Added support for running C# code in a dotnet core environment

environments/dotnet/README.md

@@ -0,0 +1,158 @@
+# Fission: dotnet C# Environment
+
+This is a simple dotnet C# environment for Fission.
+
+It's a Docker image containing the dotnet 1.1.0 runtime. The image 
+uses Kestrel with Nancy to host the internal web server and uses 
+Roslyn to compile the uploaded code.
+
+The image supports compiling and running code with types defined in
+mscorlib and does not at present support other library references.
+One workaround for this would be to add the references to this project's
+project.json file and rebuild the container.
+
+The environment works via convention where you create a C# class
+called Fission which has a static method named Run taking a single
+parameter, a dictionary containing any querystring parameters.
+
+Example of simplest possible class to be executed:
+
+```
+using System;
+using System.Collections.Generic;
+
+public class Fission {
+	public static string Run(Dictionary<string, object> args) {
+		return null;
+	}
+}
+```
+
+Please see examples below.
+
+## Rebuilding and pushing the image
+
+To rebuild the image you need either a computer with dotnet 1.1.0
+installed or else you will have to map the source directory into a
+container containing the dotnet 1.1.0 environment.
+
+### Locally installed Dotnet 1.1.0
+
+Simply move to the source directory in a terminal and run the ./build.sh script.
+
+The script will restore dependencies, compile a release build and
+and build the container. If you need to change the name of the container
+simply change it in the script.
+
+After the build finishes push the new image to a Docker registry using the 
+standard procedure.
+
+### Build in a container
+
+Move to the directory containing the source and start the Docker container
+with dotnet and mount the current directory to a build location:
+
+```
+docker run -it --rm -v $PWD:/build microsoft/dotnet
+```
+
+Move to the build directory inside the container and restore the packages:
+
+```
+cd /build 
+dotnet restore
+log  : Restoring packages for /source/project.json...
+log  : Installing System.Net.WebSockets 4.0.0.
+log  : Installing runtime.native.System.IO.Compression 4.1.0.
+...
+```
+
+Compile and publish a release build of the source to the 'out' folder:
+
+```
+dotnet publish -c Release -o out
+Publishing source for .NETCoreApp,Version
+...
+```
+Exit the build container and build the Docker container on the local host:
+
+```
+exit
+docker build -t USER/dotnet-env .
+``` 
+After the build finishes push the new image to a Docker registry using the 
+standard procedure.
+
+## Echo example
+
+### Setup fission environment
+First you need to setup the fission according to your cluster setup as 
+specified here: https://github.com/fission/fission
+
+
+### Create the class to run
+
+Secondly you need to create a file /tmp/func.cs containing the following code:
+
+```
+using System;
+using System.Collections.Generic;
+
+public class Fission {
+	public static string Run(Dictionary<string, object> args) {
+		return (string)args["text"];
+	}
+}
+``` 
+### Run the example
+
+Lastly to run the example:
+
+```
+$ fission env create --name dotnet --image fission/dotnet-env
+
+$ fission function create --name echo --env dotnet --code /tmp/func.cs
+
+$ fission route create --method GET --url /echo --function echo
+
+$ curl http://$FISSION_ROUTER/echo?text=hello%20world!
+  hello world
+```
+
+## Addition service example
+
+### Setup fission environment
+First you need to setup the fission according to your cluster setup as 
+specified here: https://github.com/fission/fission
+
+
+### Create the class to run
+
+Secondly you need to create a file /tmp/func.cs containing the following code:
+
+```
+using System;
+using System.Collections.Generic;
+
+public class Fission {
+	public static string Run(Dictionary<string, object> args) {
+        var x = Convert.ToInt32(args["x"]);
+        var y = Convert.ToInt32(args["y"]);
+        return (x+y).ToString();
+	}
+}
+``` 
+### Run the example
+
+Lastly to run the example:
+
+```
+$ fission env create --name dotnet --image fission/dotnet-env
+
+$ fission function create --name addition --env dotnet --code /tmp/func.cs
+
+$ fission route create --method GET --url /add --function addition
+
+$ curl "http://$FISSION_ROUTER/add?x=30&y=12"
+  42
+```