AWS lambda使用案例——为S3中图片生成缩略图

夏宏旷
2023-12-01

本文来源:

https://amazon.qwiklabs.com/focuses/10541?catalog_rank=%7B%22rank%22%3A1%2C%22num_filters%22%3A1%2C%22has_search%22%3Atrue%7D&parent=catalog&search_id=6895488

主要是其试验经过。

 

Task1:创建两个S3

命名分别为images-NUMBER,  images-NUMBER-resized

找到一张大图,名为HappyFace.jpg,上传到images-NUMBER

https://s3.us-west-2.amazonaws.com/us-west-2-aws-training/awsu-spl/spl-88/2.3.7.prod/images/HappyFace.jpg

 

Task2:创建lambda函数

默认设置,填写名称Create-Thumbnail,Runtime:python3.7

在Choose or create an execution role中选择

Execution role:Using an existing role

Existing role:lambda-execution-role

这个role会给lambda函数访问和读写S3的权限

点击Add trigger,选择trigger:s3,Bucket选择images-NUMBER,EventType为all object create events然后Add

图中点击Create-Thumbnail,代码里选择upload a file from s3

https://s3-us-west-2.amazonaws.com/us-west-2-aws-training/awsu-spl/spl-88/2.3.7.prod/scripts/CreateThumbnail.zip

它的意思是

import boto3
import os
import sys
import uuid
from PIL import Image
import PIL.Image

s3_client = boto3.client('s3')

def resize_image(image_path, resized_path):
    with Image.open(image_path) as image:
        image.thumbnail((128, 128))
        image.save(resized_path)

def handler(event, context):
    for record in event['Records']:
        bucket = record['s3']['bucket']['name']
        key = record['s3']['object']['key']
        download_path = '/tmp/{}{}'.format(uuid.uuid4(), key)
        upload_path = '/tmp/resized-{}'.format(key)

        s3_client.download_file(bucket, key, download_path)
        resize_image(download_path, upload_path)
        s3_client.upload_file(upload_path, '{}-resized'.format(bucket), key)

在Basic settings中,编辑

Description:Create a thumbnail-sized image

Handler:CreateThumbnail.handler

保存。Lambda函数至此已配置好。

 

Task3:测试lambda函数

点击上方Test按钮,配置

Event template:搜索“Amazon S3 Put“

Event name:Upload

在下方代码中替换example-bucket的两处内容为images-NUMBER。

替换test/key的一处,为HappyFace.jpg

点击Create。随后开始Test

在images-NUMBER-resized查看新图片。

<完>

 

附:

AWS Lambda文档:https://docs.aws.amazon.com/lambda/index.html

 

 

 

 

 

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