stability and ux improvements (#3)

- ensure that input paths are always directories
- ensure that tests can be cancelled if ctrl+c is pressed
- print a error message if tests are cancelled in-flight

cmd/cmd.go

@@ -21,6 +21,7 @@ import (
 	"errors"
 	"flag"
 	"fmt"
+	"os"
 	"path/filepath"
 
 	"github.com/dustin/go-humanize"
@@ -107,6 +108,19 @@ $ dperf --serial /mnt/drive{1..6}
 			if filepath.Clean(arg) == "/" {
 				return errors.New("not allowed to write at the root of the system, please choose a valid path")
 			}
+			path := filepath.Clean(arg)
+
+			stat, err := os.Stat(path)
+			if err != nil {
+				if os.IsNotExist(err) {
+					return errors.New("directory at path '" + path + "' does not exist")
+				}
+				return err
+			}
+
+			if !stat.Mode().IsDir() {
+				return errors.New("path '" + path + "' is not a directory ")
+			}
 			paths = append(paths, filepath.Clean(arg))
 		}
 		return perf.RunAndRender(c.Context(), paths...)

pkg/dperf/perf.go

@@ -44,17 +44,19 @@ func mustGetUUID() string {
 	return u.String()
 }
 
-func (d *DrivePerf) runTests(ctx context.Context, path string) (dr *DrivePerfResult) {
-	tmpPath := filepath.Join(path, ".writable-check.tmp")
-
-	writeThroughput, err := d.runWriteTest(ctx, tmpPath)
+func (d *DrivePerf) runTests(ctx context.Context, path string, testUUID string) (dr *DrivePerfResult) {
+	testUUIDPath := filepath.Join(path, testUUID)
+	testPath := filepath.Join(testUUIDPath, ".writable-check.tmp")
+	defer os.RemoveAll(testUUIDPath)
+
+	writeThroughput, err := d.runWriteTest(ctx, testPath)
 	if err != nil {
 		return &DrivePerfResult{
 			Path:  path,
 			Error: err,
 		}
 	}
-	readThroughput, err := d.runReadTest(ctx, tmpPath)
+	readThroughput, err := d.runReadTest(ctx, testPath)
 	if err != nil {
 		return &DrivePerfResult{
 			Path:  path,
@@ -82,24 +84,24 @@ func (d *DrivePerf) Run(ctx context.Context, paths ...string) ([]*DrivePerfResul
 	results := make([]*DrivePerfResult, len(paths))
 	if d.Serial {
 		for i, path := range paths {
-			results[i] = d.runTests(childCtx, filepath.Join(path, uuidStr))
+			results[i] = d.runTests(childCtx, path, uuidStr)
 		}
 	} else {
 		var wg sync.WaitGroup
 		wg.Add(parallelism)
 		for i, path := range paths {
 			go func(idx int, path string) {
 				defer wg.Done()
-				results[idx] = d.runTests(childCtx, filepath.Join(path, uuidStr))
+				results[idx] = d.runTests(childCtx, path, uuidStr)
 			}(i, path)
 		}
 		wg.Wait()
 	}
 
-	for _, res := range results {
-		os.RemoveAll(res.Path)
+	if childCtx.Err() != nil {
+		return nil, childCtx.Err()
 	}
-
+	
 	return results, nil
 }
 

pkg/dperf/run_linux.go

@@ -38,10 +38,15 @@ type odirectReader struct {
 	buf      []byte
 	err      error
 	seenRead bool
+
+	ctx context.Context
 }
 
 // Read - Implements Reader interface.
 func (o *odirectReader) Read(buf []byte) (n int, err error) {
+	if o.ctx.Err() != nil {
+		return 0, o.ctx.Err()
+	}
 	if o.err != nil && (len(o.buf) == 0 || !o.seenRead) {
 		return 0, o.err
 	}
@@ -97,7 +102,11 @@ func (d *DrivePerf) runReadTest(ctx context.Context, path string) (float64, erro
 
 	// Read Aligned block upto a multiple of BlockSize
 	data := directio.AlignedBlock(int(d.BlockSize))
-	of := &odirectReader{File: f, Bufp: &data}
+	of := &odirectReader{
+		File: f,
+		Bufp: &data,
+		ctx:  ctx,
+	}
 	n, err := io.Copy(ioutil.Discard, of)
 	if err != nil {
 		of.Close()
@@ -149,9 +158,14 @@ func fadviseDontNeed(f *os.File) error {
 	return unix.Fadvise(int(f.Fd()), 0, 0, unix.FADV_DONTNEED)
 }
 
-type nullReader struct{}
+type nullReader struct {
+	ctx context.Context
+}
 
 func (n nullReader) Read(b []byte) (int, error) {
+	if n.ctx.Err() != nil {
+		return 0, n.ctx.Err()
+	}
 	return len(b), nil
 }
 
@@ -173,7 +187,7 @@ func (d *DrivePerf) runWriteTest(ctx context.Context, path string) (float64, err
 
 	// Write Aligned block upto a multiple of BlockSize
 	data := alignedBlock(int(d.BlockSize))
-	n, err := io.CopyBuffer(f, io.LimitReader(&nullReader{}, int64(d.FileSize)), data)
+	n, err := io.CopyBuffer(f, io.LimitReader(&nullReader{ctx: ctx}, int64(d.FileSize)), data)
 	if err != nil {
 		sync()
 		return 0, err