salt/solutions: Revamp configuration file

A new field, currently named `active` (may be a poor choice, we'll see
with first user interactions, `activeVersions` could be more explicit),
is introduced to set which version of a Solution should be used for the
cluster-wide components of this Solution (i.e. the Admin UI and CRDs for
now).
Validation of the file format is added, using the usual `kind` and
`apiVersion` fields. Later improvements could use some OpenAPI schema.

Fixes: #1582

salt/_modules/metalk8s_solutions.py

@@ -3,14 +3,12 @@
 '''
 import json
 import logging
+
 import yaml
 
 from salt.exceptions import CommandExecutionError
 
 HAS_LIBS = True
-SOLUTIONS_CONFIG_MAP = 'metalk8s-solutions'
-SOLUTIONS_CONFIG_MAP_NAMESPACE = 'metalk8s-solutions'
-SOLUTIONS_CONFIG_FILE = '/etc/metalk8s/solutions.yaml'
 try:
     import kubernetes.client
     from kubernetes.client.rest import ApiException
@@ -20,6 +18,14 @@
 
 log = logging.getLogger(__name__)
 
+SOLUTIONS_CONFIG_MAP = 'metalk8s-solutions'
+SOLUTIONS_CONFIG_MAP_NAMESPACE = 'metalk8s-solutions'
+
+SOLUTIONS_CONFIG_FILE = '/etc/metalk8s/solutions.yaml'
+SUPPORTED_CONFIG_VERSIONS = frozenset((
+    'solutions.metalk8s.scality.com/{}'.format(version)
+    for version in ['v1alpha1']
+))
 
 __virtualname__ = 'metalk8s_solutions'
 
@@ -51,16 +57,49 @@ def list_deployed(
     }
 
 
-def list_configured():
-    """Get list of Solution archives paths defined in a config file."""
+def read_config():
+    """Read the SolutionsConfiguration file and return its contents.
+
+    Empty containers will be used for `archives` and `active` in the return
+    value.
+
+    The format is expected to resemble the following example:
+
+    ..code-block:: yaml
+
+      apiVersion: metalk8s.scality.com/v1alpha1
+      kind: SolutionsConfiguration
+      archives:
+        - /path/to/solution/archive.iso
+      active:
+        solution-name: X.Y.Z-suffix (or 'latest')
+    """
     try:
         with open(SOLUTIONS_CONFIG_FILE, 'r') as fd:
-            content = yaml.safe_load(fd)
+            config = yaml.safe_load(fd)
     except Exception as exc:
         msg = 'Failed to load "{}": {}'.format(SOLUTIONS_CONFIG_FILE, str(exc))
         raise CommandExecutionError(message=msg)
 
-    return content.get('archives', []) or []
+    if config.get('kind') != 'SolutionsConfiguration':
+        raise CommandExecutionError(
+            'Invalid `kind` in configuration ({}), '
+            'must be "SolutionsConfiguration"'.format(config.get('kind'))
+        )
+
+    if config.get('apiVersion') not in SUPPORTED_CONFIG_VERSIONS:
+        raise CommandExecutionError(
+            'Invalid `apiVersion` in configuration ({}), '
+            'must be one of: {}'.format(
+                config.get('apiVersion'),
+                ', '.join(SUPPORTED_CONFIG_VERSIONS)
+            )
+        )
+
+    config.setdefault('archives', [])
+    config.setdefault('active', {})
+
+    return config
 
 
 def register_solution_version(

salt/_pillar/metalk8s_solutions.py

@@ -7,41 +7,36 @@
 
 
 def __virtual__():
+    if 'metalk8s_solutions.read_config' not in __salt__:
+        return False, "Failed to load 'metalk8s_solution' module."
     return __virtualname__
 
 
 def _load_solutions():
     """Load Solutions from ConfigMap and config file."""
-    errors = []
     try:
-        deployed = __salt__['metalk8s_solutions.list_deployed']()
-    except KeyError:
-        return __utils__['pillar_utils.errors_to_dict']([
-            "Failed to load 'metalk8s_solutions' module."
+        config_data = __salt__['metalk8s_solutions.read_config']()
+    except (IOError, CommandExecutionError) as exc:
+        config_data = __utils__['pillar_utils.errors_to_dict']([
+            "Error when reading Solutions config file: {}".format(exc)
         ])
+
+    try:
+        deployed = __salt__['metalk8s_solutions.list_deployed']()
     except Exception as exc:
-        deployed = {}
-        errors.append(
+        deployed = __utils__['pillar_utils.errors_to_dict']([
             "Error when retrieving ConfigMap 'metalk8s-solutions': {}".format(
                 exc
             )
-        )
-
-    try:
-        configured = __salt__['metalk8s_solutions.list_configured']()
-    except (IOError, CommandExecutionError) as exc:
-        configured = []
-        errors.append(
-            "Error when reading Solutions config file: {}".format(exc)
-        )
+        ])
 
     result = {
-        'configured': configured,
+        'config': config_data,
         'deployed': deployed,
     }
 
-    if errors:
-        result.update(__utils__['pillar_utils.errors_to_dict'](errors))
+    for key in result:
+        __utils__['pillar_utils.promote_errors'](result, key)
 
     return result