To unit test modules created with XML SDK, the developer needs to use the MUnit Extensions Maven plugin. This plugin allows testing XML SDK modules using MUnit by adding a dependency to the module under test and using a custom processor tag to invoke it. References: https://docs.mulesoft.com/mule-sdk/1.1/xml-sdk#testing

To communicate asynchronously between two APIs deployed to a two-node on-prem cluster, the developer can use the VM Connector if the two APIs use the same domain. The VM Connector allows passing messages between different Mule applications within a single Mule runtime instance or across different instances using shared memory or persistent storage. If two APIs are deployed under the same domain, they can share resources such as VM queues and communicate asynchronously using VM Connector operations. References: https://docs.mulesoft.com/mule-runtime/4.3/vm-connector https://docs.mulesoft.com/mule-runtime/4.3/shared-resources

To use API autodiscovery to access and enforce policies for a RESTful implementation, flowRef must be set to the name of the flow that has HTTP listener to receive all incoming RESTful operation requests. This way, API autodiscovery can identify the API implementation and associate it with the corresponding API specification and policies in API Manager. The flow that has HTTP listener is usually the main flow that contains the APIKit Router. References: https://docs.mulesoft.com/api-manager/2.x/api-auto-discovery-new-concept#flowref

To get the average number of requests and average response time of the Salesforce Connector, the developer should access Anypoint Monitoring’s built-in dashboard, select a resource (such as an application or an API), and locate the information under the Connectors tab. The Connectors tab shows metrics for each connector used by the resource, such as average requests per minute, average response time, and failures. References: https://docs.mulesoft.com/monitoring/built-in-dashboard-reference

To configure a common-global-handler flow that can be reused across all of the organization’s deployed applications, the developer should create a Mule Plugin project, create a common-global-error-handler flow inside the plugin project, and use this plugin as a dependency in all Mule applications. This way, the developer can import the common-global-error-handler flow in any application that needs it and avoid duplicating the error handling logic. References: https://docs.mulesoft.com/mule-runtime/4.3/error-handling#global-error-handler

To propagate the order ID as the correlation ID across each message using Anypoint MQ, the developer should wrap all Anypoint MQ Publish operations within a With CorrelationID scope from the Tracing module, setting the correlation ID to the order ID. The With CorrelationID scope allows setting a custom correlation ID for any event that occurs within it. The Tracing module also enables distributed tracing across different Mule applications and services using Anypoint Monitoring. References: https://docs.mulesoft.com/tracing-module/1.0/tracing-module-reference#with-correlation-id-scope https://docs.mulesoft.com/tracing-module/1.0/tracing-module-concepts

Based on the code snippet and MUnit test case below, when the MUnit test case is executed, the expected result is that the test case fails with an assertion error. This is because the assert-equals processor compares two values for equality, and fails if they are not equal. In this case, the expected value is ‘Hello World’, but the actual value returned by the implementation flow is ‘Hello Mule’. Therefore, the assertion fails and an error is thrown. References: https://docs.mulesoft.com/munit/2.3/assert-equals-processor

To create a new project that selects the correct API version and scaffolds the flows from the API specification, the developer should import a published API. This option allows importing an API specification that has been published to Anypoint Exchange or Design Center, and selecting a specific version of that API specification. The developer can also choose to scaffold flows based on that API specification. References: https://docs.mulesoft.com/apikit/4.x/apikit-4-new-project-task

To include a common application as a reusable module in all API implementations, the developer should add a Maven dependency in the POM file with jar as . This way, the developer can reuse Mule code from another application by packaging it as a JAR file and adding it as a dependency in the POM file of the API implementation. The classifier element specifies that it is a JAR file. References: https://docs.mulesoft.com/mule-runtime/4.3/mmp-concept#add-a-maven-dependency-to-the-pom-file

To get response data from the external API after it completes processing, the developer should expose an HTTP callback API in Mule and register it with the external system. This way, the external API can invoke the callback API with the response data when it is ready, instead of making the Mule application wait for a long time or poll for a response repeatedly. References: https://docs.mulesoft.com/mule-runtime/4.3/http-listener-ref#callback

To enrich every log message with the order ID, the developer should use the Tracing module to set logging variables with a Mapped Diagnostic Context (MDC). The Tracing module allows adding custom key-value pairs to log messages using MDC variables. The developer can use Set Logging Variables operation to set the order ID as an MDC variable and then use it in any logger processor within the same thread or event. References: https://docs.mulesoft.com/tracing-module/1.0/tracing-module-reference#set-logging-variables

When the HTTP Request operation raises an HTTP CONNECTIVITY error, it triggers an on-error-continue handler that sets a payload with ‘Error in processing your request’. Since no status code is explicitly set in this handler, it defaults to 500 (INTERNAL SERVER ERROR). Therefore, the web client receives an HTTP response with status code 500 and body ‘Error in processing your request’. References: https://docs.mulesoft.com/mule-runtime/4.3/error-handling#on-error-continue

When using XML SDK for creating custom message processors, all operations are public by default and can be used by any Mule application that imports them. There is no way to make an operation private or protected in XML SDK. References: https://docs.mulesoft.com/mule-sdk/1.1/xml-sdk#operations

To implement a readiness endpoint to monitor all system APIs, the developer should create a dedicated endpoint that responds with the API status and reachability of the underlying systems. This way, the DevOps team can check if the system API is ready to receive requests and if it can communicate with its backend systems without errors. References: https://docs.mulesoft.com/mule-runtime/4.3/deployment-strategies#readiness-probes

To invoke multiple HTTP APIs in parallel and roll back failed requests in sequence, the developer should use a Scatter-Gather router as a central Saga orchestrator for all API requests with compensating actions for failing routes. A Scatter-Gather router executes multiple routes concurrently and aggregates the results. A Saga orchestrator coordinates a series of actions across different services and handles failures by executing compensating actions. Therefore, using a Scatter-Gather router as a Saga orchestrator allows invoking multiple HTTP APIs in parallel and rolling back any failed requests in sequence. References: https://docs.mulesoft.com/mule-runtime/4.3/scatter-gather-concept https://docs.mulesoft.com/mule-runtime/4.3/saga