convert sample to go

.gitignore

@@ -1 +1,2 @@
-build
+build
+sample/sample

sample/main.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"math/rand"
+	"os"
+	"strconv"
+	"time"
+)
+
+func main() {
+
+	if len(os.Args) != 2 {
+		fmt.Fprintf(os.Stderr, "invalid argument. use a fraction to sample between 0.0 (no sampling) and 1.0 (100% sampling)")
+		os.Exit(1)
+	}
+
+	target, err := strconv.ParseFloat(os.Args[1], 64)
+	if err != nil || target < 0.0 || target > 1.0 {
+		fmt.Fprintf(os.Stderr, "Unable to convert %q to a float between 0.0 and 1.0", os.Args[1])
+		os.Exit(1)
+	}
+
+	rand.Seed(time.Now().UnixNano())
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		if target < rand.Float64() {
+			continue
+		}
+		fmt.Printf("%q", scanner.Text()) // Println will add back the final '\n'
+	}
+	if err := scanner.Err(); err != nil {
+		fmt.Fprintln(os.Stderr, "reading standard input:", err)
+		os.Exit(2)
+	}
+}