Aviasales API integration with Amazon Kinesis and serverless simplicity

Introduction

The main purpose of this article is to give a general understanding of the use of streaming information in AWS, we make it out of the question that the data returned by the API used is not strictly relevant and is transferred from the cache, which is generated based on searches of users of the Aviasales.ru and Jetradar.com sites for last 48 hours.

• Manual - through the AWS Management Console;
• Infrastructure from Terraform code - for lazy automation engineers;

Architecture of the system under development

• Aviasales API - the data returned by this API will be used for all subsequent work;
• EC2 Producer Instance - a regular virtual machine in the cloud on which the input data stream will be generated:
  
  
  • Kinesis Agent is a locally installed Java application that provides an easy way to collect and send data to Kinesis (Kinesis Data Streams or Kinesis Firehose). The agent constantly monitors a set of files in the specified directories and sends new data to Kinesis;
  • Caller API Script - a Python script that makes API requests and puts the response in a folder that Kinesis Agent monitors;
• Kinesis Data Streams — ;
• Kinesis Analytics — , . Amazon Kinesis Data Analytics ;
• AWS Lambda — , . ;
• Amazon DynamoDB — «‑» , 10 . DynamoDB - , . DynamoDB , . ;
• Amazon SNS — « — » (Pub/Sub), , . SNS push-, SMS- .

Initial training

http://api.travelpayouts.com/v2/prices/month-matrix?currency=rub&origin=LED&destination=HKT&show_to_affiliates=true&token=TOKEN_API

{{
   "success":true,
   "data":[{
      "show_to_affiliates":true,
      "trip_class":0,
      "origin":"LED",
      "destination":"HKT",
      "depart_date":"2015-10-01",
      "return_date":"",
      "number_of_changes":1,
      "value":29127,
      "found_at":"2015-09-24T00:06:12+04:00",
      "distance":8015,
      "actual":true
   }]
}

It is assumed that you already have an AWS account. I want to pay special attention right away that Kinesis and sending notifications via SMS are not included in the annual Free Tier (free use) . But even despite this, having a couple of dollars in mind, it is quite possible to build the proposed system and play with it. And, of course, do not forget to delete all resources after they become unnecessary.

Manual deployment system

Setting up Kinesis Data Streams

Producer Setting

Creating IAM Roles for EC2

, , EC2 Permissions:

, : AmazonKinesisFullAccess CloudWatchFullAccess.

- , : EC2-KinesisStreams-FullAccess. , , :

, :

.

sudo yum -y update
sudo yum install -y python36 python36-pip
sudo /usr/bin/pip-3.6 install --upgrade pip
sudo yum install -y aws-kinesis-agent

sudo mkdir /var/log/airline_tickets

sudo vim /etc/aws-kinesis/agent.json

{
  "cloudwatch.emitMetrics": true,
  "kinesis.endpoint": "",
  "firehose.endpoint": "",

  "flows": [
    {
      "filePattern": "/var/log/airline_tickets/*log",
      "kinesisStream": "airline_tickets",
      "partitionKeyOption": "RANDOM",
      "dataProcessingOptions": [
         {
            "optionName": "CSVTOJSON",
            "customFieldNames": ["cost","trip_class","show_to_affiliates",
                "return_date","origin","number_of_changes","gate","found_at",
                "duration","distance","destination","depart_date","actual","record_id"]
         }
      ]
    }
  ]
}

sudo service aws-kinesis-agent restart

REPO_PATH=https://raw.githubusercontent.com/igorgorbenko/aviasales_kinesis/master/producer

wget $REPO_PATH/api_caller.py -P /home/ec2-user/
wget $REPO_PATH/requirements.txt -P /home/ec2-user/
sudo chmod a+x /home/ec2-user/api_caller.py
sudo /usr/local/bin/pip3 install -r /home/ec2-user/requirements.txt

class TicketsApi:
    """Api caller class."""

    def __init__(self, headers):
        """Init method."""
        self.base_url = BASE_URL
        self.headers = headers

    async def get_data(self, data):
        """Get the data from API query."""
        response_json = {}
        async with ClientSession(headers=self.headers) as session:
            try:
                response = await session.get(self.base_url, data=data)
                response.raise_for_status()
                LOGGER.info('Response status %s: %s',
                            self.base_url, response.status)
                response_json = await response.json()
            except HTTPError as http_err:
                LOGGER.error('Oops! HTTP error occurred: %s', str(http_err))
            except Exception as err:
                LOGGER.error('Oops! An error ocurred: %s', str(err))
            return response_json


def prepare_request(api_token):
    """Return the headers and query fot the API request."""
    headers = {'X-Access-Token': api_token,
               'Accept-Encoding': 'gzip'}

    data = FormData()
    data.add_field('currency', CURRENCY)
    data.add_field('origin', ORIGIN)
    data.add_field('destination', DESTINATION)
    data.add_field('show_to_affiliates', SHOW_TO_AFFILIATES)
    data.add_field('trip_duration', TRIP_DURATION)
    return headers, data


async def main():
    """Get run the code."""
    if len(sys.argv) != 2:
        print('Usage: api_caller.py <your_api_token>')
        sys.exit(1)
        return
    api_token = sys.argv[1]
    headers, data = prepare_request(api_token)

    api = TicketsApi(headers)
    response = await api.get_data(data)
    if response.get('success', None):
        LOGGER.info('API has returned %s items', len(response['data']))
        try:
            count_rows = log_maker(response)
            LOGGER.info('%s rows have been saved into %s',
                        count_rows,
                        TARGET_FILE)
        except Exception as e:
            LOGGER.error('Oops! Request result was not saved to file. %s',
                         str(e))
    else:
        LOGGER.error('Oops! API request was unsuccessful %s!', response)

sudo ./api_caller.py TOKEN

tail -f /var/log/aws-kinesis-agent/aws-kinesis-agent.log

Setting up Kinesis Data Analytics

1. allows you to create new streams (Output Stream) based on queries to the source data;
2. provides a stream with errors that occurred during application operation (Error Stream);
3. It can automatically determine the input data scheme (it can be manually redefined if necessary).

This is an expensive service - 0.11 USD per hour, so you should use it carefully and remove it when you complete the work.

CREATE OR REPLACE STREAM "DESTINATION_SQL_STREAM" ("cost" DOUBLE, "gate" VARCHAR(16));

CREATE OR REPLACE PUMP "STREAM_PUMP" AS INSERT INTO "DESTINATION_SQL_STREAM"
SELECT STREAM "cost", "gate"
FROM "SOURCE_SQL_STREAM_001"
WHERE "cost" < 5000
    and "gate" = 'Aeroflot';

In relational databases, you work with tables using INSERT statements to add records and a SELECT statement to query data. In Amazon Kinesis Data Analytics, you work with streams (STREAM) and “pumps” (PUMP) - continuous insertion requests that insert data from one stream in an application into another stream.

Creating and subscribing to the SNS topic

Creating a table in DynamoDB

Creating a lambda collector function

Creating an IAM role for a lambda collector function

IAM Lambda-TicketsProcessingRole:

AmazonKinesisReadOnlyAccess AmazonDynamoDBFullAccess, :

"""Parsing the stream and inserting into the DynamoDB table."""
import base64
import json
import boto3
from decimal import Decimal

DYNAMO_DB = boto3.resource('dynamodb')
TABLE_NAME = 'airline_tickets'

class TicketsParser:
    """Parsing info from the Stream."""

    def __init__(self, table_name, records):
        """Init method."""
        self.table = DYNAMO_DB.Table(table_name)
        self.json_data = TicketsParser.get_json_data(records)

    @staticmethod
    def get_json_data(records):
        """Return deserialized data from the stream."""
        decoded_record_data = ([base64.b64decode(record['kinesis']['data'])
                                for record in records])
        json_data = ([json.loads(decoded_record)
                      for decoded_record in decoded_record_data])
        return json_data

    @staticmethod
    def get_item_from_json(json_item):
        """Pre-process the json data."""
        new_item = {
            'record_id': json_item.get('record_id'),
            'cost': Decimal(json_item.get('cost')),
            'trip_class': json_item.get('trip_class'),
            'show_to_affiliates': json_item.get('show_to_affiliates'),
            'origin': json_item.get('origin'),
            'number_of_changes': int(json_item.get('number_of_changes')),
            'gate': json_item.get('gate'),
            'found_at': json_item.get('found_at'),
            'duration': int(json_item.get('duration')),
            'distance': int(json_item.get('distance')),
            'destination': json_item.get('destination'),
            'depart_date': json_item.get('depart_date'),
            'actual': json_item.get('actual')
        }
        return new_item

    def run(self):
        """Batch insert into the table."""
        with self.table.batch_writer() as batch_writer:
            for item in self.json_data:
                dynamodb_item = TicketsParser.get_item_from_json(item)
                batch_writer.put_item(dynamodb_item)

        print('Has been added ', len(self.json_data), 'items')

def lambda_handler(event, context):
    """Parse the stream and insert into the DynamoDB table."""
    print('Got event:', event)
    parser = TicketsParser(TABLE_NAME, event['Records'])
    parser.run()

Creating a lambda function notifier

Create IAM Roles

IAM Lambda-KinesisAlarm , alarm_notifier:

import boto3
import base64
import os

SNS_CLIENT = boto3.client('sns')
TOPIC_ARN = os.environ['TOPIC_ARN']


def lambda_handler(event, context):
    try:
        SNS_CLIENT.publish(TopicArn=TOPIC_ARN,
                           Message='Hi! I have found an interesting stuff!',
                           Subject='Airline tickets alarm')
        print('Alarm message has been successfully delivered')
    except Exception as err:
        print('Delivery failure', str(err))

Deploy from Terraform code

Necessary preparation

How to start

terraform.exe plan

terraform.exe apply

Application Testing

sudo ./api_caller.py TOKEN

Conclusion