LINE Engineering

  • Applying CircuitBreaker to Channel Gateway
    Shin Jong Hun 2016.08.05

    I don’t like being inconvenienced. One of the focal points of my work is to reduce these inconveniences so I have more time to focus on what matters. I think that’s why I like programming. Although I can’t really figure out why I seem to be getting busier with time…

    Before reading

    If you have yet to read the introductory article to circuit breakers, I recommend you read the following article first: Circuit Breakers for distributed services

    Applying CircuitBreaker to Channel Gateway

    Channel Gateway servers provide various LINE server features to content providers. This is why Channel Gateway servers are highly affected by the servers they are connected to, with the effects easily spreading across all Channel Gateway servers.


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  • Report on Prometheus Casual Talks in Tokyo and then toward PromCon 2016
    Yukawa Wataru 2016.08.02

    He is a data engineer at LINE. He usually works with Hadoop, Hive, Presto, Azkaban, Fluentd, Elasticsearch, Prometheus, Grafana, and more.


    Hello, my name is Wataru Yukawa. I work at LINE as a data engineer.

    As a data engineer, my daily duties include using Fluentd to collect logs, Hadoop to accumulate, and Hive to aggregate and analyze logs. Our Hadoop cluster is medium-sized, consisting of 40 units and approximately 370TB of DFS used space. Data from LINE family apps is smaller compared to the LINE app. While it's nowhere near large enough to be considered as big data, it still has many types of different data, Fluentd tags, and over 400 Fluentd processes due to the various LINE family services tied to it. The Fluentd data flow amounts to 150 thousand messages per second during peak times.

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  • Introducing the LINE Game AirBorne DataCenter
    OH WANG JIN 2016.07.25

    He is a data engineer for the LINE Ads Platform. His main development areas are games, security and search and is currently working on the big data technology.

    Last time I posted an article titled, "Analyzing Large Amounts of Security Data with Spark, Mesos, Zeppelin, and HDFS." Today I will introduce how LINE applies cloud and stream processing technology to perform near-real-time processing on game data detected by AirArmor1.

    1: AirArmor is a security solution for mobile games developed by LINE.

    AirBorne DataCenter & Mesos (with DC/OS)

    To analyze security data, we built our own system named AirBorne DataCenter. The system uses Apache Mesos as its base framework. And to process big data efficiently, the system implements open source components such as Kafka, Spark, Elasticsearch, Hadoop, Zeppelin, and Spring.

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  • Circuit breakers for distributed services
    Ono Yuichi 2016.07.25

    He is a LINE engineer.

    Hello, my name is Ono and I'm a LINE engineer. In this blog post, I'd like to talk about "circuit breakers" which we use with our LINE servers.

    What is a Circuit Breaker?

    The backend server systems for various web services and apps including LINE consist of networks that have several services connected with each other through APIs and RPCs.

    What would happen if one of these networks suddenly failed to respond? The downed services would be blocked until they time-out, and all other services that rely on the blocked service would start a chain reaction of failures. If no one has been keeping an eye on the entire network, it will take a long time to figure out which service is the root cause.


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  • LINE Developer Day 2016
    Kushii Yusuke 2016.07.12

    In charge of actively and creatively promoting the technologies of LINE both in and out of the company. Also in charge of operations of LINE Developer Day 2016.

    Hello everyone. My name is Kushii, and I am in charge of organizing conferences at LINE.
    I am pleased to announce that LINE Developer Day will be taking place once again this year.

    At the event our engineering team plan to share some of the experiences, the technical challenges that exist in Japan and overseas, and introduce our latest products directly to you. Security-related topics, BOTs, and other themes will be explored during our individual sessions to explain how LINE strives to overcoming the various challenges ahead.

    Event Summary

    Date/Time: September 29, 2016 from 10 a.m. to 6:30 p.m.
    Place: Shibuya Hikarie, 9F, Hikarie Hall
    Invitees: Application and web engineers
    Admission: Free
    After-Party: To take place in the Hikarie Hall after the event

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