Each lab will consist of a small problem and details of  how to proceed. Each lab is intended to give every student hands-on experience with the core technologies utilized during the course.  A student may concentrate, as a team member, on one technology over another for the final project, but labs are designed to give each and every student exposure to all the technologies that come into play.  You need to submit labs to the TAs for grading--see submission instructions below.  Generally, unless otherwise specified, you will have one week to complete each assigned lab.

See the syllabus for information on grading.  Turning in lab assignments on time is required, without exception, and all late deliveries will be penalized, regardless of cause.  Submit your assignments to the subversion repository according to the directions on the syllabus page.

You may write this solution in Java.

Lab 3   Due: 5:00 pm, Monday, November 25, 2019

Problem 1:  Playing With Multiple Dockerized Microservices and MongoDB: 

BACKGROUND:

WHAT YOU NEED TO DO:

STEP 1:

For this fourth lab, we are going to run a prototype that consists of four distinct microservices.  This prototype consists of:

 1.  A dockerized Apache Tomcat web server microservice named WebServer running ubuntu that will serve up a web page and backing jsp and Java servlet that will prompt the user to add a new user to the system.  This web page is for adding new users only and is strictly no frills.  A field for a username, and a second field for a password, and an "Confirm New User" button that, when clicked, does no error checking and sends the new user request (over synchronous RMI from the servlet) to the UserManagement microservice, which has an RMI Server listening for remote calls.

2.  A dockerized UserManagement microservice running ubuntu that hosts an RMI Server that listens for new user requests from the WebServer's servlet-based RMI client.  A synchronous RMI client running in the servlet on the WebServer is used to communicate new user requests to the RMI server running on UserManagement. 

3.  The RMI server running on UserManagement receives the new user request and forwards that request asynchronously to a queue running in a dockerized RabbitMQ microservice called MyWabbit.

4.  A dockerized LoggingService, based on a docker MongoDB image will be listening/subscribed to the MyWabbit's "new user" queue, and upon every incoming message (about a new user to add), will write that new user's information out to a new MongoDB document.  Note that the purpose of the MongoDB database is not to store new user information, but to provide a document store for log messages from the system.

The big picture here is this:

These steps will involve running several different docker containers and installing software inside them.  Details are below.  After downloading and installing the prototype in STEPS 2-5, get the prototype running (there will be a few code and environment changes you will need to make) and examine the code carefully and observe how it executes.

First, make sure docker is running either on your laptop (Option I from the first lab) or in your VM (Option II from the first lab).

STEP 2:

docker run -di --hostname tomcat --name WebServer -p 8080:8080 tomcat:8.0

You may find the following references helpful (in addition to the links from previous labs):

Ubuntu package commands
The docker page for MongoDB
MongoDB Documentation Home Page
Microservices resources at MongoDB

General Docker Tutorial Links

Submitting:

Use the folder named "lab_4" in your Subversion repository. Upload your Lab 4 microservice tarballs to this repo.  Please include a README text file that contains any instructions for the TAs to assist with grading, and design notes are often the most useful thing you can provide. We do not usually need any info on how to compile your code unless your code layout is arcane.