Add conditional service deployment via condition field

[Copilot]

Adds support for conditional service deployment in azure.yaml. Services can now specify a condition field with environment variable expansion to control deployment based on runtime configuration.

Changes

ServiceConfig (pkg/project/service_config.go)

• Added Condition osutil.ExpandableString field supporting envvar expansion
• Added IsEnabled(getenv) (bool, error) method evaluating truthy values: 1, true|TRUE|True, yes|YES|Yes
• Returns error for malformed condition templates instead of silently disabling
• Undefined/empty conditions default to enabled (backward compatible)

ImportManager (pkg/project/importer.go)

• Added ServiceStableFiltered() method that centralizes condition filtering
• Filters services based on condition before returning to commands
• Provides clear error when targeting a disabled service

All Service Commands

• azd deploy, azd package, azd restore, azd build, azd publish all respect service conditions
• Services with false conditions are filtered out (no "skipped" messages shown)
• Targeting a specific disabled service returns error with evaluated condition value

Tests

• Unit tests for condition parsing and evaluation
• Integration tests for envvar expansion and YAML parsing
• Test for malformed condition template error handling

Usage

services:
  api:
    project: ./src/api
    host: containerapp
    
  ml-model:
    project: ./src/ml-model  
    host: ai.endpoint
    condition: ${DEPLOY_ML_MODEL}  # Deployed only when truthy

$ azd env set DEPLOY_ML_MODEL true
$ azd deploy  # Deploys both api and ml-model

$ azd env set DEPLOY_ML_MODEL false
$ azd deploy  # Deploys only api (ml-model filtered out)

$ azd deploy ml-model  # Error: condition evaluates to 'false'

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Add ability to setup 'condition:' for Service deployment</issue_title>
<issue_description>I'm trying to setup an AZD template that deploys a solution with multiple services, including a service that I want to be deployed only if a specific input parameter to the Azure Bicep is set to 'true'. Such as 'DEPLOY_AML_MODEL' = 'true'. I'm using this to conditionally provision Azure Resources in the 'infra' provisioning. In my case it's an Azure Machine Learning service. I'm using an AZD service to deploy the AML Model, and I'd like to have that model deployment conditional based on if the infra has provisioned the AML service or not.

I'd like to add a 'condition' element to the Service, when evaluated to be 'true' will trigger the deployment, when 'false' it wont deploy the service, like this:

condition: ${DEPLOY_AML_MODEL}

Here's an example of what I'm trying to do when setting up the Azure Machine Learning model deployment within the azure.yaml:

  AMLReranker:
    condition: ${DEPLOY_AML_MODEL}
    project: ./src/amlreranker
    host: ai.endpoint
    config:
      workspace: ${AZURE_AML_WORKSPACE_NAME}
      model:
        path: ./model/
        code_configuration:
          code: ./scoring/
          scoring_script: score_bgev2m3_aml.py
        environment:
          name: bgev2m3-env 
          build: 
            path: ./environment/
        instance_type: STANDARD_D16AS_V4
        instance_count: 1
        request_settings:
          request_timeout_ms: 120000
    dependsOn:
      - infra

It would be really amazing if azd could implement this functionality! Thanks!</issue_description>

<agent_instructions>Add a bool field "condition" to ServiceConfig and make it an expandable osutil.ExpandableString so it can be mapped to env vars.
When this field is defined for the service config, it disables the service if the value in it can't be parsed to a true boolean. For example, values like 1, true, TRUE, True, yes should be parsable to true to activate the service.
But any other value like 0, false, no, or random string should be resolved to false.

Then update the service manager to ignore those services which defines this field with a non-possitive value.

If the field is not defined, the service should be enabled, ensuring backward compatibility.

If the user runs azd depoy foo and foo is a service with the condition false, return an error and tell the user the service requires a possitive value as conditiion to be deployed and its currently false.

If the user runs azd deploy for all services, just skip those with a negativite resolved condition
</agent_instructions>

Comments on the Issue (you are @copilot in this section)

@vhvb1989 related and previous context: https://github.com//issues/3514

• Fixes Add ability to setup 'condition:' for Service deployment #4732

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[weikanglim]

Does condition mean disabled for azd deploy or all service commands?

[vhvb1989]

all service-commands

[weikanglim]

Left a comment here. I think this still needs to be addressed. Initial thoughts would be to have it incorporated into ServicesStable in some fashion.

[Copilot]

Implemented in c8fa45a. Added ServiceStableFiltered() to ImportManager which applies condition filtering. Now used by all service commands (deploy, package, restore, build, publish).

[Copilot]

Pull request overview

This PR adds support for conditional service deployment in azure.yaml, allowing services to be deployed only when a specified condition evaluates to a truthy value. The feature enables runtime-based deployment decisions through environment variable expansion.

Changes:

• Added Condition field to ServiceConfig with support for environment variable expansion
• Implemented IsEnabled() method to evaluate conditions based on truthy values (1, true, TRUE, True, yes, YES, Yes)
• Updated deploy command to skip services with false conditions or error when explicitly targeting a disabled service
• Added comprehensive unit and integration tests for condition parsing and evaluation

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
cli/azd/pkg/project/service_config.go	Added Condition field and IsEnabled() method to support conditional deployment logic
cli/azd/pkg/project/service_config_test.go	Added unit tests for condition evaluation with various truthy/falsy values and environment variable expansion
cli/azd/pkg/project/service_condition_integration_test.go	Added integration tests for YAML parsing and environment-based condition evaluation
cli/azd/internal/cmd/deploy.go	Updated deploy command to check service conditions and provide appropriate error messages or skip disabled services

---

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[Copilot]

When a targeted service has a false condition, the error message could be more actionable by including the condition expression itself, not just the evaluated value. Consider showing both the expression and the evaluated value, e.g., "service 'ml-model' has a deployment condition '${DEPLOY_ML_MODEL}' that evaluated to 'false'". This would help users understand which environment variable needs to be changed.

Suggested change

	return fmt.Errorf(
	"service '%s' has a deployment condition that evaluated to '%s'. "+
	"The service requires a truthy value (1, true, TRUE, True, yes, YES, Yes) to be deployed",
	svc.Name,
	conditionExpression := fmt.Sprint(svc.Condition)
	return fmt.Errorf(
	"service '%s' has a deployment condition '%s' that evaluated to '%s'. "+
	"The service requires a truthy value (1, true, TRUE, True, yes, YES, Yes) to be deployed",
	svc.Name,
	conditionExpression,

[Copilot]

The comment should list all accepted truthy values for consistency with the implementation. The implementation accepts "yes", "YES", and "Yes", but the comment only lists "yes". Consider updating to: "is a truthy boolean (1, true, TRUE, True, yes, YES, Yes)".

Suggested change

	// is a truthy boolean (1, true, TRUE, True, yes). If not defined, the service is enabled by default.
	// is a truthy boolean (1, true, TRUE, True, yes, YES, Yes). If not defined, the service is enabled by default.

[Copilot]

The error handling for malformed condition templates silently disables the service. Consider adding a test case for this scenario to ensure the behavior is intentional and well-documented. For example, a condition like "${UNCLOSED" would return an error from Envsubst, and the service would be disabled without any indication to the user that their template is malformed.

[weikanglim]

I think this feedback is really valid -- I believe it's appropriate to surface errors directly.

[Copilot]

Implemented in c8fa45a. IsEnabled() now returns (bool, error) and surfaces malformed template errors directly instead of silently disabling the service.

[Copilot]

The error from Envsubst is being silently ignored. If the condition template is malformed, the error message will show an empty string as the evaluated value, which might be misleading. Consider handling the error explicitly to provide a more informative message to the user, such as "service 'X' has a malformed deployment condition template" when err != nil.

Suggested change

	conditionValue, _ := svc.Condition.Envsubst(da.env.Getenv)
	conditionValue, err := svc.Condition.Envsubst(da.env.Getenv)
	if err != nil {
	return fmt.Errorf("service '%s' has a malformed deployment condition template: %w", svc.Name, err)
	}

[vhvb1989]

@copilot apply changes based on the comments in this thread

[weikanglim]

Overall, I'm really happy with the direction here. I do believe adding condition support is a good thing. There's been a few user asks along these lines. It is indeed the cheapest way for us to get to a "configurable AST". I'd like to see changes merged to support this feature.

I believe based on our PR discussion earlier, we are thinking the conditional should be applied to all service commands. This should be addressed and I'm waiting for this.

Implementation wise, I'd love us to clean up both implementation and UX -- avoid writing the skipped message (address #4605), and perhaps incorporate the enablement logic into ServicesStable. We can perhaps support a conditional name filter and report if the targetted service was disabled one way or another.

[vhvb1989]

@copilot implement comments from this #6684 (review)

[Copilot]

@copilot implement comments from this #6684 (review)

Implemented in c8fa45a:

• Condition filtering applied to all service commands via ServiceStableFiltered()
• No "skipped" spinner messages for disabled services (filtering happens before iteration)
• Enablement logic incorporated into ImportManager.ServiceStableFiltered()
• Clear error when targeting a disabled service with condition value shown