Lab 4

CSE 132 (Spring 2015)
Lab 4: Networked HaWUp

In this lab you will apply what you have learned about network programming to make a networked version of your HaWUp cluster. This document specifies the protocol by which a client should connect to your server. A client will be provided to test your server.

Introduction

Programs communicate across the Internet by using protocols, which specify the order and content of messages. In class, we discussed various aspects of such a protocol for telling a HaWUp server that it should perform one of a prespecified set of tasks. The result of that discussion appears below.

In writing your server, it is important that you conform to this protocol. Failure to do so will prevent the client from communicating with your server, and a crash or failure of some sort will surely ensue. There are two aspects of a protocol that are especially important:

Messages must be sent and received in the order specified.
The type of data within each message must be transmitted and received in the format that is specified. For example, if the protocol specifies a 4-byte integer, then it should be sent using writeInt and received using readInt, or code should execute that sends or receives the equivalent values.

Some types of data and their associated Java DataOutputStream and DataInputStream methods are summarized below:

Description	send	receive
A single byte	`void writeByte(int)`	`byte readByte()`
Two-byte integer	`void writeShort(int)`	`short readShort()`
Four-byte integer	`void writeInt(int)`	`int readInt()`
Java `String`	`void writeUTF(String)`	`String readUTF()`

Protocol

The server and client observe the following protocol. Any information appearing in quotes, such as "example" is sent as a String.

Server	Client
Makes service available at port 3000 and waits for a connection
	Connects to the server at port 3000
When a connection is made, spawns a new thread to service the client. In that thread, send the following: A `String` with this server's name A 2-byte integer specifying this server's number of nodes A 2-byte integer specifying the max queue size for each node
	Receives what was sent in the row above
	Sends the following: This client's name as a `String`. It will help if this `String` is something unique. The password for connection `"xyzzy"`, as a `String`
Receives what was sent in the row above.
Sends one of two messages as a `String`: `"ok"`, if the password is accepted `"bye"`, if the password is rejected The connection is closed if `"bye"` is sent
	Receives what was sent in the row above.
	Submits a job using one of the following messages: Sleep job `"sleep"` number of tasks, as a 4-byte integer maximum sleep time in milliseconds, as a 4-byte integer Sum job `"sum"` first integer `lo` in the range of the sum, inclusively, as a two-byte integer last integer `hi` in the range of the sum, inclusive, as a two-byte integer RSA job `"rsa"` a (perhaps large) integer `num`, sent as a `String` an integer value `lo`, sent as a `String` an integer value `hi`, sent as a `String`
Receives what was sent in the row above.
Sends one of two messages as a `String`: `"ok"`, if the job is accepted `"bye"`, if the job is rejected The connection is closed if `"bye"` is sent
	Receives and displays the `ok` or `bye` message
It is up to the server to take the job and break it into pieces (if possible) to run on the server's nodes. For example, if `sum` is requested on the integers between 10,001 and 20,000, inclusively, and the server has 10 nodes, then each node should perform a sum of 1,000 integers to contribute to the server's overall answer. An exception is `sleep`, whose behavior is simply as described below. Sleep job Each task deployed on the server for this job will sleep for a random amont of time, up to the specified number of milliseconds. When all sleeping is done for this job, send `"done"` as a `String`. Sum job The server computes the sum from `lo` to `hi`, inclusively, and sends the result as a `String`. RSA job The server tries each integer in the range [`lo`…`hi`] (inclusively). If one of them is a factor of `num`, then send that factor to the client as a `String`. If none of the integers in the specified range is a factor of `num`, send the integer 0 to the client as a `String`.
	Waits for server to send answer as a `String`
When answer is ready, send to client as a `String`
	After receiving answer, close connection

Procedure

Update your repositories to obtain the hawup.client code
Implement your server, initially trying only for the sleep job.
Test your code by first launching your server and then the client. The client prompts for information and submits the job to your server using the specified protocol.
Have somebody else run the client but specify your IP address for its server. You should see jobs starting up on your server from that client too.
This other person must be on the same network as you to be able to connect.
When that is working, move on to sum and rsa

As given, the sum and rsa code assumes a lower bound that is not part of the specification. You will have to modify those classes in your workspace so that they take in not only an upper bound but also a lower bound.

Demo

Show the TA your work by launching the RSASubmitter client and submitting the following jobs to your server:

Run as-is, factoring the product of two large primes.
Run so as to factor 100 using a lower bound of 70 and an upper bound of 80.
Allow the TA to submit a factor job and see the answer.

Note!

Your server should continue running and accept client after client.
It should be insensitive to failures (exceptions) thrown on behalf of the client jobs.

Demo

When you done with this studio, you must be cleared by the TA to receive credit.

Commit all your work to your repository!
If you do not commit, the TAs cannot grade your work and you will receive a 0 for this assignment!

Fill in the form below with the relevant information
Have a TA check your work
The TA should check your work and then fill in his or her name
Click OK while the TA watches
If you request propagation, it does not happen immediately, but should be posted in the next day or so

Last name WUSTL Key Propagate?

(or your numeric ID) Do not propagate

e.g. Smith j.smith

1 Copy from 1 to all others

2 Copy from 2 to all others

TA: Make sure they commit their code before you sign them out!
TA: Password:

	Last name	WUSTL Key	Propagate?
		(or your numeric ID)		Do not propagate
e.g.	`Smith`	`j.smith`
1				Copy from 1 to all others
2				Copy from 2 to all others

Last modified 15:05:38 CDT 03 April 2015 by Ron K. Cytron

CSE 132 (Spring 2015) Lab 4: Networked HaWUp

Introduction

Protocol

Procedure

Demo

Demo

CSE 132 (Spring 2015)
Lab 4: Networked HaWUp