Google-datastore-emulator NPM

Google Cloud Datastore Emulator

This package helps to start / stop Google Datatstore Emulator with javascript. From 1.1.0 also could usable with google/cloud-sdk docker image. The wrapper automatically pull the image is not exists on the host, but I suggest to pull the image in the 'before_test' section in the CI script Important: Be careful with the timeouts, need time to pull the image, start and stop the container.

Perfect to support unit testing where the persistent layer is the gcloud Datastore.

The wrapper sets DATASTORE_EMULATOR_HOST and DATASTORE_PROJECT_ID environment variables.

Prerequisites

To use the emulator locally you need to install Google Cloud SDK or with Docker you need to install Docker host

Installation

npm install google-datastore-emulator --save-dev

Usage

I think the package is the most suitable for unit testing.

const datastore = require('@google-cloud/datastore');
const Emulator = require('google-datastore-emulator');

describe('test suit', ()=>{
    process.env.GCLOUD_PROJECT = 'project-id'; // Set the datastore project Id globally

    let emulator;
    
    before(()=>{
        const options = {
            useDocker: true // if you need docker image
        };
        
        emulator = new Emulator(options);
        
        return emulator.start();
    });
    
    after(()=>{
        return emulator.stop();
    });
    
    it('test case', ()=>{
        // your test
    });
})

Options

parameter (type)	default value	description
project (string)	test	This variable is datastore project Id.
storeOnDisk (boolean)	false	The datastore either persists the entities on disk or not.
dataDir (string)	empty	The emulator creates a directory where the project files are stored. If it is empty the emulator default value will be used. You could set relative ./directory or absolute path /tmp/dir1/dir2/. If this directory does not exist, it will be created. Bug : With linux Docker host don't delete the folder
clean (boolean)	true	If dataDir value is set and 'clean' value is true then the package deletes the dataDir. The package does not delete the gcloud emulator default directory.
host (string)	localhost	If it is empty the'localhost' of google default value is used. It can take the form of a single address (hostname, IPv4, or IPv6)
port (number)	empty	If it is empty the emulator selects a random free port.
debug (boolean)	false	If it is true, it writes the console.logs of the emulator onto the main process console.
consistency (string)	'1.0'	The consistency level of the Datastore Emulator. More details
useDocker (boolean)	false	If it is true, it use docker image to run emulator instead of locally installed version.
dockerImage (string)	'google/cloud-sdk:latest'	This image will be use by docker. The default: google/cloud-sdk:latest