entrypoint.sh

#!/bin/bash

set -euo pipefail

# Validate environment variables

MISSING=""

[ -z "${DOMAIN}" ] && MISSING="${MISSING} DOMAIN"
[ -z "${UPSTREAM}" ] && MISSING="${MISSING} UPSTREAM"
[ -z "${EMAIL}" ] && MISSING="${MISSING} EMAIL"


if [ "${MISSING}" != "" ]; then
  echo "Missing required environment variables:" >&2
  echo " ${MISSING}" >&2
  exit 1
  fi

#Processing DOMAIN into an array
DOMAINSARRAY=($(echo "${DOMAIN}" | awk -F ";" '{for(i=1;i<=NF;i++) print $i;}'))
echo "Provided domains"
printf "%s\n" "${DOMAINSARRAY[@]}"

#Processing UPSTREAM into an array
UPSTREAMARRAY=($(echo "${UPSTREAM}" | awk -F ";" '{for(i=1;i<=NF;i++) print $i;}'))
echo "Services to reverse-proxy"
printf "%s\n" "${UPSTREAMARRAY[@]}"

#The two arrays should have the same lenght
if [ "${#DOMAINSARRAY[@]}" != "${#UPSTREAMARRAY[@]}" ]; then
  echo "The number of domains must match the number of upstream services"
fi

# Default other parameters
STAGING=${STAGING:-0}
if [ "$STAGING" = "1" ] ; then
    SERVER="--server https://acme-staging.api.letsencrypt.org/directory"
else
    SERVER=""
fi


# Generate strong DH parameters for nginx, if they don't already exist.
if [ ! -f /etc/ssl/dhparams.pem ]; then
  if [ -f /cache/dhparams.pem ]; then
    cp /cache/dhparams.pem /etc/ssl/dhparams.pem
  else
    openssl dhparam -out /etc/ssl/dhparams.pem 2048
    # Cache to a volume for next time?
    if [ -d /cache ]; then
      cp /etc/ssl/dhparams.pem /cache/dhparams.pem
    fi
  fi
fi

#create temp file storage
mkdir -p /var/cache/nginx
chown nginx:nginx /var/cache/nginx

mkdir -p /var/tmp/nginx
chown nginx:nginx /var/tmp/nginx

#create vhost directory
mkdir -p /etc/nginx/vhosts/

# Process the nginx.conf with raw values of $DOMAIN and $UPSTREAM to ensure backward-compatibility
  dest="/etc/nginx/nginx.conf"
  echo "Rendering template of nginx.conf"
  sed -e "s/\${DOMAIN}/${DOMAIN}/g" \
      -e "s/\${UPSTREAM}/${UPSTREAM}/" \
      /templates/nginx.conf > "$dest"


# Process templates
upstreamId=0
letscmd=""
for t in "${DOMAINSARRAY[@]}"
do
  dest="/etc/nginx/vhosts/$(basename "${t}").conf"
  src="/templates/vhost.sample.conf"

  if [ -r /configs/"${t}".conf ]; then
    echo "Manual configuration found for $t"
    src="/configs/${t}.conf"
  fi

  echo "Rendering template of $t in $dest"
  sed -e "s/\${DOMAIN}/${t}/g" \
      -e "s/\${UPSTREAM}/${UPSTREAMARRAY[upstreamId]}/" \
      -e "s/\${PATH}/${DOMAINSARRAY[0]}/" \
      "$src" > "$dest"

  upstreamId=$((upstreamId+1))

  #prepare the letsencrypt command arguments
  letscmd="$letscmd -d $t "
done

# Check if the SAN list has changed
if [ ! -f /etc/letsencrypt/san_list ]; then
 cat <<EOF >/etc/letsencrypt/san_list
 "${DOMAIN}"
EOF
  fresh=true
else
  old_san=$(cat /etc/letsencrypt/san_list)
  if [ "${DOMAIN}" != "${old_san}" ]; then
    fresh=true
  else
    fresh=false
  fi
fi

# Initial certificate request, but skip if cached
if [ $fresh = true ]; then
  echo "The SAN list has changed, removing the old certificate and ask for a new one."
  rm -rf /etc/letsencrypt/{live,archive,keys,renewal}

 echo "certbot certonly "${letscmd}" \
  --standalone --preferred-challenges http --text \
  "${SERVER}" \
  --email "${EMAIL}" --agree-tos \
  --expand " > /etc/nginx/lets

  echo "Running initial certificate request... "
  /bin/bash /etc/nginx/lets
fi

#update the stored SAN list
echo "${DOMAIN}" > /etc/letsencrypt/san_list

#Create the renewal directory (containing well-known challenges)
mkdir -p /etc/letsencrypt/webrootauth/

# Template a cronjob to renew certificate with the webroot authenticator
echo "Creating a cron job to keep the certificate updated"
  cat <<EOF >/etc/periodic/weekly/renew
#!/bin/sh
# First renew certificate, then reload nginx config
certbot renew --webroot --webroot-path /etc/letsencrypt/webrootauth/ --post-hook "/usr/sbin/nginx -s reload"
EOF

chmod +x /etc/periodic/weekly/renew

# Kick off cron to reissue certificates as required
# Background the process and log to stderr
/usr/sbin/crond -f -d 8 &

echo Ready
# Launch nginx in the foreground
/usr/sbin/nginx -g "daemon off;"