run.sh

#!/usr/bin/env bash

#
# Copyright 2020 Brian Shaw
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

#
# Run dotnet in a container
#
# This script will attempt to mirror the host paths by using volumes for the
# following paths:
#   * $(pwd)
#   * $HOME if it's set
#

set -e

VERSION="3.1"
IMAGE="mcr.microsoft.com/dotnet/core/sdk:$VERSION"

# Setup options for connecting to docker host
if [ -z "$DOCKER_HOST" ]; then
    DOCKER_HOST="/var/run/docker.sock"
fi

if [ -S "$DOCKER_HOST" ]; then
    DOCKER_ADDR="-v $DOCKER_HOST:$DOCKER_HOST -e DOCKER_HOST"
else
    DOCKER_ADDR="-e DOCKER_HOST -e DOCKER_TLS_VERIFY -e DOCKER_CERT_PATH"
fi

# Setup volume mounts
if [ "$(pwd)" != '/' ]; then
    VOLUMES="-v $(pwd):$(pwd)"
fi

if [ -n "$HOME" ]; then
    VOLUMES="$VOLUMES -v $HOME:$HOME -e HOME" # Pass in HOME to allow ~/-relative paths to work.
fi

# Only allocate tty if we detect one
if [ -t 0 ] && [ -t 1 ]; then
    DOCKER_RUN_OPTIONS="$DOCKER_RUN_OPTIONS -t"
fi

# Always set -i to support piped and terminal input in run/exec
DOCKER_RUN_OPTIONS="$DOCKER_RUN_OPTIONS -i"

# Handle userns security
if docker info --format '{{json .SecurityOptions}}' 2>/dev/null | grep -q 'name=userns'; then
    DOCKER_RUN_OPTIONS="$DOCKER_RUN_OPTIONS --userns=host"
fi

# Run as the current user on Linux (the docker daemon runs as root)
if [ "$(uname -s)" = 'Linux' ]; then
    DOCKER_RUN_OPTIONS="$DOCKER_RUN_OPTIONS -u $(id -u ${USER}):$(id -g ${USER})"
fi

# shellcheck disable=SC2086
exec docker run --rm $DOCKER_RUN_OPTIONS $DOCKER_ADDR $VOLUMES -w "$(pwd)" $IMAGE dotnet "$@"