Create docker configuration file with authentication info

create-docker-config.sh

#!/bin/bash
set -euo pipefail

if [[ "$DOCKER_USER" = "" ]]; then
    echo "Please set \$DOCKER_USER"
    exit 1
fi
if [[ "$DOCKER_PASSWORD" = "" ]]; then
    echo "Please set \$DOCKER_PASSWORD"
    exit 1
fi

if [[ -z "$CONFIG_PATH" ]]; then
    if [[ "$HOME" = "" ]]; then
        echo "Please set \$HOME"
        exit 1
    fi
    mkdir -p $HOME/.docker
    CONFIG_PATH="$HOME/.docker/config.json"
    if [[ -f "$CONFIG_PATH" ]]; then
        mv "$CONFIG_PATH" "$CONFIG_PATH.$(date +%s)"
    fi
fi

AUTH="$(echo -n $DOCKER_USER:$DOCKER_PASSWORD | base64)"
echo -en "{
    \"auths\": {
        \"https://index.docker.io/v1/\": {
            \"auth\": \"$AUTH\"
        }
    }
}" > "$CONFIG_PATH"