97 lines
2.0 KiB
Go
97 lines
2.0 KiB
Go
package wallet
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import (
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"context"
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"database/sql"
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"fmt"
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)
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type PricesPerTokenAndCurrency = map[string]map[string]float64
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type PriceManager struct {
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db *sql.DB
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cryptoCompare *CryptoCompare
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}
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func NewPriceManager(db *sql.DB, cryptoCompare *CryptoCompare) *PriceManager {
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return &PriceManager{db: db, cryptoCompare: cryptoCompare}
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}
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func (pm *PriceManager) FetchPrices(symbols []string, currencies []string) (PricesPerTokenAndCurrency, error) {
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result, err := pm.cryptoCompare.fetchPrices(symbols, currencies)
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if err != nil {
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return nil, err
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}
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if err = pm.updatePriceCache(result); err != nil {
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return nil, err
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}
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return result, nil
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}
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func (pm *PriceManager) updatePriceCache(prices PricesPerTokenAndCurrency) error {
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tx, err := pm.db.BeginTx(context.Background(), &sql.TxOptions{})
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if err != nil {
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return err
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}
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defer func() {
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if err == nil {
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err = tx.Commit()
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return
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}
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// don't shadow original error
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_ = tx.Rollback()
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}()
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insert, err := tx.Prepare(`INSERT OR REPLACE INTO price_cache
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(token, currency, price)
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VALUES
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(?, ?, ?)`)
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if err != nil {
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return err
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}
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for token, pricesPerCurrency := range prices {
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for currency, price := range pricesPerCurrency {
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_, err = insert.Exec(token, currency, fmt.Sprintf("%f", price))
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if err != nil {
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return err
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}
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}
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}
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return nil
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}
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func getCachedPricesFromDBRows(rows *sql.Rows) (PricesPerTokenAndCurrency, error) {
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prices := make(PricesPerTokenAndCurrency)
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for rows.Next() {
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var token string
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var currency string
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var price float64
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if err := rows.Scan(&token, ¤cy, &price); err != nil {
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return nil, err
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}
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_, present := prices[token]
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if !present {
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prices[token] = map[string]float64{}
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}
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prices[token][currency] = price
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}
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return prices, nil
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}
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func (pm *PriceManager) GetCachedPrices() (PricesPerTokenAndCurrency, error) {
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rows, err := pm.db.Query("SELECT token, currency, price FROM price_cache")
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if err != nil {
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return nil, err
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}
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defer rows.Close()
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return getCachedPricesFromDBRows(rows)
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}
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