MCD-Level-2 Questions and Answers

To validate the data before posting to the target system, the developer should add the JSON module dependency and add the validate-schema operation in the flow, configured to reference the schema. The JSON module provides a validate-schema operation that validates a JSON payload against a JSON schema and throws an error if the payload is invalid. References: https://docs.mulesoft.com/json-module/1.1/json-validate-schema

To log all the errors raised by the VM Connector, the developer needs to add an async logger with the name ‘org.mule.extension.vm’ and the level ‘ERROR’ inside the appenders tag of the log4j2.xml file. This will enable logging all error-level events generated by the VM Connector to the console appender. References: https://docs.mulesoft.com/mule-runtime/4.3/logging-in-mule#configuring-custom-logging-settings

To temporarily persist large files over 10MB between flow executions, and routinely query whether the file data exists on separate executions, the developer should store the contents of the file on separate storage, and store the key and location of the file object using Object Store v2. This way, the developer can avoid storing large files in memory or exceeding the size limit of Object Store v2 (10MB per object). The developer can also use Object Store v2 operations to query, retrieve, or delete the file object by its key. References: https://docs.mulesoft.com/object-store/osv2-faq#can-i-store-files-in-object-store-v2

 Based on the code snippet, schema.json file, and payload below, the outcome of the given code snippet when a request is sent with the payload is that the Mule flow will throw the exception ‘JSON:SCHEMA_NOT_HONOURED’. This is because the payload does not conform to the schema.json file, which specifies that age must be a number greater than or equal to zero. The payload has age as a string with a negative value, which violates the schema. Therefore, the validate-schema operation throws an error with type ‘JSON:SCHEMA_NOT_HONOURED’. References: https://docs.mulesoft.com/json-module/1.1/json-validate-schema

To reuse Mule Maven plugin configuration across multiple individual Mule applications, the developer should use a parent pom.xml file. A parent pom.xml file defines common configuration for one or more child projects that inherit from it. The developer can specify common properties and dependencies for all child projects in the parent pom.xml file, such as Mule Maven plugin configuration, and then reference them in each child project’s pom.xml file using placeholders. References: https://docs.mulesoft.com/mule-runtime/4.3/mmp-concept#parent-pom https://maven.apache.org/guides/introduction/introduction-to-the-pom.html#Project_Inheritance

Based on the configuration below, when a HTTP request arrives at the Mule application’s endpoint, the execution order will be A1, B1, F1, B2, A2. This is because policies are executed before and after the API implementation flow according to their order attribute. Policy A has order 1, which means it is executed first before Policy B, which has order 2. The flow is executed after both policies are executed before the flow. Then, Policy B is executed after the flow before Policy A is executed after the flow. References: https://docs.mulesoft.com/api-manager/2.x/policies-policy-order

When implementing a synchronous API where the event source is an HTTP Listener, Mule automatically propagates some message attributes between flows via outbound and inbound properties. One of these attributes is correlation ID, which is returned to the caller in the response header by default as MULE_CORRELATION_ID. References: https://docs.mulesoft.com/mule-runtime/4.3/about-mule-message#message-attributes

The MuleSoft recommended method to encrypt sensitive property data is to use the Secure Properties Tool that comes with Anypoint Studio. This tool allows encrypting properties files with a secret key and then decrypting them at runtime using the same key. The encryption key and sensitive data should be different for each environment to ensure security and avoid accidental exposure of sensitive data. References: https://docs.mulesoft.com/mule-runtime/4.3/secure-configuration-properties

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 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 configure API Functional Monitoring to monitor the health of 10 public APIs periodically while minimizing operational overhead and cost, the developer should use one public location with all 10 APIs in a single schedule. A public location is a worker that runs in a CloudHub shared environment, which is cheaper and easier to maintain than a private location. A single schedule allows running all 10 APIs tests at the same time and frequency, which reduces complexity and resource consumption. References: https://docs.mulesoft.com/functional-monitoring/fm-create-monitor#create-a-monitor

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 <classifier>. 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 encrypt the data before sending it to the backend application using PGP encryption, the application needs the public key from the backend service. PGP encryption uses a public-key cryptography system, which means that each party has a pair of keys: a public key and a private key. The public key is used to encrypt data, and the private key is used to decrypt data. Therefore, to encrypt data for a specific recipient (the backend service), the application needs to use the recipient’s public key. The recipient can then use its own private key to decrypt the data. References: https://docs.mulesoft.com/mule-runtime/4.3/cryptography-pgp