OCM-3226 | feat: improving ocm login and ocm list rh-region url resolution

[macgregor]

This MR tweaks the ocm login --url resolution algorithm to try to reuse cfg.URL before falling back to "api.openshift.com". New --url resolution algorithm (from highest priority to lowest priority):

1. runtime --url cli arg (key found in urlAliases)
2. runtime --url cli arg (non-empty string)
3. [NEW] config file URL value (non-empty string)
4. sdk.DefaultURL

I also improved the recently added ocm list rh-region to be a bit more helpful:

• show discovery URL used
• add optional --discovery-url flag with the same url resolution behavior as ocm login
• tabular formatting
• display region name and its associated url rather than just region name

[macgregor]

New url config fallback behavior:

# no change: --url gets saved to config
> ocm login --token=$OCM_OFFLINE_ACCESS_TOKEN --url=int && ocm config get url
https://api.integration.openshift.com

# previous: when no --url is provided, this would log in against api.openshift.com
# new behavior: fallback to cfg.URL if its available
> ocm login --token=$OCM_OFFLINE_ACCESS_TOKEN && ocm config get url 
https://api.integration.openshift.com

New url fallback behavior plus --rh-region override behavior:

# no change: --url gets saved
> ocm login --token=$OCM_OFFLINE_ACCESS_TOKEN --url=int && ocm config get url
https://api.integration.openshift.com

# no change: --url used for discovery, --rh-region url gets saved to cfg.URL 
> ocm login --token=$OCM_OFFLINE_ACCESS_TOKEN --url=stage --rh-region=rh-singapore && ocm config get url
https://api.aws.xcm.stage.openshift.com

# previous: when no --url provided, api.openshift.com would be used for service discovery when --rh-region is provided
# new behavior: use cfg.URL if its available for service discovery when --rh-region is provided 
> ocm login --token=$OCM_OFFLINE_ACCESS_TOKEN --rh-region=rh-singapore && ocm config get url 
https://api.aws.xcm.stage.openshift.com

ocm list rh-regions improvements:

# no change: cfg.URL is used for service discovery
# new behaviour: print discovery url used, table format, print discovered gateway urls rather than just region names
> ocm login --token=$OCM_OFFLINE_ACCESS_TOKEN --url=stage && ocm list rh-regions                  
Discovery URL: https://api.stage.openshift.com

RH Region       Gateway URL
rh-na           api.stage.openshift.com
rh-singapore    api.aws.xcm.stage.openshift.com

> ocm login --token=$OCM_OFFLINE_ACCESS_TOKEN --url=stage && ocm list rh-regions --discovery-url=int
Discovery URL: https://api.integration.openshift.com

RH Region       Gateway URL
rh-na           api.integration.openshift.com
rh-singapore    api.aws.xcm.integration.openshift.com

[tirthct]

Can we add some tests here to confirm the behavior?

[macgregor]

Can we add some tests here to confirm the behavior?

added tests for the now shared ResolveGatewayURL method

[ciaranRoche]

Can we squash down these commits before we merge 🙏

[macgregor]

Can we squash down these commits before we merge 🙏

squash on merge? thats the convenient option unless a bot that cant squash is doing the merging or something. Anyway, I figured out how to do it the inconvenient way and force pushed 😄

[ciaranRoche]

lgtm