MCD-Level-1 Sample Questions Answers

Scatter-Gather Router

The Scatter-Gather component is a routing event processor that processes a Mule event through different parallel processing routes that contain different event processors. Each route receives a reference to the Mule event and executes a sequence of one or more event processors. Each of these routes uses a separate thread to execute the event processors, and the resulting Mule event can be either the same Mule event without modifications or a new Mule event with its own payload, attributes, and variables. The Scatter-Gather component then combines the Mule events returned by each processing route into a new Mule event that is passed to the next event processor only after every route completes successfully.

The Scatter-Gather component executes each route in parallel, not sequentially. Parallel execution of routes can greatly increase the efficiency of your Mule application and may provide more information than sequential processing.

Mule Ref Doc : https://docs.mulesoft.com/mule-runtime/4.3/scatter-gather-concept

API portal are created by API Exchange and cannot be created by Design Center

Correct answer is A global element

Global error handlers are to be created in global element .

Quick note to remember here is Global error handlers come in to picture only when there are no error handlers specified as flow level.

Steps to create Global error handler

1) Click Global Elements to open Global Configuration Elements. Global Elements is located below the Studio canvas

2) In Global Configuration Elements, click Create to open the Choose Global Type dialog

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3) From the dialog, select Global Configuration -→ Configuration, and then click OK to open the Configuration dialog.

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4) From the select Configuration dialog, select allErrorHandler for the Default Error Handler field, and click OK.

This kind of questions are best solved with filtering technique. Key thing to note here is XML attributes are always access by @ notation. So in this example orderId can be accessed as @OrderId which makes option 3 and option 4 false. Now difference in optin and option 2 is in mapping of lineItemPrice. Correct syntax to format a String in Numbse is value.price as Number. Hence option 2 is correct

* Batch scope has filter criteria which says paylod mod 2 = 0 whch means only 2, 4 and 6 will be in batch scope.

* So payload for each of these will be incremented by 10.

* Aggregator has batch size defined as 2. So it will process in batch of two records.

* Hence option 3 is correct answer.

[20,40]

[60]

Behavior with aggregator configured with fixed size

In this scenario, the batch step sends the processed records to an aggregator, which starts processing the records and buffering them until the configured aggregator’s size is reached. After that, the aggregator sends the aggregated records to the stepping queue.

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The batch job builds record blocks of the configured block size and sends them to their corresponding batch step for processing. Each batch step receives one or more record blocks and starts processing them in parallel. After the batch step processes a record, the batch step sends the record to the aggregator for further processing. The aggregator continues processing records until the number of aggregated records reaches the configured aggregator’s size.

https://docs.mulesoft.com/mule-runtime/4.3/batch-processing-concept

Mule applications can be scaled vertically by changing worker size. Mule applications can be scaled horizontally by adding more workers.

Correct answer is Creates a mock service for an API

API Notebook is an open source, shareable web application for API documentation, interactive API tutorial and example generatation, and a client for your API endpoints. Using API Notebook, you can make requests and quickly transform the responses into readable format. However it cannot be used to mock service for an API.

MuleSoft Doc Ref : https://docs.mulesoft.com/api-manager/1.x/api-notebook-concept

Returns an array that is the result of applying a transformation function (lambda) to each of the elements.

MuleSoft Doc Ref : https://docs.mulesoft.com/mule-runtime/4.3/dataweave-cookbook-map

The map operator is a function in Dataweave which iterates over the items in an array and outputs them into a new array. It basically accepts input as a list of items in an array and manipulates the items in the array in order to form a new array as an output.

I have created below chart for your easier understanding:

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Paths

The path of an HTTP listener can be static, which requires exact matches, or feature placeholders. Placeholders can be wildcards (*), which match against anything they are compared to, or parameters ({param}), which not only match against anything but also capture those values on a URI parameters map.

Take the following example paths for three listeners using a configuration that establishes api/v1 as the base path:

account/mulesoft/main-contact: only match the exact path request http://awesome-company.com/api/v1/account/mulesoft/main-contact

account/{accountId}/main-contact: matches all path requests structured similarly, such as http://awesome-company.com/api/v1/account/salesforce/main-contact , and save salesforce as the value of accountId.

account/{accountId}/*: matches all path requests different from main-contact, such as http://awesome-company.com/api/v1/account/mulesoft/users , and save mulesoft as the value of accountId.

Mule Ref Doc : https://docs.mulesoft.com/http-connector/1.6/http-listener-ref#paths

Organization Administrators can approve/revoke/delete SLA tier access requests via API Manager only

Application properties can be defined in .yaml or in .properties file.

MuleSoft Doc Ref : https://docs.mulesoft.com/mule-runtime/4.3/configuring-properties#supported_files

* Watermark allows the poll scope to poll for new resources instead of getting the same resource over and over again.

* The database table must be ordered so that the “watermark functionality” can move effectively in the ordered list. Watermark stores the current/last picked up “record id.”

* If the Mule application is shut down, it will store the last picked up “record id” in the Java Object Store and the data will continue to exist in the file. This watermark functionality is valuable and enables developers to have increased transparency.

* Developers do not need to create code to handle caching; it is all configurable!

* There are two columns and both are unique but user_id can't guaranty sequence whereas date_time will always be in increasing order and table content can easily be ordered on the basis of last processed date_time.

So correct answer is: Set the watermark column to the date_time column

1. Set Payload “Start”

2. 'Is Balnk String' Creates an Error object with #[error.description] =“String is not blank”

3. Default Error Handler catches and Propagates error

4. 'On Error Propogate' is 'RED IN RED OUT'. It Returns Status Code : 500 & #[error.description]

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Correct answer is String is not blank. Because validation component will throw an error as payload is not blank.

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This is a trick question.

You can call only flows from DataWeave using lookup function. Note that lookup function does not support calling subflows.

A subflow needs a parent context to inherit behaviors from such as exception handling, which a flow does not need

Hence correct answer is Not possible in Mule 4

Correct answer is Nothing needs to be changed in the other APIs or their associated applications

This is the benefit of having separate interface layer. As there are no changes to interface , no changes are required on the API's which consumes this API in context

In this case as outbound call is made using HTTP: POST /child , all attributes will be replaced by this invocation. Hence query parameter will not be accessible at logger.

URI parameter (Path Param) is basically used to identify a specific resource or resources . For eg : the URL to get employee details on the basis of employeeID will be GET /employees/{employeeID} where employees is resource and {employeeID} is URI parameter. Hence option 1is the correct answer

Choice router finds the FIRST true condition, then distribute the event to the ONE matched route.

MuleSoft Doc Ref : https://docs.mulesoft.com/mule-runtime/4.1/choice-router-concept

The Choice router dynamically routes messages through a flow according to a set of DataWeave expressions that evaluate message content. Each expression is associated with a different routing option. The effect is to add conditional processing to a flow, similar to an if/then/else code block in most programming languages.

Only one of the routes in the Choice router executes, meaning that the first expression that evaluates to true triggers that route’s execution and the others are not checked. If none of the expressions are true, then the default route executes.

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Correct Answer: Response body: "Error" Default response status code: 200.

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1) Payload is successfully set to “Success – Started Flow”

2) When HTTP Request throws an error, execution halts

#[error.description] = “ABC"

#[error.errorType] = "XYZ"

3) The On Error Continue scope handles the error. When On Error Continue scope is invoked, all the processors in error block are executed and success response is sent back to the client with payload which is set in error flow. In this case payload is set to "Error" value in error block.

4) “Error” is returned to the requestor in the body of the HTTP request with HTTP Status Code: 200 as On error continue always sends success error code.

Reference Diagram:

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The current version of the RAML specification is 1.0

You can check RAML version in RAML definition by referring to first comment. See highlighted part in below image.

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* To use custom modules, you need to import the module or functions you want to use by adding the import directive to the head of your DataWeave script, for example:

1) Does not identify any functions to import from the String module:

import dw::core::Strings

2) To identify a specific function to import from the String module:

import camelize, capitalize from dw::core::Strings

3) To import all functions from the String module:

import * from dw::core::Strings

The way you import a module impacts the way you need to call its functions from a DataWeave script. If the directive does not list specific functions to import or use * from to import all functions from a function module, you need to specify the module when you call the function from your script.

* In given scenario, it's mentioned to import all of the WebStore.dwl

So correct answer is:

* When a client application is registered in Anypoint Platform, a pair of credentials consisting of a client ID and client secret is generated.

* When the client application requests access to an API, a contract is created between the application and that API.

* An API that is protected with a Client ID Enforcement policy is accessible only to applications that have an approved contract.

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Correct Answer: In the organization's public API portal in Anypoint Exchange, from an approved client application for the API proxy

Below are the Key performance indicators (KPIs), to measure and track the and success of the C4E and its activities, as well as the growth and health of the application network. Most of the metrics can be extracted automatically, through REST APIs, from Anypoint Platform.

• # of assets published to Anypoint Exchange

• # of interactions with Anypoint Exchange assets

• # of APIs managed by Anypoint Platform

• # of System APIs managed by Anypoint Platform

• # of API clients registered for access to APIs

• # of API implementations deployed to Anypoint Platform

• # of API invocations

• # or fraction of lines of code covered by automated tests in CI/CD pipeline

• Ratio of info/warning/critical alerts to number of API invocations

The HTTP 415 Unsupported Media Type client error response code indicates that the server refuses to accept the request because the payload format is in an unsupported format. The format problem might be due to the request's indicated Content-Type or Content-Encoding , or as a result of inspecting the data directly. As per RAML input is expected in application/xml.

Hence correct answer is Set a request header with the name Content-Type to a

Sequence can be described as follows.

* When web client sends the request , it sends payload as Blue (mentioned in question)

* In first iteration this will go to default choice , which sets payload to Red

* Via default route , flow will call itself with payload as Red

* In second iteration , as payload is Red , it will go to first route in choice router which will set payload to Blk and second iteration will end returning back payload as Blk to first iteration.

* This Blk will be again set to payload and first iteration will end returning back response as Blk

URI parameter is basically used to identify a specific resource or resources

* Here we want to update details about specific department, so question is asking 'How to use URI parameter' in RAML

* Correct answer is

/departments:

/{deptId}:

patch:

Entire event would be sent to each route in parallel.

Scatter-Gather works as follows :

- The Scatter-Gather component receives a Mule event and sends a reference of this Mule event to each processing route.

- Each of the processing routes starts executing in parallel. After all processors inside a route finish processing, the route returns a Mule event, which can be either the same Mule event without modifications or a new Mule event created by the processors in the route as a result of the modifications applied.

- After all processing routes have finished execution, the Scatter-Gather component creates a new Mule event that combines all resulting Mule events from each route, and then passes the new Mule event to the next component in the flow.

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Process section is must to get compiles. Process section must have one or more processors

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As dependency is not present in Mulesoft Maven repository, we need to install the dependency on computer's local Maven repository.

https://docs.mulesoft.com/mule-runtime/4.3/maven-reference

In General > Request > Query Parameters, click the plus icon (+) to add a parameter to a request. Type a name and value for the parameter or use a DataWeave expression to define the name and value.

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Correct answer is ${training.host}

Correct answer is /accounts?account_type=retail&industry=finance

Query parameters are a defined set of parameters attached to the end of a url. They are extensions of the URL that are used to help define specific content or actions based on the data being passed. To append query params to the end of a URL, a ‘?’ Is added followed immediately by a query parameter.

To add multiple parameters, an ‘&’ is added in between each.

Exchange is the odd man out here. Rest all are type of asset

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Correct answer is Anypoint Visualizer

MuleSoft Doc Ref : https://docs.mulesoft.com/visualizer/

Anypoint Visualizer provides a real-time, graphical representation of the APIs, and Mule applications that are running and discoverable. It also displays third-party systems that are invoked by a Mule API, proxy, or application within your application network. The data displayed in the graph is dynamically updated and does not require prior configuration. Additionally, the data displayed is secure, as only users with the proper permissions can view the application network graph.

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* RAML file contains lot of information that could be considered as "not API-describing". Sort of "economy-class" members.

Equally important, but not necessarily part of the main RAML file.

* Through !includes, RAML allows us to build file-distributed API definitions, which is not only useful to encourage code reuse but also improves readability.

* We can create RAML fragments with such code and then include them in main RAML project using !include like:

types:

Book: !include bookDataType.raml and

examples:

input: !include bookExample.raml

* Additionally for

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Correct Answer: D

Correct answer is System layer

System APIs provide a means for insulating the data consumers from the complexity or changes to the underlying backend systems.

MuleSoft recommends three-layered approach to API-led connectivity, highlighting the three layers:

* System APIs

* Process APIs

* Experience APIs

System APIs are the core systems of record underlying core systems of record (e.g. ERPs, key customer and billing systems, databases, etc.). Process APIs allow you to define a common process which the organization can share, and these APIs perform specific functions, provide access to non-central data, and may be built by either Central IT or Line of Business IT. And finally, the Experience APIs are the means by which data can be reconfigured so that it is most easily consumed by its intended audience, all from a common data source.

The three-layered structure allows for a seamless flow of data from systems of record to new experiences, and allows for reusability of assets rather than point to point connections. This approach provides a distributed and tailored approach to architecture, greater flexibility through loose coupling, and deeper operational visibility into what is being built.

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API Exchange creates REST conenctor automtaically once API is published. Hence correct answer is Publish the API specification to Any point Exchange

Logs would look like:

INFO 2021-06-09 19:14:56,039 [[MuleRuntime].uber.06: [validationtest].batch-job-validationtestBatch_Job-work-manager @6de10f3e] [processor: validationtestFlow/processors/1/route/0/route/0/aggregator/processors/0; event: bfb751e1-9939-11eb-9f69-02053763653a] org.mule.runtime.core.internal.processor.LoggerMessageProcessor:

[

“\”A\””,

“\”C\””,

“\”D\””

]

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INFO 2021-06-09 19:15:02,486 [[MuleRuntime].uber.06: [validationtest].batch-job-validationtestBatch_Job-work-manager @6de10f3e] [processor: validationtestFlow/processors/1/route/0/route/0/aggregator/processors/0; event: bfb751e1-9939-11eb-9f69-02053763653a] org.mule.runtime.core.internal.processor.LoggerMessageProcessor: [

“\”E\””

]

Batch aggregator value is 3. Hence in first time it will print [“A”, “C”, “D”] and in next iteration it will print [ “E” ]

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Correct answer is [ “E” ]

Attributes are replaced with new attributes from the HTTP Request response.

Attributes include everything apart from Payload/body. For ex: Headers, query parameters, URI parameters.

So, when outbound HTTP request is made, new attributes need to pass the outbound HTTP request and old attributes are replaced.

I have created below diagram to make it easy for you to understand:

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To compare, DataWeave syntax is #[payload == "FR"].

In this case only one = is used so it will give syntax error.

Hence the correct answer is A dataweave syntax error

Correct answer is Add required headers to RAML specification and redeploy new API proxy

MuleSoft Doc Ref : https://docs.mulesoft.com/api-manager/2.x/tutorial-manage-an-api

Steps are as below :

Add the Required RAML Snippet

SLA-based rate limiting requires adding a RAML or OAS snippet to your API. This procedure demonstrates adding a RAML snippet.

Specify the client ID and secret as query parameters.

Add a section called traits: at the RAML root level to define query parameters:

traits:

- client-id-required:

queryParameters:

client_id:

type: string

client_secret:

type: string

Add the client-id-required trait to every method that requires these query parameters:

/users:

get:

is: [client-id-required]

description: Gets a list of JSONPlaceholder users.

Step 2 : Add the SLA Tier in API Manager

Step 3 : Apply the policy and redeploy