Salesforce MuleSoft-Platform-Architect-I Practice Test Questions Answers

Understanding Circuit Breaker Policy:

A circuit breaker is a design pattern used to detect failures and prevent an application from continually trying to execute a failing operation. In this case, it will help improve response time and reduce demand on the downstream API.

The specified configuration includes conditions for opening, half-opening, and closing the circuit based on error rates over time:

Circuit Open: Triggered if there are more than 10 errors per minute for three consecutive minutes.

Circuit Half-Open: The circuit transitions to half-open if there is one error per minute.

Circuit Closed: The circuit closes if the error rate is less than one error per minute for five minutes.

Evaluating the Options:

Option A: Creating a custom policy with template expressions could work, but it would require custom development. Since the Anypoint Platform already has a Circuit Breaker policy available, this would be a less efficient and more complex solution.

Option B: Anypoint Monitoring alerts can be used for monitoring the API, but they do not provide circuit-breaking functionality. Additionally, implementing a retry strategy for the half-open state is not sufficient to achieve the required circuit breaker behavior.

Option C (Correct Answer): Adding the Circuit Breaker policy to the API instance on Anypoint Platform allows you to set up circuit-breaking conditions directly. This approach uses the built-in Circuit Breaker policy, where you can configure parameters such as error thresholds and time intervals to match the requirements. This solution is efficient, reliable, and leverages Anypoint’s out-of-the-box capabilities.

Option D: Implementing the strategy within a Mule application with a YAML configuration could be complex and less manageable. Additionally, it does not leverage Anypoint Platform’s built-in Circuit Breaker policy, which is more suited to this scenario.

Conclusion:

Option C is the correct choice, as it leverages Anypoint Platform’s Circuit Breaker policy. This solution allows for configuring thresholds and time intervals as specified, improving response time and reducing demand on the downstream API while utilizing Anypoint's managed policy feature.

Refer to MuleSoft’s documentation on implementing the Circuit Breaker policy in API Manager for detailed configuration guidance.

Explanation

Correct Answer: IP whitelist

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>> OAuth 2.0 access token and Client ID enforcement policies are VERY common to apply on Experience APIs as API consumers need to register and access the APIs using one of these mechanisms

>> JSON threat protection is also VERY common policy to apply on Experience APIs to prevent bad or suspicious payloads hitting the API implementations.

>> IP whitelisting policy is usually very common in Process and System APIs to only whitelist the IP range inside the local VPC. But also applied occassionally on some experience APIs where the End User/ API Consumers are FIXED.

>> When we know the API consumers upfront who are going to access certain Experience APIs, then we can request for static IPs from such consumers and whitelist them to prevent anyone else hitting the API.

However, the experience API given in the question/ scenario is intended to work with a consumer mobile phone or tablet application. Which means, there is no way we can know all possible IPs that are to be whitelisted as mobile phones and tablets can so many in number and any device in the city/state/country/globe.

So, It is very LEAST LIKELY to apply IP Whitelisting on such Experience APIs whose consumers are typically Mobile Phones or Tablets.

Explanation

Correct Answer: They provide an additional layer of resilience on top of the underlying backend system, thereby insulating clients from extended failure of these systems.

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In API-led connectivity,

>> Experience APIs - allow for innovation at the user interface level by consuming the underlying assets without being aware of how data is being extracted from backend systems.

>> Process APIs - compose data from various sources and combine them with orchestration logic to create higher level value

>> System APIs - reduce the dependency on the underlying backend systems by helping unlock data from backend systems in a reusable and consumable way.

However, they NEVER promise that they provide an additional layer of resilience on top of the underlying backend system, thereby insulating clients from extended failure of these systems.

https://dzone.com/articles/api-led-connectivity-with-mule

In API-led design, an Experience API is enhanced to improve how data is delivered to end-user applications. One primary reason to enhance an Experience API is when new data standards, such as a Canonical Data Model, are adopted. Here’s why:

Canonical Data Model (CDM):

Adopting a CDM standardizes data representations across the organization, making APIs more consistent and easier to consume across various services and applications.

Updating the Experience API ensures that it delivers data in this standardized format, improving interoperability and reusability.

Explanation of Correct Answer (D):

A CDM impacts the structure and types of data the API provides, and this update would be directly relevant to an Experience API, as it is the primary point of interaction for applications.

Explanation of Incorrect Options:

Option A involves adapting to consumer-specific standards, which is against API-led design principles.

Option B involves changes in System APIs, which don’t directly mandate changes to the Experience API unless data formatting adjustments are required.

Option C (IP Allowlist) relates to security rather than API design and would not motivate a functional enhancement of the API.

ReferencesFor more details on the use of Canonical Data Models in API-led architecture, refer to MuleSoft’s guidelines on data standardization and Experience API best practices​.

Explanation

Correct Answer: At the process and system tiers

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>> Experience Layer APIs are modeled and designed exclusively for the end user's experience. So, the data models of experience layer vary based on the nature and type of such API consumer. For example, Mobile consumers will need light-weight data models to transfer with ease on the wire, where as web-based consumers will need detailed data models to render most of the info on web pages, so on. So, enterprise data models fit for the purpose of canonical models but not of good use for experience APIs.

>> That is why, EDMs should be used extensively in process and system tiers but NOT in experience tier.