#!/bin/sh
set -e

function write_config() {
    # Checks for the environment variables *_PROXY.
    # If at least one variables is found, it writes all found variables
    # into a docker config file
    docker_cfg="$1"
    httpProxy="${HTTP_PROXY:-$http_proxy}"
    httpsProxy="${HTTPS_PROXY:-$https_proxy}"
    noProxy="${NO_PROXY:-$no_proxy}"
    # If no proxy vars are set, do nothing
    [ -z "$httpProxy" ] && [ -z "$httpsProxy" ] && [ -z "$noProxy" ] && return
    [ -f "$1" ] && echo "$1 already exists. Not touching it. You are responsible for setting your proxy vars there yourself" >&2 && return
    sep=""
    mkdir -p "$(dirname $docker_cfg)"
    cat <<EOF > "$docker_cfg"
{
"proxies": {
  "default": {
EOF
    [ -n "$httpProxy" ] && echo -ne "$sep"'    "httpProxy": "'"$httpProxy"'"' >> "$docker_cfg" && sep=",\n"
    [ -n "$httpsProxy" ] && echo -ne "$sep"'    "httpsProxy": "'"$httpsProxy"'"' >> "$docker_cfg" && sep=",\n"
    [ -n "$noProxy" ] && echo -ne "$sep"'    "noProxy": "'"$noProxy"'"' >> "$docker_cfg" && sep=",\n"
    cat <<EOF >> "$docker_cfg"

  }
}
}
EOF
}

write_config /root/.docker/config.json

exec "$@"