use-buildset-registry: add URL to buildset_registry_namespaces

This is a no-op change for the current setup, but the URL is required
to build config files for containerd passthrough setup in a follow-on
change.

Change-Id: Iacbb08a6bf4a22bb6b91ffa781267a5eda106d48

roles/use-buildset-registry/README.rst

@@ -37,11 +37,16 @@ Use this role on any host which should use the buildset registry.
    default, the user Ansible is running as.
 
 .. zuul:rolevar:: buildset_registry_namespaces
-   :default: ['docker.io', 'quay.io', 'gcr.io']
+   :default: [ ('docker.io', 'https://...'), ('quay.io', ...), ('gcr.io', ...)]
 
-   The namespaces that the buildset registry supports.  The buildset
-   registry will be consulted first for images in these namespaces.
-   Any others will be fetched only from their upstream sources.
+   The namespaces that the buildset registry supports.  Each entry
+   should be a tuple with the first elemnet being the registry host
+   (usually the internet domain name) and the second being the URL the
+   registry is hosted at.
+
+   The buildset registry will be consulted first for images in these
+   namespaces.  Any others will be fetched only from their upstream
+   sources.
 
    Add any local or third-party registries necessary here.
 

roles/use-buildset-registry/defaults/main.yaml

@@ -1,4 +1,4 @@
 buildset_registry_namespaces:
-  - docker.io
-  - quay.io
-  - gcr.io
+  - ['docker.io', 'https://registry-1.docker.io']
+  - ['quay.io', 'https://quay.io']
+  - ['gcr.io', 'https://gcr.io']

roles/use-buildset-registry/library/modify_buildkitd_toml.py

@@ -50,7 +50,7 @@ def ansible_main():
 
     if 'registry' not in data:
         data['registry'] = {}
-    for namespace in set(p['namespaces']):
+    for namespace in set([n[0] for n in p['namespaces']]):
         n_config = data['registry'].setdefault(namespace, {})
         mirrors = n_config.setdefault('mirrors', [])
         new_loc = get_location(namespace, location)

roles/use-buildset-registry/library/modify_registries_conf.py

@@ -48,7 +48,7 @@ def ansible_main():
         input_data = None
         data = {}
 
-    unseen = set(p['namespaces'])
+    unseen = set([n[0] for n in p['namespaces']])
     if 'registry' not in data:
         data['registry'] = []
     for reg in data['registry']: