Options Reference
Options are configured via functional option constructors. Each function's API page documents which options it accepts. This page provides a consolidated overview.
Option Categories
| Category | Interface | Accepted by |
|---|---|---|
| Shared | GoOption + GroupOption | Do, Wait, WaitWithStop, WaitWithReady, Go, Start, StartWithReady, StartWithStop, GoWithCancel, NewGroup, Group.Add |
| Go-only | GoOption | Do, Wait, WaitWithStop, WaitWithReady, Go, Start, StartWithReady, StartWithStop, GoWithCancel, Group.Add |
| Group-only | GroupOption | NewGroup, All, Map |
The compiler enforces these constraints. You cannot pass a groupOnlyOpt to Go() or a goOnlyOpt to NewGroup().
Defaults
When no options are passed, the following defaults apply:
| Setting | Default |
|---|---|
| Name | Function-specific (e.g. "gofuncy.go", "gofuncy.group") |
| Tracing | Enabled |
| Started counter | Enabled |
| Error counter | Enabled |
| Active counter | Enabled |
| Duration histogram | Disabled |
Error handler (Go/Start/StartWithReady/StartWithStop/GoWithCancel only) | slog.ErrorContext |
| Limit | No limit |
| Fail-fast | Disabled |
| Retry | Disabled |
| Circuit breaker | Disabled |
| Fallback | Disabled |
Resilience Chain Order
The framework applies resilience options in a fixed order, regardless of the order they appear in your code:
| Position | Middleware | Behavior |
|---|---|---|
| Innermost | Timeout | Each invocation gets a fresh deadline |
| ↑ | Retry | Retries the timeout-wrapped function |
| ↑ | Circuit Breaker | Sees the final outcome after all retries |
| Outermost | Fallback | Last resort -- catches everything |
For custom ordering, use WithMiddleware with the middleware constructors (Retry(), Fallback(), etc.) directly.
Option Merging in Group.Add
When you pass options to Group.Add, they are merged on top of the group's options using these rules:
| Field type | Merge rule |
|---|---|
string (name) | Override if non-empty |
*slog.Logger | Override if non-nil |
[]Middleware | Append |
time.Duration | Override if > 0 |
bool (metrics/tracing) | OR (enable, never disable) |
MeterProvider / TracerProvider | Override if non-nil |
*semaphore.Weighted | Override if non-nil |
*CircuitBreaker | Override if non-nil |
| Retry / Fallback | Override if set |
limit, failFast | Not merged (group-only) |