General Purpose Message Simulator

This script generates messages from a given input source to a given output sink. For example it can read from a csv-file (implemented) and generate MQTT messages (implemented).

Messages produced from input plugin (see below) are expected to have a timestamp field with date formatted like 2018-11-25 14:23:14:142. Timestamp is used to calculate waiting time between two messages.

Plugins

Implemented plugins

INPUT
- CSV-File input (input.csv)
OUTPUT
- Console Output (output.console)
- MQTT Output (output.mqtt)
TRANSFORMER
- id - do nothing (mapper.id)
- setDateTimeNow (mapper.setDateTimeNow)

Implement your Input

Feed data generator with message object. Input modules should be implemented according to this pattern:

module.exports = {
    next: () => {
        // run your calculations
        return {
            timestamp: "2018-11-25 14:23:14:142", // timestamp is required
            data1: "", // your data
            data2: "" // your data etc.
        }
    }
}

Examples: See input.csv.js

Implement your Output

Message generator writes messages to a given output. Output module export is an object containing a write(object) function and returns a Promise-Object.

Output modules should be implemented according to this pattern:

module.exports = {
    write: obj => new Promise((resolve, reject) => {
        console.log(`sent: ${obj.timestamp} ${obj.acceleration} ${obj.speed}`)
        resolve()
    })
}

Examples: See output.console.js, output.mqtt.js

Implement your Message Transformer

You have the opportunity to transform messages before they are send to output plugin. Transformation Plugin should be implemented according to this pattern:

Example #1

// this function do not transform the object
const id = obj => obj
module.exports = id

Example #2

const moment = require("moment")
const transformTimeStampToNow = obj => {
    obj.timestamp = moment().format("YYYY-MM-DD HH:mm:ss.SSS")
    return obj
}

module.exports = transformTimeStampToNow

Configuration

Required Configuration

output: Which plugin feeds our generator
input: Which plugin use our generator to write messages
beforeSendMapper: function is called to transform message before it is send to output plugin. This can be used to transform e.g. timestamp to current time.

Other configurations are plugin specific. E.g. for MQTT output.mqtt.options object is passed to client generation. See https://www.npmjs.com/package/mqtt#client

{
    "output": "./output.mqtt",
    "output.mqtt": {
        "url": "mqtts://yourserver.com",
        "topic": "test",
        "options": {
            "username": "???",
            "password": "???",
            "clientId": "test-client"
        }
    },
    "input": "./input.csv-ketag",
    "input.csv": {
        "file": "./data/Rad2.csv"
    },
    "beforeSendMapper": "./mapper.setDateTimeNow"
}

Example

File: data/testdata.csv

2018-10-16 14:40:44.036;-1.52648950205082e-3;0.0
2018-10-16 14:40:48.037;-1.52648950205082e-3;0.0
2018-10-16 14:40:54.038;-1.52648950205082e-3;0.0
2018-10-16 14:41:10.039;-1.52648950205082e-3;0.0

File: `config.json``

{
    "output": "./output.console",
    "input": "./input.csv",
    "input.csv": {
        "file": "./data/testdata.csv"
    },
    "beforeSendMapper": "./mapper.setDateTimeNow"
}