Cluster name cannot include dots, the error message says otherwise

[MagicalTux]

Describe the problem

Running cockroachdb with a cluster name containing dots produces this error message:

ERROR: invalid argument "xxx.xxx" for "--cluster-name" flag: cluster name must contain only letters, numbers or the "-" and "." characters

To Reproduce

1. Pass --cluster-name a value that contains a dot.

Expected behavior

Either the dot should be accepted, or the error message changed to reflects dots aren't allowed.

Additional data / screenshots

Error message defined at: https://github.com/cockroachdb/cockroach/blob/master/pkg/cli/flags.go#L207

The regexp is a few lines below:

var errClusterNameInvalidFormat = errors.New(`cluster name must contain only letters, numbers or the "-" and "." characters`)

// clusterNameRe matches valid cluster names.
// For example, "a", "a123" and "a-b" are OK,
// but "0123", "a-" and "123a" are not OK.
var clusterNameRe = regexp.MustCompile(`^[a-zA-Z](?:[-a-zA-Z0-9]*[a-zA-Z0-9]|)$`)

The regexp includes hyphens, but no dots.

Jira issue: CRDB-39994

[blathers-crl[bot]]

Hi @MagicalTux, please add branch-* labels to identify which branch(es) this C-bug affects.

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[MagicalTux]

Looking at the documentation it seems that allowing dots was supposed to be the right behavior, in which case the regexp can be updated as below (this would also filter a few things like forbidding hyphen groups).

var clusterNameRe = regexp.MustCompile(`^[a-zA-Z][a-zA-Z0-9]*(?:[-.][a-zA-Z0-9]+)*$`)

The tests in pkg/cli/flags_test.go in func TestClusterNameFlag should also have (at least) one valid cluster name with a dot added to ensure this is handled properly and doesn't break in the future.

[mohitsethia]

Hi @rimadeodhar @MagicalTux , can I contribute to this?