# Golang Samber Oops

> Manejo estructurado de errores en Golang con samber/oops: builders, stack traces, códigos, contexto, wrapping, mensajes públicos y recuperación de panics.

Fuente: https://skillsagentes.com/skills/samber/cc-skills-golang/golang-samber-oops
Markdown: https://skillsagentes.com/skills/samber/cc-skills-golang/golang-samber-oops.md

Repositorio: https://github.com/samber/cc-skills-golang
Autor: samber
Licencia: MIT
Actualizado: el mes pasado
Coste de contexto: 82 tok instalada, 2.6k tok al activarse, 6.2k tok con todos los archivos del bundle
Bundle: 3 archivos, 24 KB
Permisos que pide: read edit write glob grep bash(go:*) bash(golangci-lint:*) bash(git:*) agent webfetch mcp__context7__resolve-library-id mcp__context7__query-docs bash(godig:*) bash(gopls:*) lsp mcp__gopls__*

## Instalación

Un skill son archivos markdown: los mismos archivos valen para cualquier agente y lo único que cambia es el directorio de destino, es decir la bandera `--agent`. Añade `-g` para instalarlo en todos los proyectos de la máquina.

```bash
# Claude Code
npx -y skills add samber/cc-skills-golang --skill golang-samber-oops --agent claude-code
# Cursor
npx -y skills add samber/cc-skills-golang --skill golang-samber-oops --agent cursor
# Codex
npx -y skills add samber/cc-skills-golang --skill golang-samber-oops --agent codex
# Gemini CLI
npx -y skills add samber/cc-skills-golang --skill golang-samber-oops --agent gemini
# Windsurf
npx -y skills add samber/cc-skills-golang --skill golang-samber-oops --agent windsurf
# Cline
npx -y skills add samber/cc-skills-golang --skill golang-samber-oops --agent cline
```

## Qué hace

- Aplica el patrón de builder fluido de samber/oops para crear y envolver errores con contexto, códigos, tags y trazas
- Añade atributos estructurados (.With, .User, .Tenant, .Trace) en vez de interpolar datos en el mensaje de error
- Convierte panics en errores estructurados con .Recover()/.Recoverf()
- Separa mensajes públicos (.Public) de mensajes técnicos para desarrolladores
- Propaga el contexto de error entre capas usando oops.WithBuilder y oops.FromContext

## Cuándo usarla

- Al usar o adoptar samber/oops en un proyecto Golang
- Cuando el código ya importa github.com/samber/oops
- Al manejar errores en capas de repositorio, servicio o handler HTTP
- Al necesitar recuperación de panics en goroutines

## Qué la activa

- "Añade manejo de errores estructurado con samber/oops a este repositorio"
- "Envuelve este error con oops incluyendo contexto y stack trace"
- "Convierte este panic en un error estructurado usando oops.Recover"

## Antes de instalar

- Requiere Go instalado y el proyecto debe usar o adoptar el paquete github.com/samber/oops.

## Archivos

- SKILL.md — 10 KB
- evals/evals.json — 13 KB
- references/advanced.md — 1 KB

## SKILL.md

Reproducido tal cual desde samber/cc-skills-golang bajo MIT. Esta sección es el documento original y está en inglés.

**Persona:** You are a Go engineer who treats errors as structured data. Every error carries enough context — domain, attributes, trace — for an on-call engineer to diagnose the problem without asking the developer.

# samber/oops Structured Error Handling

**samber/oops** is a drop-in replacement for Go's standard error handling that adds structured context, stack traces, error codes, public messages, and panic recovery. Variable data goes in `.With()` attributes (not the message string), so APM tools (Datadog, Loki, Sentry) can group errors properly. Unlike the stdlib approach (adding `slog` attributes at the log site), oops attributes travel with the error through the call stack.

## Why use samber/oops

Standard Go errors lack context — you see `connection failed` but not which user triggered it, what query was running, or the full call stack. `samber/oops` provides:

- **Structured context** — key-value attributes on any error
- **Stack traces** — automatic call stack capture
- **Error codes** — machine-readable identifiers
- **Public messages** — user-safe messages separate from technical details
- **Low-cardinality messages** — variable data in `.With()` attributes, not the message string, so APM tools group errors properly

This skill is not exhaustive. Please refer to library documentation and code examples for more information. For Go package docs, symbols, versions, importers, and known vulnerabilities, → See `samber/cc-skills-golang@golang-pkg-go-dev` skill (`godig`) — prefer it over Context7 for Go package facts. To navigate this library's usage in your own code (definitions, call sites, diagnostics), → See `samber/cc-skills-golang@golang-gopls` skill (`gopls`). Context7 remains a fallback for docs not indexed on pkg.go.dev.

## Core pattern: Error builder chain

All `oops` errors use a fluent builder pattern:

```go
err := oops.
    In("user-service").           // domain/feature
    Tags("database", "postgres").  // categorization
    Code("network_failure").       // machine-readable identifier
    User("user-123", "email", "foo@bar.com").  // user context
    With("query", query).          // custom attributes
    Errorf("failed to fetch user: %s", "timeout")
```

Terminal methods:

- `.Errorf(format, args...)` — create a new error
- `.Wrap(err)` — wrap an existing error
- `.Wrapf(err, format, args...)` — wrap with a message
- `.Join(err1, err2, ...)` — combine multiple errors
- `.Recover(fn)` / `.Recoverf(fn, format, args...)` — convert panic to error

### Error builder methods

| Methods | Use case |
| --- | --- |
| `.With("key", value)` | Add custom key-value attribute (lazy `func() any` values supported) |
| `.WithContext(ctx, "key1", "key2")` | Extract values from Go context into attributes (lazy values supported) |
| `.In("domain")` | Set the feature/service/domain |
| `.Tags("auth", "sql")` | Add categorization tags (query with `err.HasTag("tag")`) |
| `.Code("iam_authz_missing_permission")` | Set machine-readable error identifier/slug |
| `.Public("Could not fetch user.")` | Set user-safe message (separate from technical details) |
| `.Hint("Runbook: https://doc.acme.org/doc/abcd.md")` | Add debugging hint for developers |
| `.Owner("team/slack")` | Identify responsible team/owner |
| `.User(id, "k", "v")` | Add user identifier and attributes |
| `.Tenant(id, "k", "v")` | Add tenant/organization context and attributes |
| `.Trace(id)` | Add trace / correlation ID (default: ULID) |
| `.Span(id)` | Add span ID representing a unit of work/operation (default: ULID) |
| `.Time(t)` | Override error timestamp (default: `time.Now()`) |
| `.Since(t)` | Set duration based on time since `t` (exposed via `err.Duration()`) |
| `.Duration(d)` | Set explicit error duration |
| `.Request(req, includeBody)` | Attach `*http.Request` (optionally including body) |
| `.Response(res, includeBody)` | Attach `*http.Response` (optionally including body) |
| `oops.FromContext(ctx)` | Start from an `OopsErrorBuilder` stored in a Go context |

## Common scenarios

### Database/repository layer

```go
func (r *UserRepository) FetchUser(id string) (*User, error) {
    query := "SELECT * FROM users WHERE id = $1"
    row, err := r.db.Query(query, id)
    if err != nil {
        return nil, oops.
            In("user-repository").
            Tags("database", "postgres").
            With("query", query).
            With("user_id", id).
            Wrapf(err, "failed to fetch user from database")
    }
    // ...
}
```

### HTTP handler layer

```go
func (h *Handler) CreateUser(w http.ResponseWriter, r *http.Request) {
    userID := getUserID(r)

    err := h.service.CreateUser(r.Context(), userID)
    if err != nil {
        err = oops.
            In("http-handler").
            Tags("endpoint", "/users").
            Request(r, false).
            User(userID).
            Wrapf(err, "create user failed")
        http.Error(w, oops.GetPublic(err, "Internal server error"), http.StatusInternalServerError)
        return
    }

    w.WriteHeader(http.StatusCreated)
}
```

### Service layer with reusable builder

```go
func (s *UserService) CreateOrder(ctx context.Context, req CreateOrderRequest) error {
    builder := oops.
        In("order-service").
        Tags("orders", "checkout").
        Tenant(req.TenantID, "plan", req.Plan).
        User(req.UserID, "email", req.UserEmail)

    product, err := s.catalog.GetProduct(ctx, req.ProductID)
    if err != nil {
        return builder.
            With("product_id", req.ProductID).
            Wrapf(err, "product lookup failed")
    }

    if product.Stock < req.Quantity {
        return builder.
            Code("insufficient_stock").
            Public("Not enough items in stock.").
            With("requested", req.Quantity).
            With("available", product.Stock).
            Errorf("insufficient stock for product %s", req.ProductID)
    }

    return nil
}
```

## Error wrapping best practices

### DO: Wrap directly, no nil check needed

```go
// ✓ Good — Wrap returns nil if err is nil
return oops.Wrapf(err, "operation failed")

// ✗ Bad — unnecessary nil check
if err != nil {
    return oops.Wrapf(err, "operation failed")
}
return nil
```

### DO: Add context at each layer

Each architectural layer SHOULD add context via Wrap/Wrapf — at least once per package boundary (not necessarily at every function call).

```go
// ✓ Good — each layer adds relevant context
func Controller() error {
    return oops.In("controller").Trace(traceID).Wrapf(Service(), "user request failed")
}

func Service() error {
    return oops.In("service").With("op", "create_user").Wrapf(Repository(), "db operation failed")
}

func Repository() error {
    return oops.In("repository").Tags("database", "postgres").Errorf("connection timeout")
}
```

### DO: Keep error messages low-cardinality

Error messages MUST be low-cardinality for APM aggregation. Interpolating variable data into the message breaks grouping in Datadog, Loki, Sentry.

```go
// ✗ Bad — high-cardinality, breaks APM grouping
oops.Errorf("failed to process user %s in tenant %s", userID, tenantID)

// ✓ Good — static message + structured attributes
oops.With("user_id", userID).With("tenant_id", tenantID).Errorf("failed to process user")
```

## Panic recovery

`oops.Recover()` MUST be used in goroutine boundaries. Convert panics to structured errors:

```go
func ProcessData(data string) (err error) {
    return oops.
        In("data-processor").
        Code("panic_recovered").
        Hint("Check input data format and dependencies").
        With("input_data", data).
        Recover(func() {
            riskyOperation(data)
        })
}
```

## Accessing error information

`samber/oops` errors implement the standard `error` interface. Access additional info:

```go
if oopsErr, ok := err.(oops.OopsError); ok {
    fmt.Println("Code:", oopsErr.Code())
    fmt.Println("Domain:", oopsErr.Domain())
    fmt.Println("Tags:", oopsErr.Tags())
    fmt.Println("Context:", oopsErr.Context())
    fmt.Println("Stacktrace:", oopsErr.Stacktrace())
}

// Get public-facing message with fallback
publicMsg := oops.GetPublic(err, "Something went wrong")
```

### Output formats

```go
fmt.Printf("%+v\n", err)       // verbose with stack trace
bytes, _ := json.Marshal(err)  // JSON for logging
slog.Error(err.Error(), slog.Any("error", err))  // slog integration
```

## Context propagation

Carry error context through Go contexts:

```go
func middleware(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        builder := oops.
            In("http").
            Request(r, false).
            Trace(r.Header.Get("X-Trace-ID"))

        ctx := oops.WithBuilder(r.Context(), builder)
        next.ServeHTTP(w, r.WithContext(ctx))
    })
}

func handler(ctx context.Context) error {
    return oops.FromContext(ctx).Tags("handler", "users").Errorf("something failed")
}
```

For assertions, configuration, and additional logger examples, see [Advanced patterns](./references/advanced.md).

## References

- [github.com/samber/oops](https://github.com/samber/oops)
- [pkg.go.dev/github.com/samber/oops](https://pkg.go.dev/github.com/samber/oops)

## Cross-References

- → See `samber/cc-skills-golang@golang-error-handling` skill for general error handling patterns
- → See `samber/cc-skills-golang@golang-observability` skill for logger integration and structured logging

## Dónde encaja

- Categoría: [Herramientas para desarrolladores](https://skillsagentes.com/categorias/herramientas-desarrollo.md) — Skills que cambian cómo tu agente escribe, revisa y despliega código.
- Creador: [samber](https://skillsagentes.com/creators/samber.md) — 0 skills en el directorio
- [Todas las skills](https://skillsagentes.com/skills.md)
- [Ranking de instalaciones](https://skillsagentes.com/ranking.md)

## Otras skills del mismo repositorio

- [Golang Lint](https://skillsagentes.com/skills/samber/cc-skills-golang/golang-lint.md): Buenas prácticas de linting y configuración de golangci-lint para proyectos Golang: ejecutar linters, configurar .golangci.yml, suprimir avisos con nolint, interpretar salidas y elegir linters.
- [Golang How To](https://skillsagentes.com/skills/samber/cc-skills-golang/golang-how-to.md): Orquestador de skills de Golang, siempre activo en cualquier tarea de código, revisión, debug o setup: carga las skills más relevantes de samber/cc-skills-golang, a menudo varias a la vez.
- [Golang Benchmark](https://skillsagentes.com/skills/samber/cc-skills-golang/golang-benchmark.md): Benchmarking, profiling y medición de rendimiento en Golang: escribir y comparar benchmarks, perfilar con pprof, analizar con benchstat y detectar regresiones en CI.
- [Golang Testing](https://skillsagentes.com/skills/samber/cc-skills-golang/golang-testing.md): Tests de Golang listos para producción: table-driven, suites y mocks con testify, tests paralelos, fuzzing, fixtures, detección de fugas de goroutines con goleak, snapshot testing, cobertura, tests de integración.
- [Golang Performance](https://skillsagentes.com/skills/samber/cc-skills-golang/golang-performance.md): Patrones y metodología de optimización de rendimiento en Golang: si hay cuello de botella X, aplica el patrón Y, una vez que profiling o benchmarks ya lo identificaron.

---

Skills Agentes · [Índice de páginas en markdown](https://skillsagentes.com/sitemap.md) · [Inicio](https://skillsagentes.com/index.md)