/mqtt-simulator

Easy-to-configure MQTT simulator written in Python to simulate the sending of JSON objects from sensors or devices to a broker.

Primary LanguagePythonMIT LicenseMIT

MQTT Simulator

Easy-to-configure MQTT simulator written in Python 3 to simulate the sending of JSON objects from sensors or devices to a broker.

Features • Getting Started • Configuration • Authors

Simulator Running

Features

  • Small and easy-to-configure simulator for publishing data to a broker
  • Configuration from a single JSON file
  • Connection on pre-defined fixed topics
  • Connection on multiple topics that have a variable id or items at the end
  • Random variation of data generated according to configuration parameters

Getting Started

Prerequisites

Installing Dependencies

To install all dependencies with a virtual environment:

python3 -m venv venv
source venv/bin/activate
pip3 install -r requirements.txt

Running

The default simulator settings can be changed in the config/settings.json file.

python3 mqtt-simulator/main.py

Runs the simulator according to the settings file.
The terminal will show the simulator event log.

Optionally, you can pass a flag with the path to settings file:

python3 mqtt-simulator/main.py -f <path/settings.json>

Configuration

  • The config/settings.json file has three main configuration parameters:

    {
    "BROKER_URL": "mqtt.eclipse.org",
    "BROKER_PORT": 1883,
    "TOPICS": [
        ...
    ]
}
    Key Type Description Required
    BROKER_URL string The broker URL where the data will be published yes
    BROKER_PORT number The port used by the broker yes
    TOPICS array<Objects> Specification of topics and how they will be published yes

  • The key DATA inside TOPICS has an array of objects where each one has the format:

{
    "NAME": "temperature",
    "TYPE": "float",
    "INITIAL_VALUE": 35,
    "MIN_VALUE": 30,
    "MAX_VALUE": 40,
    "MAX_STEP": 0.2,
    "RETAIN_PROBABILITY": 0.5,
    "RESET_PROBABILITY": 0.1,
    "INCREASE_PROBABILITY": 0.7,
    "RESTART_ON_BOUNDARIES": true
}
  • Continued from above but for TYPE string
{
    "NAME": "Content",
    "TYPE": "string",
    "STRING_VALUES": ["Material", "Zone"],
    "RETAIN_PROBABILITY": 0.5
}
  • Continued from above but for TYPE timestamp
{
    "NAME": "timestamp",
    "TYPE": "timestamp"
}
  • Continued from above but for TYPE object
{
    "NAME": "Sensors",
    "TYPE": "object",
    "COLLECTION_TYPE": "array",   //or "dictionary"
    "CHILDREN": [
        {
            "NAME": "Sensor",
            "TYPE": "object",
            "COLLECTION_TYPE": "dictionary",
            "INITIAL_VALUE": 1,
            "CHILDREN": [
                {
                    "NAME": "Name",
                    "TYPE": "string",
                    "STRING_VALUES": ["A"],
                    "RETAIN_PROBABILITY": 1
                },
                {
                    "NAME": "Timestamp",
                    "TYPE": "timestamp"
                },
                {
                    "NAME": "Result",
                    "TYPE": "int",
                    "MIN_VALUE": 0,
                    "MAX_VALUE": 100,
                    "MAX_STEP": 10,
                    "RETAIN_PROBABILITY": 0.5,
                    "INCREASE_PROBABILITY": 0.5
                }
            ]
        }
    ]
}
Key Type Description Required
NAME string JSON property name to be sent yes
TYPE string It can be "int", "float", "bool", "math_expression", "string", "object", "timestamp" yes
INITIAL_VALUE number or bool (same as defined in TYPE) Initial value that the property will assume when the simulation starts (random otherwise) optional. Only valid if TYPE is different from "math_expression" and "timestamp"
MIN_VALUE number Minimum value that the property can assume if TYPE is "int" or "float"
MAX_VALUE number Maximum value that the property can assume if TYPE is "int" or "float"
MAX_STEP number Maximum change that can be applied to the property from a published data to the next if TYPE is "int" or "float"
RETAIN_PROBABILITY number Number between 0 and 1 for the probability of the value being retained and sent again All except if TYPE is "object"
RESET_PROBABILITY number Number between 0 and 1 for the probability of the value being reset to INITIAL_VALUE optional, default is 0. Only valid if TYPE is different from "math_expression" and "timestamp"
INCREASE_PROBABILITY number Number between 0 and 1 for the probability of the next value being greater than the previous one optional, default is 0.5 (same probability to increase or decrease). Only valid if TYPE is "int" or "float"
RESTART_ON_BOUNDARIES bool When true and the value reaches MAX_VALUE or MIN_VALUE the next value will be the INITIAL_VALUE optional, default is false. Only valid if TYPE is "int" or "float"
STRING_VALUES array<string> Array of string values that the property can assume if TYPE is "string"
MATH_EXPRESSION string Math expression written in a Pythonic way
Also accepts functions from Math modules		 if TYPE is "math_expression"
INTERVAL_START number Minimum value that the MATH_EXPRESSION's variable x can assume if TYPE is "math_expression"
INTERVAL_END number Maximum value that the MATH_EXPRESSION's variable x can assume if TYPE is "math_expression"
MIN_DELTA number Minimum value that can be added to the MATH_EXPRESSION's variable x from a published data to the next if TYPE is "math_expression"
MAX_DELTA number Maximum value that can be added to the MATH_EXPRESSION's variable x from a published data to the next if TYPE is "math_expression"
COLLECTION_TYPE string It can be "array" or "dictionary" if TYPE is "object"
CHILDREN array An array of objects if TYPE is "object"

NOTE: Access math_expression.md file for more explanations and an example of TYPE: "math_expression".

ADDITIONS This addition allows the appending of timestamps, nested objects, and nested arrays for data

Authors

DamascenoRafael  Maasouza