Fix wildcard and other issues with win_perf_counters (#4189)

2018-05-25 03:25:06 +02:00
parent ce3b367dac
commit 010e4f5b0b
6 changed files with 1502 additions and 629 deletions
--- a/plugins/inputs/win_perf_counters/performance_query.go
+++ b/plugins/inputs/win_perf_counters/performance_query.go
@@ -0,0 +1,189 @@
+// Go API over pdh syscalls
+// +build windows
+
+package win_perf_counters
+
+import (
+	"errors"
+	"syscall"
+	"unsafe"
+)
+
+//PerformanceQuery provides wrappers around Windows performance counters API for easy usage in GO
+type PerformanceQuery interface {
+	Open() error
+	Close() error
+	AddCounterToQuery(counterPath string) (PDH_HCOUNTER, error)
+	AddEnglishCounterToQuery(counterPath string) (PDH_HCOUNTER, error)
+	GetCounterPath(counterHandle PDH_HCOUNTER) (string, error)
+	ExpandWildCardPath(counterPath string) ([]string, error)
+	GetFormattedCounterValueDouble(hCounter PDH_HCOUNTER) (float64, error)
+	CollectData() error
+	AddEnglishCounterSupported() bool
+}
+
+//PdhError represents error returned from Performance Counters API
+type PdhError struct {
+	ErrorCode uint32
+	errorText string
+}
+
+func (m *PdhError) Error() string {
+	return m.errorText
+}
+
+func NewPdhError(code uint32) error {
+	return &PdhError{
+		ErrorCode: code,
+		errorText: PdhFormatError(code),
+	}
+}
+
+//PerformanceQueryImpl is implementation of PerformanceQuery interface, which calls phd.dll functions
+type PerformanceQueryImpl struct {
+	query PDH_HQUERY
+}
+
+// Open creates a new counterPath that is used to manage the collection of performance data.
+// It returns counterPath handle used for subsequent calls for adding counters and querying data
+func (m *PerformanceQueryImpl) Open() error {
+	if m.query != 0 {
+		err := m.Close()
+		if err != nil {
+			return err
+		}
+	}
+	var handle PDH_HQUERY
+	ret := PdhOpenQuery(0, 0, &handle)
+	if ret != ERROR_SUCCESS {
+		return NewPdhError(ret)
+	}
+	m.query = handle
+	return nil
+}
+
+// Close closes the counterPath, releases associated counter handles and frees resources
+func (m *PerformanceQueryImpl) Close() error {
+	if m.query == 0 {
+		return errors.New("uninitialised query")
+	}
+	ret := PdhCloseQuery(m.query)
+	if ret != ERROR_SUCCESS {
+		return NewPdhError(ret)
+	}
+	m.query = 0
+	return nil
+}
+
+func (m *PerformanceQueryImpl) AddCounterToQuery(counterPath string) (PDH_HCOUNTER, error) {
+	var counterHandle PDH_HCOUNTER
+	if m.query == 0 {
+		return 0, errors.New("uninitialised query")
+	}
+	ret := PdhAddCounter(m.query, counterPath, 0, &counterHandle)
+	if ret != ERROR_SUCCESS {
+		return 0, NewPdhError(ret)
+	}
+	return counterHandle, nil
+}
+
+func (m *PerformanceQueryImpl) AddEnglishCounterToQuery(counterPath string) (PDH_HCOUNTER, error) {
+	var counterHandle PDH_HCOUNTER
+	if m.query == 0 {
+		return 0, errors.New("uninitialised query")
+	}
+	ret := PdhAddEnglishCounter(m.query, counterPath, 0, &counterHandle)
+	if ret != ERROR_SUCCESS {
+		return 0, NewPdhError(ret)
+	}
+	return counterHandle, nil
+}
+
+//GetCounterPath return counter information for given handle
+func (m *PerformanceQueryImpl) GetCounterPath(counterHandle PDH_HCOUNTER) (string, error) {
+	var bufSize uint32
+	var buff []byte
+
+	ret := PdhGetCounterInfo(counterHandle, 0, &bufSize, nil)
+	if ret == PDH_MORE_DATA {
+		buff = make([]byte, bufSize)
+		bufSize = uint32(len(buff))
+		ret = PdhGetCounterInfo(counterHandle, 0, &bufSize, &buff[0])
+		if ret == ERROR_SUCCESS {
+			ci := (*PDH_COUNTER_INFO)(unsafe.Pointer(&buff[0]))
+			return UTF16PtrToString(ci.SzFullPath), nil
+		}
+	}
+	return "", NewPdhError(ret)
+}
+
+// ExpandWildCardPath  examines local computer and returns those counter paths that match the given counter path which contains wildcard characters.
+func (m *PerformanceQueryImpl) ExpandWildCardPath(counterPath string) ([]string, error) {
+	var bufSize uint32
+	var buff []uint16
+
+	ret := PdhExpandWildCardPath(counterPath, nil, &bufSize)
+	if ret == PDH_MORE_DATA {
+		buff = make([]uint16, bufSize)
+		bufSize = uint32(len(buff))
+		ret = PdhExpandWildCardPath(counterPath, &buff[0], &bufSize)
+		if ret == ERROR_SUCCESS {
+			list := UTF16ToStringArray(buff)
+			return list, nil
+		}
+	}
+	return nil, NewPdhError(ret)
+}
+
+//GetFormattedCounterValueDouble computes a displayable value for the specified counter
+func (m *PerformanceQueryImpl) GetFormattedCounterValueDouble(hCounter PDH_HCOUNTER) (float64, error) {
+	var counterType uint32
+	var value PDH_FMT_COUNTERVALUE_DOUBLE
+	ret := PdhGetFormattedCounterValueDouble(hCounter, &counterType, &value)
+	if ret == ERROR_SUCCESS {
+		if value.CStatus == PDH_CSTATUS_VALID_DATA || value.CStatus == PDH_CSTATUS_NEW_DATA {
+			return value.DoubleValue, nil
+		} else {
+			return 0, NewPdhError(value.CStatus)
+		}
+	} else {
+		return 0, NewPdhError(ret)
+	}
+}
+
+func (m *PerformanceQueryImpl) CollectData() error {
+	if m.query == 0 {
+		return errors.New("uninitialised query")
+	}
+	ret := PdhCollectQueryData(m.query)
+	if ret != ERROR_SUCCESS {
+		return NewPdhError(ret)
+	}
+	return nil
+}
+
+func (m *PerformanceQueryImpl) AddEnglishCounterSupported() bool {
+	return PdhAddEnglishCounterSupported()
+}
+
+// UTF16PtrToString converts Windows API LPTSTR (pointer to string) to go string
+func UTF16PtrToString(s *uint16) string {
+	if s == nil {
+		return ""
+	}
+	return syscall.UTF16ToString((*[1 << 29]uint16)(unsafe.Pointer(s))[0:])
+}
+
+// UTF16ToStringArray converts list of Windows API NULL terminated strings  to go string array
+func UTF16ToStringArray(buf []uint16) []string {
+	var strings []string
+	nextLineStart := 0
+	stringLine := UTF16PtrToString(&buf[0])
+	for stringLine != "" {
+		strings = append(strings, stringLine)
+		nextLineStart += len(stringLine) + 1
+		remainingBuf := buf[nextLineStart:]
+		stringLine = UTF16PtrToString(&remainingBuf[0])
+	}
+	return strings
+}