Error if bucket name contains scheme

[pgporada]

Return an error to the operator if the supplied bucket name contains a scheme e.g. s3://bucketname, whatever://bucketname, http://bucketname, etc. The aws-sdk-go s3 service examples show the bucket name without the scheme. This change does not enforce that a bucket is properly named according to the s3 docs nor do I think it should. Instead that work should be left to the aws-sdk-go. This is just a nice ease of use improvement for myself because I didn't know what an appropriate bucket name was.

[jsha]

Looking at the documentation for ParseRequestURI it doesn't seem to say it will reject absolute URIs (starting with a scheme). It actually seems to say the opposite - that it will accept them. Does this definitely work?

[pgporada]

From my manual testing, yes it works.

$ go run . -log-url https://oak.ct.letsencrypt.org/2023 -tile-size 256 -s3-bucket s3://whatever
2023/09/11 14:36:11 scheme provided for s3-bucket, but should not be
exit status 1

$ go run . -log-url https://oak.ct.letsencrypt.org/2023 -tile-size 256 -s3-bucket whoops://hasotherscheme
2023/09/11 14:36:34 scheme provided for s3-bucket, but should not be
exit status 1

# As expected, runs ctile instead of erroring out
$ go run . -log-url https://oak.ct.letsencrypt.org/2023 -tile-size 256 -s3-bucket noscheme
^Csignal: interrupt

What I'm ultimately relying on using url.ParseRequestURI is that the call to getScheme returns nil, because if it does there's a good chance that a scheme was found and I can return an error to the ctile user.