[Aspire] Add support for default.value for parameter.v0 (#4371)

* Adding support for parameter.v0 default value

* support mapping to env vars during deploy

cli/azd/pkg/apphost/generate.go

@@ -88,6 +88,12 @@ func init() {
 				},
 				"removeDot": scaffold.RemoveDotAndDash,
 				"envFormat": scaffold.EnvFormat,
+				"bicepParameterValue": func(value *string) string {
+					if value == nil {
+						return ""
+					}
+					return fmt.Sprintf(" = '%s'", *value)
+				},
 			},
 		).
 		ParseFS(resources.AppHostTemplates, "apphost/templates/*")
@@ -298,6 +304,7 @@ func BicepTemplate(name string, manifest *Manifest, options AppHostOptions) (*me
 		Name   string
 		Secret bool
 		Type   string
+		Value  *string
 	}
 	type autoGenInput struct {
 		genInput
@@ -317,14 +324,22 @@ func BicepTemplate(name string, manifest *Manifest, options AppHostOptions) (*me
 	for _, key := range genParametersKeys {
 		parameter := generator.bicepContext.InputParameters[key]
 		parameterMetadata := ""
-		if parameter.Default != nil && parameter.Default.Generate != nil {
-			pMetadata, err := inputMetadata(*parameter.Default.Generate)
-			if err != nil {
-				return nil, fmt.Errorf("generating input metadata for %s: %w", key, err)
+		var parameterDefaultValue *string
+		if parameter.Default != nil {
+			// main.bicep template handles *string for default.Value. If the value is nil, it will be ignored.
+			// if not nil, like empty string or any other string, it is used as `= '<value>'`
+			parameterDefaultValue = parameter.Default.Value
+			if parameter.Default.Generate != nil {
+				pMetadata, err := inputMetadata(*parameter.Default.Generate)
+				if err != nil {
+					return nil, fmt.Errorf("generating input metadata for %s: %w", key, err)
+				}
+				parameterMetadata = pMetadata
 			}
-			parameterMetadata = pMetadata
+			// Note: azd is not checking or validating that Default.Generate and Default.Value are not both set.
+			// The AppHost prevents this from happening by not allowing both to be set at the same time.
 		}
-		input := genInput{Name: key, Secret: parameter.Secret, Type: parameter.Type}
+		input := genInput{Name: key, Secret: parameter.Secret, Type: parameter.Type, Value: parameterDefaultValue}
 		parameters = append(parameters, autoGenInput{
 			genInput:       input,
 			MetadataConfig: parameterMetadata,
@@ -1565,6 +1580,15 @@ func (b infraGenerator) evalBindingRef(v string, emitType inputEmitType) (string
 		case inputEmitTypeBicep:
 			return fmt.Sprintf("{{%s}}", replaceDash), nil
 		case inputEmitTypeYaml:
+			if param.Default != nil && param.Default.Value != nil {
+				if param.Secret {
+					return "", fmt.Errorf("default value for secured parameter %s is not supported", resource)
+				}
+				inputType = "parameterWithDefault"
+				// parameter with default value will either use the default value or the value passed in the environment
+				return fmt.Sprintf(`{{ %s "%s" "%s"}}`, inputType, replaceDash, *param.Default.Value), nil
+			}
+			// parameter without default value
 			return fmt.Sprintf(`{{ %s "%s" }}`, inputType, replaceDash), nil
 		default:
 			panic(fmt.Sprintf("unexpected parameter %s", string(emitType)))

cli/azd/pkg/apphost/manifest.go

@@ -195,6 +195,7 @@ type InputDefaultGenerate struct {
 
 type InputDefault struct {
 	Generate *InputDefaultGenerate `json:"generate,omitempty"`
+	Value    *string               `json:"value,omitempty"`
 }
 
 // ManifestFromAppHost returns the Manifest from the given app host.

cli/azd/pkg/apphost/testdata/TestAspireContainerGeneration-main.bicep.snap

@@ -54,6 +54,8 @@ param noVolume_pas_sw_ord string
 })
 @secure()
 param noVolume_password string
+param param_with_empty_value string = ''
+param param_with_value string = 'default value for param'
 
 var tags = {
   'azd-env-name': environmentName

cli/azd/pkg/apphost/testdata/TestAspireContainerGeneration-main.parameters.json.snap

@@ -23,6 +23,12 @@
       "noVolume_password": {
         "value": "${AZURE_NO_VOLUME_PASSWORD}"
       },
+      "param_with_empty_value": {
+        "value": "${AZURE_PARAM_WITH_EMPTY_VALUE}"
+      },
+      "param_with_value": {
+        "value": "${AZURE_PARAM_WITH_VALUE}"
+      },
       "environmentName": {
         "value": "${AZURE_ENV_NAME}"
       },

cli/azd/pkg/apphost/testdata/TestAspireContainerGeneration-mysqlabstract.snap

@@ -39,6 +39,10 @@ properties:
         env:
           - name: AZURE_CLIENT_ID
             value: {{ .Env.MANAGED_IDENTITY_CLIENT_ID }}
+          - name: EMPTY_VALUE
+            value: '{{ parameterWithDefault "param_with_empty_value" ""}}'
+          - name: WITH_VALUE
+            value: '{{ parameterWithDefault "param_with_value" "default value for param"}}'
           - name: MYSQL_ROOT_PASSWORD
             secretRef: mysql-root-password
           - name: SpecialChar

cli/azd/pkg/apphost/testdata/aspire-container.json

@@ -16,6 +16,32 @@
         }
       }
     },
+    "param-with-value": {
+      "type": "parameter.v0",
+      "value": "{param-with-value.inputs.value}",
+      "inputs": {
+        "value": {
+          "type": "string",
+          "secret": false,
+          "default":{
+            "value": "default value for param"
+          }
+        }
+      }
+    },
+    "param-with-empty-value": {
+      "type": "parameter.v0",
+      "value": "{param-with-empty-value.inputs.value}",
+      "inputs": {
+        "value": {
+          "type": "string",
+          "secret": false,
+          "default":{
+            "value": ""
+          }
+        }
+      }
+    },
     "mysqlabstract-pas-sw-ord": {
       "type": "parameter.v0",
       "value": "{mysqlabstract-pas-sw-ord.inputs.value}",
@@ -38,7 +64,9 @@
       "image": "mysql:latest",
       "env": {
         "MYSQL_ROOT_PASSWORD": "{mysqlabstract-password.value}",
-        "SpecialChar": "{mysqlabstract-pas-sw-ord.value}"
+        "SpecialChar": "{mysqlabstract-pas-sw-ord.value}",
+        "WITH_VALUE": "{param-with-value.value}",
+        "EMPTY_VALUE": "{param-with-empty-value.value}"
       },
       "volumes": [
         {

cli/azd/pkg/project/service_target_dotnet_containerapp.go

@@ -15,6 +15,7 @@ import (
 	"strings"
 	"text/template"
 
+	"github.com/azure/azure-dev/cli/azd/internal/scaffold"
 	"github.com/azure/azure-dev/cli/azd/pkg/alpha"
 	"github.com/azure/azure-dev/cli/azd/pkg/apphost"
 	"github.com/azure/azure-dev/cli/azd/pkg/async"
@@ -252,8 +253,9 @@ func (at *dotnetContainerAppTarget) Deploy(
 	}
 
 	funcMap := template.FuncMap{
-		"urlHost":   fns.UrlHost,
-		"parameter": fns.Parameter,
+		"urlHost":              fns.UrlHost,
+		"parameter":            fns.Parameter,
+		"parameterWithDefault": fns.ParameterWithDefault,
 		// securedParameter gets a parameter the same way as parameter, but supporting the securedParameter
 		// allows to update the logic of pulling secret parameters in the future, if azd changes the way it
 		// stores the parameter value.
@@ -503,7 +505,16 @@ func (_ *containerAppTemplateManifestFuncs) UrlHost(s string) (string, error) {
 
 const infraParametersKey = "infra.parameters."
 
+// Parameter resolves the name of a parameter defined in the ACA yaml definition. The parameter can be mapped to a system
+// environment variable or persisted in the azd environment configuration.
 func (fns *containerAppTemplateManifestFuncs) Parameter(name string) (string, error) {
+	envVarMapping := scaffold.EnvFormat(name)
+	// map only to system environment variables. Not adding support for mapping to azd environment by design (b/c
+	// parameters could be secured)
+	if val, found := os.LookupEnv(envVarMapping); found {
+		return val, nil
+	}
+
 	key := infraParametersKey + name
 	val, found := fns.env.Config.Get(key)
 	if !found {
@@ -516,6 +527,18 @@ func (fns *containerAppTemplateManifestFuncs) Parameter(name string) (string, er
 	return valString, nil
 }
 
+// ParameterWithDefault resolves the name of a parameter defined in the ACA yaml definition.
+// The parameter can be mapped to a system environment variable or be default to a value directly.
+func (fns *containerAppTemplateManifestFuncs) ParameterWithDefault(name string, defaultValue string) (string, error) {
+	envVarMapping := scaffold.EnvFormat(name)
+	// map only to system environment variables. Not adding support for mapping to azd environment by design (b/c
+	// parameters could be secured)
+	if val, found := os.LookupEnv(envVarMapping); found {
+		return val, nil
+	}
+	return defaultValue, nil
+}
+
 // kvSecret gets the value of the secret with the given name from the KeyVault with the given host name. If the secret is
 // not found, an error is returned.
 func (fns *containerAppTemplateManifestFuncs) kvSecret(kvHost, secretName string) (string, error) {

cli/azd/resources/apphost/templates/main.bicept

@@ -24,7 +24,7 @@ param principalId string = ''
 {{- if $parameter.Secret }}
 @secure()
 {{- end}}
-param {{bicepParameterName $parameter.Name}} {{$parameter.Type}}
+param {{bicepParameterName $parameter.Name}} {{$parameter.Type}}{{bicepParameterValue $parameter.Value}}
 {{- end}}
 
 var tags = {