Speedy Cache

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CloudFront ​

Speedy clears CloudFront when pages change, with no AWS SDK, and keeps the cost down.

Speedy detects CloudFront from its X-Amz-Cf-Id or Via header and says so on the settings and utility pages.

Without keys ​

Speedy still caches on your server, and tells CloudFront not to keep HTML pages (Cache-Control: no-cache, s-maxage=0), so CloudFront never shows a page Speedy can’t clear.

With keys ​

  1. In AWS IAM, create a user (or role) with this policy, using your distribution’s ARN:
    json
    {
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "cloudfront:CreateInvalidation",
      "Resource": "arn:aws:cloudfront::123456789012:distribution/E1ABCDEF2GHIJK"
    }
  ]
}
  2. Create an access key for it, and add it to .env with the distribution ID:
    bash
    CLOUDFRONT_DISTRIBUTION_ID="E1ABCDEF2GHIJK"
AWS_ACCESS_KEY_ID="…"
AWS_SECRET_ACCESS_KEY="…"
  3. In Settings → Plugins → Speedy Cache, enter $CLOUDFRONT_DISTRIBUTION_ID. The AWS keys are read from AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY when their fields are blank. AWS_SESSION_TOKEN is used when it’s set.
  4. On the utility page, click Test CloudFront. It sends one invalidation for a path no page uses.

Make sure your CloudFront cache policy respects the origin’s Cache-Control header, so pages are kept for as long as Speedy says.

Two more settings in the cache policy:

  • Query strings: All. Speedy’s background rebuilds add a one-off query string to reach your server. If CloudFront ignores query strings, rebuilds get its old copy, and Speedy removes those pages instead of rebuilding them.
  • Visitors with their own pages. CloudFront can’t skip its cache by part of a cookie name, so logged-in visitors and visitors part-way through a multi-page form may get the public copy from CloudFront. Pages Speedy doesn’t cache are sent as private, so CloudFront never keeps them. Use Ajax for multi-page forms, or a separate behaviour with caching off for paths like /account*.

Keeping it free ​

CloudFront includes 1,000 invalidation paths a month, then charges per path. Speedy:

  • sends one path per changed page;
  • when one clear has more than 30 paths (wildcardThreshold), groups them by first folder: /news/a, /news/b and /news/c become /news*;
  • if there are still too many, sends /*, which counts as one path;
  • sends /* for Clear all pages;
  • counts the paths used this month, shown on the utility page.

Failures ​

Invalidation errors, such as a wrong distribution ID, are shown on the utility page and in the log. Pages on your server are still cleared and rebuilt.