Go: What is Go and comprehensive error reporting?

1import (
2    "errors"
3    "fmt"
4    "runtime/debug"
5)
6
7// Structured error
8type AppError struct {
9    Code     string                 `json:"code"`
10    Message  string                 `json:"message"`
11    Err      error                  `json:"-"`
12    Stack    string                 `json:"stack,omitempty"`
13    Context  map[string]interface{} `json:"context,omitempty"`
14    Severity string                 `json:"severity"`
15}
16
17func (e *AppError) Error() string {
18    if e.Err != nil {
19        return fmt.Sprintf("[%s] %s: %v", e.Code, e.Message, e.Err)
20    }
21    return fmt.Sprintf("[%s] %s", e.Code, e.Message)
22}
23
24func (e *AppError) Unwrap() error {
25    return e.Err
26}
27
28// Error factory
29func NewError(code, message string, err error, severity string) *AppError {
30    return &AppError{
31        Code:     code,
32        Message:  message,
33        Err:      err,
34        Stack:    string(debug.Stack()),
35        Severity: severity,
36        Context:  make(map[string]interface{}),
37    }
38}
39
40func (e *AppError) WithContext(key string, value interface{}) *AppError {
41    e.Context[key] = value
42    return e
43}
44
45// Usage
46func GetUser(ctx context.Context, id int) (*User, error) {
47    user, err := db.Find(ctx, id)
48    if err != nil {
49        return nil, NewError("USER_NOT_FOUND",
50            "user not found", err, "warning").
51            WithContext("user_id", id).
52            WithContext("operation", "GetUser")
53    }
54    return user, nil
55}
56
57// Reporter
58type ErrorReporter interface {
59    Report(err error)
60}
61
62// Sentry integration
63import "github.com/getsentry/sentry-go"
64
65type SentryReporter struct{}
66
67func (r *SentryReporter) Report(err error) {
68    if appErr, ok := err.(*AppError); ok {
69        sentry.WithScope(func(scope *sentry.Scope) {
70            scope.SetTag("code", appErr.Code)
71            scope.SetTag("severity", appErr.Severity)
72            for k, v := range appErr.Context {
73                scope.SetExtra(k, v)
74            }
75            sentry.CaptureException(appErr)
76        })
77    } else {
78        sentry.CaptureException(err)
79    }
80}
81
82// HTTP error handling
83func handleError(w http.ResponseWriter, err error) {
84    var appErr *AppError
85    if errors.As(err, &appErr) {
86        // Sending to Sentry
87        reporter.Report(appErr)
88
89        // HTTP response
90        w.Header().Set("Content-Type", "application/json")
91        w.WriteHeader(getStatusCode(appErr.Code))
92        json.NewEncoder(w).Encode(appErr)
93    } else {
94        reporter.Report(err)
95        http.Error(w, "Internal Server Error", 500)
96    }
97}