TDEI-data-query-service

The Backend Service is responsible for processing dataset query operations, including spatial and non-spatial tasks such as bounding box operations, spatial joins, road information tagging, and dataset unions. This service ensures that the required dataset manipulations are performed efficiently, and it returns OSW-compliant datasets as output, enabling seamless integration with TDEI system components.

Getting Started

The project is built on NodeJS framework. All the regular nuances for a NodeJS project are valid for this.

System requirements

Software	Version
NodeJS	16.17.0
Typescript	4.8.2

Environment variables

Application configuration is read from .env file. Below are the list of environemnt variables service is dependent on. An example of environment file is available here and description of environment variable is presented in below table

Name	Description
PROVIDER	Provider for cloud service or local (optional)
QUEUECONNECTION	Queue connection string
STORAGECONNECTION	Storage connection string
PORT	Port on which application will run
AUTH_HOST	TDEI Auth service url
POSTGRES_DB	Database name
POSTGRES_HOST	Link to the database host
POSTGRES_USER	Database user
POSTGRES_PASSWORD	Database user password
SSL	Database ssl flag
OSW_SCHEMA_URL	OSW Schema Url
BACKEND_RESPONSE_TOPIC	Response topic on which result to be announced

Build

Follow the steps to install the node packages required for both building and running the application

1. Install the dependencies. Run the following command in terminal on the same directory level as package.json

   npm install

2. To start the server, use the command npm run start
3. The http server by default starts with 3000 port or whatever is declared in process.env.PORT (look at index.ts for more details)
4. Health check available at path health/ping with get and post. Make get or post request to http://localhost:3000/health/ping. Ping should respond with "healthy!" message with HTTP 200 status code.

Test

Follow the steps to install the node packages required for testing the application

1. Ensure we have installed the dependencies. Run the following command in terminal on the same directory level as package.json

   npm install

2. To start testing suits, use the command npm test , this command will execute all the unit test suites defined for application.

Service request signatures documentation

Service request signatures are defined under Service signatures

Subscription

Subscriptions to listening topics are configured in the /src/subscription.json file. This file defines the topics that the system listens to for incoming messages.

Message bbox Request

{
    "messageId": "job_id",
    "messageType": "workflow_identifier",
    "data": {
      "service" : "bbox_intersect",
      "parameters": {
        "tdei_dataset_id" : "tdei_dataset_id",
        "bbox" : [1,2,3,4]
      },
      "user_id": "user_id",
    } 
}

Message bbox Response

{
    "messageId": "job_id",
    "messageType": "workflow_identifier",
    "data": {
      "service" : "file path",
      "parameters":{...},
      "file_upload_path" : "zip file path",
      "success": true|false,
      "message": "message" // if false the error string else empty string
    } 
  }