reezocar_test

Purpose

This program goes through the pages of a www.autoreflex.com announce listing and extracts for each announce :

• Announce id
• URL
• Title of the announce
• Price
• Phone number
• Garage name
• Garage address
• Car mileage
• Car first registration date
• Announce postal code
• Car engine (Diesel/Essence)
• Transmission (Automatique/Manuelle)
• Fiscal power (this field actually contains horse power + fiscal power)

Listing used for this POC : http://www.autoreflex.com/137.0.-1.-1.-1.0.999999.1900.999999.-1.99.0.1?fulltext=&geoban=M137R99

Prerequisite

• GoLang 1.13
• Kafka 2.5.0
• Go Colly scrapper library
• Docker

Initialisation

A) Create an Announces Kafka topic :

• ./kafka-topics.sh --create --bootstrap-server localhost:9092 --replication-factor 1 --partitions 1 --topic announces

B) Use following Docker commands to run a MongoDB container :

• Create a volume to persist data docker volume create announces-volume
• Run MongoDB image docker run --name announces-mongodb -v announces-volume:/data/db -p 27017:27017 -d mongo (for the sake of the POC we use no auth. We could have set environment variables MONGO_INITDB_ROOT_USERNAME and MONGO_INITDB_ROOT_PASSWORD to set credentials)

C) Download Go Colly and MongoDB libraries :

• go get -u github.com/gocolly/colly/...
• go get -u go.mongodb.org/mongo-driver/mongo

D) Run consumer and producer

Screenshots

Producer :

Consumer (log message hidden by default) :

MongoDB announces collection :

Areas for improvment

• Better parsing of announces fields (for instance, fiscal_power field contains actually horse power + fiscal power separated by a "/", car mileage could be formatted to int ("120 000km" to "120000"), etc..)
• When scanning a lot of pages (15+/20+ pages), there could sometimes be a client timeout error which must be handled
• Avoid duplicates : can be easily done by overriding MongoDB's _id field with the announce ID