As we discussed in our previous post on how we use our Coral Gateway server instead to keep our Flutter App in sync with our Cloud DB. You can find the details in our previous post.

We build this system for Ordermaster.ca use-case where each restaurant has an app to get order information, menu information and table reservation information from Cloud. The restaurant uses the Tablet also as a POS system to take orders in the restaurant itself which should work with any internet connection. …

In this article we will be talking about how to sync your on device Sembast DB to a DB running in cloud.

There are many use-cases where you would want to store the data locally on the device first. For example: Restaurant POS app, Retail Store POS app, Warehouse inventory management app. Basically any use-case where you don’t want the operation to be blocked because of network availability.

Here we will be talk about using Sembast DB which is used by many Apps written in flutter. It’s a no-sql DB completely written in dart programming language. …

In this article we will go through how you can point multiple domains to Single ingress on Google Cloud.

For this article we are going to assume that you already understand how to host a website or service on GKE. You can also follow our one of the older post on it.

Step 1: Reserve static ip address

You should reserve an static ip address for your ingress. Follow official doc

gcloud compute addresses create ADDRESS_NAME \
    --global \
    --ip-version [IPV4 | IPV6]

Step 2: Generate Google managed certificates for each domain

You should create certificates for each domain. Follow the official document

apiVersion: networking.gke.io/v1beta2
kind: ManagedCertificate
metadata:
  name: certificate-name
spec:
  domains:
    - domain-name1kubectl…

Today we will discuss about how to build a telemetry system while building an app. In this we will be taking of how we do it in Coral Server which we have built for real time apps.

Why telemetry is important?

Telemetry is important to capture the events happening on the device with-in your app. These events can then be joined with other data to draw useful conclustions.

An example for one of our clients: Restaurants get order notification on tablet which results into a ringing bell. Once they press the accept button, they have to open the order and confirm it or cancel…

Google BigQuery offers you to analyse your data. You can build a data warehouse to run BI tools to do analysis. In this post we will discussing about a simple pipeline to publish your events data to Google BigQuery using Google pubsub.

Step by step guide

1. Create a table in Google BigQuery. You can use Google cloud console or cli

Below is a simple schema for a fact table.

2. create a google cloud function to insert the data into BigQuery. A generic cloud function which we have created would work for json serialized objects

Below is the example

This function is generic…

Let’s talk about what is a real time app means that you have ability to show information in real time to your customer as the events happening in the order parts of system.

Few example of real time apps are

Ride hailing Apps

Food Ordering Apps

Challenges in building such Apps

You have to receive a high volume of update from the Fact entities (like order, trips etc). And as you receive those updates you have to notify the Dimension Entities (Restaurant, Driver etc). The latency requirement for these systems are in the order of milli-seconds at a very high volume.

You could have updates…

In this article we will talk about how you can communicate between services running in the same cluster.

We will take example of a cluster running in Google Kubernetes engine (GKE)

When you host a service in GKE and you expose through a domain name then you can access it by accessing the domain endpoint.

An example would be http://api.example.com or something like that.

An example diagram for this traffic path is shown below

There are multiple reasons when you want the traffic not to go out to internet and you want to access your services with in the pod.

…

In this we will talk about how to redirect http traffic to https.

For this we will be using a Spring boot app which is running on Google kubernetes engine. We will also use the Tuckey url re-writer.

For this we assume you already know how to run a spring boot service on GKE. A sample repository can be found here

Step 1: Let’s implement the UrlRewrite filter

Extend the UrlRewriteFilter which re-writes the url based on the rules provided in the xml config.

import lombok.extern.log4j.Log4j2;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.env.Environment;
import org.springframework.stereotype.Component;
import org.tuckey.web.filters.urlrewrite.Conf;
import org.tuckey.web.filters.urlrewrite.UrlRewriteFilter;
import org.tuckey.web.filters.urlrewrite.UrlRewriter;

import javax.servlet.*;
import java.io.InputStream;@Component
@Log4j2
public class HttpsUrlRewriteFilter extends UrlRewriteFilter…