The Google Maps Platform Android SDK supports extensions for reactive programming, which helps you write code to handle asynchronous operations.

Write reactive and responsive mapping applications with Google Maps Platform

In mobile apps, asynchronous events can happen at any point in time: user touch events, waiting for network calls to complete, or receiving push notifications, to name a few. As an app developer, accounting for these events and composing them with other asynchronous events can be challenging. Reactive programming is an alternative to passing callbacks for different events and helps simplify the process of working with asynchronous events. In reactive programming, events are modeled as a stream, emitting items over time.

https://youtube.com/watch?v=1TmJvOZfBVQ%3Fenablejsapi%3D1%26

There are two libraries you can use to write reactive code: Kotlin Flows and RxJava. The next two videos show you how to use each one.

Writing reactive and responsive mapping applications using Kotlin

If you’re a Kotlin developer looking to use Coroutines and Flows, the KTX library allows you to use Kotlin Flows to receive events. The Maps KTX library includes extension functions that return Kotlin Flow objects, so you can listen to events in a reactive manner. Unlike suspending functions, which return a single value, Kotlin Flows can return several values over time. For example, you can use a Flow to receive camera event changes over time. To get started using Kotlin Flows in your app, include the Maps KTX library in the dependencies section in your build.gradle file.

https://youtube.com/watch?v=Cotx1ZmEYg8%3Fenablejsapi%3D1%26

Creating reactive maps on Android with RxJava

Integrate Google Maps Platform SDKs with popular Android library RxJava. RxJava is the Java implementation of Reactive Extensions, which is a library for composing asynchronous and event-based programs using observable sequences. One thing RxJava does is allows you to convert callback-based asynchronous code into a chain of transformations. Learn how this works and the other ways you can use RxJava in the third video in this series.

https://youtube.com/watch?v=AgGE7fAMrdA%3Fenablejsapi%3D1%26

​​We hope you learn more about reactive programming concepts to help you build responsive and reactive mobile apps in this three-part YouTube series. Have ideas for helpful videos you’d like to see on our channel? Leave a comment on any of our videos. And don’t forget to subscribe to our YouTube channel for the latest updates, tutorials, customer stories, and more.

For more information on Google Maps Platform, visit our website.

Editor’s note: Today’s guest post comes from Indian social media platform ShareChat. Here’s the story of how they improved performance, app development, and analytics for serving regional content to millions of users using Google Cloud. 

How do you create a social network when your country has 22 major official languages and countless active regional dialects? At ShareChat, we serve more than 160 million monthly active users who share and view videos, images, GIFs, songs, and more in 15 different Indian languages. We also launched a short video platform in 2020, Moj, which already supports over 80 million monthly active users. 

Connecting with people in the language they understand

As mobile data and smartphones have become more affordable in India, we noticed a large new segment of people, many in rural areas, being welcomed onto the internet. However, many of them didn’t speak English, and when it comes to accessing content and information—language plays a significant role. Instead of joining other social media sites where English reigned supreme, new internet users chose to join language or dialect-specific Whatsapp groups where they felt more comfortable instead.

So, we set out to build a platform where people can share their opinions, document their lives, and make new friends, all in their native language. ShareChat simplifies content and people discovery by using a personalized content newsfeed to deliver language-specific content to the right audience.

Given the high-intensity data and high volume of content and traffic, we rely heavily on IT infrastructure. On top of that, a large number of our users rely on 2G networks to post, like, view, or follow each other. Our platform needs to deliver great experiences to people who are spread out across the country and different networks without any reduction in performance.

The right cloud partner to support future growth

ShareChat was born in the cloud—we already knew how to scale systems to serve a large customer base with our existing cloud provider. But like many companies, we struggled with over-provisioning compute and storage to accommodate unpredictable traffic and avoid running out of storage. With demand rising for local language content and an increase in online interactions in response to the COVID-19 crisis, we realized that we would need a more efficient way to scale dynamically and allocate resources as needed.

Google Cloud was a natural choice for us. We wanted to partner with a technology-first company that would make it easy (and cost-effective) to manage a strong technology portfolio that would allow us to build whatever we wanted. Google is at the forefront of technology innovation and provided everything we needed to build, run, and manage our applications (including creating an efficient DevOps pipeline to fix and release new features quickly). 

We had a few issues in mind at the start of discussions with the Google Cloud team, but over time, as we got information and support from them, we realized that these were the partners we wanted in our corner when it came time to tackle our most challenging problems. In the end, we decided to take our entire infrastructure to Google Cloud.

To support millions of users, we deploy and scale using Google Kubernetes Engine. While we analyze our data using a combination of managed data cloud services, such as Pub/Sub for data pipelines, BigQuery for analytics, Cloud Spanner for real-time app serving workloads, and Cloud Bigtable for less-indexed databases. We also rely on Cloud CDN to help us distribute high-quality and reliable content delivery at low latency to our users. 

We now use just half the total core consumption of our legacy environment to run ShareChat’s existing workloads.

Google Cloud delivers better outcomes at every level 

By moving to Google Cloud, we saw major benefits in several key areas: 

Zero-downtime migration for users

At the time of migration, we had over 70 terabytes of data, consisting of 220 tables—some of which were up to 14 terabytes with nearly 50 billion rows. Due to our data’s interdependencies, moving services over one at a time wasn’t an option for us. 

Even though we were migrating such large volumes of data, we didn’t want to impact any of our customers. Latency spikes for out-of-sync data might affect message delivery. For instance, if a message or notification was delayed, we didn’t want to risk a bad user experience causing someone to abandon ShareChat. 

To prepare for the move, we ran a proof-of-concept cluster for over four months to test database performance in a real-world scenario for handling more than a million queries per second. Using an open-source API gateway, we replicated our legacy data environment into Google Cloud for performance testing and capacity analysis. As soon as we were confident Google Cloud could handle the same traffic as our previous cloud environment, we were ready to execute.

Using wrappers, we were able to migrate without having to change anything in our existing application code. The entire migration of 60 million users to Google Cloud took five hours—without any data loss or downtime. Today, ShareChat has grown to 160 million users, and Google Cloud continues to give us the support we need.

Scaling globally to meet unexpected demand

We rely on real-time data to drive everything on ShareChat by tracking everything that goes on in our app—from messages and new groups to content people like or who they follow. Our users create more than a million posts per day, so it’s critical that our systems can process massive amounts of data efficiently. 

We chose to migrate to Spanner for its global consistency and secondary index. Unlike our legacy NoSQL database, we could scale without having to rethink existing tables or schema definitions and keep our data systems in sync across multiple locations. It’s also cost-effective for us—moving over 120 tables with 17 indexes into Cloud Spanner reduced our costs by 30%.

Spanner also replicates data seamlessly in multiple locations in real time, enabling us to retrieve documents if one region fails. For instance, when our traffic unexpectedly grew by 500% over just a few days, we were able to scale horizontally with zero lines of code change. We were also launching our Moj video app simultaneously, and we were able to move it to another region without a single issue. 

Simplifying development and deployment

On average, we experience about 80,000 requests per second (RPS) –nearly 7 billion RPS per day. That means daily push notifications sent out to the entire user base about daily trending topics can often result in a spike of 130,000 RPS in just a few seconds. 

Instead of over-provisioning, Google Kubernetes Engine (GKE) enables us to pre-scale for traffic spikes around scheduled events, such as holidays like Diwali, when millions of Indians send each other greetings. 

Migrating to GKE has also enabled us to adopt more agile ways of work, such as automating deployment and saving time with writing scripts. Even though we were already using container-based solutions, they lacked transparency and coverage across the entire deployment funnel. 

Kubernetes features, such as sidecar proxy, allows us to attach peripheral tasks like logging into the application without requiring us to make code changes. Kubernetes upgrades are managed by default, so we don’t have to worry about maintenance and stay focused on more valuable work. Clusters and nodes automatically upgrade to run the latest version, minimizing security risks and ensuring we always have access to the latest features.

Low latency and real-time ML predictions

Even though many of our users may be accessing ShareChat outside of metropolitan areas, it doesn’t mean they’re more patient if the app loads slowly or their messages are delayed. We strive to deliver a high-performance experience, regardless of where our users are. 

We use Cloud CDN to cache data in five Google Cloud Point of Presence (PoP) locations at the edge in India, allowing us to bring content as close as possible to people and speeding up load time. Since moving to Cloud CDN, our cache hit ratio has improved from 90% to 98.5%—meaning our cache can handle 98.5% of content requests. 

As we expand globally, we’d like to use machine learning to reach new people with content in different languages. We want to build new algorithms to process real-time datasets in regional languages and accurately predict what people want to see. Google Cloud gives us an infrastructure optimized to handle compute-intensive workloads that will be useful to us both now—and in the future.  

The confidence to build the best platform

Our current system now performs better than before we migrated, but we are continuously building new features on top of it. Google’s data cloud has provided us with an elegant ecosystem of services that allows us to build whatever we want, more easily and faster than ever before. 

Perhaps the biggest advantage of partnering with Google Cloud has been the connection we have with the engineers at Google. If we’re working to solve a specific problem statement and find a specific solution in a library or a piece of code, we have the ability to immediately connect with the team responsible for it. 

As a result, we have experienced a massive boost in our confidence. We know that we can build a really good system because we not only have a good process in place to solve problems—we have the right support behind us.

“Nude” comes in all shapes, sizes and colors. But for Ade Hassan, finding undergarments to match her skin tone took more effort than necessary. Born in the U.K. to Nigerian parents, Hassan searched unsuccessfully for underwear and swimwear that matched her skin—a problem that continued to frustrate her through college and into her professional life. 

“My nude isn’t the nude I see in shops,” Hassan says. 

Like many other black entrepreneurs, she created her own solution. Hassan founded Nubian Skin, a company that sells lingerie, hosiery, and swimwear for women of color.

With shades like “cafe au lait” and “berry,” Nubian Skin products reflect diverse skin tones and are sold in shops located in the U.K., Nigeria and the U.S., as well as online. Beyoncé and her dancers even asked Nubian Skin to outfit them for their  2017 “Formation” tour. 

Since nearly the beginning, Hassan has used G Suite to keep her business humming.

From managing meetings with retailers and manufacturers, to coordinating publicity efforts with fashion press, to keeping track of retail invoices, G Suite has helped Hassan scale her business as quickly as people have demanded her products.

“There are so many pitfalls and so many things that are hard about business,” Hassan says. “It’s really amazing to have something like G Suite that is easy and intuitive.”

Nubian Skin’s fashion fame arrived seemingly overnight. When Hassan posted the company’s first campaign images, its Instagram followers jumped from 50 people to more than 20,000 in just a few weeks.

“People called asking, ‘Can we have the contact for the press department?,” says Hassan. “But at the time, it was just me.” To easily handle media requests, she set up a press@nubianskin.com email address through the G Suite Admin console. And because she had used Gmail for several months before launching the company, using the business version of Gmail came naturally.

“Having that nubianskin.com address gave the business an air of professionalism, which we wouldn’t have had otherwise,” Hassan says. “Usually you need a whole IT department to set up new emails and passwords, but the Admin console removes the hassle of that process.”

Because Nubian Skin employees aren’t always in the showroom together, they need to be able to access business documents—like model photos and customer invoices—from anywhere.

To help, Hassan securely stores business documents in Google Drive (which can be accessed on mobile, too) and works collaboratively with her finance team to process orders using Google Sheets.

“Everyone has access to the spreadsheet so we can fill in what we need at any given point,” says Hassan. “This way, nothing slips through the cracks.”

And when she needs to connect with colleagues quickly or face-to-face, she uses Hangouts Chat or Hangouts Meet. Chat makes it so employees are only a message away, and Meet helps her connect with people as if they’re in person at the office.

Five years after launching Nubian Skin, Hassan is a recognized entrepreneur who’s influenced other retailers to create more inclusive designs.

“Even if you’re small, you want people to see you as a professional business,” Hassan says. “If you’re still growing, you need the building blocks to get you where you want to be. I can’t imagine working without G Suite.”