Generate deps for hosting startup in external dependencies

Use publish deps file instead of build deps file

build/RuntimeStore.targets

@@ -176,7 +176,7 @@
 
     <!--- MSBuild caches things if you run inproc so have to use Exec -->
     <MSBuild Projects="$(HostingStartupWorkDir)HostingStartup.csproj"
-             Targets="Build;CollectDeps"
+             Targets="Publish;CollectDeps"
              Properties="$(_HostingStartupProps)" />
   </Target>
 
@@ -185,7 +185,8 @@
     <!-- Generate RS.Reference project -->
     <RepoTasks.ResolveHostingStartupPackages
       BuildArtifacts="@(ArtifactInfo)"
-      PackageArtifacts="@(PackageArtifact)">
+      PackageArtifacts="@(PackageArtifact)"
+      ExternalDependencies="@(ExternalDependency)">
       <Output TaskParameter="HostingStartupArtifacts" ItemName="HostingStartupArtifacts" />
     </RepoTasks.ResolveHostingStartupPackages>
 

build/tasks/ResolveHostingStartupPackages.cs

@@ -15,6 +15,9 @@ namespace RepoTasks
         [Required]
         public ITaskItem[] PackageArtifacts { get; set; }
 
+        [Required]
+        public ITaskItem[] ExternalDependencies { get; set; }
+
         [Output]
         public ITaskItem[] HostingStartupArtifacts { get; set; }
 
@@ -22,7 +25,18 @@ namespace RepoTasks
         {
             // Parse input
             var hostingStartupArtifacts = PackageArtifacts.Where(p => p.GetMetadata("HostingStartup") == "true");
-            HostingStartupArtifacts = BuildArtifacts.Where(p => hostingStartupArtifacts.Any(h => h.GetMetadata("Identity") == p.GetMetadata("PackageId"))).ToArray();
+            var externalHostingStartupArtifacts = ExternalDependencies.Where(p => p.GetMetadata("HostingStartup") == "true");
+
+            var hostingStartups = BuildArtifacts.Where(p => hostingStartupArtifacts.Any(h => h.GetMetadata("Identity") == p.GetMetadata("PackageId")));
+
+            foreach (var externalHostingStartup in externalHostingStartupArtifacts)
+            {
+                // The parameters PackageId and Version are required for output. For external dependencies, the identity is the pacakge id.
+                externalHostingStartup.SetMetadata("PackageId", externalHostingStartup.GetMetadata("Identity"));
+                hostingStartups = hostingStartups.Append(externalHostingStartup);
+            }
+
+            HostingStartupArtifacts = hostingStartups.ToArray();
 
             return true;
         }

build/tools/templates/HostingStartup/HostingStartup.csproj

@@ -26,6 +26,6 @@
       <DestinationDepsFile>$(DepsOutputPath)\$(HostingStartupPackageName)\shared\Microsoft.NETCore.App\$(DepsRuntimeFrameworkVersion)\$(HostingStartupPackageName).deps.json</DestinationDepsFile>
     </PropertyGroup>
 
-    <Copy SourceFiles="$(ProjectDepsFilePath)" DestinationFiles="$(DestinationDepsFile)" />
+    <Copy SourceFiles="$(PublishDepsFilePath)" DestinationFiles="$(DestinationDepsFile)" />
   </Target>
 </Project>