gomonop/perfdata/perfdata.go

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// Package `perfdata` provides representations for a monitoring plugin's
// performance data.
package perfdata
import (
"fmt"
"regexp"
"strings"
)
// Units of measurement, which may be used to qualify the performance data.
type UnitOfMeasurement int
const (
UOM_NONE UnitOfMeasurement = iota
UOM_SECONDS
UOM_PERCENT
UOM_BYTES
UOM_KILOBYTES
UOM_MEGABYTES
UOM_GIGABYTES
UOM_TERABYTES
UOM_COUNTER
)
func (u UnitOfMeasurement) String() string {
return [...]string{"", "s", "%", "B", "KB", "MB", "GB", "TB", "c"}[u]
}
// Flags indicating which elements of performance data have been set.
type perfDataBits int
const (
PDAT_WARN perfDataBits = 1 << iota
PDAT_CRIT
PDAT_MIN
PDAT_MAX
)
// Regexps used to check values and ranges in performance data records.
var (
// Common value check regexp
vcRegexp = `^-?(0(\.\d*)?|[1-9]\d*(\.\d*)?|\.\d+)$`
// Compiled value check regexp
valueCheck = regexp.MustCompile(vcRegexp)
// Compiled range min value check
rangeMinCheck = regexp.MustCompile(vcRegexp + `|^~$`)
)
// Performance data range
type PerfDataRange struct {
start string
end string
inside bool
}
// Creates a performance data range from -inf to 0 and from the specified
// value to +inf.
func PDRMax(max string) *PerfDataRange {
if !valueCheck.MatchString(max) {
panic("invalid performance data range maximum value")
}
r := &PerfDataRange{}
r.start = "0"
r.end = max
return r
}
// Creates a performance data range from -inf to the specified minimal value
// and from the specified maximal value to +inf.
func PDRMinMax(min, max string) *PerfDataRange {
if !valueCheck.MatchString(max) {
panic("invalid performance data range maximum value")
}
if !rangeMinCheck.MatchString(min) {
panic("invalid performance data range minimum value")
}
r := &PerfDataRange{}
r.start = min
r.end = max
return r
}
// Inverts the range.
func (r *PerfDataRange) Inside() *PerfDataRange {
r.inside = true
return r
}
// Generates the range's string representation so it can be sent to the
// monitoring system.
func (r *PerfDataRange) String() string {
var start, inside string
if r.start == "" {
start = "~"
} else if r.start == "0" {
start = ""
} else {
start = r.start
}
if r.inside {
inside = "@"
} else {
inside = ""
}
return fmt.Sprintf("%s%s:%s", inside, start, r.end)
}
// Performance data, including a label, units, a value, warning/critical
// ranges and min/max boundaries.
type PerfData struct {
Label string
units UnitOfMeasurement
bits perfDataBits
value string
warn, crit PerfDataRange
min, max string
}
// Create performance data using the specified label and units.
func New(label string, units UnitOfMeasurement, value string) *PerfData {
if value != "" && !valueCheck.MatchString(value) {
panic("invalid value")
}
r := &PerfData{}
r.Label = label
r.units = units
if value == "" {
r.value = "U"
} else {
r.value = value
}
return r
}
// Set the warning range for the performance data record.
func (d *PerfData) SetWarn(r *PerfDataRange) {
d.warn = *r
d.bits = d.bits | PDAT_WARN
}
// Set the critical range for the performance data record.
func (d *PerfData) SetCrit(r *PerfDataRange) {
d.crit = *r
d.bits = d.bits | PDAT_CRIT
}
// Set the performance data's minimal value
func (d *PerfData) SetMin(min string) {
if !valueCheck.MatchString(min) {
panic("invalid value")
}
d.min = min
d.bits = d.bits | PDAT_MIN
}
// Set the performance data's maximal value.
func (d *PerfData) SetMax(max string) {
if !valueCheck.MatchString(max) {
panic("invalid value")
}
d.max = max
d.bits = d.bits | PDAT_MAX
}
// Converts performance data to a string which may be read by the monitoring
// system.
func (d *PerfData) String() string {
var sb strings.Builder
needsQuotes := strings.ContainsAny(d.Label, " '=\"")
if needsQuotes {
sb.WriteString("'")
}
sb.WriteString(strings.ReplaceAll(d.Label, "'", "''"))
if needsQuotes {
sb.WriteString("'")
}
sb.WriteString("=")
sb.WriteString(fmt.Sprintf("%s%s;", d.value, d.units.String()))
if d.bits&PDAT_WARN != 0 {
sb.WriteString(d.warn.String())
}
sb.WriteString(";")
if d.bits&PDAT_CRIT != 0 {
sb.WriteString(d.crit.String())
}
sb.WriteString(";")
if d.bits&PDAT_MIN != 0 {
sb.WriteString(d.min)
}
sb.WriteString(";")
if d.bits&PDAT_MAX != 0 {
sb.WriteString(d.max)
}
return sb.String()
}