gomonop/pkg/plugin/plugin.go

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// Package plugin implements a helper that can be used to implement a Nagios,
// Centreon, Icinga... service monitoring plugin.
package plugin // import nocternity.net/gomonop/pkg/perfdata
import (
"container/list"
"fmt"
"os"
"strings"
"nocternity.net/gomonop/pkg/perfdata"
)
// Status represents the return status of the monitoring plugin. The
// corresponding integer value will be used as the program's exit code,
// to be interpreted by the monitoring system.
type Status int
// Plugin exit statuses.
const (
OK Status = iota
WARNING
CRITICAL
UNKNOWN
)
// String representations of the plugin statuses.
func (s Status) String() string {
return [...]string{"OK", "WARNING", "ERROR", "UNKNOWN"}[s]
}
// Plugin represents the monitoring plugin's state, including its name,
// return status and message, additional lines of text, and performance
// data to be encoded in the output.
type Plugin struct {
name string
status Status
message string
extraText *list.List
perfData map[string]*perfdata.PerfData
}
// New creates the plugin with `name` as its name and an unknown status.
func New(name string) *Plugin {
p := new(Plugin)
p.name = name
p.status = UNKNOWN
p.message = "no status set"
p.perfData = make(map[string]*perfdata.PerfData)
return p
}
// SetState sets the plugin's output code to `status` and its message to
// the specified `message`.
func (p *Plugin) SetState(status Status, message string) {
p.status = status
p.message = message
}
// AddLine adds the specified string to the extra output text buffer.
func (p *Plugin) AddLine(line string) {
if p.extraText == nil {
p.extraText = list.New()
}
p.extraText.PushBack(line)
}
// AddLinef formats the input and adds it to the text buffer.
func (p *Plugin) AddLinef(format string, data ...interface{}) {
p.AddLine(fmt.Sprintf(format, data...))
}
// AddLines add the specified `lines` to the output text.
func (p *Plugin) AddLines(lines []string) {
for _, line := range lines {
p.AddLine(line)
}
}
// AddPerfData adds performance data described by the "pd" argument to the
// output's performance data. If two performance data records are added for
// the same label, the program panics.
func (p *Plugin) AddPerfData(pd *perfdata.PerfData) {
_, exists := p.perfData[pd.Label]
if exists {
panic("duplicate performance data " + pd.Label)
}
p.perfData[pd.Label] = pd
}
// Done generates the plugin's text output from its name, status, text data
// and performance data, before exiting with the code corresponding to the
// status.
func (p *Plugin) Done() {
var strBuilder strings.Builder
strBuilder.WriteString(p.name)
strBuilder.WriteString(" ")
strBuilder.WriteString(p.status.String())
strBuilder.WriteString(": ")
strBuilder.WriteString(p.message)
if len(p.perfData) > 0 {
strBuilder.WriteString(" | ")
needSep := false
for _, data := range p.perfData {
if needSep {
strBuilder.WriteString(", ")
} else {
needSep = true
}
strBuilder.WriteString(data.String())
}
}
if p.extraText != nil {
for em := p.extraText.Front(); em != nil; em = em.Next() {
strBuilder.WriteString("\n")
//nolint:forcetypeassert // we want to panic if this isn't a string
strBuilder.WriteString(em.Value.(string))
}
}
fmt.Println(strBuilder.String())
os.Exit(int(p.status))
}