fsm: improve and convert to interface
Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>
This commit is contained in:
126
fsm/default.go
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126
fsm/default.go
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@@ -0,0 +1,126 @@
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package fsm
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import (
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"context"
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"fmt"
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"sync"
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)
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type state struct {
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body interface{}
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name string
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}
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var _ State = &state{}
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func (s *state) Name() string {
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return s.name
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}
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func (s *state) Body() interface{} {
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return s.body
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}
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// fsm is a finite state machine
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type fsm struct {
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statesMap map[string]StateFunc
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current string
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statesOrder []string
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opts Options
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mu sync.Mutex
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}
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// NewFSM creates a new finite state machine having the specified initial state
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// with specified options
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func NewFSM(opts ...Option) *fsm {
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return &fsm{
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statesMap: map[string]StateFunc{},
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opts: NewOptions(opts...),
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}
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}
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// Current returns the current state
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func (f *fsm) Current() string {
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f.mu.Lock()
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s := f.current
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f.mu.Unlock()
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return s
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}
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// Current returns the current state
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func (f *fsm) Reset() {
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f.mu.Lock()
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f.current = f.opts.Initial
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f.mu.Unlock()
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}
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// State adds state to fsm
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func (f *fsm) State(state string, fn StateFunc) {
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f.mu.Lock()
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f.statesMap[state] = fn
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f.statesOrder = append(f.statesOrder, state)
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f.mu.Unlock()
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}
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// Start runs state machine with provided data
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func (f *fsm) Start(ctx context.Context, args interface{}, opts ...Option) (interface{}, error) {
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var err error
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f.mu.Lock()
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options := f.opts
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for _, opt := range opts {
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opt(&options)
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}
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sopts := []StateOption{StateDryRun(options.DryRun)}
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cstate := options.Initial
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states := make(map[string]StateFunc, len(f.statesMap))
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for k, v := range f.statesMap {
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states[k] = v
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}
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f.current = cstate
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f.mu.Unlock()
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var s State
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s = &state{name: cstate, body: args}
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nstate := s.Name()
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for {
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select {
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case <-ctx.Done():
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return nil, ctx.Err()
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default:
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fn, ok := states[nstate]
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if !ok {
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return nil, fmt.Errorf(`state "%s" %w`, nstate, ErrInvalidState)
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}
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f.mu.Lock()
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f.current = nstate
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f.mu.Unlock()
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// wrap the handler func
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for i := len(options.Wrappers); i > 0; i-- {
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fn = options.Wrappers[i-1](fn)
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}
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s, err = fn(ctx, s, sopts...)
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switch {
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case err != nil:
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return s.Body(), err
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case s.Name() == StateEnd:
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return s.Body(), nil
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case s.Name() == "":
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for idx := range f.statesOrder {
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if f.statesOrder[idx] == nstate && len(f.statesOrder) > idx+1 {
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nstate = f.statesOrder[idx+1]
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}
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}
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default:
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nstate = s.Name()
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}
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}
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}
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}
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174
fsm/fsm.go
174
fsm/fsm.go
@@ -3,8 +3,6 @@ package fsm // import "go.unistack.org/micro/v3/fsm"
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import (
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"context"
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"errors"
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"fmt"
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"sync"
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)
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var (
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@@ -12,170 +10,20 @@ var (
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StateEnd = "end"
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)
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// Options struct holding fsm options
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type Options struct {
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// DryRun mode
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DryRun bool
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// Initial state
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Initial string
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// HooksBefore func slice runs in order before state
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HooksBefore []HookBeforeFunc
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// HooksAfter func slice runs in order after state
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HooksAfter []HookAfterFunc
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type State interface {
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Name() string
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Body() interface{}
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}
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// HookBeforeFunc func signature
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type HookBeforeFunc func(ctx context.Context, state string, args interface{})
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// HookAfterFunc func signature
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type HookAfterFunc func(ctx context.Context, state string, args interface{})
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// Option func signature
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type Option func(*Options)
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// StateOptions holds state options
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type StateOptions struct {
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DryRun bool
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}
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// StateDryRun says that state executes in dry run mode
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func StateDryRun(b bool) StateOption {
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return func(o *StateOptions) {
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o.DryRun = b
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}
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}
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// StateOption func signature
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type StateOption func(*StateOptions)
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// InitialState sets init state for state machine
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func InitialState(initial string) Option {
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return func(o *Options) {
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o.Initial = initial
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}
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}
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// HookBefore provides hook func slice
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func HookBefore(fns ...HookBeforeFunc) Option {
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return func(o *Options) {
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o.HooksBefore = fns
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}
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}
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// HookAfter provides hook func slice
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func HookAfter(fns ...HookAfterFunc) Option {
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return func(o *Options) {
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o.HooksAfter = fns
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}
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}
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// StateWrapper wraps the StateFunc and returns the equivalent
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type StateWrapper func(StateFunc) StateFunc
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// StateFunc called on state transition and return next step and error
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type StateFunc func(ctx context.Context, args interface{}, opts ...StateOption) (string, interface{}, error)
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type StateFunc func(ctx context.Context, state State, opts ...StateOption) (State, error)
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// FSM is a finite state machine
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type FSM struct {
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mu sync.Mutex
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statesMap map[string]StateFunc
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statesOrder []string
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opts *Options
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current string
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}
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// New creates a new finite state machine having the specified initial state
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// with specified options
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func New(opts ...Option) *FSM {
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options := &Options{}
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for _, opt := range opts {
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opt(options)
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}
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return &FSM{
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statesMap: map[string]StateFunc{},
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opts: options,
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}
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}
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// Current returns the current state
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func (f *FSM) Current() string {
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f.mu.Lock()
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defer f.mu.Unlock()
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return f.current
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}
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// Current returns the current state
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func (f *FSM) Reset() {
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f.mu.Lock()
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f.current = f.opts.Initial
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f.mu.Unlock()
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}
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// State adds state to fsm
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func (f *FSM) State(state string, fn StateFunc) {
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f.mu.Lock()
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f.statesMap[state] = fn
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f.statesOrder = append(f.statesOrder, state)
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f.mu.Unlock()
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}
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// Init initialize fsm and check states
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// Start runs state machine with provided data
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func (f *FSM) Start(ctx context.Context, args interface{}, opts ...Option) (interface{}, error) {
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var err error
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var ok bool
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var fn StateFunc
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var nstate string
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f.mu.Lock()
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options := f.opts
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for _, opt := range opts {
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opt(options)
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}
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sopts := []StateOption{StateDryRun(options.DryRun)}
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cstate := options.Initial
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states := make(map[string]StateFunc, len(f.statesMap))
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for k, v := range f.statesMap {
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states[k] = v
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}
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f.current = cstate
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f.mu.Unlock()
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for {
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select {
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case <-ctx.Done():
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return nil, ctx.Err()
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default:
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fn, ok = states[cstate]
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if !ok {
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return nil, fmt.Errorf(`state "%s" %w`, cstate, ErrInvalidState)
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}
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f.mu.Lock()
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f.current = cstate
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f.mu.Unlock()
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for _, fn := range options.HooksBefore {
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fn(ctx, cstate, args)
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}
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nstate, args, err = fn(ctx, args, sopts...)
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for _, fn := range options.HooksAfter {
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fn(ctx, cstate, args)
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}
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switch {
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case err != nil:
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return args, err
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case nstate == StateEnd:
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return args, nil
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case nstate == "":
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for idx := range f.statesOrder {
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if f.statesOrder[idx] == cstate && len(f.statesOrder) > idx+1 {
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nstate = f.statesOrder[idx+1]
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}
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}
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}
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cstate = nstate
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}
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}
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type FSM interface {
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Start(context.Context, interface{}, ...Option) (interface{}, error)
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Current() string
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Reset()
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State(string, StateFunc)
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}
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@@ -1,63 +1,72 @@
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package fsm
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import (
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"bytes"
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"context"
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"fmt"
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"testing"
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"go.unistack.org/micro/v3/logger"
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)
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func TestFSMStart(t *testing.T) {
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ctx := context.TODO()
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buf := bytes.NewBuffer(nil)
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pfb := func(_ context.Context, state string, _ interface{}) {
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fmt.Fprintf(buf, "before state %s\n", state)
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if err := logger.DefaultLogger.Init(); err != nil {
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t.Fatal(err)
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}
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pfa := func(_ context.Context, state string, _ interface{}) {
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fmt.Fprintf(buf, "after state %s\n", state)
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wrapper := func(next StateFunc) StateFunc {
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return func(sctx context.Context, s State, opts ...StateOption) (State, error) {
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sctx = logger.NewContext(sctx, logger.Fields("state", s.Name()))
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return next(sctx, s, opts...)
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}
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}
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f := New(InitialState("1"), HookBefore(pfb), HookAfter(pfa))
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f1 := func(_ context.Context, req interface{}, _ ...StateOption) (string, interface{}, error) {
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args := req.(map[string]interface{})
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f := NewFSM(InitialState("1"), WrapState(wrapper))
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f1 := func(sctx context.Context, s State, opts ...StateOption) (State, error) {
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_, ok := logger.FromContext(sctx)
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if !ok {
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t.Fatal("f1 context does not have logger")
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}
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args := s.Body().(map[string]interface{})
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if v, ok := args["request"].(string); !ok || v == "" {
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return "", nil, fmt.Errorf("empty request")
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return nil, fmt.Errorf("empty request")
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}
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return "2", map[string]interface{}{"response": "test2"}, nil
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return &state{name: "", body: map[string]interface{}{"response": "state1"}}, nil
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}
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f2 := func(_ context.Context, req interface{}, _ ...StateOption) (string, interface{}, error) {
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args := req.(map[string]interface{})
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if v, ok := args["response"].(string); !ok || v == "" {
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return "", nil, fmt.Errorf("empty response")
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f2 := func(sctx context.Context, s State, opts ...StateOption) (State, error) {
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_, ok := logger.FromContext(sctx)
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if !ok {
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t.Fatal("f2 context does not have logger")
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}
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return "", map[string]interface{}{"response": "test"}, nil
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args := s.Body().(map[string]interface{})
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if v, ok := args["response"].(string); !ok || v == "" {
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return nil, fmt.Errorf("empty response")
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}
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return &state{name: "", body: map[string]interface{}{"response": "state2"}}, nil
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}
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f3 := func(_ context.Context, req interface{}, _ ...StateOption) (string, interface{}, error) {
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args := req.(map[string]interface{})
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if v, ok := args["response"].(string); !ok || v == "" {
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return "", nil, fmt.Errorf("empty response")
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f3 := func(sctx context.Context, s State, opts ...StateOption) (State, error) {
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_, ok := logger.FromContext(sctx)
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if !ok {
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t.Fatal("f3 context does not have logger")
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}
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return StateEnd, map[string]interface{}{"response": "test_last"}, nil
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args := s.Body().(map[string]interface{})
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if v, ok := args["response"].(string); !ok || v == "" {
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return nil, fmt.Errorf("empty response")
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}
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return &state{name: StateEnd, body: map[string]interface{}{"response": "state3"}}, nil
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}
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f.State("1", f1)
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f.State("2", f2)
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f.State("3", f3)
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rsp, err := f.Start(ctx, map[string]interface{}{"request": "test1"})
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rsp, err := f.Start(ctx, map[string]interface{}{"request": "state"})
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if err != nil {
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t.Fatal(err)
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}
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args := rsp.(map[string]interface{})
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if v, ok := args["response"].(string); !ok || v == "" {
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t.Fatalf("nil rsp: %#+v", args)
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} else if v != "test_last" {
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} else if v != "state3" {
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t.Fatalf("invalid rsp %#+v", args)
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}
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if !bytes.Contains(buf.Bytes(), []byte(`before state 1`)) ||
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!bytes.Contains(buf.Bytes(), []byte(`before state 2`)) ||
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!bytes.Contains(buf.Bytes(), []byte(`after state 1`)) ||
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!bytes.Contains(buf.Bytes(), []byte(`after state 2`)) ||
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!bytes.Contains(buf.Bytes(), []byte(`after state 3`)) ||
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!bytes.Contains(buf.Bytes(), []byte(`after state 3`)) {
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t.Fatalf("fsm not works properly or hooks error, buf: %s", buf.Bytes())
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}
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}
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52
fsm/options.go
Normal file
52
fsm/options.go
Normal file
@@ -0,0 +1,52 @@
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package fsm
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// Options struct holding fsm options
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type Options struct {
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// Initial state
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Initial string
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// Wrappers runs before state
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Wrappers []StateWrapper
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// DryRun mode
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DryRun bool
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}
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// Option func signature
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type Option func(*Options)
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// StateOptions holds state options
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type StateOptions struct {
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DryRun bool
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}
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// StateDryRun says that state executes in dry run mode
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func StateDryRun(b bool) StateOption {
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return func(o *StateOptions) {
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o.DryRun = b
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}
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}
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// StateOption func signature
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type StateOption func(*StateOptions)
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// InitialState sets init state for state machine
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func InitialState(initial string) Option {
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return func(o *Options) {
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o.Initial = initial
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}
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}
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// WrapState adds a state Wrapper to a list of options passed into the fsm
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func WrapState(w StateWrapper) Option {
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return func(o *Options) {
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o.Wrappers = append(o.Wrappers, w)
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}
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}
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// NewOptions returns new Options struct filled by passed Option
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func NewOptions(opts ...Option) Options {
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options := Options{}
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for _, o := range opts {
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o(&options)
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}
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return options
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}
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