translate_from_s3.py

import json
import urllib.parse
import boto3
import datetime

print('Loading function')

s3 = boto3.client('s3')

def read_input_text(bucket_name, input_key):
    obj = s3.get_object(Bucket = bucket_name, Key = input_key)
    body = obj['Body'].read().decode('utf-8')
    return json.loads(body)['results']['transcripts'][0]['transcript']

def translate_text(text):
    translate = boto3.client('translate')
    response = translate.translate_text(
        Text = text,
        SourceLanguageCode = 'en',
        TargetLanguageCode = 'ja'
    )
    return response['TranslatedText']

def upload_json(bucket_name, output_key, json_text):
    resource_s3 = boto3.resource('s3')
    obj = resource_s3.Object(bucket_name, output_key)
    obj.put(Key = output_key, Body = json_text)

def lambda_handler(event, context):
    bucket = event['Records'][0]['s3']['bucket']['name']
    input_key = urllib.parse.unquote_plus(event['Records'][0]['s3']['object']['key'], encoding='utf-8')
    
    try:
        input_text = read_input_text(bucket, input_key)
        
        translated_text = translate_text(input_text)
        
        output_key = datetime.datetime.now().strftime("%Y%m%d%H%M%S") + '_translated.json'
        json_text = json.dumps({
            'input_text': input_text,
            'translated_text': translated_text
        }, ensure_ascii = False)
        upload_json(bucket, output_key, json_text)

    except Exception as e:
        print(e)
        raise e