Enable user functions in configurations

dsc/tests/dsc_functions.tests.ps1

@@ -295,7 +295,7 @@ Describe 'tests for function expressions' {
     $out = dsc -l trace config get -i $config_yaml 2>$TestDrive/error.log | ConvertFrom-Json
     $LASTEXITCODE | Should -Be 2 -Because (Get-Content $TestDrive/error.log -Raw)
     $out | Should -BeNullOrEmpty -Because "Output should be null or empty"
-    (Get-Content $TestDrive/error.log -Raw) | Should -Match 'utcNow function can only be used as a parameter default'
+    (Get-Content $TestDrive/error.log -Raw) | Should -Match "The 'utcNow\(\)' function can only be used as a parameter default"
   }
 
   It 'uniqueString function works for: <expression>' -TestCases @(
@@ -428,7 +428,7 @@ Describe 'tests for function expressions' {
     $LASTEXITCODE | Should -Be 0 -Because (Get-Content $TestDrive/error.log -Raw)
     ($out.results[0].result.actualState.output | Out-String) | Should -BeExactly ($expected | Out-String)
   }
-  
+
   It 'skip function works for: <expression>' -TestCases @(
     @{ expression = "[skip(createArray('a','b','c','d'), 2)]"; expected = @('c', 'd') }
     @{ expression = "[skip('hello', 2)]"; expected = 'llo' }

dsc/tests/dsc_user_functions.tests.ps1

@@ -0,0 +1,154 @@
+# Copyright (c) Microsoft Corporation.
+# Licensed under the MIT License.
+
+Describe 'user function tests' {
+    It 'user function working with expression: <expression>' -TestCases @(
+        @{ expression = "[MyFunction.ComboFunction('test', 42, true)]"; expected = 'test-42-True' }
+        @{ expression = "[MyOtherNamespace.ArrayFunction(createArray('a','b','c','d'))]"; expected = @('["b","c","d"]-a') }
+    ) {
+        param($expression, $expected)
+
+        $configYaml = @"
+`$schema: https://aka.ms/dsc/schemas/v3/bundled/config/document.json
+functions:
+- namespace: MyFunction
+  members:
+    ComboFunction:
+      parameters:
+      - name: StringParam
+        type: string
+      - name: NumberParam
+        type: int
+      - name: BoolParam
+        type: bool
+      output:
+        type: string
+        value: "[format('{0}-{1}-{2}', parameters('StringParam'), parameters('NumberParam'), parameters('BoolParam'))]"
+- namespace: MyOtherNamespace
+  members:
+    ArrayFunction:
+      parameters:
+      - name: ArrayParam
+        type: array
+      output:
+        type: array
+        value: "[array(format('{0}-{1}', string(skip(parameters('ArrayParam'),1)), first(parameters('ArrayParam'))))]"
+resources:
+- name: test
+  type: Microsoft.DSC.Debug/Echo
+  properties:
+    output: "$expression"
+"@
+
+        $out = dsc -l trace config get -i $configYaml 2>$testdrive/error.log | ConvertFrom-Json
+        $LASTEXITCODE | Should -Be 0 -Because (Get-Content $testdrive/error.log | Out-String)
+        $out.results[0].result.actualState.output | Should -Be $expected -Because ($out | ConvertTo-Json -Depth 10 | Out-String)
+    }
+
+    It 'user function returning object works' {
+        $configYaml = @"
+`$schema: https://aka.ms/dsc/schemas/v3/bundled/config/document.json
+functions:
+- namespace: MyObjectFunction
+  members:
+    ObjectFunction:
+      parameters:
+      - name: ObjectParam
+        type: object
+      output:
+        type: object
+        value: "[createObject('myKey', concat('#', string(parameters('ObjectParam'))))]"
+resources:
+- name: test
+  type: Microsoft.DSC.Debug/Echo
+  properties:
+    output: "[MyObjectFunction.ObjectFunction(createObject('key','value'))]"
+"@
+
+        $out = dsc -l trace config get -i $configYaml 2>$testdrive/error.log | ConvertFrom-Json
+        $LASTEXITCODE | Should -Be 0 -Because (Get-Content $testdrive/error.log | Out-String)
+        $out.results[0].result.actualState.output.myKey | Should -Be '#{"key":"value"}' -Because ($out | ConvertTo-Json -Depth 10 | Out-String)
+    }
+
+    It 'user functions cannot call function with expression: <expression>' -TestCases @(
+        @{ expression = "[reference('foo/bar')]"; errorText = "The 'reference()' function is not available in user-defined functions" }
+        @{ expression = "[utcNow()]"; errorText = "The 'utcNow()' function can only be used as a parameter default" }
+        @{ expression = "[variables('myVar')]"; errorText = "The 'variables()' function is not available in user-defined functions" }
+        @{ expression = "[MyFunction.OtherFunction()]"; errorText = "Unknown user function 'MyFunction.OtherFunction'" }
+        @{ expression = "[MyFunction.BadFunction()]"; errorText = "Unknown user function 'MyFunction.BadFunction'" }
+    ) {
+        param($expression, $errorText)
+
+        $configYaml = @"
+`$schema: https://aka.ms/dsc/schemas/v3/bundled/config/document.json
+variables:
+  myVar: someValue
+functions:
+- namespace: MyFunction
+  members:
+    BadFunction:
+      output:
+        type: string
+        value: "$expression"
+    OtherFunction:
+      output:
+        type: string
+        value: "test"
+resources:
+- name: test
+  type: Microsoft.DSC.Debug/Echo
+  properties:
+    output: "[MyFunction.BadFunction()]"
+"@
+
+        dsc -l trace config get -i $configYaml 2>$testdrive/error.log | Out-Null
+        $LASTEXITCODE | Should -Be 2 -Because (Get-Content $testdrive/error.log | Out-String)
+        (Get-Content $testdrive/error.log -Raw) | Should -BeLike "*$errorText*" -Because (Get-Content $testdrive/error.log | Out-String)
+    }
+
+    It 'user function with invalid parameter fails' {
+        $configYaml = @"
+`$schema: https://aka.ms/dsc/schemas/v3/bundled/config/document.json
+functions:
+- namespace: MyFunction
+  members:
+    BadFunction:
+      parameters:
+      - name: Param1
+        type: string
+      output:
+        type: string
+        value: "[parameters('BadParam')]"
+resources:
+- name: test
+  type: Microsoft.DSC.Debug/Echo
+  properties:
+    output: "[MyFunction.BadFunction('test')]"
+"@
+
+        dsc -l trace config get -i $configYaml 2>$testdrive/error.log | Out-Null
+        $LASTEXITCODE | Should -Be 2 -Because (Get-Content $testdrive/error.log | Out-String)
+        (Get-Content $testdrive/error.log -Raw) | Should -BeLike "*Parameter 'BadParam' not found in context*" -Because (Get-Content $testdrive/error.log | Out-String)
+    }
+
+    It 'user function with wrong output type fails' {
+        $configYaml = @"
+`$schema: https://aka.ms/dsc/schemas/v3/bundled/config/document.json
+functions:
+- namespace: MyFunction
+  members:
+    BadFunction:
+      output:
+        type: int
+        value: "'this is a string'"
+resources:
+- name: test
+  type: Microsoft.DSC.Debug/Echo
+  properties:
+    output: "[MyFunction.BadFunction()]"
+"@
+        dsc -l trace config get -i $configYaml 2>$testdrive/error.log | Out-Null
+        $LASTEXITCODE | Should -Be 2 -Because (Get-Content $testdrive/error.log | Out-String)
+        (Get-Content $testdrive/error.log -Raw) | Should -BeLike "*Output of user function 'MyFunction.BadFunction' did not return expected type 'int'*" -Because (Get-Content $testdrive/error.log | Out-String)
+    }
+}

dsc_lib/locales/en-us.toml

@@ -76,6 +76,8 @@ unrollingCopy = "Unrolling copy for resource '%{name}' with count %{count}"
 copyModeNotSupported = "Copy mode is not supported"
 copyBatchSizeNotSupported = "Copy batch size is not supported"
 copyNameResultNotString = "Copy name result is not a string"
+userFunctionAlreadyDefined = "User function '%{name}' in namespace '%{namespace}' is already defined"
+addingUserFunction = "Adding user function '%{name}'"
 
 [discovery.commandDiscovery]
 couldNotReadSetting = "Could not read 'resourcePath' setting"
@@ -426,6 +428,7 @@ description = "Retrieves the output of a previously executed resource"
 invoked = "reference function"
 keyNotFound = "Invalid resourceId or resource has not executed yet: %{key}"
 cannotUseInCopyMode = "The 'reference()' function cannot be used when processing a 'Copy' loop"
+unavailableInUserFunction = "The 'reference()' function is not available in user-defined functions"
 
 [functions.resourceId]
 description = "Constructs a resource ID from the given type and name"
@@ -476,15 +479,22 @@ invalidArgType = "All arguments must either be arrays or objects"
 description = "Returns a deterministic unique string from the given strings"
 invoked = "uniqueString function"
 
+[functions.userFunction]
+expectedNoParameters = "User function '%{name}' does not accept parameters"
+unknownUserFunction = "Unknown user function '%{name}'"
+wrongParamCount = "User function '%{name}' expects %{expected} parameters, but %{got} were provided"
+incorrectOutputType = "Output of user function '%{name}' did not return expected type '%{expected_type}'"
+
 [functions.utcNow]
 description = "Returns the current UTC time"
 invoked = "utcNow function"
-onlyUsedAsParameterDefault = "utcNow function can only be used as a parameter default"
+onlyUsedAsParameterDefault = "The 'utcNow()' function can only be used as a parameter default"
 
 [functions.variables]
 description = "Retrieves the value of a variable"
 invoked = "variables function"
 keyNotFound = "Variable '%{key}' does not exist or has not been initialized yet"
+unavailableInUserFunction = "The 'variables()' function is not available in user-defined functions"
 
 [parser.expression]
 functionNodeNotFound = "Function node not found"

dsc_lib/src/configure/config_doc.rs

@@ -6,7 +6,7 @@ use rust_i18n::t;
 use schemars::{JsonSchema, json_schema};
 use serde::{Deserialize, Serialize};
 use serde_json::{Map, Value};
-use std::collections::HashMap;
+use std::{collections::HashMap, fmt::Display};
 
 use crate::{dscerror::DscError, schemas::DscRepoSchema};
 
@@ -105,6 +105,30 @@ pub struct Metadata {
     pub other: Map<String, Value>,
 }
 
+#[derive(Debug, Clone, PartialEq, Deserialize, Serialize, JsonSchema)]
+pub struct UserFunction {
+    pub namespace: String,
+    pub members: HashMap<String, UserFunctionDefinition>,
+}
+
+#[derive(Debug, Clone, PartialEq, Deserialize, Serialize, JsonSchema)]
+pub struct UserFunctionDefinition {
+    pub parameters: Option<Vec<UserFunctionParameter>>,
+    pub output: UserFunctionOutput,
+}
+
+#[derive(Debug, Clone, PartialEq, Deserialize, Serialize, JsonSchema)]
+pub struct UserFunctionParameter {
+    pub name: String,
+    pub r#type: DataType,
+}
+
+#[derive(Debug, Clone, PartialEq, Deserialize, Serialize, JsonSchema)]
+pub struct UserFunctionOutput {
+    pub r#type: DataType,
+    pub value: String,
+}
+
 #[derive(Debug, Clone, PartialEq, Deserialize, Serialize, JsonSchema)]
 #[serde(deny_unknown_fields)]
 pub struct Configuration {
@@ -114,6 +138,8 @@ pub struct Configuration {
     #[serde(rename = "contentVersion")]
     pub content_version: Option<String>,
     #[serde(skip_serializing_if = "Option::is_none")]
+    pub functions: Option<Vec<UserFunction>>,
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub parameters: Option<HashMap<String, Parameter>>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub variables: Option<Map<String, Value>>,
@@ -162,6 +188,21 @@ pub enum DataType {
     Array,
 }
 
+impl Display for DataType {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let type_str = match self {
+            DataType::String => "string",
+            DataType::SecureString => "secureString",
+            DataType::Int => "int",
+            DataType::Bool => "bool",
+            DataType::Object => "object",
+            DataType::SecureObject => "secureObject",
+            DataType::Array => "array",
+        };
+        write!(f, "{type_str}")
+    }
+}
+
 #[derive(Debug, Clone, PartialEq, Deserialize, Serialize, JsonSchema)]
 pub enum CopyMode {
     #[serde(rename = "serial")]
@@ -296,10 +337,11 @@ impl Configuration {
         Self {
             schema: Self::default_schema_id_uri(),
             content_version: Some("1.0.0".to_string()),
+            metadata: None,
             parameters: None,
-            variables: None,
             resources: Vec::new(),
-            metadata: None,
+            functions: None,
+            variables: None,
         }
     }
 }

dsc_lib/src/configure/context.rs

@@ -2,7 +2,7 @@
 // Licensed under the MIT License.
 
 use chrono::{DateTime, Local};
-use crate::{configure::config_doc::ExecutionKind, extensions::dscextension::DscExtension};
+use crate::{configure::config_doc::{ExecutionKind, UserFunctionDefinition}, extensions::dscextension::DscExtension};
 use security_context_lib::{get_security_context, SecurityContext};
 use serde_json::{Map, Value};
 use std::{collections::HashMap, path::PathBuf};
@@ -34,6 +34,7 @@ pub struct Context {
     pub security_context: SecurityContextKind,
     pub start_datetime: DateTime<Local>,
     pub system_root: PathBuf,
+    pub user_functions: HashMap<String, UserFunctionDefinition>,
     pub variables: Map<String, Value>,
 }
 
@@ -58,6 +59,7 @@ impl Context {
             },
             start_datetime: chrono::Local::now(),
             system_root: get_default_os_system_root(),
+            user_functions: HashMap::new(),
             variables: Map::new(),
         }
     }