SOA in Practice: The Art of Distributed System Design

SOA in Practice......Page 1
Contents......Page 6
Preface......Page 10
Structure of the Book......Page 11
Conventions Used in This Book......Page 13
Feedback, Comments, and Questions......Page 14
Acknowledgments......Page 15
Motivation......Page 18
1.1 Characteristics of Large Distributed Systems......Page 20
1.2 The Tale of the Magic Bus......Page 21
1.3 What We Can Learn from the Tale of the Magic Bus......Page 23
1.4 History of SOA......Page 24
1.5.1 Slide 1: SOA......Page 25
1.5.3 Slide 3: Web Services......Page 26
1.5.5 Slide 5: SOA Governance and Management Support......Page 27
2.1 Definitions of SOA......Page 28
2.1.2 SOA Aims to Improve Flexibility......Page 29
2.2.2 Different Owners......Page 30
2.2.3 Heterogeneity......Page 31
2.3.1 Services......Page 33
2.3.3 Loose Coupling......Page 34
2.4.1 Infrastructure......Page 35
2.4.4 Governance......Page 36
2.5 SOA Is Not a Silver Bullet......Page 38
2.6 SOA Is Not a Specific Technology......Page 39
2.8 SOA Terminology......Page 40
2.9 Summary......Page 41
3.1 Services......Page 42
3.2 Interfaces and Contracts......Page 43
3.3.1 Self-Contained......Page 46
3.3.2 Coarse-Grained......Page 47
3.3.3 Visible/Discoverable......Page 48
3.3.8 Technical......Page 49
3.3.12 Interoperable......Page 50
3.4 Summary......Page 51
4.1 The Need for Fault Tolerance......Page 52
4.2 Forms of Loose Coupling......Page 53
4.2.1 Asynchronous Communication......Page 54
4.2.2 Heterogeneous Data Types......Page 55
4.2.3 Mediators......Page 58
4.2.4 Weak Type Checking......Page 59
4.2.7 Interaction Patterns......Page 60
4.2.8 Compensation......Page 61
4.3 Dealing with Loose Coupling......Page 62
4.4 Summary......Page 63
5.1 ESB Responsibilities......Page 64
5.2 Heterogeneous ESBs......Page 66
5.3.1 Point-to-Point Connections Versus Mediation......Page 67
5.3.2 Interceptors......Page 69
5.3.3 Protocol-Driven Versus API-Driven ESB......Page 70
5.4.2 Intelligent Routing......Page 73
5.4.6 Monitoring and Logging......Page 74
5.4.8 Service Implementation Support......Page 75
5.5 Summary......Page 76
Service Classification......Page 78
6.1 A Fundamental Service Classification......Page 79
6.2.1 Basic Data Services......Page 80
6.2.2 Basic Logic Services......Page 81
6.2.3 Fundamental SOA......Page 82
6.3 Composed Services......Page 84
6.3.2 Composed Services for One Backend......Page 85
6.3.3 Federated SOA......Page 86
6.3.4 Security......Page 87
6.4 Process Services......Page 88
6.4.2 Service State Versus Backend State......Page 89
6.5 Other Service Classifications......Page 90
6.5.1 Dealing with Different Types of Consumers......Page 91
6.5.3 Business Categorizations......Page 92
Categorization according to Erl......Page 93
6.6 Technical and Infrastructure Services......Page 94
6.7 Beyond Services......Page 95
6.8 Summary......Page 96
Business Process Management......Page 98
7.1 BPM Terminology......Page 99
7.2 BPM and SOA......Page 100
7.3 Example for BPM with Services......Page 101
7.4 Business Process Modeling......Page 104
7.4.1 Using Business Process Modeling Tools......Page 105
7.4.2 BPEL......Page 106
7.4.3 Other Business Process Modeling Standards......Page 108
7.4.4 Business Process Modeling with BPEL in Practice......Page 109
7.5.1 Portfolio Management......Page 111
7.5.2 Don’t Switch Off Your Brain......Page 112
7.6 Orchestration Versus Choreography......Page 113
7.6.1 Choreography and SOA......Page 114
7.8 Summary......Page 115
8.1.1 From Monolithic Systems to Distribution......Page 118
8.1.2 Solution Management......Page 120
8.1.3 Collaboration......Page 121
8.2 Funding Models......Page 123
8.3 Summary......Page 124
9.1 SOA-Based Architecture Models......Page 126
9.1.1 Logical Architecture Models......Page 127
9.1.2 Mixed Architecture Models......Page 128
9.1.3 Technical Architecture Models......Page 129
9.1.4 Choosing the Right Architecture Model......Page 130
9.2.1 Roles and Responsibilities......Page 131
9.2.2 Multilayer Validation......Page 134
9.2.4 Multiapplication Frontends......Page 136
9.2.5 Future Management......Page 137
9.3 Summary......Page 138
10.1 Introduction to MEPs......Page 140
10.2.1 Request/Response......Page 141
10.2.2 One-Way......Page 142
10.2.3 Request/Response Versus Two One-Way Messages......Page 143
10.3.1 Request/Callback......Page 145
10.4 Dealing with Reliability and Errors......Page 146
10.4.2 Technical Errors......Page 147
10.5 Dealing with Different MEP Layers......Page 148
10.6 Event-Driven Architecture......Page 151
10.7 Summary......Page 153
11.1 Services Under Development......Page 154
11.1.1 Iterative Service Development......Page 155
11.1.2 Service Identification......Page 156
11.2 Services in Production......Page 157
11.2.1 Modifying Services in Production......Page 158
11.2.2 Withdrawing a Service......Page 159
11.3 Summary......Page 160
12.1 Versioning Requirements......Page 162
12.2 Domain-Driven Versioning......Page 163
12.2.1 Trivial Domain-Driven Versioning......Page 164
12.3 Versioning of Data Types......Page 166
12.3.1 Using Different Types for Different Versions of a Data Type......Page 167
12.3.2 Using the Same Type for Different Versions of a Data Type......Page 169
12.3.4 Summary of Versioning of Data Types......Page 171
12.4 Configuration-Management-Driven Versioning......Page 172
12.5.2 Call Constraints Should be Considered......Page 173
12.6 Summary......Page 174
13.1 Where Performance Matters......Page 176
13.2 From Remote Stored Procedures to Services......Page 179
13.3 Performance and Reusability......Page 181
13.3.1 Call Constraints......Page 183
13.3.2 Customized Services......Page 184
13.3.3 Reusability in Practice......Page 185
13.4 Performance and Backward Compatibility......Page 186
13.5 Summary......Page 188
14.1 Security Requirements......Page 190
14.2 Dealing with Security Requirements......Page 191
14.2.3 Distributed Processes and Many Layers of Abstraction......Page 192
14.2.4 Multiclient Capabilities......Page 194
14.3.1 Infrastructures Don’t Provide Sufficient Security......Page 195
14.3.2 Dealing with Confidentiality and Integrity......Page 196
14.3.3 Security as a Service......Page 197
14.3.4 Security, Performance, and State......Page 198
14.4 Security with XML and Web Services......Page 199
14.4.1 SAML......Page 200
14.4.2 XML and Web Services Security Standards......Page 201
14.4.3 XML and Web Services Attacks......Page 202
14.6 Summary......Page 205
15.1 Services and State......Page 208
15.1.1 Stateless Services......Page 209
15.1.2 Stateful Services......Page 210
15.1.3 Why Stateless Services Are Better......Page 213
15.1.4 Stateless Services in Practice......Page 214
15.2 Idempotency......Page 215
15.2.1 Idempotent Services......Page 216
15.2.2 Implementing Idempotency......Page 217
15.3.2 Distributed Testing......Page 218
15.3.3 Correlation IDs......Page 219
15.4 Dealing with Technical Data (Header Data)......Page 220
15.5.1 Fundamental Data Types......Page 221
15.5.2 Reference Semantics......Page 222
15.5.3 Higher Data Types......Page 223
15.6 Error Handling......Page 224
15.7 Summary......Page 225
16.1 Motivation for Using Web Services......Page 226
16.1.2 History of Web Services......Page 227
16.2.1 WSDL......Page 228
16.2.2 WSDL by Example......Page 229
16.2.3 SOAP......Page 234
16.2.4 UDDI......Page 235
16.3.1 Open Standardization......Page 237
16.3.2 Protocol Aspects......Page 238
16.3.3 The WSDL Lifecycle......Page 240
16.3.4 WSDL Deficits......Page 241
16.3.5 So, Should You Use Web Services?......Page 243
16.4 Closing Notes......Page 245
16.5 Summary......Page 246
17.1 The History of Service Brokers......Page 248
17.2.1 Designing Repositories and Registries......Page 250
17.2.2 Establishing Repositories and Registries......Page 252
17.3 Summary......Page 253
18.1 Generated Service Code......Page 254
18.2.1 Terminology......Page 256
18.2.2 The Model-Driven Tool Chain......Page 259
18.3 Meta Models in Practice......Page 261
18.4.1 Consumer-Driven Transformations......Page 264
18.4.2 Provider-Driven Transformations......Page 266
18.4.5 Labeling......Page 267
18.4.7 Manually Modified Generated Code......Page 268
18.4.8 The Code-Generation Granularity Dilemma......Page 270
18.4.9 Deployment and Robustness......Page 271
18.5.1 XSLT......Page 272
18.7 Summary......Page 275
19.1 Introducing SOA......Page 278
19.2.1 Definition of Governance......Page 279
19.2.2 Central SOA Teams......Page 282
19.3.1 Step 1: Understand SOA......Page 283
19.3.2 Step 2: The SOA Pilot......Page 284
19.3.3 Step 3: The Second and Third SOA Projects......Page 285
19.3.4 Step 4: Grow and Become a General Strategy......Page 286
19.3.5 Tasks Necessary over All Steps......Page 287
19.4.2 Architectural Roadmap, by Krafzig, Banke, and Slama......Page 288
19.4.3 Top-Down or Bottom-Up, by Krafzig and Slama......Page 289
19.4.5 Essence of Different SOA Approaches......Page 290
19.5.1 Policies......Page 291
19.5.3 SOA Maturity Models......Page 293
19.6 Summary......Page 295
20.1 Is SOA Something New?......Page 298
20.3 What Are the Key Success Factors for SOA?......Page 299
20.5 Does SOA Replace OOP?......Page 300
References......Page 302
Glossary......Page 310
Index......Page 320