Use machine mono install (#24766)

build/scripts/docker/Dockerfile

@@ -30,6 +30,14 @@ RUN apt-get install -y  libunwind8 \
             libcurl4-openssl-dev && \
     apt-get clean
 
+# Install Mono
+RUN apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF && \
+    (echo "deb http://download.mono-project.com/repo/ubuntu stable-xenial main" | \
+    tee /etc/apt/sources.list.d/mono-official.list) && \
+    apt-get update && \
+    apt-get install -y mono-devel=5.8.0.108-0xamarin1+ubuntu1604b1 && \
+    apt-get clean
+
 # Setup User to match Host User, and give superuser permissions
 ARG USER_ID=0
 RUN useradd -m code_executor -u ${USER_ID} -g sudo

build/scripts/obtain_mono.sh

-#!/usr/bin/env bash
-# Copyright (c) .NET Foundation and contributors. All rights reserved.
-# Licensed under the MIT license. See LICENSE file in the project root for full license information.
-
-# Source this script to ensure mono is installed and on the path.
-
-# This is a function to keep variable assignments out of the parent script (that is sourcing this file)
-install_mono () {
-    # Download and install `mono` locally
-    local THIS_DIR="$(cd -P "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-    source "${THIS_DIR}"/build-utils.sh
-
-    local MONO_VERSION="$(get_tool_version mono)"
-    # the tar file has `mono` as the root directory
-    local MONO_PATH="${THIS_DIR}"/../../Binaries/Tools
-
-    if [[ ! -x "${MONO_PATH}/mono/bin/mono" ]]
-    then
-        echo "Downloading mono ${MONO_VERSION}"
-        mkdir -p "${MONO_PATH}"
-        curl -L https://roslyninfra.blob.core.windows.net/jenkins/mono/mono-${MONO_VERSION}.tar.gz | tar xz -C "${MONO_PATH}"
-    fi
-
-    export PATH="${MONO_PATH}/mono/bin:${PATH}"
-}
-install_mono

build/scripts/tests.sh

@@ -22,7 +22,6 @@ if [[ "${runtime}" == "dotnet" ]]; then
     target_framework=netcoreapp2.0
     xunit_console="${nuget_dir}"/xunit.runner.console/"${xunit_console_version}"/tools/${target_framework}/xunit.console.dll
 elif [[ "${runtime}" == "mono" ]]; then
-    source ${root_path}/build/scripts/obtain_mono.sh
     target_framework=net461
     xunit_console="${nuget_dir}"/xunit.runner.console/"${xunit_console_version}"/tools/net452/xunit.console.exe
 else
@@ -64,7 +63,7 @@ do
         continue
     fi
 
-    echo Running "${file_name[@]}"
+    echo Running "${runtime} ${file_name[@]}"
     if [[ "${runtime}" == "dotnet" ]]; then
         runner="dotnet exec --depsfile ${deps_json} --runtimeconfig ${runtimeconfig_json}"
     elif [[ "${runtime}" == "mono" ]]; then