WebSphere Liberty Dockerfile & custom scripts (executing prior to server start) updating server configuration files with IBM Bluemix service credential information dynamically

Dockerfile

FROM registry-ice.ng.bluemix.net/ibmliberty:latest

RUN apt-get update && apt-get install -y \
	git \
	python-lxml

# Add a SSH key, this will allow to perform SSH into containers
COPY id_rsa.pub /root/.ssh/ 

RUN chmod 600 /root/.ssh/id_rsa.pub \
    && cat /root/.ssh/id_rsa.pub >> /root/.ssh/authorized_keys \
    && rm -rf /opt/ibm/wlp/usr/servers/defaultServer/apps/* \
    && mkdir -p /opt/ibm/wlp/usr/extension/lib

# Extract binaries from public IDS repo
RUN rm -rf /src
RUN mkdir /src

# Clone MobileFirst Platform Foundation application into the local image
RUN git clone --verbose --progress https://github.com/osowski/mobilefirst-liberty-resources.git /src/wishlist

COPY update-server-xml.py /src/update-server-xml.py
COPY init-liberty.sh /src/init-liberty.sh
RUN chmod +x /src/init-liberty.sh
CMD ["/src/init-liberty.sh"]

# Accept Liberty license
ENV LICENSE accept

EXPOSE 9080
EXPOSE 22

init-liberty.sh

#!/bin/bash

python /src/update-server-xml.py /opt/ibm/wlp/usr/servers/defaultServer/server.xml /opt/ibm/wlp/usr/servers/defaultServer/server.xml

/opt/ibm/wlp/bin/server run defaultServer

update-server-xml.py

## update-server-xml.py
##
## Usage: python update-server-xml.py [input server.xml] [output server.xml]
##
## This script will extract the appropriate Cloudant service instance credentials
## from the VCAP_SERVICES environment variable inside a running container.  It will
## then update those credentials in the server.xml file, passed in as the primary parameter.
## These credentials are used to configure the Cloudant Data Proxy inside the MobileFirst
## Foundations Platform and saved in the output file passed in as the second parameter.
##

import sys
import os
import json
from lxml import etree as ETree
from io import StringIO

if "VCAP_SERVICES" in os.environ:
  vcaps = json.loads(os.environ["VCAP_SERVICES"])
  
  if "cloudantNoSQLDB" in vcaps:
    hostname = vcaps["cloudantNoSQLDB"][0]["credentials"]["host"]
    username = vcaps["cloudantNoSQLDB"][0]["credentials"]["username"]
    password = vcaps["cloudantNoSQLDB"][0]["credentials"]["password"]
    port = vcaps["cloudantNoSQLDB"][0]["credentials"]["port"]
    protocol = vcaps["cloudantNoSQLDB"][0]["credentials"]["url"]
    protocol = protocol.split(":")[0]

    serverxml = sys.argv[1]
    tree = ETree.parse(serverxml)
    root = tree.getroot()

    #set hostname
    for element in root.xpath("/server/jndiEntry[@jndiName='datastore/CloudantProxyDbAccount']"):
      element.attrib['value'] = hostname
    #set protocol
    for element in root.xpath("/server/jndiEntry[@jndiName='datastore/CloudantProtocol']"):
      element.attrib['value'] = protocol
    #set port
    for element in root.xpath("/server/jndiEntry[@jndiName='datastore/CloudantPort']"):
      element.attrib['value'] = str(port)
    #set username
    for element in root.xpath("/server/jndiEntry[@jndiName='datastore/CloudantProxyDbAccountUser']"):
      element.attrib['value'] = username
    #set password
    for element in root.xpath("/server/jndiEntry[@jndiName='datastore/CloudantProxyDbAccountPassword']"):
      element.attrib['value'] = password

    tree.write(sys.argv[2], pretty_print=True, xml_declaration=True);