cmd/geth, metrics: separate process metric collection, add disk

metrics/disk_linux.go

@@ -0,0 +1,55 @@
+// Contains the Linux implementation of process disk IO counter retrieval.
+
+package metrics
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// ReadDiskStats retrieves the disk IO stats belonging to the current process.
+func ReadDiskStats(stats *DiskStats) error {
+	// Open the process disk IO counter file
+	inf, err := os.Open(fmt.Sprintf("/proc/%d/io", os.Getpid()))
+	if err != nil {
+		return err
+	}
+	in := bufio.NewReader(inf)
+
+	// Iterate over the IO counter, and extract what we need
+	for {
+		// Read the next line and split to key and value
+		line, err := in.ReadString('\n')
+		if err != nil {
+			if err == io.EOF {
+				return nil
+			}
+			return err
+		}
+		key, value := "", int64(0)
+		if parts := strings.Split(line, ":"); len(parts) != 2 {
+			continue
+		} else {
+			key = strings.TrimSpace(parts[0])
+			if value, err = strconv.ParseInt(strings.TrimSpace(parts[1]), 10, 64); err != nil {
+				return err
+			}
+		}
+		// Update the counter based on the key
+		switch key {
+		case "syscr":
+			stats.ReadCount = value
+		case "syscw":
+			stats.WriteCount = value
+		case "rchar":
+			stats.ReadBytes = value
+		case "wchar":
+			stats.WriteBytes = value
+		}
+	}
+	return nil
+}