Microservices in .NET Core, with Examples in Nancy

Microservices in .NET Core......Page 1
brief contents......Page 7
contents......Page 9
preface......Page 15
acknowledgments......Page 16
Who should read this book......Page 17
How this book is organized......Page 18
Code conventions and downloads......Page 19
About the author......Page 20
about the cover illustration......Page 21
Part 1: Getting started with microservices......Page 23
1.1 What is a microservice?......Page 25
1.1.2 Microservice characteristics......Page 27
1.2 Why microservices?......Page 32
1.2.1 Enabling continuous delivery......Page 33
1.2.2 High level of maintainability......Page 34
1.3 Costs and downsides of microservices......Page 35
1.4 Greenfield vs. brownfield......Page 36
1.5 Code reuse......Page 37
1.6 Serving a user request: an example of how microservices work in concert......Page 38
1.6.1 Main handling of the user request......Page 39
1.6.2 Side effects of the user request......Page 40
1.6.3 The complete picture......Page 41
1.7.1 Nancy......Page 42
1.7.2 OWIN......Page 43
1.7.3 Setting up a development environment......Page 44
1.8 A simple microservices example......Page 45
1.8.2 Adding Nancy to the project......Page 46
1.8.3 Adding a Nancy module with an implementation of the endpoint......Page 47
1.8.4 Adding OWIN middleware......Page 49
1.9 Summary......Page 50
Chapter 2: A basic shopping cart microservice......Page 52
2.1 Overview of the Shopping Cart microservice......Page 53
2.1.1 Components of the Shopping Cart microservice......Page 55
2.2.1 Creating an empty project......Page 56
2.2.2 The Shopping Cart microservice’s API for other services......Page 57
2.2.3 Fetching product information......Page 64
2.2.4 Parsing the product response......Page 66
2.2.5 Adding a failure-handling policy......Page 68
2.2.6 Implementing a basic event feed......Page 70
2.4 Summary......Page 74
Part 2: Building microservices......Page 77
Chapter 3: Identifying and scoping microservices......Page 79
3.1.1 What is a business capability?......Page 80
3.1.2 Identifying business capabilities......Page 81
3.1.3 Example: point-of-sale system......Page 82
3.2.2 Examples of supporting technical capabilities......Page 87
3.3 What to do when the correct scope isn’t clear......Page 91
3.3.1 Starting a bit bigger......Page 92
3.3.2 Carving out new microservices from existing microservices......Page 95
3.4 Well-scoped microservices adhere to the microservice characteristics......Page 97
3.4.2 Secondarily scoping to supporting technical capabilities leads to good microservices......Page 98
3.5 Summary......Page 99
Chapter 4: Microservice collaboration......Page 101
4.1 Types of collaboration: commands, queries, and events......Page 102
4.1.1 Commands and queries: synchronous collaboration......Page 104
4.1.2 Events: asynchronous collaboration......Page 107
4.1.3 Data formats......Page 109
4.2 Implementing collaboration......Page 110
4.2.1 Setting up a project for Loyalty Program......Page 111
4.2.3 Implementing commands with HTTP POST or PUT......Page 113
4.2.4 Implementing queries with HTTP GET......Page 117
4.2.5 Data formats......Page 118
4.2.6 Implementing an event-based collaboration......Page 120
4.3 Summary......Page 129
Chapter 5: Data ownership and data storage......Page 131
5.2.1 Rule 1: Ownership of data follows business capabilities......Page 132
5.2.2 Rule 2: Replicate for speed and robustness......Page 135
5.2.3 Where does a microservice store its data?......Page 138
5.3 Implementing data storage in a microservice......Page 140
5.3.1 Storing data owned by a microservice......Page 141
5.3.2 Storing events raised by a microservice......Page 144
5.3.3 Setting cache headers in Nancy responses......Page 151
5.3.4 Reading and using cache headers......Page 152
5.4 Summary......Page 154
Chapter 6: Designing for robustness......Page 156
6.1 Expect failures......Page 157
6.1.1 Keeping good logs......Page 158
6.1.3 Rolling forward vs. rolling back......Page 160
6.1.4 Don’t propagate failures......Page 161
6.2 The client side’s responsibility for robustness......Page 162
6.2.1 Robustness pattern: retry......Page 164
6.2.2 Robustness pattern: circuit breaker......Page 166
6.3 Implementing robustness patterns......Page 168
6.3.1 Implementing a fast-paced retry strategy with Polly......Page 170
6.3.2 Implementing a circuit breaker with Polly......Page 171
6.3.3 Implementing a slow-paced retry strategy......Page 172
6.3.4 Logging all unhandled exceptions......Page 175
6.4 Summary......Page 176
Chapter 7: Writing tests for microservices......Page 177
7.1.1 The test pyramid: what to test in a microservices system......Page 178
7.1.2 System-level tests: testing a complete microservice system end-to-end......Page 179
7.1.3 Service-level tests: testing a microservice from outside its process......Page 180
7.1.4 Unit-level tests: testing endpoints from within the process......Page 183
7.2.1 Meet Nancy.Testing......Page 184
7.2.3 xUnit and Nancy.Testing working together......Page 185
7.3 Writing unit tests using Nancy.Testing......Page 186
7.3.1 Setting up a unit-test project......Page 187
7.3.2 Using the Browser object to unit-test endpoints......Page 189
7.3.3 Using a configurable bootstrapper to inject mocks into endpoints......Page 192
7.4 Writing service-level tests......Page 195
7.4.2 Creating mocked endpoints......Page 197
7.4.3 Starting all the processes of the microservice under test......Page 199
7.4.4 Executing the test scenario against the microservice under test......Page 201
7.5 Summary......Page 202
Part 3: Handling cross-cutting concerns: building a reusable microservice platform......Page 205
Chapter 8: Introducing OWIN: writing and testing OWIN middleware......Page 207
8.1 Handling cross-cutting concerns......Page 208
8.2 The OWIN pipeline......Page 210
8.2.1 What belongs in OWIN, and what belongs in Nancy?......Page 213
8.3 Writing middleware......Page 214
8.3.1 Middleware as lambdas......Page 215
8.3.2 Middleware classes......Page 216
8.4 Testing middleware and pipelines......Page 217
8.5 Summary......Page 220
Chapter 9: Cross-cutting concerns: monitoring and logging......Page 221
9.1 Monitoring needs in microservices......Page 222
9.2 Logging needs in microservices......Page 225
9.2.1 Structured logging with Serilog......Page 227
9.3 Implementing the monitoring middleware......Page 228
9.3.1 Implementing the shallow monitoring endpoint......Page 229
9.3.2 Implementing the deep monitoring endpoint......Page 230
9.3.3 Adding the monitoring middleware to the OWIN pipeline......Page 232
9.4 Implementing the logging middleware......Page 234
9.4.1 Adding correlation tokens to all log messages......Page 236
9.4.2 Adding a correlation token to all outgoing HTTP requests......Page 237
9.4.3 Logging requests and request performance......Page 241
9.4.4 Configuring an OWIN pipeline with a correlation token and logging middleware......Page 242
9.5 Summary......Page 244
Chapter 10: Securing microservice-to- microservice communication......Page 245
10.1 Microservice security concerns......Page 246
10.1.1 Authenticating users at the edge......Page 247
10.1.2 Authorizing users in microservices......Page 248
10.1.3 How much should microservices trust each other?......Page 249
10.2 Implementing secure microservice-to-microservice communication......Page 251
10.2.1 Meet IdentityServer......Page 253
10.2.2 Implementing authentication with IdentityServer middleware......Page 259
10.2.3 Implementing microservice-to-microservice authorization with IdentityServer and middleware......Page 261
10.2.4 Implementing user authorization in Nancy modules......Page 264
10.3 Summary......Page 268
Chapter 11: Building a reusable microservice platform......Page 270
11.2 Creating a reusable microservice platform......Page 271
11.3 Packaging and sharing middleware with NuGet......Page 273
11.3.1 Creating a package with logging and monitoring middleware......Page 274
11.3.2 Creating a package with authorization middleware......Page 281
11.3.3 Creating a package with rest client factory......Page 284
11.3.4 Automatically registering an HTTP client factory in Nancy’s container......Page 287
11.3.5 Using the microservice platform......Page 289
11.4 Summary......Page 292
Part 4: Building applications......Page 293
Chapter 12: Creating applications over microservices......Page 295
12.1.1 General-purpose applications......Page 296
12.1.2 Specialized applications......Page 297
12.2.1 Composite applications: integrating at the frontend......Page 298
12.2.2 API gateway......Page 301
12.2.3 Backend for frontend (BFF) pattern......Page 303
12.2.4 When to use each pattern......Page 304
12.2.5 Client-side or server-side rendering?......Page 305
12.3 Example: a shopping cart and product list......Page 306
12.3.1 Creating an API gateway......Page 309
12.3.2 Creating the product list GUI......Page 311
12.3.3 Creating the shopping cart GUI......Page 316
12.3.4 Letting users add products to the shopping cart......Page 319
12.3.5 Letting users remove products from the shopping cart......Page 321
12.4 Summary......Page 322
Appendix A: Development environment setup......Page 325
A.1.3 ATOM......Page 326
A.3 Setting up Yeoman ASP.NET generator......Page 327
A.4 Setting up Postman......Page 328
A.5 Installing SQL Server Express......Page 329
B.1 Deploying HTTP APIs......Page 330
B.1.3 Azure Web Apps......Page 331
B.2.2 Linux servers......Page 332
B.2.5 Amazon Lambda......Page 333
Software design and architecture in general......Page 334
Technologies used......Page 335
B......Page 337
D......Page 338
H......Page 339
M......Page 340
N......Page 341
R......Page 342
S......Page 343
Y......Page 344