코드보면서 공부해보기

from datetime import datetime, timedelta, timezone

import boto3

import pymysql

# 00. AWS Resource Initialize

dynamodb = boto3.resource('dynamodb')

# 01. UTC to Local Converter

def convert_utc_to_local(utctime_str, offset):                                                            

    return datetime.strptime(utctime_str, "%Y-%m-%d %H:%M:%S") \

        .replace(tzinfo=timezone.utc).astimezone(tz=timezone(timedelta(hours=offset))) \

        .strftime("%Y-%m-%d %H:%M:%S %Z")

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offset이란

컴퓨터 과학에서 배열이나 자료 구조 오브젝트 내의 오프셋(offset)은 일반적으로 동일 오브젝트 안에서 오브젝트 처음부터 주어진 요소나 지점까지의 변위차를 나타내는 정수형이다.

offset이란 변위차이라고 한다.

 astimezone은 localtime에 맞게 바꿔주는것같다.

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def lambda_handler(event, context):

    # 02. MySQL and DynamoDB Instance

    mysql_g2_obj = pymysql.connect(host=“mj3.*****.us-east-1.rds.amazonaws.com",

                                   user="mj", passwd=“****", db="g2instance", connect_timeout=5)

    mysql_migration_obj = pymysql.connect(host=“mj3.****.us-east-1.rds.amazonaws.com", user="mj",

                                          passwd=“*****",

                                          db="migration", connect_timeout=5)

    dynamo_obj = dynamodb.Table('g2-instance')

    # 03. Request Params

    param_local = int(event.get('local', 0))

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event.get의 지원하는 type는 int, str 등등 dictionary이다.

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    # 04. Get current pricetable

    pricetable = dynamo_obj.scan()

    resp_pricetable_dict = {}

    for item in pricetable["Items"]:

        resp_pricetable_dict[str(item['az'])] = item['price']

    # 05. Get last information (Current az, current price of az, current steps, last update time)

    with mysql_g2_obj.cursor() as cur:

        resp_lastinfo_dict = {}

        cur.execute("select * from Spottable ORDER BY Time DESC LIMIT 1")

        try:

            row = cur.fetchall()[0]

            resp_lastinfo_dict["time"] = convert_utc_to_local(str(row[0]), param_local)

            resp_lastinfo_dict["az"] = row[1]

            resp_lastinfo_dict["price"] = row[2]

            resp_lastinfo_dict["step"] = int(row[3])

        except:

            pass

---

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    mysql_g2_obj.close()

    # 06. Get migration route

    with mysql_migration_obj.cursor() as cur:

        resp_migration_list = []

        cur.execute("select az,current_price,time from Route ORDER BY id ASC")

        rows = cur.fetchall()

        for row in rows:

            resp_migration_list.append({

                "az": str(row[0]),

                "price": row[1],

                "time": convert_utc_to_local(str(row[2]), param_local) if row[2] else None

            })

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row[2]가 true이면 저 함수를 쓰고 else 면 아무것도 아니라는 건거 같다. None이라고 처리해주는 거 같다.

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    mysql_migration_obj.close()

    # 07. Return JSON

    return {

        "pricetable": resp_pricetable_dict,

        "lastinfo": resp_lastinfo_dict,

        "migration": resp_migration_list

    }

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동언이 보기 좋게 잘 짠듯  낼 다시 봐봐야겠다 좋은 코드라고 느낄수있다.

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