lorax-composer: Add basic recipe checker function

This makes sure that required fields are included, and that sections are
not empty. It does not check for all optional fields.

If there are errors it will gather up all of them and then raise a
RecipeError with a string of all the errors.

(cherry picked from commit 61059a2699)

Resolves: rhbz#1716596

src/pylorax/api/recipes.py

@@ -269,6 +269,118 @@ def recipe_from_toml(recipe_str):
     recipe_dict = toml.loads(recipe_str)
     return recipe_from_dict(recipe_dict)
 
+def check_required_list(lst, fields):
+    """Check a list of dicts for required fields
+
+    :param lst: A list of dicts with fields
+    :type lst: list of dict
+    :param fields: A list of field name strings
+    :type fields: list of str
+    :returns: A list of error strings
+    :rtype: list of str
+    """
+    errors = []
+    for i, m in enumerate(lst):
+        m_errs = []
+        for f in fields:
+            if f not in m:
+                m_errs.append("'%s'" % f)
+        if m_errs:
+            errors.append("%d is missing %s" % (i, ",".join(m_errs)))
+    return errors
+
+def check_recipe_dict(recipe_dict):
+    """Check a dict before using it to create a new Recipe
+
+    :param recipe_dict: A plain dict of the recipe
+    :type recipe_dict: dict
+    :returns: True if dict is ok
+    :rtype: bool
+    :raises: RecipeError
+
+    This checks a dict to make sure required fields are present,
+    that optional fields are correct, and that other optional fields
+    are of the correct format, when included.
+
+    This collects all of the errors and returns a single RecipeError with
+    a string that can be presented to users.
+    """
+    errors = []
+
+    if "name" not in recipe_dict:
+        errors.append("Missing 'name'")
+    if "description" not in recipe_dict:
+        errors.append("Missing 'description'")
+    if "version" in recipe_dict:
+        try:
+            semver.Version(recipe_dict["version"])
+        except ValueError:
+            errors.append("Invalid 'version', must use Semantic Versioning")
+
+    # Examine all the modules
+    if recipe_dict.get("modules"):
+        module_errors = check_required_list(recipe_dict["modules"], ["name", "version"])
+        if module_errors:
+            errors.append("'modules' errors:\n%s" % "\n".join(module_errors))
+
+    # Examine all the packages
+    if recipe_dict.get("packages"):
+        package_errors = check_required_list(recipe_dict["packages"], ["name", "version"])
+        if package_errors:
+            errors.append("'packages' errors:\n%s" % "\n".join(package_errors))
+
+    if recipe_dict.get("groups"):
+        groups_errors = check_required_list(recipe_dict["groups"], ["name"])
+        if groups_errors:
+            errors.append("'groups' errors:\n%s" % "\n".join(groups_errors))
+
+    if recipe_dict.get("repos") and recipe_dict.get("repos").get("git"):
+        repos_errors = check_required_list(recipe_dict.get("repos").get("git"),
+                           ["rpmname", "rpmversion", "rpmrelease", "summary", "repo", "ref", "destination"])
+        if repos_errors:
+            errors.append("'repos.git' errors:\n%s" % "\n".join(repos_errors))
+
+    # No customizations to check, exit now
+    c = recipe_dict.get("customizations")
+    if not c:
+        return errors
+
+    # Make sure to catch empty sections by testing for keywords, not just looking at .get() result.
+    if "kernel" in c and "append" not in c.get("kernel", []):
+        errors.append("'customizations.kernel': missing append field.")
+
+    if "sshkey" in c:
+        sshkey_errors = check_required_list(c.get("sshkey"), ["user", "key"])
+        if sshkey_errors:
+            errors.append("'customizations.sshkey' errors:\n%s" % "\n".join(sshkey_errors))
+
+    if "user" in c:
+        user_errors = check_required_list(c.get("user"), ["name"])
+        if user_errors:
+            errors.append("'customizations.user' errors:\n%s" % "\n".join(user_errors))
+
+    if "group" in c:
+        group_errors = check_required_list(c.get("group"), ["name"])
+        if group_errors:
+            errors.append("'customizations.group' errors:\n%s" % "\n".join(group_errors))
+
+    if "timezone" in c and not c.get("timezone"):
+        errors.append("'customizations.timezone': missing timezone or ntpservers fields.")
+
+    if "locale" in c and not c.get("locale"):
+        errors.append("'customizations.locale': missing languages or keyboard fields.")
+
+    if "firewall" in c and not c.get("firewall"):
+        errors.append("'customizations.firewall': missing ports field or services section.")
+
+    if "firewall" in c and "services" in c.get("firewall", []) and not c.get("firewall").get("services"):
+        errors.append("'customizations.firewall.services': missing enabled or disabled fields.")
+
+    if "services" in c and not c.get("services"):
+        errors.append("'customizations.services': missing enabled or disabled fields.")
+
+    return errors
+
 def recipe_from_dict(recipe_dict):
     """Create a Recipe object from a plain dict.
 
@@ -278,6 +390,11 @@ def recipe_from_dict(recipe_dict):
     :rtype: Recipe
     :raises: RecipeError
     """
+    errors = check_recipe_dict(recipe_dict)
+    if errors:
+        msg = "\n".join(errors)
+        raise RecipeError(msg)
+
     # Make RecipeModule objects from the toml
     # The TOML may not have modules or packages in it. Set them to None in this case
     try:

tests/pylorax/test_compose.py

@@ -29,7 +29,7 @@ from pylorax.api.compose import services_cmd, get_services, get_default_services
 from pylorax.api.compose import get_kernel_append, bootloader_append, customize_ks_template
 from pylorax.api.config import configure, make_dnf_dirs
 from pylorax.api.dnfbase import get_base_object
-from pylorax.api.recipes import recipe_from_toml
+from pylorax.api.recipes import recipe_from_toml, RecipeError
 from pylorax.sysutils import joinpaths
 
 BASE_RECIPE = """name = "test-cases"
@@ -472,8 +472,8 @@ disabled = ["postfix", "telnetd"]
         blueprint3_data = blueprint_data + disable_services
         blueprint4_data = blueprint_data + enable_services + disable_services
 
+        with self.assertRaises(RecipeError):
             recipe = recipe_from_toml(blueprint_data)
-        self.assertEqual(get_services(recipe), {'enabled': [], 'disabled': []})
 
         recipe = recipe_from_toml(blueprint2_data)
         self.assertEqual(get_services(recipe),
@@ -526,8 +526,8 @@ disabled = ["postfix", "telnetd"]
         blueprint3_data = blueprint_data + disable_services
         blueprint4_data = blueprint_data + enable_services + disable_services
 
+        with self.assertRaises(RecipeError):
             recipe = recipe_from_toml(blueprint_data)
-        self.assertEqual(get_default_services(recipe), "")
 
         recipe = recipe_from_toml(blueprint2_data)
         self.assertEqual(get_default_services(recipe), "services")