Category Archives: Back-End

Developer interview with Trustin

Q. Hello, Trustin! Let’s start with a brief introduction of yourself. A. Hi. My name is Trustin, and I’m currently involved in open source development of Armeria and Central Dogma at LINE. Before I joined LINE, I worked at Twitter, responsible for the maintenance of Netty as well as the development of new features and upgrades to next versions. Q. You seem to …

Cutting through the smog: making an air quality bot with Haskell

Short and long-term exposure to air pollution can result in significant health problems. When air quality is considered unhealthy we should avoid certain activities, which poses a question that bears asking: how can we get notified when air quality is poor? This post is an attempt at solving this. In this tutorial, I want to …

Troubleshooting Data Engineering Software

Hello, I’m Keiji Yoshida. I currently work as a data engineer at LINE Data Labs. In this posting, I’d like to share a few cases on data engineering software troubleshooting: Apache Hadoop YARN ResourceManager failover Apache Hadoop HDFS NameNode failover Apache Zeppelin Notebook scheduler issue Apache Zeppelin deadlock issue Apache Spark SQL performance issue Troubleshooting failover issue in Apache Hadoop …

Making a Flex Message with LINE’s Go SDK

Hi there, this is @sugyan (Twitter, GitHub) from LINE Kyoto office. This was first time for me to experience  Kyoto’s Summer, and boy, was it really hot or what!? (The original post in Japanese was published in August 2018.) In June 2018, a new message type, Flex Message, was introduced in the LINE Message API, allowing more complex …

Developing server-side with Kotlin & entering Clova Skill Awards

Hello fellow readers! We are, Kagaya, working on the LINE GAME Platform development team and Akira, on the LINE LIVE Android app development team. Have you ever used Kotlin? Kotlin is a static-typed programming language that runs on JVM, and has been developed by JetBrains, well-known for making IDEs like IntelliJ and Android Studio. Kotlin …

Redis Lua script for atomic operations and cache stampede

Hello, this is Kagaya, a member of the LINE GAME Platform development team. It’s nice to be back after writing a post on Lazybones (Japanese post), in 2016. Redis and LINE GAME Platform The LINE GAME Platform uses Redis — in-memory no SQL database — for its main database, mainly for cache. For instance, we are using …

Effective code review

Now and then, code quality becomes an issue in a team and everyone starts to talk about how we can improve unit test and code coverage, but not for long. Eventually, it’s not a hot topic anymore as people get busy. But then, you will experience déjà vu probably within a year, because the same idea comes back the next year. My name is Bryan Liu, a quality engineer working on test automation of LINE NOW, and I’d like to share what I did to facilitate unit test and code review process in LINE Taiwan.

Presenting on RedisConf18

Hello, I am Jongyeol Choi, a member of the Redis team at LINE. LINE’s services use various storage systems based on their needs. Our messaging service uses various open source storage systems such as Redis, HBase, and Kafka. As a member of the Redis team, I participated the RedisConf18 conference in San Francisco in U.S.A, on April 26th, as a speaker. The topic of my session was, “Redis at LINE, 25 billion messages per day”. I’d like to take this opportunity to share the presentation preparation process, the conference itself and the responses I got for my session.

RedisConf18 Venue

API the Docs Recap

Hi, my name is Serizawa and I’m a technical writer in LINE. LINE has a program that allows engineers to attend overseas conferences on company expense so that they can grasp the latest technology trends. In this article, I’d like to share my report on API the Docs, the API documentation conference that I attended, thanks to the program.

The structure of the LINE LIVE’s encoder layer

On December 10th of 2017, we celebrated our second anniversary for LINE LIVE, our live streaming service. The service has been up and running ever since the launch with no trouble, thanks to the efforts put in by countless engineers at LINE. On this blog post, as a member of ITSC, a team at LINE running a global infrastructure system, I’d like to share with you some of decisions we had to make in the initial phase of designing and implementing the system. Back then, I had absolutely no experience in building or running a live media service.