Copilot instructions

1---
2applyTo: "**/*.go"
3---
4 
5# Go Coding Style
6 
7> This file extends [common/coding-style.md](../common/coding-style.md) with Go specific content.
8 
9## Formatting
10 
11- **gofmt** and **goimports** are mandatory — no style debates
12 
13## Design Principles
14 
15- Accept interfaces, return structs
16- Keep interfaces small (1-3 methods)
17 
18## Error Handling
19 
20Always wrap errors with context:
21 
22```go
23if err != nil {
24    return fmt.Errorf("failed to create user: %w", err)
25}
26```
27 
28## Reference
29 
30See skill: `golang-patterns` for comprehensive Go idioms and patterns.
31 
32 
33# Go Patterns
34 
35> This file extends [common/patterns.md](../common/patterns.md) with Go specific content.
36 
37## Functional Options
38 
39```go
40type Option func(*Server)
41 
42func WithPort(port int) Option {
43    return func(s *Server) { s.port = port }
44}
45 
46func NewServer(opts ...Option) *Server {
47    s := &Server{port: 8080}
48    for _, opt := range opts {
49        opt(s)
50    }
51    return s
52}
53```
54 
55## Small Interfaces
56 
57Define interfaces where they are used, not where they are implemented.
58 
59## Dependency Injection
60 
61Use constructor functions to inject dependencies:
62 
63```go
64func NewUserService(repo UserRepository, logger Logger) *UserService {
65    return &UserService{repo: repo, logger: logger}
66}
67```
68 
69## Reference
70 
71See skill: `golang-patterns` for comprehensive Go patterns including concurrency, error handling, and package organization.
72 
73 
74# Go Security
75 
76> This file extends [common/security.md](../common/security.md) with Go specific content.
77 
78## Secret Management
79 
80```go
81apiKey := os.Getenv("OPENAI_API_KEY")
82if apiKey == "" {
83    log.Fatal("OPENAI_API_KEY not configured")
84}
85```
86 
87## Security Scanning
88 
89- Use **gosec** for static security analysis:
90```bash
91  gosec ./...
92```
93 
94## Context & Timeouts
95 
96Always use `context.Context` for timeout control:
97 
98```go
99ctx, cancel := context.WithTimeout(ctx, 5*time.Second)
100defer cancel()
101```
102 
103 
104# Go Testing
105 
106> This file extends [common/testing.md](../common/testing.md) with Go specific content.
107 
108## Framework
109 
110Use the standard `go test` with **table-driven tests**.
111 
112## Race Detection
113 
114Always run with the `-race` flag:
115 
116```bash
117go test -race ./...
118```
119 
120## Coverage
121 
122```bash
123go test -cover ./...
124```
125 
126## Reference
127 
128See skill: `golang-testing` for detailed Go testing patterns and helpers.