fix(inputs.intel_powerstat): Add MSR read timeout (influxdata#14088)

Signed-off-by: Alyson Deives Pereira <alyson.deivespereira@windriver.com>

plugins/inputs/intel_powerstat/README.md

@@ -48,6 +48,10 @@ See the [CONFIGURATION.md][CONFIGURATION.md] for more details.
   ##   "cpu_busy_frequency"
   ## ATTENTION: cpu_busy_cycles is DEPRECATED - use cpu_c0_state_residency
   # cpu_metrics = []
+
+  # The user can set the timeout duration in milliseconds for MSR reading
+  # The Default value is 100 ms.
+  # msr_read_timeout_ms = 100
 ```
 
 ## Example: Configuration with no per-CPU telemetry

plugins/inputs/intel_powerstat/file.go

@@ -21,7 +21,7 @@ type fileService interface {
 	getStringsMatchingPatternOnPath(path string) ([]string, error)
 	readFile(path string) ([]byte, error)
 	readFileToFloat64(reader io.Reader) (float64, int64, error)
-	readFileAtOffsetToUint64(reader io.ReaderAt, offset int64) (uint64, error)
+	readFileAtOffsetToUint64(reader io.ReaderAt, offset int64, timeout time.Duration) (uint64, error)
 }
 
 type fileServiceImpl struct {
@@ -133,19 +133,34 @@ func (fs *fileServiceImpl) readFileToFloat64(reader io.Reader) (float64, int64,
 }
 
 // readFileAtOffsetToUint64 reads 8 bytes from passed file at given offset.
-func (fs *fileServiceImpl) readFileAtOffsetToUint64(reader io.ReaderAt, offset int64) (uint64, error) {
+func (fs *fileServiceImpl) readFileAtOffsetToUint64(reader io.ReaderAt, offset int64, timeout time.Duration) (uint64, error) {
 	buffer := make([]byte, 8)
 
 	if offset == 0 {
 		return 0, fmt.Errorf("file offset %d should not be 0", offset)
 	}
 
-	_, err := reader.ReadAt(buffer, offset)
-	if err != nil {
+	value := make(chan uint64)
+	errs := make(chan error)
+
+	go func() {
+		if n, readErr := reader.ReadAt(buffer, offset); n >= 0 {
+			value <- binary.LittleEndian.Uint64(buffer)
+		} else {
+			errs <- readErr
+		}
+		close(value)
+		close(errs)
+	}()
+
+	select {
+	case val := <-value:
+		return val, nil
+	case err := <-errs:
 		return 0, fmt.Errorf("error on reading file at offset %d: %w", offset, err)
+	case <-time.After(timeout):
+		return 0, fmt.Errorf("timeout reading file at offset %d", offset)
 	}
-
-	return binary.LittleEndian.Uint64(buffer), nil
 }
 
 func newFileService() *fileServiceImpl {

plugins/inputs/intel_powerstat/intel_powerstat.go

@@ -41,6 +41,7 @@ const (
 type PowerStat struct {
 	CPUMetrics     []string        `toml:"cpu_metrics"`
 	PackageMetrics []string        `toml:"package_metrics"`
+	ReadTimeout    int64           `toml:"msr_read_timeout"`
 	Log            telegraf.Logger `toml:"-"`
 
 	fs   fileService
@@ -96,7 +97,7 @@ func (p *PowerStat) initMSR() {
 	// Initialize MSR service only when there is at least one metric enabled
 	if p.cpuFrequency || p.cpuBusyFrequency || p.cpuTemperature || p.cpuC0StateResidency || p.cpuC1StateResidency ||
 		p.cpuC6StateResidency || p.cpuBusyCycles || p.packageTurboLimit || p.packageUncoreFrequency || p.packageCPUBaseFrequency {
-		p.msr = newMsrServiceWithFs(p.Log, p.fs)
+		p.msr = newMsrServiceWithFs(p.Log, p.fs, p.ReadTimeout)
 	}
 }
 
@@ -903,6 +904,7 @@ func newPowerStat(fs fileService) *PowerStat {
 		skipFirstIteration: true,
 		fs:                 fs,
 		logOnce:            make(map[string]error),
+		ReadTimeout:        100,
 	}
 
 	return p

plugins/inputs/intel_powerstat/msr.go

@@ -9,6 +9,7 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
+	"time"
 
 	"golang.org/x/sync/errgroup"
 
@@ -62,6 +63,7 @@ type msrServiceImpl struct {
 	msrOffsets   []int64
 	fs           fileService
 	log          telegraf.Logger
+	readTimeout  time.Duration
 }
 
 func (m *msrServiceImpl) getCPUCoresData() map[string]*msrData {
@@ -187,7 +189,7 @@ func (m *msrServiceImpl) readSingleMsr(core string, msr string) (uint64, error)
 		return 0, fmt.Errorf("incorect name of MSR %s", msr)
 	}
 
-	value, err := m.fs.readFileAtOffsetToUint64(msrFile, msrAddress)
+	value, err := m.fs.readFileAtOffsetToUint64(msrFile, msrAddress, m.readTimeout)
 	if err != nil {
 		return 0, err
 	}
@@ -256,7 +258,7 @@ func (m *msrServiceImpl) readDataFromMsr(core string, reader io.ReaderAt) error
 }
 
 func (m *msrServiceImpl) readValueFromFileAtOffset(ctx context.Context, ch chan uint64, reader io.ReaderAt, offset int64) error {
-	value, err := m.fs.readFileAtOffsetToUint64(reader, offset)
+	value, err := m.fs.readFileAtOffsetToUint64(reader, offset, m.readTimeout)
 	if err != nil {
 		return err
 	}
@@ -309,10 +311,11 @@ func (m *msrServiceImpl) setCPUCores() error {
 	return nil
 }
 
-func newMsrServiceWithFs(logger telegraf.Logger, fs fileService) *msrServiceImpl {
+func newMsrServiceWithFs(logger telegraf.Logger, fs fileService, readTimeout int64) *msrServiceImpl {
 	msrService := &msrServiceImpl{
-		fs:  fs,
-		log: logger,
+		fs:          fs,
+		log:         logger,
+		readTimeout: time.Duration(readTimeout) * time.Millisecond,
 	}
 	err := msrService.setCPUCores()
 	if err != nil {

plugins/inputs/intel_powerstat/msr_test.go

@@ -182,7 +182,8 @@ func getMsrServiceWithMockedFs() (*msrServiceImpl, *mockFileService) {
 	fsMock := &mockFileService{}
 	fsMock.On("getStringsMatchingPatternOnPath", mock.Anything).
 		Return(cores, nil).Once()
-	msr := newMsrServiceWithFs(logger, fsMock)
+	timeout := int64(100)
+	msr := newMsrServiceWithFs(logger, fsMock, timeout)
 
 	return msr, fsMock
 }

plugins/inputs/intel_powerstat/sample.conf

@@ -25,3 +25,7 @@
   ##   "cpu_busy_frequency"
   ## ATTENTION: cpu_busy_cycles is DEPRECATED - use cpu_c0_state_residency
   # cpu_metrics = []
+
+  # The user can set the timeout duration in milliseconds for MSR reading
+  # The Default value is 100 ms.
+  # msr_read_timeout_ms = 100