[NET-7571] Ensure services function uses specified Consul namespace

[kkavish]

• bug fix: Services function in CT (consul-template) does not update the namespace for each services API call
• opts should be defaulted to the opts at query creation.
• then they should be merged with the opts present in Fetch.
• currently the merge was the other way around.
• ENT test support is not there, so no test cases added as of now.

How I've tested this PR

How I expect reviewers to test this PR

Checklist

• Tests added
• CHANGELOG entry added

[tauhid621]

Looks good. I see that other functions are using the opts.Merge(&QueryOptions{ way. Would we need to update some of them as well?

[tauhid621]

Should we have this comment here as the updated code will not have reference of what was used earlier?

[kkavish]

yes, some of the other functions have that problem too.
that's why I want to enable ENT and write proper tests for them before touching them.

[komapa]

Unfortunately this is also not complete implementation. I tested it locally and you need to change:

// String returns the human-friendly version of this dependency.
func (d *CatalogServicesQuery) String() string {
	if d.dc != "" {
		return fmt.Sprintf("catalog.services(@%s)", d.dc)
	}
	return "catalog.services"
}

to

// String returns the human-friendly version of this dependency.
func (d *CatalogServicesQuery) String() string {
	opts := &QueryOptions{
		Datacenter:      d.dc,
		ConsulPartition: d.partition,
		ConsulNamespace: d.namespace,
	}

	if opts.String() != "" {
		return fmt.Sprintf("catalog.services(@%s)", opts.String())
	}

	return "catalog.services"
}

This way you are actually watching different catalog.services for every dc, partition and namespace combination.

[kkavish]

Unfortunately this is also not complete implementation. I tested it locally and you need to change:

// String returns the human-friendly version of this dependency.
func (d *CatalogServicesQuery) String() string {
	if d.dc != "" {
		return fmt.Sprintf("catalog.services(@%s)", d.dc)
	}
	return "catalog.services"
}

to

// String returns the human-friendly version of this dependency.
func (d *CatalogServicesQuery) String() string {
	opts := &QueryOptions{
		Datacenter:      d.dc,
		ConsulPartition: d.partition,
		ConsulNamespace: d.namespace,
	}

	if opts.String() != "" {
		return fmt.Sprintf("catalog.services(@%s)", opts.String())
	}

	return "catalog.services"
}

This way you are actually watching different catalog.services for every dc, partition and namespace combination.

@komapa thanks for pointing that out. please see - #1880

[lkysow]

I don't think this was the problem, I think it was the String() function not being unique for different ns/partition queries. I think this function is only ever called here: https://github.com/hashicorp/consul-template/blob/main/watch/view.go#L218-L222 and so there's no issue with the merge order.