Simulators

Virtual-hosted addressing

Virtual-hosted addressing puts the bucket in the host name, as <bucket>.s3.us-east-1.amazonaws.com or <bucket>.s3.amazonaws.com, where path-style puts it first in the path. The simulator serves every route both ways: a request whose Host names one of those hosts is the path-style request with that bucket first in the path. Reach a local simulator by naming the host yourself:

s3curl() { curl -s --aws-sigv4 'aws:amz:us-east-1:s3' --user 'AKIAIOSFODNN7EXAMPLE:wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY' "$@"; }
s3curl -H 'Host: acme-demo-site.s3.us-east-1.amazonaws.com' "$RYSTIC_URL/robots.txt"
# -> User-agent: *
# -> Allow: /
s3curl -H 'Host: acme-demo-site.s3.amazonaws.com' "$RYSTIC_URL/?list-type=2&prefix=about/" | grep -oE '<Key>[^<]*'
# -> <Key>about/index.html

Keep S3’s own hostnames

An SDK that is not given an endpoint override sends virtual-hosted requests to S3’s hostnames, and the CLI’s HTTPS gateway can route two of them to the simulator:

Boot the simulator behind the gateway with rystic run s3-twin -d --port 0 --intercept --scenario s3_static_site.
Run your client under rystic exec -- <command>, or eval "$(rystic env)" for a shell. The gateway routes the calls of clients that honor its proxy and CA settings to the simulator.

Of S3’s hosts, the gateway routes only s3.amazonaws.com and s3.us-east-1.amazonaws.com to the simulator. A request to any other S3 region’s host tunnels through to real AWS. Give that client an endpoint override, or add --strict to rystic exec or rystic env so the gateway refuses every host no simulator claims.

For example, this command reads the site’s robots.txt from the simulator: rystic exec -- curl -s --aws-sigv4 'aws:amz:us-east-1:s3' --user 'AKIAIOSFODNN7EXAMPLE:wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY' https://acme-demo-site.s3.us-east-1.amazonaws.com/robots.txt.

A client that keeps its own certificate store needs the gateway’s CA configured. Path-style on an endpoint override needs nothing, and is the form to use when you control the client.

What is not compared with S3

Virtual-hosted addressing is unconfirmed, meaning not yet compared with S3. The simulator’s own tests cover it, but no request to S3 can set its Host.