我正在尝试根据文章使用云端分布调整图像大小： https ://aws.amazon.com/tr/blogs/networking-and-content-delivery/resizing-images-with-amazon-cloudfront-lambdaedge-aws-cdn -博客/
我在文章上创建了具有给定 Origin-Response 和 Viewer-Request 函数的项目文件夹，并下载了依赖项，使用 cloudformation 模板部署了 zip 包。
IAM 角色、s3 存储桶、存储桶策略、使用 lambda@edge 函数的分配均在没有任何错误的情况下创建，并且它们似乎都兼容。
但是当我尝试调整原始存储桶中的图像大小时出现以下错误；
“503 错误无法满足请求。与 CloudFront 分配关联的 Lambda 函数无效或没有所需的权限。”
我也没有看到任何关于监控的内容，这意味着我的函数没有被调用。
我使用“AdministratorAccess”策略和信任关系创建了另一个管理员角色“edgelambda.amazonaws.com”、“lambda.amazonaws.com”
我将我的存储桶策略更改为所有公共。
我可以查看图像，但是当我尝试通过将查询字符串添加到云端分发 url 来调整大小时仍然出现 503 错误
“xxxxxxxxx.net/images/pexels.jpeg?d=100x100”
这是我的存储桶、存储桶策略、IAM 角色和功能。
存储桶名称：image-resize-488052071209-us-east-1
桶装政策：
{
"Version": "2008-10-17",
"Statement": [
{
"Sid": "AllowPublicRead",
"Effect": "Allow",
"Principal": {
"AWS": "*"
},
"Action": "s3:GetObject",
"Resource": "arn:aws:s3:::image-resize-488052071209-us-east-1/*"
},
{
"Effect": "Allow",
"Principal": {
"AWS": "*"
},
"Action": "s3:PutObject",
"Resource": "arn:aws:s3:::image-resize-488052071209-us-east-1/*"
},
{
"Effect": "Allow",
"Principal": {
"AWS": "*"
},
"Action": "s3:GetObject",
"Resource": "arn:aws:s3:::image-resize-488052071209-us-east-1/*"
}
]
}
IAM 角色：
Admin:
AdministratorAccess, "edgelambda.amazonaws.com","lambda.amazonaws.com" trust relationships
ImageFunctionsAndRole-EdgeLambdaRole-1U93T440VWXKT:
AmazonS3FullAccess, CloudFrontFullAccess, AWSLambdaExecute, CloudFrontReadOnlyAccess, AWSLambdaBasicExecutionRole
查看者请求函数
'use strict';
const querystring = require('querystring');
// defines the allowed dimensions, default dimensions and how much variance from allowed
// dimension is allowed.
const variables = {
allowedDimension : [ {w:100,h:100}, {w:200,h:200}, {w:300,h:300}, {w:400,h:400} ],
defaultDimension : {w:200,h:200},
variance: 20,
webpExtension: 'webp'
};
exports.handler = (event, context, callback) => {
const request = event.Records[0].cf.request;
const headers = request.headers;
// parse the querystrings key-value pairs. In our case it would be d=100x100
const params = querystring.parse(request.querystring);
// fetch the uri of original image
let fwdUri = request.uri;
// if there is no dimension attribute, just pass the request
if(!params.d){
callback(null, request);
return;
}
// read the dimension parameter value = width x height and split it by 'x'
const dimensionMatch = params.d.split("x");
// set the width and height parameters
let width = dimensionMatch[0];
let height = dimensionMatch[1];
// parse the prefix, image name and extension from the uri.
// In our case /images/image.jpg
const match = fwdUri.match(/(.*)\/(.*)\.(.*)/);
let prefix = match[1];
let imageName = match[2];
let extension = match[3];
// define variable to be set to true if requested dimension is allowed.
let matchFound = false;
// calculate the acceptable variance. If image dimension is 105 and is within acceptable
// range, then in our case, the dimension would be corrected to 100.
let variancePercent = (variables.variance/100);
for (let dimension of variables.allowedDimension) {
let minWidth = dimension.w - (dimension.w * variancePercent);
let maxWidth = dimension.w + (dimension.w * variancePercent);
if(width >= minWidth && width <= maxWidth){
width = dimension.w;
height = dimension.h;
matchFound = true;
break;
}
}
// if no match is found from allowed dimension with variance then set to default
//dimensions.
if(!matchFound){
width = variables.defaultDimension.w;
height = variables.defaultDimension.h;
}
// read the accept header to determine if webP is supported.
let accept = headers['accept']?headers['accept'][0].value:"";
let url = [];
// build the new uri to be forwarded upstream
url.push(prefix);
url.push(width+"x"+height);
// check support for webp
if (accept.includes(variables.webpExtension)) {
url.push(variables.webpExtension);
}
else{
url.push(extension);
}
url.push(imageName+"."+extension);
fwdUri = url.join("/");
// final modified url is of format /images/200x200/webp/image.jpg
request.uri = fwdUri;
callback(null, request);
};
源响应函数：
'use strict';
const http = require('http');
const https = require('https');
const querystring = require('querystring');
const AWS = require('aws-sdk');
const S3 = new AWS.S3({
signatureVersion: 'v4',
});
const Sharp = require('sharp');
// set the S3 and API GW endpoints
const BUCKET = 'image-resize-${AWS::AccountId}-us-east-1';
exports.handler = (event, context, callback) => {
let response = event.Records[0].cf.response;
console.log("Response status code :%s", response.status);
//check if image is not present
if (response.status == 404) {
let request = event.Records[0].cf.request;
let params = querystring.parse(request.querystring);
// if there is no dimension attribute, just pass the response
if (!params.d) {
callback(null, response);
return;
}
// read the dimension parameter value = width x height and split it by 'x'
let dimensionMatch = params.d.split("x");
// read the required path. Ex: uri /images/100x100/webp/image.jpg
let path = request.uri;
// read the S3 key from the path variable.
// Ex: path variable /images/100x100/webp/image.jpg
let key = path.substring(1);
// parse the prefix, width, height and image name
// Ex: key=images/200x200/webp/image.jpg
let prefix, originalKey, match, width, height, requiredFormat, imageName;
let startIndex;
try {
match = key.match(/(.*)\/(\d+)x(\d+)\/(.*)\/(.*)/);
prefix = match[1];
width = parseInt(match[2], 10);
height = parseInt(match[3], 10);
// correction for jpg required for 'Sharp'
requiredFormat = match[4] == "jpg" ? "jpeg" : match[4];
imageName = match[5];
originalKey = prefix + "/" + imageName;
}
catch (err) {
// no prefix exist for image..
console.log("no prefix present..");
match = key.match(/(\d+)x(\d+)\/(.*)\/(.*)/);
width = parseInt(match[1], 10);
height = parseInt(match[2], 10);
// correction for jpg required for 'Sharp'
requiredFormat = match[3] == "jpg" ? "jpeg" : match[3];
imageName = match[4];
originalKey = imageName;
}
// get the source image file
S3.getObject({ Bucket: BUCKET, Key: originalKey }).promise()
// perform the resize operation
.then(data => Sharp(data.Body)
.resize(width, height)
.toFormat(requiredFormat)
.toBuffer()
)
.then(buffer => {
// save the resized object to S3 bucket with appropriate object key.
S3.putObject({
Body: buffer,
Bucket: BUCKET,
ContentType: 'image/' + requiredFormat,
CacheControl: 'max-age=31536000',
Key: key,
StorageClass: 'STANDARD'
}).promise()
// even if there is exception in saving the object we send back the generated
// image back to viewer below
.catch(() => { console.log("Exception while writing resized image to bucket")});
// generate a binary response with resized image
response.status = 200;
response.body = buffer.toString('base64');
response.bodyEncoding = 'base64';
response.headers['content-type'] = [{ key: 'Content-Type', value: 'image/' + requiredFormat }];
callback(null, response);
})
.catch( err => {
console.log("Exception while reading source image :%j",err);
});
} // end of if block checking response statusCode
else {
// allow the response to pass through
callback(null, response);
}
};