Prevent S3 information on non-S3 mirrors

[josephsnyder]

Switch from looking at the presence of the S3 information keys to
determine if the dictionary URL is used to instead look at the value
in the keys.

Add s3_endpoint_url as an additional key value for the S3 information.

See #27694 (comment)

[scheibelp]

Does this fix #27694? If so, you can add Fixes #27694 to the initial post in this thread and it will be automatically closed when this is merged.

[josephsnyder]

@scheibelp, #27694 is a pull request and the reason it is linked is that there is a comment requesting this particular change. I separated them to make things easier.

[josephsnyder]

@opadron, I'd like to keep these moving. Do you have the time for a review on this and #27694?

[josephsnyder]

@alalazo, I don't see that happening on the develop branch (commit SHA: b7b6542)

(spack_env) snyder@irune-journal:~/Work/ECP/spack$ ./bin/spack mirror add  minio s3://sample --s3-endpoint-url http://10.50.57.119:9000 --s3-access-key-id 892W696SB0HMCPS2BDIA --s3-access-key-secret <Secret>
(spack_env) snyder@irune-journal:~/Work/ECP/spack$ ./bin/spack mirror add  miniolocal file:///tmp/mirror
(spack_env) snyder@irune-journal:~/Work/ECP/spack$ ./bin/spack mirror list
spack-public    https://mirror.spack.io
miniolocal      file:///tmp/mirror (fetch)
miniolocal      file:///tmp/mirror (push)
minio           s3://sample (fetch)
minio           s3://sample (push)

[alalazo]

@josephsnyder Yeah, sorry for the noise. I could reproduce the error I posted reliably until I tried:

$ spack clean -a

and cleaning the cache made it disappear somehow. I am not sure what could have caused it in the first place though I have been moving across branches a lot...

[opadron]

I seem to recall that args is now supposed to be a namespace object with attributes instead of a mapping with keys. (That would explain the use of vars, here).

I think that's fine, but something would need to be done about the default for args, since it doesn't make sense to default to an empty dict, anymore.

Maybe default to None and have some branch that handles None?

[becker33]

The code is only called from one place, and it supplies args. Maybe it should just make args a required argument?