Implement concurrent CUR processing with goroutines

cur/gwenn/main.go

@@ -0,0 +1,83 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+)
+
+// Result holds parsed cost info
+type Result struct {
+	cost float64
+}
+
+// Worker function (Requirement #1)
+func parseRow(row string, results chan<- Result, wg *sync.WaitGroup) {
+	defer wg.Done()
+
+	// Simulate slow database
+	time.Sleep(100 * time.Millisecond)
+
+	fields := strings.Split(row, ",")
+	if len(fields) < 3 {
+		return
+	}
+
+	cost, err := strconv.ParseFloat(fields[2], 64)
+	if err != nil {
+		return
+	}
+
+	results <- Result{cost: cost}
+}
+
+func main() {
+	start := time.Now()
+
+	file, err := os.Open("/home/gwenn/internship-samplecodes/cur/testcur.csv")
+	if err != nil {
+		panic(err)
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+
+	// Skip header
+	scanner.Scan()
+
+	results := make(chan Result)
+	var wg sync.WaitGroup
+
+	rowsProcessed := 0
+	totalCost := 0.0
+
+	// Collector goroutine
+	go func() {
+		for res := range results {
+			totalCost += res.cost
+			rowsProcessed++
+		}
+	}()
+
+	// Read file line by line
+	for scanner.Scan() {
+		line := scanner.Text()
+
+		wg.Add(1)
+		go parseRow(line, results, &wg)
+	}
+
+	// Wait for workers
+	wg.Wait()
+	close(results)
+
+	elapsed := time.Since(start)
+
+	fmt.Println("Rows processed:", rowsProcessed)
+	fmt.Printf("Total cost: %.2f\n", totalCost)
+	fmt.Println("Time taken:", elapsed)
+}

go.mod

@@ -1,6 +1,6 @@
 module github.com/alphauslabs/internship-samplecodes
 
-go 1.25
+go 1.22
 
 require (
 	cloud.google.com/go/spanner v1.87.0