Add script to validate length of clustergroup chart and pattern names

[dminnear-rh]

Fixes validatedpatterns/clustergroup-chart#61 by ensuring that we fail before install if the length of the names will cause invalid DNS problems.

Also, will fix validatedpatterns/pattern-install-chart#18. In addition to the validation added, this PR reads the pattern name from the values-global.yaml file rather than just taking the basename of whatever directory the git repo is cloned into locally.

A failed validation looks like:

Validating that the pattern and clustergroup names don't exceed DNS limits after the pattern is installed.

Checking file: values-group-one.yaml
  -> FAILED: Length of clustergroup 'group-one' and pattern 'validated-patterns-multicloud-gitops' will exceed DNS limits in clustergroup chart. Please shorten one or both.

Checking file: values-hub.yaml
  -> PASSED: Length of clustergroup 'hub' and pattern 'validated-patterns-multicloud-gitops' are within clustergroup chart limits.

Checking file: values-standalone.yaml
  -> FAILED: Length of clustergroup 'standalone' and pattern 'validated-patterns-multicloud-gitops' will exceed DNS limits in clustergroup chart. Please shorten one or both.

One or more cluster group names failed the length validation.
--------------------------------------------------------------------------------
Validation Explanation:
This script ensures that generated Kubernetes resource names do not exceed the 63-character limit.
A DNS-compatible name is constructed in the 'clustergroup' Helm chart using the following pattern:
  -> {{ .Values.clusterGroup.name }}-gitops-server-{{ .Values.global.pattern }}-{{ .Values.clusterGroup.name }}

The total length is calculated as:
  (2 * length of 'clusterGroup.name') + length of 'global.pattern' + 15 (for '-gitops-server-') + 1 (for the namespace separator '-')

To stay under the 63-character limit, the variable part of the name must be less than 47 characters:
  (2 * length of 'clusterGroup.name') + length of 'global.pattern' < 47
--------------------------------------------------------------------------------

A passed validation looks like:

Validating that the pattern and clustergroup names don't exceed DNS limits after the pattern is installed.

Checking file: values-group-one.yaml
  -> PASSED: Length of clustergroup 'group-one' and pattern 'multicloud-gitops' are within clustergroup chart limits.

Checking file: values-hub.yaml
  -> PASSED: Length of clustergroup 'hub' and pattern 'multicloud-gitops' are within clustergroup chart limits.

Checking file: values-standalone.yaml
  -> PASSED: Length of clustergroup 'standalone' and pattern 'multicloud-gitops' are within clustergroup chart limits.

All names are within clustergroup chart limits.

[mbaldessari]

Maybe add a fallback to the old ways here? I am just not remembering when we introduced the .global.pattern. Unless you're sure we have it set everywhere that is

[dminnear-rh]

I'm not sure it is set everywhere (although it probably should be). What if we use yq --exit-status .global.pattern values-global.yaml to enforce that it is set. Then, rather than falling back to the directory name, we enforce they have a proper value.

[mbaldessari]

So we error out if it does not have it set? Yeah let's go for that! I suppose the pattern's that don't have it, probably won't update common much anyways

[dminnear-rh]

I added the check:

ifeq ($(NAME),)
$(error Pattern name MUST be set in values-global.yaml with the value .global.pattern)
endif
ifeq ($(NAME),null)
$(error Pattern name MUST be set in values-global.yaml with the value .global.pattern)
endif

so if it's not set (or if the pattern name is set to be an empty string) we'll error out:

❯ make show
make -f common/Makefile show
make[1]: Entering directory '/home/drewminnear/gh-repos/dminnear-rh/multicloud-gitops'
common/Makefile:7: *** Pattern name MUST be set in values-global.yaml with the value .global.pattern.  Stop.
make[1]: Leaving directory '/home/drewminnear/gh-repos/dminnear-rh/multicloud-gitops'
make: *** [Makefile:12: show] Error 2