check

package module

v0.5.0-rc1 Latest Latest Go to latest Published: Jul 10, 2023 License: GPL-2.0 Imports: 12 Imported by: 26

Details

Valid go.mod file
Redistributable license
Tagged version
Stable version
Learn more about best practices

Repository

github.com/NETWAYS/go-check

Links

Open Source Insights

README ¶

go-check

GitHub go.mod Go version GitHub

go-check is a library to help with development of monitoring plugins for tools like Icinga.

See the documentation on pkg.go.dev for more details and examples.

Usage

Simple Example

package main

import (
	"github.com/NETWAYS/go-check"
)

func main() {
	config := check.NewConfig()
	config.Name = "check_test"
	config.Readme = `Test Plugin`
	config.Version = "1.0.0"

	_ = config.FlagSet.StringP("hostname", "H", "localhost", "Hostname to check")

	config.ParseArguments()

	// Some checking should be done here, when --help is not passed
	check.Exitf(check.OK, "Everything is fine - answer=%d", 42)
    // Output:
    // OK - Everything is fine - answer=42
}

Exit Codes

check.Exitf(OK, "Everything is fine - value=%d", 42) // OK, 0

check.ExitRaw(check.Critical, "CRITICAL", "|", "percent_packet_loss=100") // CRITICAL, 2

err := fmt.Errorf("connection to %s has been timed out", "localhost:12345")

check.ExitError(err) // UNKNOWN, 3

Timeout Handling

checkPluginTimeoutInSeconds := 10
go check.HandleTimeout(checkPluginTimeoutInSeconds)

Thresholds

warnThreshold, err := check.ParseThreshold("~:3")

if err != nil {
    return t, err
}

if warnThreshold.DoesViolate(3.6) {
    fmt.Println("Not great, not terrible.")
}

Perfdata

var pl perfdata.PerfdataList

pl.Add(&perfdata.Perfdata{
    Label: "process.cpu.percent",
    Value: 25,
    Uom:   "%",
    Warn:  50,
    Crit:  90,
    Min:   0,
    Max:   100})

fmt.Println(pl.String())

Results

allStates = []int{0,2,3,0,1,2}

switch result.WorstState(allStates...) {
case 0:
    rc = check.OK
case 1:
    rc = check.Warning
case 2:
    rc = check.Critical
default:
    rc = check.Unknown
}

Partial Results

o := Overall{}
o.Add(0, "Something is OK")

pr := PartialResult{
    State:  check.OK,
    Output: "My Subcheck",
}

o.AddSubcheck(pr)

fmt.Println(o.GetOutput())

// states: ok=1
// [OK] Something is OK
// \_ [OK] My Subcheck

Examples

A few plugins using go-check:

License

This library is distributed under the GPL-2.0 or newer license found in the COPYING file.

Documentation ¶

Index ¶

Constants
Variables
func BaseExit(rc int)
func BoundaryToString(value float64) (s string)
func CatchPanic()
func ExitError(err error)
func ExitRaw(rc int, output ...string)
func Exitf(rc int, output string, args ...interface{})
func FormatFloat(value float64) string
func HandleTimeout(timeout int)
func StatusText(status int) string
type Config
- func NewConfig() *Config
type Threshold
- func ParseThreshold(spec string) (t *Threshold, err error)
- func (t Threshold) DoesViolate(value float64) bool
- func (t Threshold) String() (s string)

Constants ¶

View Source

const (
	// OK means everything is fine
	OK = 0
	// Warning means there is a problem the admin should review
	Warning = 1
	// Critical means there is a problem that requires immediate action
	Critical = 2
	// Unknown means the status can not be determined, probably due to an error or something missing
	Unknown = 3
)

Variables ¶

View Source

var (
	PosInf = math.Inf(1)
	NegInf = math.Inf(-1)
)

View Source

var AllowExit = true

AllowExit lets you disable the call to os.Exit() in ExitXxx() functions of this package.

This should be used carefully and most likely only for testing.

View Source

var PrintStack = true

PrintStack prints the error stack when recovering from a panic with CatchPanic()

Functions ¶

func BaseExit ¶

func BaseExit(rc int)

func BoundaryToString ¶

func BoundaryToString(value float64) (s string)

BoundaryToString returns the string representation of a Threshold boundary.

func CatchPanic ¶

func CatchPanic()

CatchPanic is a general function for defer, to capture any panic that occurred during runtime of a check

The function will recover from the condition and exit with a proper UNKNOWN status, while showing error and the call stack.

Example ¶

defer CatchPanic()

panic("something bad happened")

Output:

[UNKNOWN] - Golang encountered a panic: something bad happened
would exit with code 3

func ExitError ¶

func ExitError(err error)

ExitError exists with an Unknown state while reporting the error

Example ¶

err := fmt.Errorf("connection to %s has been timed out", "localhost:12345")
ExitError(err)

Output:

[UNKNOWN] - connection to localhost:12345 has been timed out (*errors.errorString)
would exit with code 3

func ExitRaw ¶ added in v0.2.0

func ExitRaw(rc int, output ...string)

ExitRaw prints the plugin output with the state prefixed and exits the program.

Example:

OK - everything is fine

Example ¶

ExitRaw(OK, "Everything is fine")

Output:

[OK] - Everything is fine
would exit with code 0

func Exitf ¶ added in v0.2.0

func Exitf(rc int, output string, args ...interface{})

Exitf prints the plugin output using formatting and exits the program.

Output is the formatting string, and the rest of the arguments help adding values.

Also see fmt package: https://golang.org/pkg/fmt

Example ¶

Exitf(OK, "Everything is fine - value=%d", 42)

Output:

[OK] - Everything is fine - value=42
would exit with code 0

func FormatFloat ¶ added in v0.3.0

func FormatFloat(value float64) string

FormatFloat returns a string representation of floats, avoiding scientific notation and removes trailing zeros.

func HandleTimeout ¶

func HandleTimeout(timeout int)

Helper for a goroutine, to wait for signals and timeout, and exit with a proper code

func StatusText ¶

func StatusText(status int) string

StatusText returns the string corresponding to a state

Example ¶

fmt.Println(StatusText(OK), StatusText(Warning), StatusText(Critical), StatusText(Unknown))

Output:

OK WARNING CRITICAL UNKNOWN

Types ¶

type Config ¶

type Config struct {
	Name          string
	Readme        string
	Version       string
	Timeout       int
	Verbose       bool
	Debug         bool
	PrintVersion  bool
	DefaultFlags  bool
	DefaultHelper bool
	FlagSet       *flag.FlagSet
}

Example ¶

config := NewConfig()
config.Name = "check_test"
config.Readme = `Test Plugin`
config.Version = "1.0.0"

_ = config.FlagSet.StringP("hostname", "H", "localhost", "Hostname to check")

config.ParseArguments()

// Some checking should be done here

Exitf(OK, "Everything is fine - answer=%d", 42)

Output:

[OK] - Everything is fine - answer=42
would exit with code 0

func NewConfig ¶

func NewConfig() *Config

func (*Config) EnableTimeoutHandler ¶

func (c *Config) EnableTimeoutHandler()

Start the timeout and signal handler in a goroutine

func (*Config) ParseArguments ¶

func (c *Config) ParseArguments()

func (*Config) ParseArray ¶

func (c *Config) ParseArray(arguments []string)

type Threshold ¶

type Threshold struct {
	Inside bool
	Lower  float64
	Upper  float64
}

Defining a threshold for any numeric value

Format: [@]start:end

Threshold Generate an alert if x... 10 < 0 or > 10, (outside the range of {0 .. 10}) 10: < 10, (outside {10 .. ∞}) ~:10 > 10, (outside the range of {-∞ .. 10}) 10:20 < 10 or > 20, (outside the range of {10 .. 20}) @10:20 ≥ 10 and ≤ 20, (inside the range of {10 .. 20})

Reference: https://www.monitoring-plugins.org/doc/guidelines.html#THRESHOLDFORMAT

func ParseThreshold ¶

func ParseThreshold(spec string) (t *Threshold, err error)

Parse a Threshold from a string.

See Threshold for details.

func (Threshold) DoesViolate ¶

func (t Threshold) DoesViolate(value float64) bool

Compares a value against the threshold, and returns true if the value violates the threshold.

func (Threshold) String ¶

func (t Threshold) String() (s string)

String returns the plain representation of the Threshold

Source Files ¶

View all Source files

Directories ¶

Path	Synopsis
convert
examples
check_example command
check_example2 command
perfdata
result result tries to	result tries to
testhelper

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