ClojureLT_OXUT

lagenorhynque

Scala vs Clojure

Opt had some history of Scala vs Clojure

Introduction

excited for first physical event for long time

Talk is about Clojure usage at Opt, but personal role has been more manager

3 topics

Opt technologies summary

How clojure is used

Lessons learned

hopefully 15 mins

Opt technologies

internet advertising agency

Opt technologies is an internal development org with 40~50 members

I am defacto CTO

please check official site and tech blog

characteristics

autonomy

office/not is flexible

time is also flexible

annyal 60 days holiday

tech

JVM language

Ruby

PHP

very wide range

and accompanying chaos

Hiring

Clojure usages at opt

several articles/blog

2017 first usage - mail sending batch

2019 Talk titled Clojurian conquest

How to make Clojure prevail in a Scala dominated environment

Graphql API made with Clojure

Introduction to functional programming

Scala usage was huge, but currently Scala usage is declining

Scala usage was huge among web companies circa 2016

Typescript & Go also growing

I introduced Clojure and usage has been expanding

Used in important system

Haskell and elm were attempted in the past

Challenge: why use Clojure when there is Scala?

Now 10 Clojure engineers

Products using Clojure

Task Driver

task manager for ad operation

send mails

luminus

immutant

hugsql

Schema (clojure spec was not a thing)

aws api

New Opt editor

Talk to rest apis provided by Ad platforms like yahoo etc

duct+pedestal

made original duct module

struct for validation

honeysql

great for dynamic sql

amazonica

a little out dated

Wrote a mini book as well

Ams API

ad related master data

solution against chaos arising from shared database that hosted every data

lacinia

graphql library provided by walmart labs

superlifter

dataloader

malli

input validation

lessons learned

Had to fight with Scala

Dynamic nature was hard to argue

Long term stability was great for selling

Scala is famous for breaking changes

Japanse resource is limited

Contributed material by self

Had to improvise some graphql constructs that are available in Typescript out of box

Functional programming, JVM, repl driven development, community <3

questoin: What did the scala user say when using Clojure?

Great after getting over the Lack of type check and parenthesis

Pretty smooth if person is okay with dynamic lang

athos

Clojure usage at Xcoo

Intro

Clojurian since 2009

Joined Xcoo in 2018

Contributed to Clojure/ClojureScript

Past longer talks by Xcoo

Clojure/Conj 2017

Shibuya Lisp tech talk 2022

This talk is like a quick summary of above

What Xcoo does

How Clojure is used

Xcoo

founded in 2011

44 members

Business

Provide chrovis, total solution for genome medicine

Genome medicine

everyone has DNA made from ACGT

Could be damaged, leading to Cancer

Medical treatment based on genomic information is important

e.g. molecular target drug

Engineering team

Analysis

Analyse gene mutations

Athos works in this team

Database

Scrape/collect information from public sources

Report

Provide UI for medical providers

Infrastructure

Operate the systems

All Engineers can Clojure

Probably larget Clojure house

Clojure usage at Xcoo

203 repositories

2380 source files

200,000 lines of code mostly Clojure

3866 Pull requests

Many OSS products under Chrovis organization

cljam - largest, used in many places

i/o for genome specific files

need to deal with file sizes of 10s of GBs

specific file formats to deal with the scale

e.g.

fastq

sam/bam

vcf/bcf

various algoritms

Tools/libraries used in Systems

Good points from using Clojure

Sequence representation

Large files don't fit in memory

processing as sequence is very convenient

Parallelism

Large data => long processing time

several hours is typical, can take up to 1 day

speed up by some constant factor is effective

immutable data is makes multi threading easy

claypool to control parallelism

REPL exploration

esp. for analysis team, need to deal with problems that require interaction with actual data

repl works well for trial and error process

easy for debugging

as long as there is an uberjar you can start a repl

socket repl for remote debugging

Advantage for analyzing data

Looking forward to datascience/visualization development in the ecosystem

Was a Clojure conj talk on the topic as well

Might become a viable choice by data scientists

REPL might be a strong selling point

Sane package system compared to R and Python

Platforms

Clojure

ClojureScript

Babashka

scripting

also use personally

genome analysis requires handling many files, and babashka is great when sed/awk become too hard

stdin is sequence

has threads

Xcoo is hiring

_ayato_p

usabase

more casual than previous talks

name: ayapi

usabase

B2B saas

products

speeda

probably very few people using Clojure and F#

Talking about JSON

probably everyone loves JSON?

micro service architecutre

managed in a monorepo

probably 150 apis

40 project.clj

100 engineers in org

fluid team

potentially 100 Clojure engineers

Services talk to each others in JSON

camelCase is required

Typically need to return a list of companies

100 items/10 items

Need to aggregate attributes from various micro services

Batching blocks for a long time

=> great if it can be a stream?

And core.async?

great * great = really great?

clj-http

extract reader

JSON/process json

JSONL

json as steam has advantage because consumer can chose to buffer content

Usabase

Many languages used as long as JSON is used

rust is gaining popular

Might be good fit if you want to use many languages

Haokang Den

CTO at Toreta

Making POS using datomic cloud

Toreta

vertical SaaS

provide many services to Restaurants

Hiring

POS

50 yeas of history

Mobile order on the rise

Restaurants want to express their own idea

need to accomodate many flavors with one product

Product = O/X

scan QR code

great menu

post orders

complete payment

Advantage

Waiter is no longer bottleneck

customers can order whenever

Waiters can focus on recommending/hosting

Why Clojure?

From management prospective

Stability

POS is critical for restaurants

no POS no business

need long term commitment

Clojure has great track record

was a Ruby shop

Ruby is famous for breaking changes

Auditability

System

Not just processing orders, want to provide value by analytics as well

transaction

cdc with 15 mins

Near realitime info with Looker

Dyncamically change menu

Architecture

Testing is important

clean architecture inspired

Datomic+Duct+Lacinia

Fetcher layer to avoid N+1

90% coverage

Development process

Customers are restaurants

very personal

Need close understanding of customers

Accumulate domain knowledge

Datamodeling by product owner

Designers work with E-R diagrams

Prevent mismatch of UI - Backend datamodel

Used in many restaurants

Questions

TLA+

not used in Clojure, but used for validating interfaces

# of transactions?

will get back

Nicolas Modrzyk

Talk about origami

Intro

Drank too much champane and ended up in Tokyo

CTO

using many languages

Origami

library

opencv rapper on jvm

compiling installing etc taken care of

started in 2017

Was doing something with OpenCV

Wanted to make a tool to recognize sushi item

Clojure => no need to re-compile

No demo

Supported languages

Clojure

Java

Kotlin

Scala

etc

Sample Applications

3 books

Chinese Web Camera

noticed traffic to China

Usecases

motion tracking

art filters

Bought 30 webcams to compare

Recognizing a banana is hard

M1 mac broke things

opensource

feel good when people DM you about it

maintenance is a lot of work

collaboration is fun

Jetbrains IDE lisence for contributors