From 737e29378f2a8596f6ceec1f378beea2a7b0ba0b Mon Sep 17 00:00:00 2001
From: Christopher Costa <chcosta@microsoft.com>
Date: Thu, 11 Apr 2019 11:46:10 -0700
Subject: [PATCH] proposal

---
 Documentation/SharedFrameworks.md | 87 +++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 Documentation/SharedFrameworks.md

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+# Multiple Shared Framework Installations in Arcade
+
+## Proposal
+
+- define frameworks in global.json
+- no generated props file or use of a `DotNetCoreRuntimeVersions` item group
+- if runtimes section is present, assume we can't fulfill the specs globally and force use of `.dotnet` folder
+
+Notes: This will require updating darc to support the format change - https://github.com/dotnet/arcade-services/commit/9a486718cdb33c82f9bb24cf25d1207e364f71c7
+
+## Scenario 1 - Fixed set of shared frameworks for testing
+
+global.json
+
+```json
+{
+  "tools": {
+    "dotnet": {
+      "sdk": "2.2.202",
+      "runtimes": {
+        "dotnet": [ "2.1.1" ],
+        "aspnetcore": [ "2.2.3" ]
+      }
+    }
+  },
+  "msbuild-sdks": {
+    "Microsoft.DotNet.Arcade.Sdk": "1.0.0-beta.19207.1",
+    "Microsoft.DotNet.Helix.Sdk": "2.0.0-beta.19207.1"
+  }
+}
+```
+
+Define frameworks (runtimes) in global.json.
+
+Applies to:
+
+- repos with a fixed set of shared frameworks used for testing
+
+Behavior:
+
+- SDK is installed locally (into `.dotnet` folder)
+- Frameworks are installed locally (into `.dotnet` folder)
+- We print a message during install indicating that location of the installed sdk / frameworks
+
+## Scenario 2 - Dependency flow defined versions of shared frameworks for testing
+
+global.json
+
+```json
+{
+  "tools": {
+    "dotnet": {
+      "sdk": "2.2.202",
+      "runtimes": {
+        "dotnet": [ "2.1.1", "MicrosoftNetCoreAppVersion" ],
+        "aspnetcore": [ "2.2.3", "MicrosoftAspNetCoreAppVersion" ]
+      }
+  },
+  "msbuild-sdks": {
+    "Microsoft.DotNet.Arcade.Sdk": "1.0.0-beta.19207.1",
+    "Microsoft.DotNet.Helix.Sdk": "2.0.0-beta.19207.1"
+  }
+}
+```
+
+eng/Versions.props
+
+```XML
+<Project>
+  <PropertyGroup>
+    <MicrosoftNetCoreAppVersion>3.0.0-preview4-19207.1</MicrosoftNetCoreAppVersion>
+    <MicrosoftAspNetCoreAppVersion>3.0.0-preview4-19207.1</MicrosoftAspNetCoreAppVersion>
+     ...
+  </PropertyGroup>
+</Project>
+```
+
+Applies to:
+
+- repos which rely on dependency flow for defining framework versions
+
+Behavior:
+
+- SDK is installed locally (into `.dotnet` folder)
+- Frameworks are installed locally (into `.dotnet` folder)
+- For non-explicit framework versions, we read in eng/Version.props and translate identified property group values into versions
+- We print a message during install indicating that location of the installed sdk / frameworks