You’ve already been introduced to ABAP Cloud by Boris’s Blog Post, if not, I highly recommend reading it.
In this blog post, you’ll gain insight into the architectural idea of ABAP Cloud and its essential parts.
If you are directly interested in the supported technical use cases and recommended technologies, you can find them in this complementary document.
Before we dive into the details, let’s briefly recap what is ABAP Cloud and where you can use it.
ABAP Cloud is the one common development model to build cloud-ready extensions and applications, both in on-stack and side-by-side scenarios. It’s available in all current SAP S/4HANA editions and in the SAP BTP ABAP Environment.
Figure 1 – ABAP Cloud development model in SAP Products
This development model is a comprehensive development approach that covers all end-to-end aspects of the development process. It’s an overarching term that encompasses different things, both concrete and abstract, such as the underlying architecture, the actual tools used for development, development guidelines and much more. While those components are different by nature, the collection of these components support you with state-of-the-art ABAP development.
We’ll have a detailed look at each of these parts that make up ABAP Cloud, but first I want to talk about:
- Who will use ABAP Cloud,
- Some of the key concepts of this development model, and
- The general architecture of ABAP Cloud.
We will then go into a detailed analysis of the development model, with a special focus on the ABAP Cloud programming model.
Who Will Use ABAP Cloud?
ABAP Cloud is all about building enterprise grade extensions, services and applications. In general, we consider two different personas who will venture this task.
Figure 2 – ABAP Cloud Personas
Business experts, key users, and implementation consultants (key-user extensibility)
can use the key user extensibility tools.
Key user tools offer a web-based authoring environment that can be invoked from within a running SAP Fiori application. They allow users with none or limited development experience to build fully functional extensions, yet the capabilities are naturally limited.
Typical tasks are changing the user interface, adding, or removing fields, renaming labels or creating custom business objects.
Developers (developer extensibility)
use the integrated development environment (ABAP development tools for Eclipse) to create ABAP projects containing the typical ABAP artefacts such as Dictionary Objects, Core Data Services, ABAP Classes etc. This allows to leverage ABAP development expertise to fulfill even complex extensibility scenarios.
One person may of course take on both roles, especially in smaller organizations, but the approach remains different. Knowing who will be involved with ABAP Cloud, let us now look at some important concepts.
Key Concepts of ABAP Cloud
The ABAP Cloud programming model builds on the following key concepts to support lifecycle stable, cloud-ready, and efficient development in all environments:
- Released APIs: Stability of custom code is a key requirement for cloud development. This stability is guaranteed for all parties by the usage of released APIs. These APIs are stable interfaces which rely on the release contract framework and are thus safe from any incompatible changes. In other words: When developing with ABAP Cloud you can leverage the development done by SAP by using the released APIs and adapt it to your business requirements without any risk during upgrades. An overview of released APIscan be found on the SAP API Hub in the category Developer Extensibility.
- Cloud-Optimized ABAP Language: The ABAP language scope has been adapted to support ABAP Clouddevelopment, and the language versions „ABAP for Cloud Development” and “ABAP for Key Users” have been introduced. Details for the ABAP Language versions are available in the SAP Help Portal.
- Cloud-Optimized Architecture: With the architecture blueprint of RAP, the domain-specific implementation is conceptually separated from the business service exposure in different protocols. This supports the efficient reuse of data models across different domain-specificimplementations and for different purposes. In the next section, let us take a closer look at this architecture.
Architecture
ABAP Cloud is based on a model-driven architecture approach where the development efficiency is driven by standardization and formalization of the programming model and the tooling environment.
Programming models generally define the design-time software architecture with specific technologies, concepts, and development objects. It essentially defines a standard architecture for app and service development from the database to the business service exposure.
ABAP Cloud builds on the strengths of powerful frameworks and a standardized architecture for different use cases It aims at saving as much implementation time as possible while providing you with flexibility. You can model your business processes with apps and services based on your business requirements along predefined technical processes. The runtime orchestration is handled by the frameworks whenever possible to decrease the probability of consistency errors during runtime in implementations involving multiple business objects or services.
Components of ABAP Cloud
Having discussed some more general points, let us now look at the different components of ABAP Cloud. The goal of this blog post is not only that you get a better understanding of ABAP Cloud, but that you are able to visualize how the different pieces work together, and that you become familiar with the corresponding terminology.
Terminology
Figure 2 – ABAP Cloud terminology
At the core of the ABAP Cloud development model is its programming model, which defines the design-time and runtime architecture of all extensions, services, and applications. When talking about the programming model, we generally consider three different aspects:
- Transactional (OLTP): With ABAP Cloud you can build business objects and expose them as services, to consume them in UIs and integration scenarios. All standard behavior is supported (create, read, update, delete). Think of the well-known Sales Order business object as an example.
- Analytical (OLAP): ABAP Cloud is equally equipped for creating services and UIs for data analysis, for drilling down in multiple dimensions, like integrating the data in SAP Analytics Cloud.
- Integration: Both previous aspects are complemented by strong data and application integration to cater to today’s service-oriented environments.
- Don’t worry, these aspects will be discussed in more detail in the following chapter.
The programming model doesn’t stand on its own but is accompanied by two key differentiators:
- The re-use services & libraries with core business services like the number ranges, the application jobs, an ABAP integrated SAP Fiori Launchpad and UI repository to deploy SAPUI5 and SAP Fiori Elements UIs.
- The built-in qualities offering end-to-end extensibility in the programming model, major cloud qualities like scalability and upgrade stable APIs and many more.
Both reduce the needed development effort and ensures, that ABAP Cloud is the new standard to build enterprise grade solutions.
This collection is further complemented by the following two components:
- A set of tools like ABAP Development Tools in Eclipse (ADT), which for example, includes rich debugger, profiling, refactoring support.
- A reliable lifecycle management built on the hardened ABAP Change and Transport Management (CTS) and extending it with support for git-based code management.
ABAP Cloud Programming Model
Diving further into the ABAP Cloud programming model, we see that it can be divided into the following three layers: Business Service Exposure, Domain-Specific Implementation and Data Access.
Those layers are common in all programming model aspects, as we will see later in more detail.
Figure 4 – ABAP Cloud programming model
Data forms the foundation of pretty much all business processes. It is therefore no surprise that the database plays a crucial role in ABAP Cloud, as has always been the case with ABAP in general. The Data Access layer provides and stores this data, which is in turn consumed and modified in the Implementation layer. ABAP Cloud integrates with a SAP HANA database by default, profiting from a high degree of synergy. However, data today is not always local, but has to be retrieved from remote sources. The Data Access layer is therefore complemented by the Business Service Consumption capabilities of ABAP Cloud, allowing you to integrate with external services with support for various protocols (see chapter Integration Aspect for more information).
In the Domain-Specific Implementation your domain-specific models (for example your business object) are defined using Core Data Services CDS entities, RAP business objects, or analytical providers like dimensions or cubes. The domain-specific implementation (for example the business logic consisting of determinations, validations and actions) is developed using the ABAP Language, ABAP SQL or CDS implementations.
The Business Service Exposure is also a core part of the development flow and represents the foundation for services and apps. The business service exposure concept in ABAP Cloud originates from the ABAP RESTful Application Programming Model and has since become the architecture blueprint for most other business consumption scenarios besides OData like, for example, the Information Access protocol (InA) for analytical apps. This layer can be divided into two categories: UI Services and Integration Services. The categories are quite self-explanatory – UI services are consumed by business users in user interfaces, while integration services are consumed in integration scenarios in machine-to-machine communication.
When developing UI services and OData-based integration services, CDS projections allow you to introduce an additional abstraction layer to your data models. This allows you to expose different scopes of a single implementation, facilitating flexible service consumption as well as role-based service designs. CDS projections are thus protocol agnostic, but service specific. This enables maximum reuse, for example across transactional and analytical services; data models need to be built only once and can then be used in different business contexts depending on the specific requirements, with minimal additional development effort. This separation of concerns between designing the application tier and exposing the business service in a specific protocol is a strength of ABAP Cloud. It supports maximum flexibility and reuse across different use cases.
ABAP Cloud Programming Model Aspects
As already mentioned, we differentiate between three programming model aspects in the ABAP Cloud programming model.
All three of them follow the general ABAP cloud architecture as described earlier. Let’s take a closer look at each of the aspects.
Transactional – The ABAP RESTful application programming model (RAP)
Most of you have probably heard of RAP. It is the main pillar when building transactional apps and services in ABAP Cloud.
The center piece of RAP is the Business Object (RAP BO). These are modeled using CDS and enriched with transactional behavior using the Behavior Definition (BDEF). A prominent example of such a business object is the Sales Order[1] or the Business Partner. Both are developed and provided by SAP in ABAP Cloud.
RAP BOs can be exposed as services using the Service Binding. We differentiate between two exposure use cases. UI scenarios, namely for creating SAP Fiori UIs, are supported using the OData protocol, while integration scenarios are supported with Business Events, OData services and SQL services.
Figure 5 – ABAP Cloud transactional programming model aspect
You want to create a booking service with SAP Fiori UIs for airlines.
- The essential UI and service needed is the booking of a flight. Thus, your domain is flight booking.
- The overall model for the booking is a RAP BO consisting of a CDS implementation (data model) and a behavior definition (events like determinations, validations, and actions).
- The implementation of the logic is done using ABAP. In the CDS model you can already implement UI annotations to automatically create SAP Fiori Elements UIs later.
- The data is stored and retrieved in tables in the SAP HANA
- The service exposure is done on top of this RAP BO. The service definition contains all relevant entities which are needed, including your “Booking BO”, as well as the associated master data like airplanes and business partners. The exposure using OData for the UI (including your annotation metadata) is done in the service binding (for example as a service binding of the type OData V4 for UI).
Analytical
The analytical aspect comprises the end-to-end development process for analytical services. The analytical aspect uses analytical providers like cubes and dimensions to build multidimensional domain-specific models. The domain-specific logic is implemented with CDS.
The CDS analytical provider can be exposed as an InA[1] service for different analytical clients. One of these possible clients is the SAP Analytics Cloud (SAC).
Figure 6 – ABAP Cloud analytical programming model aspect
Integration
The integration aspects enable system-to-system communication using several different protocols. Integration services enable either inbound communication or outbound system communication based on communication scenarios. Inbound communication enables a system to act as service provider, since outbound communication enables a system to act as service consumer.
Figure 7 – ABAP Cloud programming model aspect for integration
Business Service Exposure
The main service exposure channels for ABAP Cloud are OData and Business Events, which have clear domain-specific data models. However, it’s not always possible to cover each use case with a fully standardized model. To mitigate for this, ABAP Cloud offers the HTTP service: here you can make specific implementations to meet your needs (with full access to the request and response data of the HTTP request).
In order to ensure compatibility and to support highly optimized scenarios RFC services are equally available in ABAP Cloud. RFC can also be used for pure data integration as well as for SQL integration, which is based on ODBC (currently read-only).
Business Service Consumption
As touched on earlier in this blog post, it’s obvious that not all data resides in the local database of your system. Service consumption therefore plays a major role, which is why ABAP Cloud offers the service consumption model as an easy way to consume external services with typed APIs in your implementation.
ABAP Cloud Development Model
Now that we’ve examined the programming model of ABAP Cloud, let’s look at the other pillars of the ABAP Cloud development model to complete the picture.
Figure 8 – ABAP Cloud Development model – ABAP Cloud map
Reuse Services and Libraries
A key element of ABAP Cloud is the existence of powerful reuse services and libraries. They are offered directly on-stack and automatically come with the respective product environment without any additional cost. Reuse services and libraries are well integrated into the ABAP Cloud programming model to optimally reduce total cost of development for apps and services. All ABAP Cloud reuse services and libraries preserve ABAP Cloud built-in qualities and can be used across all programming model aspects.
A variety of reuse services is available and ready-to-run, ranging from applications jobs, application logs, forms, and email integration up to change documents and workflows. You can find more information in your product’s documentation, for example here.
Built-In Qualities
Built-in qualities represent the quality foundation of ABAP Cloud.
In other words, they represent common characteristics all ABAP Cloud developments and extension share. They represent the best-practices and basic quality principles upon which ABAP Cloud is built on. The built-in qualities equally apply to all aspects, as well as all apps and services. They are:
- Development Efficiency
- Cloud Qualities
- Transactional Consistency
- Documentability
- Security
- Testability
- Supportability
- Extensibility
- Performance
- Localization and Internationalization
- Business Configuration
And next…
If you are now interested in the technical Use Cases and recommended technologies of ABAP Cloud, please take a deeper look at our ABAP Cloud – Technical use cases and recommended technologies document.
More content and possibilities to engage with the community is available in the ABAP Development Community.
Stay tuned for more details on ABAP Cloud in our next blog posts where we will get into more details on the re-use services & libraries, the built-in qualities, the lifecycle management, and the tools of ABAP Cloud.
Footnotes
[1] Only available in the SAP S/4HANA editions
[2] Information Access – A SAP proprietary analytical protocol
