Blog Feeds (SAM)

Fetches the latest post from each recommended blog's RSS/Atom feed daily. Outputs a single JSON file to your static site's S3 bucket, rendered client-side under "Je recommande ces blogs" on the Jekyll home page.

Architecture

EventBridge (daily 06:15 UTC)
  └─ Lambda (Node.js 22)
       ├─ Reads src/blogs.json (name, url, feedUrl per blog)
       ├─ Fetches + parses each feed (RSS or Atom)
       ├─ Writes about/data/blogs.json to website S3
       └─ Invalidates CloudFront cache

Prerequisites

• AWS CLI configured (aws configure)
• SAM CLI installed (pip install aws-sam-cli)

Deploy

sam build
sam deploy --guided

On first deploy, SAM will prompt for:

Parameter	Value
WebsiteBucket	Your website S3 bucket name
DistributionId	Your CloudFront distribution ID

SAM saves your answers in samconfig.toml for subsequent deploys (sam deploy without --guided).

Test locally

npm install
npm test

sam build
sam local invoke BlogFeedsFunction

Test in AWS (manual trigger)

aws lambda invoke \
  --region eu-west-3 \
  --cli-read-timeout 0 \
  --function-name $(sam list stack-outputs --stack-name blog-feeds --region eu-west-3 --output json | jq -r '.[] | select(.OutputKey=="FunctionName") | .OutputValue') \
  /dev/stdout

Adding / removing a blog

Edit src/blogs.json — { name, url, feedUrl } — then redeploy (sam build && sam deploy).

Output JSON shape

{
  "generated": "2026-07-30T06:15:00.000Z",
  "blogs": [
    {
      "name": "Un Spicilège",
      "url": "https://blogz.zaclys.com/un-spicilege/",
      "latestPost": { "title": "Evil Dead Burn", "date": "2026-07-15T15:08:42.000Z", "link": "https://..." }
    },
    { "name": "...", "url": "...", "latestPost": null }
  ]
}

latestPost is null when the feed couldn't be fetched or parsed that day (logged as an error in CloudWatch) — e.g. a blog whose feed is proxied through follow.it (a Blogger newsletter redirect), which returns HTTP 400 to non-browser requests.

Jekyll integration

See PostTenebrasLire/_includes/home_blogs.html and javascript/recommended-blogs.js, which fetch /about/data/blogs.json client-side (same pattern as blog-analytics's chart-snippet.html).

Monthly cost

Resource	Cost
Lambda (1 run/day, ~10s, 256MB)	~$0.00
CF invalidation (1/day)	$0.00
Total	~$0