Docs · Dewei Liu · dliu.com

How it works

dliu.com is a static site: a landing page, a 404 page, the docs pages and the résumé PDF. The files sit in a private S3 bucket and CloudFront delivers them. There are no servers, no database and no JavaScript.

0 serversonly static files

0 JavaScriptHTML and the shared CSS only

All edge locationsCloudFront, HTTP/2 and HTTP/3

1 CDK stackdliu-com in eu-west-1 (Ireland)

Request path

1Browserhttps://dliu.com

2Route 53 + CloudFrontHTTPS, certificate from ACM

3CloudFront Functionsclean URLs; visitor tag

4Private S3 bucketread only by CloudFront

The CloudFront certificate is issued in us-east-1, as CloudFront requires; everything else is in eu-west-1.

Pages. src/index.html, src/404.html and src/docs.html, plus src/style.css for the landing page's layout. The header, footer, cards and colours come from the shared dliu.com stylesheets on files.dliu.com, so every dliu.com site looks the same.
Clean URLs. A viewer-request CloudFront Function serves / from index.html, /docs from docs.html, and redirects the old /docs/health to /docs#health (301). Missing files return the 404 page.
Visitor statistics. A shared viewer-response function sets the anonymous dl_vid visitor cookie, and CloudFront's access logs feed traffic.dliu.com.
Résumé. Written in LaTeX (resume/resume.tex) and built with Tectonic by make resume into src/resume.pdf, which is served at /resume.pdf.
DNS. The dliu.com hosted zone belongs to the shared core infrastructure. This stack only adds the apex A and AAAA alias records.

Caching

Files	Browser	CloudFront edge
HTML pages	No `Cache-Control` header	Default caching, up to 1 day
`style.css`, `resume.pdf`	5 minutes	1 day (`s-maxage=86400`, `stale-while-revalidate=86400`)
Shared stylesheets and icon	Cached by files.dliu.com

Every deploy invalidates /* once, so changes show at the edge straight away. A browser may keep the old stylesheet or résumé for up to 5 minutes.
Automatic clearing on S3 changes is not used: the bucket only changes through deploys, which already clear the whole cache.

Deployment

The site is an AWS CDK app in cdk/. Deploys run locally from a machine with AWS credentials; there is no CI pipeline.

make install   # npm ci in cdk/
make test      # Jest: stack template and shared-look checks
make resume    # rebuild src/resume.pdf (only after résumé edits)
make deploy    # cdk deploy dliu-com

The deploy uploads src/ to the bucket in two steps: non-HTML files with the cache headers above, then the HTML files. Both invalidate the CloudFront cache.

Cost

Everything is billed per use, and at this site's traffic it stays inside the AWS free tiers: S3 storage for a few files, CloudFront requests and data transfer, and CloudFront Function invocations. The ACM certificate is free. The Route 53 hosted zone is shared with the other dliu.com sites.

Security

The S3 bucket blocks all public access. CloudFront reads it through an origin access identity, so files are only reachable through https://dliu.com.
HTTP requests are redirected to HTTPS. Only GET and HEAD are allowed.
There is no sign-in, form, API or JavaScript, and the site stores nothing about visitors apart from the anonymous visitor cookie used for traffic statistics.

How dliu.com is tested

Live status: status.dliu.com/site/dliu
Machine-readable version: /docs/health.md

Every 15 minutes, status.dliu.com visits dliu.com from Ireland, Virginia and Tokyo like an ordinary visitor, without signing in, and checks that each part of the site works. Once an hour it also opens the home page from inside mainland China. The checks only look; they never change anything.

4 functions testedevery part a visitor uses

8 checksin every test run

Every 15 minutesfrom Ireland, Virginia and Tokyo

0 sign-ins neededtested as a guest

Who tests what

GuestTesters

status.dliu.comIreland, Virginia, Tokyo every 15 min

Mainland Chinahome page, once an hour

like any visitor: no sign-in, read only

EdgeWhat visitors open

CloudFronthome page, docs and résumé, over a secure connection

CloudFront Functionsshort links and the friendly not-found page

reads the files

PrivateStorage

Private S3 bucketthe pages and the résumé; only CloudFront can read it

There is no server tier: dliu.com is just files, with no server or database behind it, so checking what visitors open covers the whole site.

Every run ends with one of three results

Workingevery answer right, within 3 seconds

Slowright but slow, missed once, or missed from one place only

Not workingmissed in two runs in a row (about 30 minutes)

What is checked

Function	What it does for you	How it’s tested	If it stopped working
Pages	Shows the home page and the docs	Opens the home page, /docs, the styling and /docs/health.md	✗ An error instead of dliu.com
Résumé	Shows the résumé	Opens /resume.pdf	✗ The Résumé link gives an error
Short links and “page not found”	Sends old links to the right place; friendly page for wrong addresses	Follows the old /docs/health link; visits a page that doesn’t exist	✗ Old links break, or a bare error appears
Secure connection	Moves visitors to the secure (padlock) site	Visits dliu.com without the padlock	✗ Old non-secure links stop working

✓ Every function working means dliu.com is up. If Pages stop working, it counts as down; if anything else does, it counts as partly working.

Checks per function

What isn’t tested

Nothing on dliu.com needs signing in, so no signed-in actions are left out.
Publishing updates to the site, which the owner does from his own computer.
The visitor statistics; the checker’s own visits are left out of them.

Technical version for machines (Markdown)

Source: dliu-com/dliu-com