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|
package scraper
import (
"context"
"errors"
"fmt"
"log/slog"
"time"
"github.com/ansg191/ibd-trader-backend/internal/database"
"github.com/ansg191/ibd-trader-backend/internal/ibd"
"github.com/ansg191/ibd-trader-backend/internal/leader/manager/ibd/scrape"
"github.com/ansg191/ibd-trader-backend/internal/redis/taskqueue"
"github.com/ansg191/ibd-trader-backend/internal/worker/analyzer"
"github.com/redis/go-redis/v9"
)
const (
lockTimeout = 1 * time.Minute
dequeueTimeout = 5 * time.Second
)
func RunScraper(
ctx context.Context,
redis *redis.Client,
client *ibd.Client,
db database.TransactionExecutor,
name string,
) error {
queue, err := taskqueue.New(
ctx,
redis,
scrape.Queue,
name,
taskqueue.WithEncoding[scrape.TaskInfo](scrape.QueueEncoding),
)
if err != nil {
return err
}
aQueue, err := taskqueue.New(
ctx,
redis,
analyzer.Queue,
name,
taskqueue.WithEncoding[analyzer.TaskInfo](analyzer.QueueEncoding),
)
if err != nil {
return err
}
for {
select {
case <-ctx.Done():
return ctx.Err()
default:
waitForTask(ctx, queue, aQueue, client, db)
}
}
}
func waitForTask(
ctx context.Context,
queue taskqueue.TaskQueue[scrape.TaskInfo],
aQueue taskqueue.TaskQueue[analyzer.TaskInfo],
client *ibd.Client,
db database.TransactionExecutor,
) {
task, err := queue.Dequeue(ctx, lockTimeout, dequeueTimeout)
if err != nil {
slog.ErrorContext(ctx, "Failed to dequeue task", "error", err)
return
}
if task == nil {
// No task available.
return
}
errCh := make(chan error)
resCh := make(chan string)
defer close(errCh)
defer close(resCh)
go func() {
res, err := scrapeUrl(ctx, client, db, aQueue, task.Data.Symbol)
if err != nil {
errCh <- err
return
}
resCh <- res
}()
ticker := time.NewTicker(lockTimeout / 5)
defer ticker.Stop()
for {
select {
case <-ctx.Done():
// Context was canceled. Return early.
return
case <-ticker.C:
// Extend the lock periodically.
func() {
ctx, cancel := context.WithTimeout(ctx, lockTimeout/5)
defer cancel()
err := queue.Extend(ctx, task.ID)
if err != nil {
slog.ErrorContext(ctx, "Failed to extend lock", "error", err)
}
}()
case err = <-errCh:
// scrapeUrl has errored.
slog.ErrorContext(ctx, "Failed to scrape URL", "error", err)
_, err = queue.Return(ctx, task.ID, err)
if err != nil {
slog.ErrorContext(ctx, "Failed to return task", "error", err)
return
}
return
case res := <-resCh:
// scrapeUrl has completed successfully.
slog.DebugContext(ctx, "Scraped URL", "symbol", task.Data.Symbol)
err = queue.Complete(ctx, task.ID, res)
if err != nil {
slog.ErrorContext(ctx, "Failed to complete task", "error", err)
return
}
return
}
}
}
func scrapeUrl(
ctx context.Context,
client *ibd.Client,
db database.TransactionExecutor,
aQueue taskqueue.TaskQueue[analyzer.TaskInfo],
symbol string,
) (string, error) {
ctx, cancel := context.WithTimeout(ctx, lockTimeout)
defer cancel()
stockUrl, err := getStockUrl(ctx, db, client, symbol)
if err != nil {
return "", fmt.Errorf("failed to get stock url: %w", err)
}
// Scrape the stock info.
info, err := client.StockInfo(ctx, stockUrl)
if err != nil {
return "", fmt.Errorf("failed to get stock info: %w", err)
}
// Add stock info to the database.
id, err := database.AddStockInfo(ctx, db, info)
if err != nil {
return "", fmt.Errorf("failed to add stock info: %w", err)
}
// Add the stock to the analyzer queue.
_, err = aQueue.Enqueue(ctx, analyzer.TaskInfo{ID: id})
if err != nil {
return "", fmt.Errorf("failed to enqueue analysis task: %w", err)
}
slog.DebugContext(ctx, "Added stock info", "id", id)
return id, nil
}
func getStockUrl(ctx context.Context, db database.TransactionExecutor, client *ibd.Client, symbol string) (string, error) {
// Get the stock from the database.
stock, err := database.GetStock(ctx, db, symbol)
if err == nil {
return stock.IBDUrl, nil
}
if !errors.Is(err, database.ErrStockNotFound) {
return "", fmt.Errorf("failed to get stock: %w", err)
}
// If stock isn't found in the database, get the stock from IBD.
stock, err = client.Search(ctx, symbol)
if errors.Is(err, ibd.ErrSymbolNotFound) {
return "", fmt.Errorf("symbol not found: %w", err)
}
if err != nil {
return "", fmt.Errorf("failed to search for symbol: %w", err)
}
// Add the stock to the database.
err = database.AddStock(ctx, db, stock)
if err != nil {
return "", fmt.Errorf("failed to add stock: %w", err)
}
return stock.IBDUrl, nil
}
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