implement multiple rules

Signed-off-by: tdruez <tdruez@aboutcode.org>

Author: tdruez

policy/rules.py

@@ -15,30 +15,83 @@ class BaseRule:
     rule_type = None
     label = None
     description = None
+    parameters_schema = {}
 
     def count_violations(self, policy_rule, product):
         """Count objects violating the rule for the given product."""
         raise NotImplementedError
 
 
-class ComplianceAlertRule(BaseRule):
-    rule_type = "compliance_alert"
-    label = "Compliance Alert"
+class PackageBaseRule(BaseRule):
+    """Base for rules that count packages matching a fixed filter within a product."""
+
+    package_filter = {}
+
+    def count_violations(self, policy_rule, product):
+        Package = apps.get_model("component_catalog", "package")
+
+        count = Package.objects.filter(
+            productpackages__product=product,
+            **self.package_filter,
+        ).count()
+
+        return count if count > policy_rule.threshold else 0
+
+
+class LicensePolicyErrorRule(PackageBaseRule):
+    rule_type = "license_policy_error"
+    label = "License Policy Error"
     description = (
         "Detects packages assigned a usage policy with a compliance alert level of 'error'."
     )
+    package_filter = {"usage_policy__compliance_alert": "error"}
+
+
+class LicensePolicyWarningRule(PackageBaseRule):
+    rule_type = "license_policy_warning"
+    label = "License Policy Warning"
+    description = (
+        "Detects packages assigned a usage policy with a compliance alert level of 'warning'."
+    )
+    package_filter = {"usage_policy__compliance_alert": "warning"}
+
+
+class LicenseCoverageGapRule(PackageBaseRule):
+    rule_type = "license_coverage_gap"
+    label = "License Coverage Gap"
+    description = (
+        "Detects packages with no license expression, indicating a gap in license coverage."
+    )
+    package_filter = {"license_expression": ""}
+
+
+class VulnerabilityDetectedRule(BaseRule):
+    rule_type = "vulnerability_detected"
+    label = "Vulnerability Detected"
+    description = "Detects packages with at least one known vulnerability (non-null risk score)."
+    parameters_schema = {
+        "min_risk_score": "Minimum risk score (0.0-10.0). Default: any vulnerability.",
+    }
 
     def count_violations(self, policy_rule, product):
         Package = apps.get_model("component_catalog", "package")
 
-        count = Package.objects.filter(
+        packages = Package.objects.filter(
             productpackages__product=product,
-            usage_policy__compliance_alert="error",
-        ).count()
+            risk_score__isnull=False,
+        )
+
+        min_risk_score = policy_rule.parameters.get("min_risk_score")
+        if min_risk_score is not None:
+            packages = packages.filter(risk_score__gte=min_risk_score)
 
+        count = packages.count()
         return count if count > policy_rule.threshold else 0
 
 
 RULE_REGISTRY = {
-    ComplianceAlertRule.rule_type: ComplianceAlertRule(),
+    LicensePolicyErrorRule.rule_type: LicensePolicyErrorRule(),
+    LicensePolicyWarningRule.rule_type: LicensePolicyWarningRule(),
+    LicenseCoverageGapRule.rule_type: LicenseCoverageGapRule(),
+    VulnerabilityDetectedRule.rule_type: VulnerabilityDetectedRule(),
 }