Add admin bucket quota command to manage quota

[poornas]

companion to PR minio/minio#9379

[ebozduman]

It looks like the documentation changes are missing.

[ebozduman]

@poornas
Please also check the build test failure.

[ebozduman]

The usage information should also explain the behavior when no quota flag, --fifo or --hard is provided, like
mc admin bucket quota <alias>/<bucket>
This command causes the bucket's quota configuration to be listed, if one exists.

[ebozduman]

Where the quota value needs to go is not clear in the usage and doc (doesn't exist yet) explanations.

The only place you can see it is the last example.

Don't we need to make it clear in the usage the expectation somehow. I looked at the usage in the help and tried:

mc admin bucket quota --fifo 64m <alias>/<bucket>`
mc: <ERROR> Unable to initialize admin connection. No valid configuration found for '64m' host alias.

I think this is essential usage information and needs to be clear in the help:
USAGE: mc admin bucket COMMAND [COMMAND FLAGS | -h] [ARGUMENTS...] is not clear in that respect.

Another missing information is; if there is a default value for the type information or not.
If there is no default and TYPE field is mandatory, then we need to make sure it is clear in the USAGE.
Existing USAGE shows flags optional, [COMMAND FLAGS | -h].

[ebozduman]

This suggestion can be considered as a future enhancement

IMHO, it would be a good idea to provide how much --hard space left out of the set quota limit. So, hard hitting the limit should not be the only way we communicate with the user that there is not enough space available for the transaction.

Just an idea: we can add the available space information to the output of quota list functionality.

mc admin bucket quota myminio/mybucket
Bucket `mybucket` has hard quota of 5.0 GiB
2.7GiB is available

[ebozduman]

Newly created --clear option always fails:

$ mc admin bucket quota myminio/bucket 1gb --hard
Successfully set bucket quota of 954 MiB with hard type on `bucket`
$ mc admin bucket quota --clear myminio/bucket
mc: <ERROR> Cannot clear bucket quota config. Failed to parse server response.

This looks like a server side problem though, in minio/minio#9379.

[ebozduman]

LGTM

[ebozduman]

LGTM (please fix the build test faiure)

[ebozduman]

@poornas,
As soon as you fix the test errors, I'll approve it.

[poornas]

@poornas,
As soon as you fix the test errors, I'll approve it.

@ebozduman , travis will pass when the minio/minio PR gets merged.

[ebozduman]

LGTM

[poornas]

#3182 needs to be merged before this PR

[harshavardhana]

The dependencies are still not updated looks like @poornas CI is failing.

[ebozduman]

LGTM