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• Table of Contents
• System Requirements
• Message Structure
• Message Bus
• Producer
• Consumer
• User
  • 1. Notes

• Linux is the operating system.

• Python is the programming language.

• Invocation is from the command line.

• All communication among AGENTS, PRODUCERS, and CONSUMERS is over TCP/IP.

• The TCP/IP ports used start at 30000 and may range up to 31000.

• The PRODUCER and CONSUMER will pass a MESSAGE.

• The format of the MESSAGE is JSON.

• The MESSAGE contains the following fields:

  • AGENT_NAME - A string that uniquely identifies an AGENT.

  • AGENT_TYPE - A string that provides the type of AGENT.

  • OPERATION - A string that describes an ACTION performed by an AGENT.

  • OPERAND-1 - A number that participates in an OPERATION.

  • OPERAND-2 - A number that participates in an OPERATION.

  • ANSWER - A number that is produced from an OPERATION.

• The AGENT_TYPE must have exactly one of the values "producer" or "consumer".

• Any AGENT_TYPE that is not one of the allowed values must cause the process to terminate with a graceful message.

• The OPERATIONS must have exactly one of the values "add", "multiply", or "answer".

• The purpose of the MESSAGE_BUS is to facilitate the passing of MESSAGES among AGENTS, PRODUCERS, and CONSUMERS.

• The invocation of the MESSAGE_BUS from the command line is done with "python bus.py"

• The MESSAGE_BUS maintains a FIFO queue of messages.

• The MESSAGE_BUS puts all MESSAGES on the FIFO queue when the AGENT_TYPE in the message is "consumer".

• The MESSAGE_BUS listens on TCP/IP for AGENTS, PRODUCERS, or CONSUMERS to send MESSAGES or request MESSAGES.

• The MESSAGE_BUS runs indefinitely until a USER sends Control-C.

• The invocation of the PRODUCER from the command line is done with "python producer.py"

• The PRODUCER listens to the TCP/IP port.

• The PRODUCER consumes a MESSAGE from the TCP/IP port.

• The PRODUCER finds the OPERATION in the MESSAGE.

• If the OPERATION is "multiply", the PRODUCER determines the product of OPERAND-1 and OPERAND-2 as the ANSWER

• If the OPERATION is "add", the PRODUCER determines the sum of OPERAND-1 and OPERAND-2 as the ANSWER.

• The PRODUCER builds a message to return in the manner prescribed next.

• The PRODUCER puts all the original parts of the message it received so that the inputs are traceable.

• The PRODUCER puts the ANSWER into the MESSAGE.

• The PRODUCER shows the message on the command line so the USER can see the content.

• The PRODUCER sends the MESSAGE over the TCP/IP port so the CONSUMER can receive it.

• The PRODUCER waits for another message.

• The PRODUCER runs indefinitely until a USER sends Control-C.

• The invocation of the CONSUMER from the command line is done with "python consumer.py"

• The command line takes the following positional parameters:

  • AGENT_NAME

  • OPERATION

  • OPERAND-1

  • OPERAND-2

• If any parameters are not present, the user is given a help message on how to properly pass parameters.

• The CONSUMER puts AGENT_NAME, OPERATION, OPERAND-1, OPERAND-2 into the MESSAGE format that is common to both the PRODUCER and CONSUMER.

• The CONSUMER leaves the ANSWER blank.

• The CONSUMER connects to TCP/IP port 30101 and sends the MESSAGE it has built.

• The CONSUMER waits for a MESSAGE from the PRODUCER to come over the TCP/IP port.

• When a return MESSAGE is received from the PRODUCER, the CONSUMER displays it on the screen for the USER.

• The USER is a human at the Linux command line.

• The USER will invoke the PRODUCER for it to run indefinitely.

• The USER will invoke the CONSUMER each time it needs an ANSWER by running "python consumer.py" with parameters.

• The USER may provide different parameters to the CONSUMER each time the CONSUMER is run.