMinutes(15) - new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)).TotalMilliseconds);
+        ctx.Response.Headers["Lambda-Runtime-Deadline-Ms"] = deadline.ToString();
 
         ctx.Response.Headers["Lambda-Runtime-Aws-Request-Id"] = activeEvent.AwsRequestId;
         ctx.Response.Headers["Lambda-Runtime-Trace-Id"] = Guid.NewGuid().ToString();