基于AWS Lambda的图片处理示例

需求场景：用户上传一个图片文件到S3上时，自动触发Lambda函数，生成一个thumbnail小图片。

如图片上传到source-bucket，则会在source-bucketresized中生成同样文件名的小图片
source-bucket/image.png -> source-bucketresized/image.png

参考链接：http://docs.aws.amazon.com/lambda/latest/dg/with-s3-example-deployment-pkg.html
github链接：https://github.com/wfhu/aws-Lambda-S3-Thumbnail

主要的技术点：

  • python2.7环境运行通过
  • PUT事件触发Lambda函数执行
  • 使用 boto3 package来进行S3相关操作
  • 使用 PIL package来进行图片的处理
  • Lambda运行环境支持/tmp目录

常见使用场景：

  • 图片自动打水印
  • 图片压缩
  • 原图上传后，为各种使用场景自动处理生成不同大小的图片

附上修改过的示例代码：

from __future__ import print_function
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(tuple(x / 2 for x in image.size))
        image.save(resized_path)
     
def handler(event, context):
    for record in event['Records']:
        bucket = record['s3']['bucket']['name']
	print("Log bucket name:", bucket)
        key = record['s3']['object']['key'] 
	print("Log key name:", key)
        download_path = '/tmp/{}{}'.format(uuid.uuid4(), key)
	print("Log download_path name:", download_path)
        upload_path = '/tmp/resized-{}'.format(key)
	print("Log upload_path name:", upload_path)
        
	# create source directory
	directory = os.path.dirname(download_path)
	print("Log directory name :", directory)

	if not os.path.exists(directory):
		os.makedirs(directory)

	#create target directory
	targetdirectory = os.path.dirname(upload_path)
	print("Log targetdirectory name :", targetdirectory)

	if not os.path.exists(targetdirectory):
		os.makedirs(targetdirectory)

	with open(download_path, 'wb') as data:
	        s3_client.download_fileobj(bucket, key, data)
        resize_image(download_path, upload_path)
        s3_client.upload_file(upload_path, '{}resized'.format(bucket), key)