Documentation
¶
Overview ¶
Package workflow provides a Validate-step middleware that enforces permitted state transitions on a model. Use it for status-driven workflows where only certain transitions are legal — e.g. invoices that flow draft → submitted → approved → paid.
Rules are checked against the *current* stored value of the chosen status field on update, so every PATCH that touches the field issues one extra `ctx.GetModel(...).Read(id)`. Reads are routed through `ctx.Tx` when one is active, so the cost is bounded by the request's existing transaction.
On rejection the middleware aborts with `422 INVALID_TRANSITION`. Guard errors (e.g. role checks) use the same code; the guard's error string becomes the response message.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Guard ¶
type Guard interface {
Check(ctx *maniflex.ServerContext, from, to string) error
}
Guard gates a state transition on something beyond the from/to pair — typically the caller's roles, but it may inspect any aspect of the request. Returning a non-nil error rejects the transition with the error's message as the 422 detail.
func RequireRole ¶
RequireRole accepts the transition only if the caller holds any one of the listed roles (OR-semantics, matching maniflex.HasRole). With no roles passed, the guard always rejects — that protects against accidentally declaring an unguarded "require" rule.
type GuardFunc ¶
type GuardFunc func(ctx *maniflex.ServerContext, from, to string) error
GuardFunc adapts a plain function to the Guard interface.
type Machine ¶
type Machine struct {
// contains filtered or unexported fields
}
Machine is a compiled set of allowed transitions on a single status field. Build one with New and pass Middleware() to the Validate step.
func New ¶
New compiles a state-machine for the named status field.
sm := workflow.New("status",
workflow.Allow("draft", "submitted"),
workflow.Allow("submitted", "approved", workflow.RequireRole("manager")),
workflow.AllowAny(workflow.RequireRole("admin")),
)
`field` is the JSON field name as it appears in `ctx.ParsedBody`.
func (*Machine) Middleware ¶
func (m *Machine) Middleware() maniflex.MiddlewareFunc
Middleware returns the Validate-step MiddlewareFunc for this Machine.
type Option ¶
type Option func(*Machine)
Option mutates a Machine during construction. Returned by Allow, AllowAny, and AllowInitial.
func Allow ¶
Allow permits the transition from -> to. `from` may be "*" to match any prior state; `to` may be "*" to match any new state. Guards run in order after a rule matches; the first guard error rejects the transition.
func AllowAny ¶
AllowAny is shorthand for Allow("*", "*", guards...). Typical use is an admin escape hatch: AllowAny(RequireRole("admin")).
func AllowInitial ¶
AllowInitial declares the set of states a Create may seed the record with. When set, OpCreate is allowed only if the body's field value is in the set. When not set, any initial state passes.
Source Files