1 ... Foreword ... 21

1 ... Preface ... 25

... Purpose ... 25

... Who Should Read This Book ... 26

... Structure and Content of the Book ... 27

... How to Read This Book ... 33

... How to Use the Code Examples ... 34

... Additional Resources and Feedback Channels ... 36

... Acknowledgements ... 38

... Part 1: The Intelligent ERP ... 41

1 ... SAP S/4HANA: The Intelligent ERP ... 43

1.1 ... Digital Transformation ... 43

1.2 ... SAP S/4HANA Evolution ... 44

1.3 ... SAP S/4HANA Design Principles ... 46

1.4 ... Summary ... 54

2 ... SAP S/4HANA Extensibility ... 55

2.1 ... Separation of Concerns ... 56

2.2 ... In-App Extensions ... 58

2.3 ... Side-by-Side Extensions ... 64

2.4 ... Extension Use Cases ... 72

2.5 ... Nonfunctional Requirements of Extension Applications ... 74

2.6 ... Summary ... 76

... Part II: Building Side-by-Side Extensions ... 77

3 ... Side-by-Side Extensibility ... 79

3.1 ... Cloud-Native Development ... 79

3.2 ... SAP Cloud Platform ... 93

3.3 ... The SAP Cloud Platform SDK for Service Development and the SAP S/4HANA Cloud SDK ... 97

3.4 ... Business Partner Address Manager Application ... 102

3.5 ... Summary ... 106

4 ... Building the Application ... 109

4.1 ... A First Hello World! Microservice ... 110

4.2 ... Reading Business Partners ... 117

4.3 ... Integrating the Frontend ... 129

4.4 ... Deploying the Application to Cloud Foundry ... 130

4.5 ... Writing Business Partner Addresses to SAP S/4HANA ... 133

4.6 ... Engineering with Cloud Qualities ... 140

4.7 ... Summary ... 153

5 ... Application Security ... 155

5.1 ... Security on SAP Cloud Platform ... 155

5.2 ... Configuring Authentication ... 159

5.3 ... Configuring Authorization Using OAuth2 ... 169

5.4 ... Protecting against Common Web Application Threats ... 180

5.5 ... Summary ... 184

6 ... Integrating with SAP S/4HANA ... 185

6.1 ... Introduction ... 185

6.2 ... Technical Users, Business Users, and Principal Propagation ... 186

6.3 ... Using and Configuring Destination Service on SAP Cloud Platform Cloud Foundry ... 189

6.4 ... Integration with SAP S/4HANA Cloud ... 192

6.5 ... Integration with SAP S/4HANA On-Premise ... 211

6.6 ... Summary ... 230

7 ... Multitenancy ... 231

7.1 ... Motivations for Multitenancy ... 231

7.2 ... Multitenancy on SAP Cloud Platform ... 232

7.3 ... Multitenancy Aspects in the Existing Application ... 238

7.4 ... Adding Multitenant Persistence to the Application ... 240

7.5 ... Summary ... 258

8 ... REST APIs ... 259

8.1 ... Designing RESTful APIs ... 264

8.2 ... Building RESTful APIs ... 275

8.3 ... Provisioning OData Services with the SAP Cloud Platform SDK for Service Development ... 282

8.4 ... Summary ... 290

9 ... Automated Testing ... 291

9.1 ... Concepts of Testing ... 292

9.2 ... Building Unit Tests ... 297

9.3 ... Building Integration Tests ... 304

9.4 ... Testing Complex Applications ... 308

9.5 ... Summary ... 309

... Part III: Delivering and Operating Side-by-Side Extensions ... 311

10 ... DevOps and Continuous Delivery ... 313

10.1 ... The Importance of DevOps ... 313

10.2 ... Introducing the Principles of DevOps ... 314

10.3 ... Introducing Continuous Delivery ... 319

10.4 ... How to Monitor Applications ... 323

10.5 ... Case Study: Working Model of a DevOps Team ... 327

10.6 ... Summary ... 331

11 ... Implementing Continuous Delivery ... 333

11.1 ... The SAP S/4HANA Cloud SDK CX-Server ... 333

11.2 ... Setting Up and Configuring a Continuous Delivery Server ... 338

11.3 ... Zero-Downtime Shipments to the Cloud ... 347

11.4 ... Feature Toggles: Decoupling Deployment and Release ... 352

11.5 ... Summary ... 357

12 ... Quality Assurance ... 359

12.1 ... What Is Software Quality and How to Achieve It? ... 359

12.2 ... Static Code Checks ... 361

12.3 ... Automated