Dummy Component

Description

Dummy component is a simulation component that can be used to test the simulation platform installation. It can also be used to add delays to the execution of the simulation run if there is a desire to follow the progress of the simulation during the simulation run.

Functionalities

• Listens to the message bus and catches all messages for the topics SimState and Epoch in the given exchange.
• Offers parameters that can be used to adjust waiting times before the component sends Status message.
• Offers parameters that can be used to set the probabilities that the component fails to react to a new Epoch message or fails to send a Status message.
• Offers parameter that can be used to set the probability that the component sends an Error message instead of Ready message.
• Sends a randomly generated result message to a topic Result before sending a Status message for each epoch.

Technical details

• Dummy component is written in Python (3.7.9) and the source code is part of Simulation Manager repository. The code related to the dummy component specifically is found at folder: https://github.com/simcesplatform/Simulation-Manager/tree/master/dummy
• Dummy component connects to RabbitMQ message bus. Both local and remote message bus servers are supported.

Workflow

In the following rand(a, b) is a random number in the interval [a, b].

• 1. Receive the message bus connection parameters and dummy component related parameters upon startup.
• 2. Open the connection to the message bus and start a message listener for topics SimState and Epoch.
• 3. After receiving simulation start message respond with status ready message.
• 4. For each incoming epoch message received from the message bus:
  • 4.1. If rand(0, 1) < RECEIVE_MISS_CHANCE, ignore the epoch message. Otherwise, move to 4.2.
  • 4.2. If rand(0, 1) < ERROR_CHANCE, send an error message. Otherwise, move to 4.3.
  • 4.3. Wait for rand(MIN_SLEEP_TIME, MAX_SLEEP_TIME) seconds.
  • 4.4. Create and send a randomly created result message to topic Result.
  • 4.5. If rand(0, 1) < SEND_MISS_CHANCE, skip sending a status ready message. Otherwise, move to 4.6.
  • 4.6. Send a status ready message for the epoch.
    • If rand(0, 1) < WARNING_CHANCE, include a warning in the status message.
• 5. Close the component after receiving a simulation stopped message.

Input parameters

Parameter name	Datatype	Corresponding Start message attribute	Default	Description
MIN_SLEEP_TIME	Float	MinSleepTime	2.0	Minimum waiting time in seconds before sending Status message.
MAX_SLEEP_TIME	Float	MaxSleepTime	15.0	Maximum waiting time in seconds before sending Status message.
WARNING_CHANCE	Float	WarningChance	0.0	Probability (0-1) that a warning is included in Status message.
SEND_MISS_CHANCE	Float	SendMissChance	0.0	Probability (0-1) that sending Status message is skipped after processing the epoch.
RECEIVE_MISS_CHANCE	Float	ReceiveMissChance	0.0	Probability (0-1) that received Epoch message is ignored.
ERROR_CHANCE	Float	ErrorChance	0.0	Probability (0-1) that Error message is sent after receiving Epoch message.