Collecting Data

This is a HOWTO for collecting data in Ruby and Python applications.

Scraping your Gmail Inbox

Define a schema for our emails

While it is cumbersome to define static schemas, we need only do so once with Avro. Our data is then accessible by any of the languages or tools we will use.

Email's format is defined in RFC-5322. A corresponding Avro schema for email looks like this:

{
    "namespace": "agile.data.avro",
    "name": "Email",
    "type": "record",
    "fields": [
        {"name":"message_id", "type": ["string", "null"]},
        {"name":"from","type": ["string", "null"]},
        {"name":"to","type": [{"type":"array", "items":"string"}, "null"]},
        {"name":"cc","type": [{"type":"array", "items":"string"}, "null"]},
        {"name":"bcc","type": [{"type":"array", "items":"string"}, "null"]},
        {"name":"reply_to", "type": [{"type":"array", "items":"string"}, "null"]},
        {"name":"subject", "type": ["string", "null"]},
        {"name":"body", "type": ["string", "null"]},
        {"name":"date", "type": ["string", "null"]}
    ]
}

Scrape your Inbox

Setup:

cd src/ruby
sudo gem install bundler
bundle install

Execute:

bundle exec bin/scrape_mail <email_address> <password> <message_count> <output_filename>

Processing via Pig

Generating to/from pair sent counts from all emails:

REGISTER /me/pig/build/ivy/lib/Pig/avro-1.5.3.jar
REGISTER /me/pig/build/ivy/lib/Pig/json-simple-1.1.jar
REGISTER /me/pig/contrib/piggybank/java/piggybank.jar
REGISTER /me/pig/build/ivy/lib/Pig/jackson-core-asl-1.7.3.jar
REGISTER /me/pig/build/ivy/lib/Pig/jackson-mapper-asl-1.7.3.jar

DEFINE AvroStorage org.apache.pig.piggybank.storage.avro.AvroStorage();
sh rm -rf '/tmp/sent_counts.avro' /* Workaround for PIG-2441 */

messages = LOAD '/tmp/10000_emails.avro' USING AvroStorage();
messages = FILTER messages BY from IS NOT NULL AND to IS NOT NULL;
smaller = FOREACH messages GENERATE from, to;
pairs = FOREACH smaller GENERATE from, FLATTEN(to) AS to:chararray;
pairs = FOREACH pairs GENERATE LOWER(from) AS from, LOWER(to) AS to;

froms = GROUP pairs BY (from, to);
sent_counts = FOREACH froms GENERATE FLATTEN(group) AS (from, to), SIZE(pairs) AS total;
STORE sent_counts INTO '/tmp/sent_counts.avro' USING AvroStorage();

Publishing with MongoDB

MongoDB (from "humongous") is an open source, high-performance, schema-free, document-oriented database written in the C++ programming language

MongoDB is available here. Once you install it and get it running,