host

Documentation

Index

• Constants
• Variables
• type Reporter
  • func NewReporter(hostID, hostName string, localNets report.Networks) *Reporter
  • func (Reporter) Name() string
  • func (r *Reporter) Report() (report.Report, error)
• type Tagger
  • func NewTagger(hostID, probeID string) Tagger
  • func (Tagger) Name() string
  • func (t Tagger) Tag(r report.Report) (report.Report, error)

Constants

const (
	Timestamp     = "ts"
	HostName      = "host_name"
	LocalNetworks = "local_networks"
	OS            = "os"
	KernelVersion = "kernel_version"
	Uptime        = "uptime"
	Load1         = "load1"
	Load5         = "load5"
	Load15        = "load15"
	CPUUsage      = "cpu_usage_percent"
	MemUsage      = "mem_usage_percent"
)

Keys for use in Node.Metadata.

const (
	ProcUptime  = "/proc/uptime"
	ProcLoad    = "/proc/loadavg"
	ProcStat    = "/proc/stat"
	ProcMemInfo = "/proc/meminfo"
)

Exposed for testing.

Variables

var GetCPUUsagePercent = func() (float64, float64) {
	stat, err := linuxproc.ReadStat(ProcStat)
	if err != nil {
		return 0.0, 0.0
	}

	// From http://stackoverflow.com/questions/23367857/accurate-calculation-of-cpu-usage-given-in-percentage-in-linux
	var (
		currentStat = stat.CPUStatAll
		prevIdle    = previousStat.Idle + previousStat.IOWait
		idle        = currentStat.Idle + currentStat.IOWait
		prevNonIdle = (previousStat.User + previousStat.Nice + previousStat.System +
			previousStat.IRQ + previousStat.SoftIRQ + previousStat.Steal)
		nonIdle = (currentStat.User + currentStat.Nice + currentStat.System +
			currentStat.IRQ + currentStat.SoftIRQ + currentStat.Steal)
		prevTotal = prevIdle + prevNonIdle
		total     = idle + nonIdle
		// differentiate: actual value minus the previous one
		totald = total - prevTotal
		idled  = idle - prevIdle
	)
	previousStat = currentStat
	return float64(totald-idled) * 100. / float64(totald), float64(len(stat.CPUStats)) * 100.
}

GetCPUUsagePercent returns the percent cpu usage and max (ie #cpus * 100)

var GetKernelVersion = func() (string, error) {
	var utsname syscall.Utsname
	if err := Uname(&utsname); err != nil {
		return "unknown", err
	}
	return fmt.Sprintf("%s %s", charsToString(utsname.Release), charsToString(utsname.Version)), nil
}

GetKernelVersion returns the kernel version as reported by uname.

var GetLoad = func(now time.Time) report.Metrics {
	buf, err := ioutil.ReadFile("/proc/loadavg")
	if err != nil {
		return nil
	}
	toks := strings.Fields(string(buf))
	if len(toks) < 3 {
		return nil
	}
	one, err := strconv.ParseFloat(toks[0], 64)
	if err != nil {
		return nil
	}
	five, err := strconv.ParseFloat(toks[1], 64)
	if err != nil {
		return nil
	}
	fifteen, err := strconv.ParseFloat(toks[2], 64)
	if err != nil {
		return nil
	}
	return report.Metrics{
		Load1:  report.MakeMetric().Add(now, one),
		Load5:  report.MakeMetric().Add(now, five),
		Load15: report.MakeMetric().Add(now, fifteen),
	}
}

GetLoad returns the current load averages as metrics.

var GetMemoryUsagePercent = func() (float64, float64) {
	meminfo, err := linuxproc.ReadMemInfo(ProcMemInfo)
	if err != nil {
		return 0.0, 0.0
	}

	used := meminfo.MemTotal - meminfo.MemFree - meminfo.Buffers - meminfo.Cached
	return float64(used) * 100. / float64(meminfo.MemTotal), 100.
}

GetMemoryUsagePercent returns the percent memory usage and max (ie 100)

var GetUptime = func() (time.Duration, error) {
	buf, err := ioutil.ReadFile("/proc/uptime")
	if err != nil {
		return 0, err
	}

	fields := strings.Fields(string(buf))
	if len(fields) != 2 {
		return 0, fmt.Errorf("invalid format: %s", string(buf))
	}

	uptime, err := strconv.ParseFloat(fields[0], 64)
	if err != nil {
		return 0, err
	}

	return time.Duration(uptime) * time.Second, nil
}

GetUptime returns the uptime of the host.

var Uname = syscall.Uname

Uname is swappable for mocking in tests.

Types

type Reporter

type Reporter struct {
	// contains filtered or unexported fields
}

Reporter generates Reports containing the host topology.

func NewReporter

func NewReporter(hostID, hostName string, localNets report.Networks) *Reporter

NewReporter returns a Reporter which produces a report containing host topology for this host.

func (Reporter) Name

func (Reporter) Name() string

Name of this reporter, for metrics gathering

func (*Reporter) Report

func (r *Reporter) Report() (report.Report, error)

Report implements Reporter.

type Tagger

type Tagger struct {
	// contains filtered or unexported fields
}

Tagger tags each node in each topology of a report with the origin host node ID of this (probe) host. Effectively, a foreign key linking every node in every topology to an origin host node in the host topology.

func NewTagger

func NewTagger(hostID, probeID string) Tagger

NewTagger tags each node with a foreign key linking it to its origin host in the host topology.

func (Tagger) Name

func (Tagger) Name() string

Name of this tagger, for metrics gathering

func (Tagger) Tag

func (t Tagger) Tag(r report.Report) (report.Report, error)

Tag implements Tagger.