ibm-cloud-architecture / refarch-jee-micro-customer-service

A component of the https://github.com/ibm-cloud-architecture/refarch-jee reference application. This repository contains the detail of the new Customer microservice during the evolution of an existing JEE monolith to microservices.

Overview

CustomerOrderService is a microservice that redirects service requests from BFF layer to Legacy Backend Layer. This service is introduced to implement Strangler Pattern. Currently it only redirects the requests to EJB layer. In future it can be used to redirect requests to new implementations of services using new technologies e.g. nodejs and nosql

The CustomerOrderService exposes the following interfaces

• /Customer
• /Customer/Address
• /Customer/OpenOrder/LineItem
• /Customer/OpenOrder/LineItem/id
• /Customer/OpenOrder
• /Customer/Orders
• /Customer/TypeForm
• /Customer/Info

Configuration

One configuration parameter that this micro service requires is the IP address of the EJB services host. The EJB services host IP address is specified in the environment variables of this application. The environment variable goes as EJBServiceIP=""

Build WAR using Maven

1. Ensure maven is installed
2. On command prompt, navigate to CustomerOrderService project
3. Run "mvn clean package" command
4. CustomerOrderService-0.1.war is created under CustomerOrderService/target directory
5. Use this war file for deploying the CustomerOrderService module on app server

Security Configuration in server.xml

The backend services are secured with basic authentication. Hence the intermediate REST service layer also needs to be secured. Add the following Basic Registry in server.xml file

<ldapRegistry baseDN="dc=purplecompute,dc=com" bindDN="cn=admin,dc=purplecompute,dc=com" bindPassword="{xor}Dz4sLChvLTs=" host="<ldap-server ip>" id="ldap" ignoreCase="true" ldapType="Custom" port="31252" realm="<ldap-server ip>:31252" searchTimeout="8m">
 
    <contextPool enabled="true" initialSize="1" maxSize="0" preferredSize="3" timeout="0s" waitTime="3000ms"/>
    
    <ldapCache>
        <attributesCache enabled="true" size="4000" sizeLimit="2000" timeout="1200s"/>
        <searchResultsCache enabled="true" resultsSizeLimit="1000" size="2000" timeout="600s"/>
    </ldapCache>

</ldapRegistry>

Challenges resolved:
1) Client application expects "ETag" header and it's value to be present in response headers. Hence had to 1) Pass the value from client to EJB Layer and then 2) Extract the Etag header value from response of EJB layer to the client (again as ETag header in response to client)