feat: Implement methods to extract the package name and parameters defined within a policy from the engine

.gitignore

@@ -27,4 +27,7 @@ bindings/*/target
 
 # C# build folders
 **bin
-**obj
+**obj
+
+# Visual Studio folders
+**/*.vs

Cargo.toml

@@ -23,6 +23,7 @@ default = ["full-opa", "arc"]
 
 arc = ["scientific/arc"]
 ast = []
+azure_policy = []
 base64 = ["dep:data-encoding"]
 base64url = ["dep:data-encoding"]
 coverage = []

bindings/csharp/Regorus.Tests/RegorusTests.cs

@@ -173,4 +173,43 @@
 
         Assert.IsTrue(JsonNode.DeepEquals(JsonNode.Parse(expected), JsonNode.Parse(result!)), $"Actual: {result}");
     }
+
+    [TestMethod]
+    public void GetPolicyPackageNames_succeeds()
+    {
+        using var engine = new Engine();
+        engine.AddPolicy(
+            "test.rego",
+            "package test\nx = 1\nmessage = `Hello`");
+
+        engine.AddPolicy(
+            "test.rego",
+            "package test.nested.name\nx = 1\nmessage = `Hello`");
+
+        var result = engine.GetPolicyPackageNames();
+
+        var packageNames = JsonNode.Parse(result!);
+
+        Assert.AreEqual("test", packageNames![0]["package_name"].ToString());
+        Assert.AreEqual("test.nested.name", packageNames![1]["package_name"].ToString());
+    }
+
+    [TestMethod]
+    public void GetPolicyParameters_succeeds()
+    {
+        using var engine = new Engine();
+        engine.AddPolicy(
+            "test.rego",
+            "package test\n default parameters.a = 5\nparameters.b = 10\nx = 1\nmessage = `Hello`");
+
+        var result = engine.GetPolicyParameters();
+
+        var parameters = JsonNode.Parse(result!);
+
+        Assert.AreEqual(1, parameters![0]["parameters"].AsArray().Count);
+        Assert.AreEqual(1, parameters![0]["modifiers"].AsArray().Count);
+
+        Assert.AreEqual("a", parameters![0]["parameters"][0]["name"].ToString());
+        Assert.AreEqual("b", parameters![0]["modifiers"][0]["name"].ToString());
+    }
 }

bindings/csharp/Regorus/Regorus.cs

@@ -217,6 +217,16 @@ public void SetGatherPrints(bool enable)
             return CheckAndDropResult(Regorus.Internal.API.regorus_engine_get_ast_as_json(E));
         }
 
+        public string? GetPolicyPackageNames()
+        {
+            return CheckAndDropResult(Regorus.Internal.API.regorus_engine_get_policy_package_names(E));
+        }
+
+        public string? GetPolicyParameters()
+        {
+            return CheckAndDropResult(Regorus.Internal.API.regorus_engine_get_policy_parameters(E));
+        }
+
         string? StringFromUTF8(IntPtr ptr)
         {
 

bindings/csharp/Regorus/RegorusFFI.cs

@@ -193,6 +193,22 @@ internal static unsafe partial class API
         [DllImport(__DllName, EntryPoint = "regorus_engine_get_ast_as_json", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
         internal static extern RegorusResult regorus_engine_get_ast_as_json(RegorusEngine* engine);
 
+        /// <summary>
+        ///  Gets the package names of policies added to the engine.
+        ///
+        ///  See https://docs.rs/regorus/latest/regorus/coverage/struct.Engine.html#method.get_policy_package_names
+        /// </summary>
+        [DllImport(__DllName, EntryPoint = "regorus_engine_get_policy_package_names", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_engine_get_policy_package_names(RegorusEngine* engine);
+
+        /// <summary>
+        ///  Gets the parameters defined in each policy added to the engine
+        ///
+        ///  See https://docs.rs/regorus/latest/regorus/coverage/struct.Engine.html#method.get_policy_parameters
+        /// </summary>
+        [DllImport(__DllName, EntryPoint = "regorus_engine_get_policy_parameters", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_engine_get_policy_parameters(RegorusEngine* engine);
+
         /// <summary>
         ///  Enable/disable rego v1.
         ///

bindings/csharp/global.json

@@ -4,7 +4,7 @@
     },
     "sdk": {
       "allowPrerelease": false,
-      "version": "8.0.408",
+      "version": "8.0.412",
       "rollForward": "disable"
     }
 }

bindings/ffi/Cargo.toml

@@ -23,8 +23,9 @@ lto = true
 codegen-units = 1
 
 [features]
-default = ["ast", "std", "coverage", "regorus/arc", "regorus/full-opa"]
+default = ["ast", "azure_policy", "std", "coverage", "regorus/arc", "regorus/full-opa"]
 ast = ["regorus/ast"]
+azure_policy = ["regorus/azure_policy"]
 std = ["regorus/std"]
 coverage = ["regorus/coverage"]
 custom_allocator = []

bindings/ffi/src/lib.rs

@@ -457,6 +457,40 @@ pub extern "C" fn regorus_engine_get_ast_as_json(engine: *mut RegorusEngine) ->
     }
 }
 
+/// Gets the package names defined in each policy added to the engine.
+///
+/// See https://docs.rs/regorus/latest/regorus/coverage/struct.Engine.html#method.get_policy_package_names
+#[no_mangle]
+#[cfg(feature = "azure_policy")]
+pub extern "C" fn regorus_engine_get_policy_package_names(engine: *mut RegorusEngine) -> RegorusResult {
+    let output = || -> Result<String> { serde_json::to_string_pretty(&to_ref(engine)?.engine.get_policy_package_names()?).map_err(anyhow::Error::msg) }();
+    match output {
+        Ok(out) => RegorusResult {
+            status: RegorusStatus::RegorusStatusOk,
+            output: to_c_str(out),
+            error_message: std::ptr::null_mut(),
+        },
+        Err(e) => to_regorus_result(Err(e)),
+    }
+}
+
+/// Gets the parameters defined in each policy added to the engine.
+///
+/// See https://docs.rs/regorus/latest/regorus/coverage/struct.Engine.html#method.get_policy_parameters
+#[no_mangle]
+#[cfg(feature = "azure_policy")]
+pub extern "C" fn regorus_engine_get_policy_parameters(engine: *mut RegorusEngine) -> RegorusResult {
+    let output = || -> Result<String> { serde_json::to_string_pretty(&to_ref(engine)?.engine.get_policy_parameters()?).map_err(anyhow::Error::msg) }();
+    match output {
+        Ok(out) => RegorusResult {
+            status: RegorusStatus::RegorusStatusOk,
+            output: to_c_str(out),
+            error_message: std::ptr::null_mut(),
+        },
+        Err(e) => to_regorus_result(Err(e)),
+    }
+}
+
 /// Enable/disable rego v1.
 ///
 /// See https://docs.rs/regorus/latest/regorus/struct.Engine.html#method.set_rego_v0

src/engine.rs

@@ -23,6 +23,31 @@ pub struct Engine {
     rego_v1: bool,
 }
 
+#[derive(Debug, Clone, Serialize)]
+pub struct PolicyPackageNameDefinition {
+    pub source_file: String,
+    pub package_name: String,
+}
+
+#[derive(Debug, Clone, Serialize)]
+pub struct PolicyParameter {
+    pub name: String,
+    pub modifiable: bool,
+    pub required: bool,
+}
+
+#[derive(Debug, Clone, Serialize)]
+pub struct PolicyModifier {
+    pub name: String,
+}
+
+#[derive(Debug, Clone, Serialize)]
+pub struct PolicyParameters {
+    pub source_file: String,
+    pub parameters: Vec<PolicyParameter>,
+    pub modifiers: Vec<PolicyModifier>,
+}
+
 /// Create a default engine.
 impl Default for Engine {
     fn default() -> Self {
@@ -907,6 +932,113 @@ impl Engine {
         serde_json::to_string_pretty(&ast).map_err(anyhow::Error::msg)
     }
 
+    /// Get the package names of each policy added to the engine.
+    ///
+    ///
+    /// ```rust
+    /// # use regorus::*;
+    /// # use anyhow::{bail, Result};
+    /// # fn main() -> Result<()> {
+    /// # let mut engine = Engine::new();
+    /// engine.add_policy("test.rego".to_string(), "package test\n x := 1".to_string())?;
+    /// engine.add_policy("test2.rego".to_string(), "package test.multi.segment\n x := 1".to_string())?;
+    ///
+    /// let package_names = engine.get_policy_package_names()?;
+    ///
+    /// assert_eq!("test", package_names[0].package_name);
+    /// assert_eq!("test.multi.segment", package_names[1].package_name);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[cfg(feature = "azure_policy")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "azure_policy")))]
+    pub fn get_policy_package_names(&self) -> Result<Vec<PolicyPackageNameDefinition>> {
+        let mut package_names = vec![];
+        for m in &self.modules {
+            let package_name = Interpreter::get_path_string(&m.package.refr, None)?;
+            package_names.push(PolicyPackageNameDefinition {
+                source_file: m.package.span.source.file().to_string(),
+                package_name,
+            });
+        }
+
+        Ok(package_names)
+    }
+
+    /// Get the parameters defined in each policy.
+    ///
+    ///
+    /// ```rust
+    /// # use regorus::*;
+    /// # use anyhow::{bail, Result};
+    /// # fn main() -> Result<()> {
+    /// # let mut engine = Engine::new();
+    /// engine.add_policy("test.rego".to_string(), "package test default parameters.a = 5 parameters.b = 10\n x := 1".to_string())?;
+    ///
+    /// let parameters = engine.get_policy_parameters()?;
+    ///
+    /// assert_eq!("a", parameters[0].parameters[0].name);
+    /// assert_eq!("b", parameters[0].modifiers[0].name);
+    ///
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[cfg(feature = "azure_policy")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "azure_policy")))]
+    pub fn get_policy_parameters(&self) -> Result<Vec<PolicyParameters>> {
+        let mut policy_parameter_definitions = vec![];
+        for m in &self.modules {
+            let mut parameters = vec![];
+            let mut modifiers = vec![];
+
+            for rule in &m.policy {
+                // Extract parameter definitions from the policy rule
+                // e.g. default parameters.a = 5
+                if let Rule::Default { refr, .. } = rule.as_ref() {
+                    let path = Parser::get_path_ref_components(refr)?;
+                    let paths: Vec<&str> = path.iter().map(|s| s.text()).collect();
+
+                    if paths.len() == 2 && paths[0] == "parameters" {
+                        // Todo: Fetch fields other than name from rego metadoc for the parameter
+                        parameters.push(PolicyParameter {
+                            name: paths[1].to_string(),
+                            modifiable: false,
+                            required: false,
+                        })
+                    }
+                }
+
+                // Extract modifiers to the parameters from the policy rule
+                // e.g. parameters.a = 5
+                if let Rule::Spec { head, .. } = rule.as_ref() {
+                    match head {
+                        RuleHead::Compr { refr, .. } => {
+                            let path = Parser::get_path_ref_components(refr)?;
+                            let paths: Vec<&str> = path.iter().map(|s| s.text()).collect();
+
+                            if paths.len() == 2 && paths[0] == "parameters" {
+                                // Todo: Fetch fields other than name from rego metadoc for the parameter
+                                modifiers.push(PolicyModifier {
+                                    name: paths[1].to_string(),
+                                })
+                            }
+                        }
+                        RuleHead::Func { .. } => {}
+                        RuleHead::Set { .. } => {}
+                    }
+                }
+            }
+
+            policy_parameter_definitions.push(PolicyParameters {
+                source_file: m.package.span.source.file().to_string(),
+                parameters,
+                modifiers,
+            });
+        }
+
+        Ok(policy_parameter_definitions)
+    }
+
     fn make_parser<'a>(&self, source: &'a Source) -> Result<Parser<'a>> {
         let mut parser = Parser::new(source)?;
         if self.rego_v1 {