MCD-Level-1 MuleSoft Certified Developer - Level 1 (Mule 4) Questions and Answers

MuleSoft Doc Ref : https://docs.mulesoft.com/api-manager/2.x/policy-mule3-tutorial-manage-an-api#to-add-the-tier

Steps to create SLA Tier are as follows:

1) In API Manager, in API Administration, click a version.

2) Check that the API supports resource-level policies: On the API version details page, in Status, click Configure Endpoint, and check that Type is RAML.

3) Choose the SLA Tiers, and click Add SLA Tier. Set up limit on SLA tier

Correct answer is as below. In this case address will be stored in a variable. Hence payload will not be overwritten and will contain order details

{

orderkey: " payload.order " ,

addresskey: " vars.address "

}

Correct answer is as below.  On complete phase only has access to batch job result statistics and payload is not available.

Total Records Processed : 3

Successful Records : 3

Failed Records : 0

On Complete

During this phase, you can optionally configure the runtime to create a report or summary of the records it processed for the particular batch job instance. This phase exists to give system administrators and developers some insight into which records failed to address any issues that might exist with the input data.

Sample output is as below

Mule Ref Doc :  https://docs.mulesoft.com/mule-runtime/4.3/batch-processing-concept#on-complete

You can choose Attach Project Sources to include metadata that Studio requires to reimport the deployable file as an open Mule project into your workspace. You must keep the Attach Project Sources option selected to be able to import the packaged JAR file back into a Studio workspace. But requirement here is to create smallest deployable archive that will successfully deploy to Cloudhub. Hence we can ignore this option.

We need to select Include project module and dependencies

As actual modules and external dependencies required to run the Mule application in a Mule runtime engine

Hence correct answer is

Select only below option 2) Include project module and dependencies

MuleSoft Doc Ref : https://docs.mulesoft.com/studio/7.5/import-export-packages#exporting-a-studio-project-to-a-deployable-mule-application

Note that private flow has error scope defined as On Error Continue . So when error occurs in private flow , it is handled by this On Error Continue scope which sends success response back to main flow and does not throw back an error. So main continues normally and payload is set to Success - main flow.

Hence correct answer is  Success - main flow

1) HTTP listener received request

2) The Flow Reference calls the child flow

3) The Is Number validator creates an Error Object because the payload isn’t an integer. Child Flow execution stops

#[error.description] = “payload is not a valid INTEGER value”

#[error.errorType] = VALIDATION:INVALID_NUMBER

4) The On Error Continue handles the errorThe payload is set to “Error – Sub Flow”

5) “Error – Sub Flow” is returned to the main flow as if the child flow was a success. The Set Payload is executed. The payload is reset to “Success – Finished Main Flow”

6) “Success – Main Flow” is returned to the requestor in the body of the HTTP request. HTTP Status Code: 200

As you can see, in the above example, because the error was caught by an On Error Continue scope in the child flow (RED in, GREEN out) when the Mule Message returns to the parent flow, the parent flow knows none-the-different that there was a failure because the on error continue returns a 200 success message. Note that because, to the mainFlow, the childFlow appeared to succeed, the processing of mainFlow resumed after the flow reference.

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This helps CloudHub to dynamically allocates a port at deployment time.

MuleSoft Doc Ref :  https://docs.mulesoft.com/mule-runtime/4.3/deploy-to-cloudhub#prerequisites

Option 2 is the correct answer as /api/* accespts everything starting with /api/

APIKIt Creates a separate flow for each HTTP method

Option 3 is the only corect answer as it concatenates payload with String.

Below option wont work.

#[ " The payload is " ++ payload]

Concatenation function expects both arguments to be string. As the question says payload is json object , this will throw error while running it. You can try this in Anypoint Studio and you will get the same result which I mentioned.

hence correct answer is

The payload is: #[payload]

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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In this case three configurations will be required each for port 8000, 6000 and 7000.

There would be three global elements defined for HTTP connections.

Each HTTP connection will have host and port. One example shown below with host as localhost and port 6000

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To use an HTTP listener, you need to declare a configuration with a corresponding connection. This declaration establishes the HTTP server that will listen to requests.

Additionally, you can configure a base path that applies to all listeners using the configuration.

< http:listener-config name= " HTTP_Listener_config " basePath= " api/v1 " >

< http:listener-connection host= " 0.0.0.0 " port= " 8081 " / >

< /http:listener-config >

https://docs.mulesoft.com/http-connector/1.6/http-listener-ref#http-listener-configuration

By default, Debugger listens for incoming TCP connections on localhost port 6666 You can change this in a project ' s run configuration.

MuleSoft Doc Ref : https://docs.mulesoft.com/studio/7.5/visual-debugger-concept

Correct answer is 200.1234 as String {format: " .0# " } . Rest all options are not syntactically correct.

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.

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:

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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Pick First is not valid type. Rest all are valid type of event processor.

Choice : https://docs.mulesoft.com/mule-runtime/4.3/choice-router-concept

Round Robin : https://docs.mulesoft.com/mule-runtime/4.3/round-robin

First Successful : https://docs.mulesoft.com/mule-runtime/4.3/first-successful

As can be seen in RAML, POST expects input in application/json format which eliminates two of the options as two options are in xml format.

Now out of the two remaining options, one has id field in request which is only mentioned for get response and not for POST request. Hence id field is not expected in POST request.

Hence correct answer is

{

" name " : " GoerdiLa Forge " ,

" address " : " 1 Westland CA " ,

" customer_since " : " 2014-01-04 " ,

" balance " : " 4829.29 " ,

" bank_agend_id " : " 12556 "

}

To include property. To keep the API definition concise, you can include external content, such as documentation, schemas, and frequently used patterns outside the definition itself. The parser interprets !include as if the content of the externally-hosted file or a URL were declared in-line.

To use the fragments in RAML you have to include the exact path(copy the path) of that fragment you want to use as shown below

Option 3 is the correct as correct syntax is

examples: !include examples/StudentExample.raml

Debugger can be used to debug applications to see event data movine from one flow to other

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

The List operation returns an array of messages in which: Each message holds the file’s content in its payload. The file’s attributes section carries the file’s metadata (such as name, creation time, and size). The payload is empty if the element is a folder.

vars: Keyword for accessing a variable, for example, through a DataWeave expression in a Mule component, such as the Logger, or from an Input or Output parameter of an operation. If the name of your variable is myVar, you can access it like this: vars.myVar

Hence correct answer is Account Type: #[vars.accountType]

Anypoint Exchange provided a way to publish , share and search API ' s.

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

The First Successful router iterates through a list of configured processing routes until one of the routes executes successfully. This is sequential execution. In all other options mentioned in the question ,we can achieve parallel execution.

* 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

Correct answer is ${training.host}

Mule event is correct answer. Mule event has two parts which are as follows

1) Message (which contains payload and attributes like headers and query/uri parameters

2) Variables

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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

Correct answer is 8 as events are processed in parallel in case of scatter gather router

This is a trcik question. On complete phase pyalod consists of summary of records processed which gives insight on which records failed or passed. Hence option 4 is correct answer

MuleSoft Documentation Reference : https://docs.mulesoft.com/mule-runtime/4.3/batch-processing-concept#on-complete

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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Correct answer is Validation modules Is Number operation.

Mule 4 does not use filters anymore. The functionality provided by filters in Mule 3 can be achieved by using the Validation Module.

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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WSDL is used to define the contract in case of SOAP . RAML/OAS is used to REST services

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

Correct answer is [[5, 10, 15, 20], 5]

Key thing to note here is that any changes made to payload in for each loop are not available outside for each scope where as variable value updated in for each loop is visible out side for each loop too.

In this example , sequence can be described as follows

1) Payload is set to the value [5, 10, 15, 20]

2) Variable is set to the value of 1

3) For each loop is executed four times and in each loop payload value is updated to append " Req " and variable is count is increased by 1

4) Once control comes out of for each , payload changes made within for each are not visible. Hence payload at this point of time is equal to payload available before entering for each loop which was  [5, 10, 15, 20] . Similarly variable value updated in for each loop is also available outside hence variable value is 5 as it was updated in loop.

5) Hence correct answer is [[5, 10, 15, 20], 5]

For Each Scope

The For Each scope splits a payload into elements and processes them one by one through the components that you place in the scope. It is similar to a  for-each / for  loop code block in most programming languages and can process any collection, including lists and arrays. The collection can be any supported content type, such as  application/json ,  application/java , or  application/xml .

General considerations about the For Each scope:

By default, For Each tries to split the payload. If the payload is a simple Java collection, the For Each scope can split it without any configuration. The payload inside the For Each scope is each of the split elements. Attributes within the original message are ignored because they are related to the entire message.

For Each does not modify the current payload. The output payload is the same as the input.

For non-Java collections, such as XML or JSON, use a DataWeave expression to split data. Use the  Collection  field for this purpose.

Core (dw::Core) This module contains core DataWeave functions for data transformations. It is automatically imported into any DataWeave script.

Correct answer is Array.

Flatten turns a set of subarrays (such as [ [1,2,3], [4,5,[6]] , [], [null] ]) into a single, flattened array (such as [ 1, 2, 3, 4, 5, [6] , null ]).

This example defines three arrays of numbers, creates another array containing those three arrays, and then uses the flatten function to convert the array of arrays into a single array with all values.

Source

%dw 2.0

output application/json

var array1 = [1,2,3]

var array2 = [4,5,6]

var array3 = [7,8,9]

var arrayOfArrays = [array1, array2, array3]

---

flatten(arrayOfArrays)

Output

[ 1,2,3,4,5,6,7,8,9 ]

Variables are stored under Mule event. Please refer to below image for the hierarchy .

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Keyword to ad function in Dataweave transformation is fun. Hence option 2 and 4 are invalid. Also parameters needs to be passed exactly in same order as defined in function definition. Hence correct answer is '

fun addKV( object: Object, key: String, value: Any) =

object ++ {(key):(value)}

---

addKV ( { " hello ' : " world " }, " hola " , " mundo " )

MuleSoft Documentation Reference : https://docs.mulesoft.com/mule-runtime/4.3/dataweave-functions

DataWeave Function Definition Syntax

To define a function in DataWeave use the following syntax:

fun myFunction(param1, param2, ...) = < code to execute >

The fun keyword starts the definition of a function.

myFunction is the name you define for the function.

Function names must be valid identifiers.

(param1, param2, … , paramn) represents the parameters that your function accepts.

You can specify from zero to any number of parameters, separated by commas (,) and enclosed in parentheses.

The = sign marks the beginning of the code block to execute when the function is called.

< code to execute > represents the actual code that you define for your function.

Correct answer is  Attributes.

Query parameters , URI parameters and headers are some of examples which are part of attributes.

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Correct answer is

%dw 2.0

output application/json

import modules::Utility

---

Utility::encryptString( " John Smith " )

DataWeave 2.0 functions are packaged in modules. Before you begin, note that DataWeave 2.0 is for Mule 4 apps. For Mule 3 apps, refer to DataWeave Operators in the Mule 3.9 documentation. For other Mule versions, you can use the version selector for the Mule Runtime table of contents.

Functions in the Core (dw::Core) module are imported automatically into your DataWeave scripts. To use other 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:

import dw::core::Strings

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

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. For example, this import directive does not identify any functions to import from the String module, so it calls the pluralize function like this: Strings::pluralize( " box " ).

Transform

%dw 2.0

import dw::core::Strings

output application/json

---

{ ' plural ' : Strings::pluralize( " box " ) }

Correct answer is String is not blank.

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Here’s specifically what is happening here:

1) Payload is successfully set to “Start”

2) The Is Blank String validator creates an Error Object because the payload is string " Start " . Execution stops

#[error.description] = “String is not blank”

3) Because no error handler is defined, the Mule default error handler handles the error. Remember, at its heart, the Mule Default Error handler is an error handling scope with just an on error propagate

4) “String is not blank” is the error message returned to the requestor in the body of the HTTP requestHTTP Status Code: 500

Reference Diagram:

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Database always return rows as an array.

Array is the correct answer

Creates reusable APIs and assets designed to be consumed by other business units

Gold is not valid category for connector types.

MuleSoft Doc Ref : https://docs.mulesoft.co m/mule-runtime/3.7/anypoint-connectors#connector-support-categories

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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/aggreg ator/processors/0; event: bfb751e1- 9939-11eb-9f69-02053763653a] org.mule.runtime.core.internal.processor.LoggerMessageProcessor:

[

“\”A\””,

“\”C\””,

“\”D\””

]

—-

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” ]

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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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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