How to set pathPattern in CloudFront CDN?

Question

Pulumi · Accepted Answer

To set the `pathPattern` in CloudFront CDN, we would typically use the `aws.cloudfront.Distribution` resource from the AWS provider. This `Distribution` resource creates a new Amazon CloudFront distribution to route traffic to specified origins (like an S3 bucket).

You can define multiple behaviors, each with their own `pathPattern`, that tell CloudFront how to route requests to different origins based on the URL path in the request.

Here's a simple example program for setting the `pathPattern` in CloudFront CDN:

```typescript
import * as pulumi from "@pulumi/pulumi";
import * as aws from "@pulumi/aws";

const originId = "s3-website"

// S3 bucket for static files
const bucket = new aws.s3.Bucket("Bucket", {
    website: {
        indexDocument: "index.html"
    }
});

// CloudFront distribution to serve static files
let distributionArgs: aws.cloudfront.DistributionArgs = {
    enabled: true,
    isIpv6Enabled: true,
    comment: "Bucket distribution",
    defaultRootObject: "index.html",
    origins: [
        {
            domainName: bucket.bucketRegionalDomainName,
            originId: originId,
            customOriginConfig: {
                originProtocolPolicy: "http-only",
                httpPort: 80,
                httpsPort: 443,
                originSslProtocols: ["TLSv1.2"],
            },
        },
    ],
    defaultCacheBehavior: {
        targetOriginId: originId,
        viewerProtocolPolicy: "redirect-to-https",
        allowedMethods: ["GET", "HEAD", "OPTIONS"],
        cachedMethods: ["GET", "HEAD", "OPTIONS"],
        forwardedValues: {
            queryString: false,
            cookies: { forward: "none" },
        },
        minTtl: 0,
        defaultTtl: 3600,
        maxTtl: 86400,
    },
    priceClass: "PriceClass_100",
    restrictions: {
        geoRestriction: { restrictionType: "none" },
    },
    viewerCertificate: {
        cloudfrontDefaultCertificate: true,
    }
};

// Adding the pathPattern to the CloudFront distribution
distributionArgs["orderedCacheBehaviors"] = [
    {
        pathPattern: "/content/*",
        allowedMethods: ["GET", "HEAD", "OPTIONS"],
        cachedMethods: ["GET", "HEAD"],
        targetOriginId: originId,
        forwardedValues: {
            queryString: false,
            headers: ["Origin"],
            cookies: { forward: "none"},
        },
        minTtl: 0,
        defaultTtl: 86400,
        maxTtl: 31536000,
        compress: true,
        viewerProtocolPolicy: "redirect-to-https",
    },
];
    
const cdn = new aws.cloudfront.Distribution("cdnDistribution", distributionArgs);

// Export the distribution details
export const distributionId = cdn.id;
export const distributionDomainName = cdn.domainName;
```
In this program, we create an S3 bucket and a CloudFront distribution. We specify the `pathPattern` when defining the CloudFront distribution's `orderedCacheBehaviors`. This configuration section allows you to specify the path patterns for files that you want CloudFront to serve from your S3 bucket.

If a URL matches the path pattern `/content/*`, then the requested file is served from the CloudFront cache. If the file isn't in the cache, CloudFront retrieves it from the S3 bucket and then caches it for future requests.

Finally, we export the distribution's id and domain name for easy access later.