91 lines
2.2 KiB
Go
91 lines
2.2 KiB
Go
package terra
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import (
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"context"
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"sync"
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"time"
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"github.com/pkg/errors"
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"github.com/shopspring/decimal"
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)
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type PriceService struct {
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routers []Router
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cache map[string]cachedPrice
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cacheMutex *sync.Mutex
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cacheTimeout time.Duration
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maxRouteLength int
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}
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type cachedPrice struct {
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price decimal.Decimal
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updatedTime time.Time
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}
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type PriceServiceOption func(s *PriceService) *PriceService
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func WithCacheTimeout(timeout time.Duration) PriceServiceOption {
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return func(s *PriceService) *PriceService {
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s.cacheTimeout = timeout
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return s
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}
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}
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func WithMaxRouteLength(maxRouteLenght int) PriceServiceOption {
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return func(s *PriceService) *PriceService {
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s.maxRouteLength = maxRouteLenght
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return s
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}
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}
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func NewPriceService(options ...PriceServiceOption) *PriceService {
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p := &PriceService{
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routers: nil,
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cache: make(map[string]cachedPrice),
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cacheMutex: &sync.Mutex{},
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cacheTimeout: 30 * time.Second,
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maxRouteLength: 2,
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}
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for _, option := range options {
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p = option(p)
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}
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return p
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}
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func (s *PriceService) AddRouter(router Router) {
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s.routers = append(s.routers, router)
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}
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func (s *PriceService) GetPriceCached(ctx context.Context, token Token) (decimal.Decimal, error) {
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s.cacheMutex.Lock()
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defer s.cacheMutex.Unlock()
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if p, ok := s.cache[token.Id()]; ok && p.updatedTime.Add(s.cacheTimeout).After(time.Now()) {
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return p.price, nil
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}
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p, err := s.getCurrentPrice(ctx, token)
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if err != nil {
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return decimal.Zero, errors.Wrap(err, "getting current price")
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}
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s.cache[token.Id()] = cachedPrice{
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price: p,
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updatedTime: time.Now(),
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}
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return p, nil
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}
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func (s *PriceService) getCurrentPrice(ctx context.Context, token Token) (decimal.Decimal, error) {
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var bestprice decimal.Decimal
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var bestroute Route
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for _, router := range s.routers {
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newprice, newroute, err := router.SimulateSwap(ctx, token, UST, decimal.NewFromInt(1), s.maxRouteLength)
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if err != nil && err != ErrNoRouteFund {
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return decimal.Zero, errors.Wrapf(err, "simulating swap with router %s", router)
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}
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if newprice.GreaterThan(bestprice) || (newprice.Equals(bestprice) && len(newroute) < len(bestroute)) {
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bestprice = newprice
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bestroute = newroute
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}
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}
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return bestprice, nil
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}
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