thebluemagician / NGSIToJson

Custom Apache Nifi (Fiware Draco) Processor to convert NGSIv2 flowfile to Json

NGSIToJson

This is a custom Apache Nifi (Fiware Draco) Processor, aims to convert incoming NGSIv2 HTTP notifications from Orion ContextBroker to Flat or Nested Json with or without requests metadata.
This processor has provision to convert both type of attrsFormat payload mentioned in notification section of subscriptions created at Fiware Orion Context Broker.

Getting Started

Install

1. Install and run Apache Nifi (Fiware Draco), Follow Draco Quick Start Guide.
2. Clone this repo git clone https://github.com/thebluemagician/NGSIToJson.git
3. Change the directory, build the code base clean install
4. Above step will create a nar file in ./nifi-ngsi2json-nar/target/.
5. Move the generated nar to lib directory of draco.
6. Start the draco server bin/nifi.sh start

Processor Configuration

NGSIToJson is configured through following parameters:

Property Name	Default Value	Allowable Values	Description
Json Structure	Flat	Flat, Nested	Specifies whether the output Json should be Flat or Nested
NGSI version	v2		Only NGSIv2 is supported
Include Metadata	False	True, False	If true, the general metadata like- id, type, subscriptionId will be included in the FlowFile, Attributes metadata will be ignored

Usage

Changing the Json Structure and Include Metadata property will have impact on the contents of output flowfile.
The notification generated at Orion Context Broker can be normalized or in keyValues format based on the subscriptions payload. The sample data can be found here:

• normalized
• keyValues

Properties Configuration scenarios are:

1. Json Structure:Flat and Include Metadata:False, Output flowFile will be in simple format:

{
    "timeStamp": "2020-06-04 19:00:00",
    "pm2p5": "201.10",
    "airQualityLevel": "SEVERE",
    "humidity": "61.45",
    "aqiPollutant": "PM2.5",
    "co": "0.72",
    "deviceId": "fixedEnv011-001"
}

2. Json Structure:Flat and Include Metadata:True, Output FlowFile will include metadata in base structure:

{
    "timeStamp": "2020-06-04 19:00:00",
    "pm2p5": "201.10",
    "airQualityLevel": "SEVERE",
    "humidity": "61.45",
    "aqiPollutant": "PM2.5",
    "id": "fixedEnvAir",
    "co": "0.72",
    "type": "envAir",
    "subscriptionId": "5f9431ed5d8d27ba56582358",
    "deviceId": "fixedEnv011-001",
    "TimeInstant": "2020-10-24T15:03:10.734Z"
}

3. Json Structure:Nested and Include Metadata:False, Output FlowFile will have data with empty metadata objects:

{
    "metadata": {},
    "data": {
        "timeStamp": "2020-06-04 19:00:00",
        "pm2p5": "201.10",
        "airQualityLevel": "SEVERE",
        "humidity": "61.45",
        "aqiPollutant": "PM2.5",
        "co": "0.72",
        "deviceId": "fixedEnv011-001"
    }
}

4. Json Structure:Nested and Include Metadata:True, Output FlowFile will have both data and metadata populated objects:

{
    "metadata": {
        "id": "fixedEnvAir",
        "type": "envAir",
        "subscriptionId": "5f9431ed5d8d27ba56582358",
        "TimeInstant": "2020-10-24T15:06:27.305Z"
    },
    "data": {
        "timeStamp": "2020-06-04 19:00:00",
        "pm2p5": "201.10",
        "airQualityLevel": "SEVERE",
        "humidity": "61.45",
        "aqiPollutant": "PM2.5",
        "co": "0.72",
        "deviceId": "fixedEnv011-001"
    }
}

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Ref

1. Apache Nifi Developer Guide
2. NGSIv2 Walkthrough