Thread by @tpschmidt_

📚AWS 1x1 - 𝗖𝗹𝗼𝘂𝗱𝗙𝗿𝗼𝗻𝘁

A low latency and high transfer speed content delivery network.

What does it offer? ↓

𝗧𝗵𝗿𝗲𝗮𝗱 𝗢𝘃𝗲𝗿𝘃𝗶𝗲𝘄 🧵

• Introduction
• Distributions
• Origins
• Edge Behaviors
• Geo-Restrictions
• Edge Computing
• Pricing & Free Tier

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𝗜𝗻𝘁𝗿𝗼𝗱𝘂𝗰𝘁𝗶𝗼𝗻

CloudFront is a 𝗖ontent 𝗗elivery 𝗡etwork: a globally distributed set of caching servers that can store content returned by your origin servers that enable fast & low latency requests to your content around the globe.

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Citing AWS' blog for Prime Days 2021, CloudFront "handled a peak load of over 𝟮𝟵𝟬 𝗺𝗶𝗹𝗹𝗶𝗼𝗻 𝗛𝗧𝗧𝗣 𝗿𝗲𝗾𝘂𝗲𝘀𝘁𝘀 𝗽𝗲𝗿 𝗺𝗶𝗻𝘂𝘁𝗲, for a total of over 𝟲𝟬𝟬 𝗯𝗶𝗹𝗹𝗶𝗼𝗻 𝗛𝗧𝗧𝗣 𝗿𝗲𝗾𝘂𝗲𝘀𝘁𝘀" 🔥

aws.amazon.com/blogs/aws/prim…

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𝗗𝗶𝘀𝘁𝗿𝗶𝗯𝘂𝘁𝗶𝗼𝗻𝘀

A distribution is an actual instantiation of CloudFront. It's where you define all your settings, including the origins from where CloudFront can fetch the content if it's not yet stored in its edge locations.

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𝗢𝗿𝗶𝗴𝗶𝗻𝘀

An origin for your content can be basically anything that is able to serve content via HTTP. If looking at AWS native services, S3 is a common choice to store content and distribute it via CloudFront.

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You can specify a 𝗢rigin 𝗔ccess 𝗜dentity (OAI) and add a policy to your S3 bucket so only this CloudFront distribution is able to retrieve content from this bucket.

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𝗘𝗱𝗴𝗲 𝗕𝗲𝗵𝗮𝘃𝗶𝗼𝗿𝘀

With CloudFront, you can customize how it will handle your requests. Define desired behaviors for:

• how caching is done
• which headers and metadata is forwarded to the origin
• which compression should be used

and much more.

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𝗚𝗲𝗼 𝗥𝗲𝘀𝘁𝗿𝗶𝗰𝘁𝗶𝗼𝗻𝘀

As CloudFront is able to detect the request's origin, you can add geo-restriction rules which prevent users from specific geographic locations from accessing content.

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𝗟𝗮𝗺𝗯𝗱𝗮@𝗘𝗱𝗴𝗲

Run general-purpose code on regional edge locations around the world.

It's possible to
• do third party calls via HTTP
• invoke other AWS services like DynamoDB or S3
• integrations with 3rd party authorization providers

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There are four different occasions for which you can attach a Lambda@Edge function:

• Viewer Request & Response - invoked at the start/end of all requests
• Origin Request & Response - only when CloudFront does request the origin or retrieves a response

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𝗖𝗹𝗼𝘂𝗱𝗙𝗿𝗼𝗻𝘁 𝗙𝘂𝗻𝗰𝘁𝗶𝗼𝗻𝘀

The lightweight version of Lambda@Edge with fewer capabilities, but even better latency and way (1/6th of Lambda@Edge) cheaper.

Example use-cases:
• access control and authorization
• HTTP redirects
• cache manipulation

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From a location perspective, both function types are very different.

Your Lambda@Edge function will be executed in one of AWS' 𝟭𝟯 𝗿𝗲𝗴𝗶𝗼𝗻𝗮𝗹 edge caches.
Your CloudFront function on the other hand can run at more than 𝟮𝟭𝟴 𝗲𝗱𝗴𝗲 𝗹𝗼𝗰𝗮𝘁𝗶𝗼𝗻𝘀!

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More technical differences between CloudFront functions & Lambda@Edge:

• Runtimes: JS | JS/Python
• Max Exec Time: 1ms | 5s (Viewer) & 30s (Origin Triggers)
• Max Memory: 2MB | 128MB (Viewer) & 10GB (Origin Triggers)
• Network Access: ❌ | ✅

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𝗣𝗿𝗶𝗰𝗶𝗻𝗴 & 𝗙𝗿𝗲𝗲 𝗧𝗶𝗲𝗿

If you're using AWS native services for your origins, you're not paying additional fees for the data transfer between those services and CloudFront.

Additionally, AWS grants 50GB/month outgoing traffic at its first-year free tier.

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That's it for the small introduction to CloudFront - thank you for reading!

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