An architectural pattern is a general, reusable solution to a commonly occurring problem in software architecture within a given context. Architectural patterns are similar to software design patterns but have a broader scope. The architectural patterns address various issues in software engineering, such as computer hardware performance limitations, high availability and minimization of a.
-->These design patterns are useful for building reliable, scalable, secure applications in the cloud.
Each pattern describes the problem that the pattern addresses, considerations for applying the pattern, and an example based on Microsoft Azure. Most of the patterns include code samples or snippets that show how to implement the pattern on Azure. However, most of the patterns are relevant to any distributed system, whether hosted on Azure or on other cloud platforms.
Challenges in cloud development
AvailabilityAvailability is the proportion of time that the system is functional and working, usually measured as a percentage of uptime. It can be affected by system errors, infrastructure problems, malicious attacks, and system load. Cloud applications typically provide users with a service level agreement (SLA), so applications must be designed to maximize availability. |
Data ManagementData management is the key element of cloud applications, and influences most of the quality attributes. Data is typically hosted in different locations and across multiple servers for reasons such as performance, scalability or availability, and this can present a range of challenges. For example, data consistency must be maintained, and data will typically need to be synchronized across different locations. |
Design and ImplementationGood design encompasses factors such as consistency and coherence in component design and deployment, maintainability to simplify administration and development, and reusability to allow components and subsystems to be used in other applications and in other scenarios. Decisions made during the design and implementation phase have a huge impact on the quality and the total cost of ownership of cloud hosted applications and services. |
MessagingThe distributed nature of cloud applications requires a messaging infrastructure that connects the components and services, ideally in a loosely coupled manner in order to maximize scalability. Asynchronous messaging is widely used, and provides many benefits, but also brings challenges such as the ordering of messages, poison message management, idempotency, and more. |
Management and MonitoringCloud applications run in a remote datacenter where you do not have full control of the infrastructure or, in some cases, the operating system. This can make management and monitoring more difficult than an on-premises deployment. Applications must expose runtime information that administrators and operators can use to manage and monitor the system, as well as supporting changing business requirements and customization without requiring the application to be stopped or redeployed. |
Performance and ScalabilityPerformance is an indication of the responsiveness of a system to execute any action within a given time interval, while scalability is ability of a system either to handle increases in load without impact on performance or for the available resources to be readily increased. Cloud applications typically encounter variable workloads and peaks in activity. Predicting these, especially in a multitenant scenario, is almost impossible. Instead, applications should be able to scale out within limits to meet peaks in demand, and scale in when demand decreases. Scalability concerns not just compute instances, but other elements such as data storage, messaging infrastructure, and more. |
ResiliencyResiliency is the ability of a system to gracefully handle and recover from failures. The nature of cloud hosting, where applications are often multitenant, use shared platform services, compete for resources and bandwidth, communicate over the Internet, and run on commodity hardware means there is an increased likelihood that both transient and more permanent faults will arise. Detecting failures, and recovering quickly and efficiently, is necessary to maintain resiliency. |
SecuritySecurity is the capability of a system to prevent malicious or accidental actions outside of the designed usage, and to prevent disclosure or loss of information. Cloud applications are exposed on the Internet outside trusted on-premises boundaries, are often open to the public, and may serve untrusted users. Applications must be designed and deployed in a way that protects them from malicious attacks, restricts access to only approved users, and protects sensitive data. |
Catalog of patterns
![Architectural Architectural](/uploads/1/2/6/3/126380967/360815798.png)
Pattern | Summary |
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Ambassador | Create helper services that send network requests on behalf of a consumer service or application. |
Anti-Corruption Layer | Implement a façade or adapter layer between a modern application and a legacy system. |
Asynchronous Request-Reply | Decouple backend processing from a frontend host, where backend processing needs to be asynchronous, but the frontend still needs a clear response. |
Backends for Frontends | Create separate backend services to be consumed by specific frontend applications or interfaces. |
Bulkhead | Isolate elements of an application into pools so that if one fails, the others will continue to function. |
Cache-Aside | Load data on demand into a cache from a data store |
Choreography | Let each service decide when and how a business operation is processed, instead of depending on a central orchestrator. |
Circuit Breaker | Handle faults that might take a variable amount of time to fix when connecting to a remote service or resource. |
Claim Check | Split a large message into a claim check and a payload to avoid overwhelming a message bus. |
Compensating Transaction | Undo the work performed by a series of steps, which together define an eventually consistent operation. |
Competing Consumers | Enable multiple concurrent consumers to process messages received on the same messaging channel. |
Compute Resource Consolidation | Consolidate multiple tasks or operations into a single computational unit |
CQRS | Segregate operations that read data from operations that update data by using separate interfaces. |
Event Sourcing | Use an append-only store to record the full series of events that describe actions taken on data in a domain. |
External Configuration Store | Move configuration information out of the application deployment package to a centralized location. |
Federated Identity | Delegate authentication to an external identity provider. |
Gatekeeper | Protect applications and services by using a dedicated host instance that acts as a broker between clients and the application or service, validates and sanitizes requests, and passes requests and data between them. |
Gateway Aggregation | Use a gateway to aggregate multiple individual requests into a single request. |
Gateway Offloading | Offload shared or specialized service functionality to a gateway proxy. |
Gateway Routing | Route requests to multiple services using a single endpoint. |
Health Endpoint Monitoring | Implement functional checks in an application that external tools can access through exposed endpoints at regular intervals. |
Index Table | Create indexes over the fields in data stores that are frequently referenced by queries. |
Leader Election | Coordinate the actions performed by a collection of collaborating task instances in a distributed application by electing one instance as the leader that assumes responsibility for managing the other instances. |
Materialized View | Generate prepopulated views over the data in one or more data stores when the data isn't ideally formatted for required query operations. |
Pipes and Filters | Break down a task that performs complex processing into a series of separate elements that can be reused. |
Priority Queue | Prioritize requests sent to services so that requests with a higher priority are received and processed more quickly than those with a lower priority. |
Publisher/Subscriber | Enable an application to announce events to multiple interested consumers asynchronously, without coupling the senders to the receivers. |
Queue-Based Load Leveling | Use a queue that acts as a buffer between a task and a service that it invokes in order to smooth intermittent heavy loads. |
Retry | Enable an application to handle anticipated, temporary failures when it tries to connect to a service or network resource by transparently retrying an operation that's previously failed. |
Scheduler Agent Supervisor | Coordinate a set of actions across a distributed set of services and other remote resources. |
Sequential Convoy | Process a set of related messages in a defined order, without blocking processing of other groups of messages. |
Sharding | Divide a data store into a set of horizontal partitions or shards. |
Sidecar | Deploy components of an application into a separate process or container to provide isolation and encapsulation. |
Static Content Hosting | Deploy static content to a cloud-based storage service that can deliver them directly to the client. |
Strangler | Incrementally migrate a legacy system by gradually replacing specific pieces of functionality with new applications and services. |
Throttling | Control the consumption of resources used by an instance of an application, an individual tenant, or an entire service. |
Valet Key | Use a token or key that provides clients with restricted direct access to a specific resource or service. |
(Redirected from Software Architecture styles and patterns)
An architectural pattern is a general, reusable solution to a commonly occurring problem in software architecture within a given context.[1] Architectural patterns are similar to software design patterns but have a broader scope. The architectural patterns address various issues in software engineering, such as computer hardware performance limitations, high availability and minimization of a business risk. Some architectural patterns have been implemented within software frameworks.
Definition[edit]
Even though an architectural pattern conveys an image of a system, it is not an architecture. An architectural pattern is a concept that solves and delineates some essential cohesive elements of a software architecture. Countless different architectures may implement the same pattern and share the related characteristics. Patterns are often defined as 'strictly described and commonly available'.[2][3]
Architectural style[edit]
Following traditional building architecture, a 'software architectural style' is a specific method of construction, characterized by the features that make it notable'.
“ | An architectural style defines: a family of systems in terms of a pattern of structural organization; a vocabulary of components and connectors, with constraints on how they can be combined.[4] | ” |
“ | An architectural style is a named collection of architectural design decisions that (1) are applicable in a given development context, (2) constrain architectural design decisions that are specific to a particular system within that context, and (3) elicit beneficial qualities in each resulting system.[1] | ” |
Some treat architectural patterns and architectural styles as the same,[5] some treat styles as specializations of patterns. What they have in common is both patterns and styles are idioms for architects to use, they 'provide a common language'[5] or 'vocabulary'[4] with which to describe classes of systems.
The main difference is that a pattern can be seen as a solution to a problem, while a style is more general and does not require a problem to solve for its appearance.
Examples[edit]
Here is a list of architecture patterns, and corresponding software design patterns and solution patterns.
Sub-domain area | Architecture pattern | Software design patterns | Solution patterns | Related patterns |
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Data integration/SOA |
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Data architecture |
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Analytics and business intelligence |
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Master data management |
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Data modeling |
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Artificial intelligence |
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Some additional examples of architectural patterns:
- Action-domain-responder, Model–view–controller, Presentation-abstraction-control, Model-view-presenter, and Model-view-viewmodel
- Multitier architecture (often three-tier or n-tier)
- Operational data store (ODS)
![Software architecture pdf Software architecture pdf](/uploads/1/2/6/3/126380967/961893903.png)
See also[edit]
References[edit]
- ^ abR. N. Taylor, N. Medvidović and E. M. Dashofy, Software architecture: Foundations, Theory and Practice. Wiley, 2009.
- ^Chang, Chih-Hung; Lu, Chih-Wei; Lin, Chih-Hao; Yang, Ming-Feng; Tsai, Ching-Fu (June 2008). 'An Experience of Applying Pattern-based Software Framework to Improve the Quality of Software Development: 4. The Design and Implementation of OS2F'. Journal of Software Engineering Studies, Vol. 2, No. 6. the Third Taiwan Conference on Software Engineering (TCSE07). pp. 185–194. Archived from the original on 2011-09-22. Retrieved 2012-05-16.
Furthermore, patterns are often defined as something 'strictly described and commonly available'. For example, layered architecture is a call-and-return style, when it defines an overall style to interact.
- ^'Architectural Patterns: Definition'. AAHN INFOTECH (INDIA) PVT. LTD. Archived from the original on 2012-06-23. Retrieved 2012-05-16.
Even though an architectural pattern conveys an image of a system, it is not an architecture as such. An architectural pattern is rather a concept that solves and delineates some essential cohesive elements of a software architecture. Countless different architectures may implement the same pattern and thereby share the related characteristics. Furthermore, patterns are often defined as something 'strictly described and commonly available'.
- ^ abM. Shaw and D. Garlan, Software architecture: perspectives on an emerging discipline. Prentice Hall, 1996.
- ^ abhttp://msdn.microsoft.com/en-us/library/ee658117.aspx
Bibliography[edit]
- Avgeriou, Paris; Uwe Zdun (2005). 'Architectural patterns revisited:a pattern language'. 10th European Conference on Pattern Languages of Programs (EuroPlop 2005), Irsee, Germany, July.
- Buschmann F.; Meunier R.; Rohnert H.; Sommerlad P.; Stal M. (1996). Pattern-Oriented Software Architecture: A System of Patterns. John Wiley & Sons.
- Bass L.; Clements P.; Kazman R. (2005). Software Architecture in Practice: Second Edition. Addison-Wesley.
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