Introduction xvii
Getting Started xxi
Chapter 1 Writing Command-Line Applications 1
Your First Application 1
Writing Unit Tests 8
Using the Flag Package 14
Testing the Parsing Logic 20
Improving the User Interface 22
Removing Duplicate Error Messages 23
Customizing Usage Message 24
Accept Name via a Positional Argument 25
Updating the Unit Tests 28
Summary 32
Chapter 2 Advanced Command-Line Applications 33
Implementing Sub-commands 33
An Architecture for Sub-command-Driven Applications 37
Testing the Main Package 43
Testing the Cmd Package 45
Making Your Applications Robust 47
User Input with Deadlines 48
Handling User Signals 52
Summary 56
Chapter 3 Writing HTTP Clients 57
Downloading Data 57
Testing the Data Downloader 59
Deserializing Received Data 61
Sending Data 66
Working with Binary Data 72
Summary 80
Chapter 4 Advanced HTTP Clients 81
Using a Custom HTTP Client 81
Downloading from an Overloaded Server 81
Testing the Time-Out Behavior 85
Configuring the Redirect Behavior 88
Customizing Your Requests 91
Implementing Client Middleware 92
Understanding the RoundTripper Interface 93
A Logging Middleware 94
Add a Header to All Requests 96
Connection Pooling 99
Configuring the Connection Pool 103
Summary 104
Chapter 5 Building HTTP Servers 105
Your First HTTP Server 105
Setting Up Request Handlers 108
Handler Functions 109
Testing Your Server 112
The Request Struct 114
Method 115
Url 115
Proto, ProtoMajor, and ProtoMinor 116
Header 116
Host 116
Body 116
Form, PostForm 116
MultipartForm 117
Attaching Metadata to a Request 118
Processing Streaming Requests 121
Streaming Data as Responses 126
Summary 132
Chapter 6 Advanced HTTP Server Applications 133
The Handler Type 133
Sharing Data across Handler Functions 134
Writing Server Middleware 139
Custom HTTP Handler Technique 139
The HandlerFunc Technique 140
Chaining Middleware 142
Writing Tests for Complex Server Applications 147
Code Organization 147
Testing the Handler Functions 153
Testing the Middleware 155
Testing the Server Startup 157
Summary 159
Chapter 7 Production- Ready HTTP Servers 161
Aborting Request Handling 161
Strategies to Abort Request Processing 165
Handling Client Disconnects 169
Server-Wide Time- Outs 173
Implement a Time- Out for All Handler Functions 173
Implementing Server Time- Out 174
Implementing Graceful Shutdown 179
Securing Communication with TLS 184
Configuring TLS and HTTP/2 184
Testing TLS Servers 188
Summary 192
Chapter 8 Building RPC Applications with gRPC 193
gRPC and Protocol Buffers 193
Writing Your First Service 197
Writing the Server 198
Writing a Client 203
Testing the Server 207
Testing the Client 211
A Detour into Protobuf Messages 214
Marshalling and Unmarshalling 214
Forward and Backward Compatibility 219
Multiple Services 220
Error Handling 226
Summary 228
Chapter 9 Advanced gRPC Applications 229
Streaming Communication 229
Server- Side Streaming 230
Client- Side Streaming 237
Bidirectional Streaming 239
Receiving and Sending Arbitrary Bytes 247
Implementing Middleware Using Interceptors 256
Client- Side Interceptors 257
Server- Side Interceptors 263
Wrapping Streams 269
Chaining Interceptors 271
Summary 272
Chapter 10 Production- Ready gRPC Applications 275
Securing Communication with TLS 275
Robustness in Servers 278
Implementing Health Checks 278
Handling Runtime Errors 286
Aborting Request Processing 289
Robustness in Clients 297
Improving Connection Setup 298
Handling Transient Failures 300
Setting Time- Outs for Method Calls 305
Connection Management 306
Summary 309
Chapter 11 Working with Data Stores 311
Working with Object Stores 312
Integration with Package Server 313
Testing Package Uploads 323
Accessing Underlying Driver Types 325
Working with Relational Databases 327
Integration with Package Server 328
Testing Data Storage 339
Data Type Conversions 343
Using Database Transactions 346
Summary 348
Appendix A Making Your Applications Observable 349
Logs, Metrics, and Traces 349
Emitting Telemetry Data 352
Command- Line Applications 352
HTTP Applications 360
gRPC Applications 364
Summary 366
Appendix B Deploying Applications 367
Managing Configuration 367
Distributing Your Application 370
Deploying Server Applications 372
Summary 373
Index 375
