Add condition support to resources within config

dsc/tests/dsc_resource_condition.tests.ps1

@@ -0,0 +1,41 @@
+# Copyright (c) Microsoft Corporation.
+# Licensed under the MIT License.
+
+Describe 'Resource condition tests' {
+    BeforeAll {
+        $configYaml = @'
+        $schema: https://aka.ms/dsc/schemas/v3/bundled/config/document.json
+        resources:
+          - name: test
+            type: Microsoft.DSC.Debug/Echo
+            condition: "[equals('skip', 'yes')]"
+            properties:
+              output: "This should not be executed"
+          - name: test2
+            type: Microsoft.DSC.Debug/Echo
+            condition: "[equals('no', 'no')]"
+            properties:
+              output: "This should be executed"
+'@
+    }
+
+    It 'resource should be skipped for <operation>' -TestCases @(
+        @{ operation = 'get'; property = 'actualState' },
+        @{ operation = 'set'; property = 'afterState' },
+        @{ operation = 'test'; property = 'actualState' }
+    ) {
+        param($operation, $property)
+        $out = dsc config $operation -i $configYaml 2>$TestDrive/error.log | ConvertFrom-Json
+        $LASTEXITCODE | Should -Be 0 -Because (Get-Content $TestDrive/error.log -Raw | Out-String)
+        $out.results.count | Should -Be 1
+        $out.results[0].result.$property.Output | Should -BeExactly "This should be executed"
+    }
+
+    It 'resource should be skipped for export' {
+        $out = dsc config export -i $configYaml 2>$TestDrive/error.log | ConvertFrom-Json
+        $LASTEXITCODE | Should -Be 0 -Because (Get-Content $TestDrive/error.log -Raw | Out-String)
+        $out.resources.count | Should -Be 1
+        $out.resources[0].type | Should -BeExactly 'Microsoft.DSC.Debug/Echo'
+        $out.resources[0].properties.output | Should -BeExactly "This should be executed"
+    }
+}

dsc_lib/locales/en-us.toml

@@ -3,6 +3,7 @@ _version = 1
 [configure.config_doc]
 configurationDocumentSchemaTitle = "Configuration document schema URI"
 configurationDocumentSchemaDescription = "Defines the JSON Schema the configuration document adheres to."
+skippingResource = "Skipping resource '%{name}' due to condition '%{condition}' with result '%{result}'"
 
 [configure.constraints]
 minLengthIsNull = "Parameter '%{name}' has minimum length constraint but is null"

dsc_lib/src/configure/config_doc.rs

@@ -160,6 +160,8 @@ pub struct Resource {
     pub properties: Option<Map<String, Value>>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub metadata: Option<Metadata>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub condition: Option<String>,
 }
 
 impl Default for Configuration {
@@ -217,6 +219,7 @@ impl Resource {
             kind: None,
             properties: None,
             metadata: None,
+            condition: None,
         }
     }
 }

dsc_lib/src/configure/mod.rs

@@ -311,6 +311,10 @@ impl Configurator {
         for resource in resources {
             progress.set_resource(&resource.name, &resource.resource_type);
             progress.write_activity(format!("Get '{}'", resource.name).as_str());
+            if self.skip_resource(&resource)? {
+                progress.write_increment(1);
+                continue;
+            }
             let Some(dsc_resource) = discovery.find_resource(&resource.resource_type) else {
                 return Err(DscError::ResourceNotFound(resource.resource_type));
             };
@@ -387,6 +391,10 @@ impl Configurator {
         for resource in resources {
             progress.set_resource(&resource.name, &resource.resource_type);
             progress.write_activity(format!("Set '{}'", resource.name).as_str());
+            if self.skip_resource(&resource)? {
+                progress.write_increment(1);
+                continue;
+            }
             let Some(dsc_resource) = discovery.find_resource(&resource.resource_type) else {
                 return Err(DscError::ResourceNotFound(resource.resource_type));
             };
@@ -535,6 +543,10 @@ impl Configurator {
         for resource in resources {
             progress.set_resource(&resource.name, &resource.resource_type);
             progress.write_activity(format!("Test '{}'", resource.name).as_str());
+            if self.skip_resource(&resource)? {
+                progress.write_increment(1);
+                continue;
+            }
             let Some(dsc_resource) = discovery.find_resource(&resource.resource_type) else {
                 return Err(DscError::ResourceNotFound(resource.resource_type));
             };
@@ -608,6 +620,10 @@ impl Configurator {
         for resource in &resources {
             progress.set_resource(&resource.name, &resource.resource_type);
             progress.write_activity(format!("Export '{}'", resource.name).as_str());
+            if self.skip_resource(resource)? {
+                progress.write_increment(1);
+                continue;
+            }
             let Some(dsc_resource) = discovery.find_resource(&resource.resource_type) else {
                 return Err(DscError::ResourceNotFound(resource.resource_type.clone()));
             };
@@ -642,6 +658,17 @@ impl Configurator {
         Ok(result)
     }
 
+    fn skip_resource(&mut self, resource: &Resource) -> Result<bool, DscError> {
+        if let Some(condition) = &resource.condition {
+            let condition_result = self.statement_parser.parse_and_execute(condition, &self.context)?;
+            if condition_result != Value::Bool(true) {
+                info!("{}", t!("configure.config_doc.skippingResource", name = resource.name, condition = condition, result = condition_result));
+                return Ok(true);
+            }
+        }
+        Ok(false)
+    }
+
     /// Set the mounted path for the configuration.
     ///
     /// # Arguments

dscecho/echo.dsc.resource.json

@@ -30,6 +30,15 @@
             }
         ]
     },
+    "export": {
+        "executable": "dscecho",
+        "args": [
+            {
+                "jsonInputArg": "--input",
+                "mandatory": true
+            }
+        ]
+    },
     "schema": {
         "command": {
             "executable": "dscecho"