Adding Policy Field Count Expression Support

.vscode/settings.json

@@ -15,6 +15,10 @@
     "[yaml]": {
         "editor.tabSize": 2
     },
+    "[json]": {
+        "editor.formatOnSave": true,
+        "editor.tabSize": 2
+    },
     "[markdown]": {
         "editor.tabSize": 2
     },
@@ -32,25 +36,37 @@
         "agentpool",
         "APIM",
         "apiserver",
+        "APIVERSION",
         "APPGW",
         "Architected",
         "AUTOMATIONACCOUNT",
         "autoscaler",
         "cmdlet",
         "cmdlets",
         "Concat",
+        "DEFAULTVALUE",
+        "DISPLAYNAME",
         "endregion",
         "failover",
+        "GREATEROREQUAL",
+        "GREATEROREQUALS",
         "Hashtable",
         "kube",
         "kubelet",
         "kubenet",
         "Kubernetes",
+        "LESSOREQUAL",
+        "LESSOREQUALS",
         "lifecycle",
+        "Newtonsoft",
         "nics",
+        "NOTCOUNT",
+        "NOTEQUALS",
+        "NOTIN",
         "NSGs",
         "OWASP",
         "POLICYDEFINITIONID",
+        "POLICYRULE",
         "psarm",
         "PUBLICIP",
         "pwsh",

docs/CHANGELOG-v1.md

@@ -25,6 +25,9 @@ What's changed since v1.16.1:
   - Deployment:
     - Check for secure values in outputs by @BernieWhite.
       [#297](https://github.com/Azure/PSRule.Rules.Azure/issues/297)
+- New features:
+  - Added more field count expression support for Azure Policy JSON rules by @ArmaanMcleod.
+    [#181](https://github.com/Azure/PSRule.Rules.Azure/issues/181)
 
 ## v1.16.1
 

src/PSRule.Rules.Azure/Common/StringExtensions.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+using System;
 using System.Linq;
 
 namespace PSRule.Rules.Azure
@@ -16,7 +17,17 @@ internal static string ToCamelCase(this string str)
 
         internal static int CountCharacterOccurrences(this string str, char chr)
         {
-            return str.Count(c => c == chr);
+            return !string.IsNullOrEmpty(str)
+                ? str.Count(c => c == chr)
+                : 0;
+        }
+
+        internal static string[] SplitByLastSubstring(this string str, string substring)
+        {
+            var lastSubstringIndex = str.LastIndexOf(substring, StringComparison.OrdinalIgnoreCase);
+            var firstPart = str.Substring(0, lastSubstringIndex);
+            var secondPart = str.Substring(lastSubstringIndex + substring.Length);
+            return new string[] { firstPart, secondPart };
         }
 
         internal static bool IsExpressionString(this string str)

src/PSRule.Rules.Azure/Data/Policy/PolicyAliasProviderHelper.cs

@@ -34,11 +34,10 @@ internal bool ResolvePolicyAliasPath(string aliasName, out string aliasPath)
             // Handle aliases like Microsoft.Compute/imageId with only one slash
             if (slashOccurrences == 1)
             {
-                if (_DefaultRuleType != null && _Providers.TryResourceType(_DefaultRuleType, out var type2))
-                    return type2.Aliases != null &&
-                        type2.Aliases.TryGetValue(aliasName, out aliasPath);
-
-                return false;
+                return _DefaultRuleType != null
+                    && _Providers.TryResourceType(_DefaultRuleType, out var type2)
+                    && type2.Aliases != null
+                    && type2.Aliases.TryGetValue(aliasName, out aliasPath);
             }
 
             // Any aliases with two slashes or more will be resolved here

src/PSRule.Rules.Azure/Data/Policy/PolicyAssignmentHelper.cs

@@ -40,8 +40,8 @@ internal PolicyDefinition[] ProcessAssignment(string assignmentFile, out PolicyA
             {
                 var assignmentArray = ReadFileArray(rootedAssignmentFile);
 
-                foreach (JObject assignment in assignmentArray)
-                    visitor.Visit(assignmentContext, assignment);
+                foreach (var assignment in assignmentArray)
+                    visitor.Visit(assignmentContext, assignment.ToObject<JObject>());
             }
             catch (Exception inner)
             {
@@ -60,13 +60,9 @@ internal PolicyDefinition[] ProcessAssignment(string assignmentFile, out PolicyA
 
         private static JArray ReadFileArray(string path)
         {
-            using (var stream = new StreamReader(path))
-            {
-                using (var reader = new CamelCasePropertyNameJsonTextReader(stream))
-                {
-                    return JArray.Load(reader);
-                }
-            }
+            using var stream = new StreamReader(path);
+            using var reader = new CamelCasePropertyNameJsonTextReader(stream);
+            return JArray.Load(reader);
         }
 
         private sealed class CamelCasePropertyNameJsonTextReader : JsonTextReader