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https://github.com/qor/transition
Transition is a Golang state machine implementation
https://github.com/qor/transition
Last synced: 20 days ago
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Transition is a Golang state machine implementation
- Host: GitHub
- URL: https://github.com/qor/transition
- Owner: qor
- License: mit
- Created: 2016-01-08T04:32:52.000Z (almost 9 years ago)
- Default Branch: master
- Last Pushed: 2023-05-05T08:31:58.000Z (over 1 year ago)
- Last Synced: 2024-11-15T01:04:27.113Z (28 days ago)
- Language: Go
- Size: 25.4 KB
- Stars: 433
- Watchers: 24
- Forks: 72
- Open Issues: 7
-
Metadata Files:
- Readme: README.md
- License: LICENSE.txt
Awesome Lists containing this project
- awesome-go - Transition - state machine implementation. (State Machines)
README
# Transition
Transition is a [Golang](http://golang.org/) [*state machine*](https://en.wikipedia.org/wiki/Finite-state_machine) implementation.
it can be used standalone, but it integrates nicely with [GORM](https://github.com/jinzhu/gorm) models. When integrated with [GORM](https://github.com/jinzhu/gorm), it will also store state change logs in the database automatically.
[](https://godoc.org/github.com/qor/transition)
[](https://travis-ci.com/qor/transition)
# Usage
### Enable Transition for your struct
Embed `transition.Transition` into your struct, it will enable the state machine feature for the struct:
```go
import "github.com/qor/transition"
type Order struct {
ID uint
transition.Transition
}
```
### Define States and Events
```go
var OrderStateMachine = transition.New(&Order{})
// Define initial state
OrderStateMachine.Initial("draft")
// Define a State
OrderStateMachine.State("checkout")
// Define another State and what to do when entering and exiting that state.
OrderStateMachine.State("paid").Enter(func(order interface{}, tx *gorm.DB) error {
// To get order object use 'order.(*Order)'
// business logic here
return
}).Exit(func(order interface{}, tx *gorm.DB) error {
// business logic here
return
})
// Define more States
OrderStateMachine.State("cancelled")
OrderStateMachine.State("paid_cancelled")
// Define an Event
OrderStateMachine.Event("checkout").To("checkout").From("draft")
// Define another event and what to do before and after performing the transition.
OrderStateMachine.Event("paid").To("paid").From("checkout").Before(func(order interface{}, tx *gorm.DB) error {
// business logic here
return nil
}).After(func(order interface{}, tx *gorm.DB) error {
// business logic here
return nil
})
// Different state transitions for one event
cancellEvent := OrderStateMachine.Event("cancel")
cancellEvent.To("cancelled").From("draft", "checkout")
cancellEvent.To("paid_cancelled").From("paid").After(func(order interface{}, tx *gorm.DB) error {
// Refund
}})
```
### Trigger an Event
```go
// func (*StateMachine) Trigger(name string, value Stater, tx *gorm.DB, notes ...string) error
OrderStatemachine.Trigger("paid", &order, db, "charged offline by jinzhu")
// notes will be used to generate state change logs when works with GORM
// When using without GORM, just pass nil to the db, like
OrderStatemachine.Trigger("cancel", &order, nil)
OrderStatemachine.Trigger("cancel", &order, db)
// order's state will be changed to cancelled if current state is "draft"
// order's state will be changed to paid_cancelled if current state is "paid"
```
### Get/Set State
```go
var order Order
// Get Current State
order.GetState()
// Set State
order.SetState("finished") // this will only update order's state, won't save it into database
```
## State change logs
When working with [GORM](https://github.com/jinzhu/gorm), `Transition` will store all state change logs in the database. Use `GetStateChangeLogs` to get those logs.
```go
// create the table used to store logs first
db.AutoMigrate(&transition.StateChangeLog{})
// get order's state change logs
var stateChangeLogs = transition.GetStateChangeLogs(&order, db)
// type StateChangeLog struct {
// From string // from state
// To string // to state
// Note string // notes
// }
```
## License
Released under the [MIT License](http://opensource.org/licenses/MIT).