Rewrite in Golang

.gitignore

@@ -0,0 +1,10 @@
+.idea
+\#*
+.\#*
+
+vendor/
+coverage.html
+coverage.out
+dist/
+
+check_sms3status

.golangci.yml

@@ -0,0 +1,60 @@
+version: "2"
+run:
+  tests: false
+linters:
+  default: all
+  enable:
+    - wsl_v5
+    - gomodguard_v2
+  disable:
+    - wsl
+    - gomodguard
+    - cyclop
+    - depguard
+    - err113
+    - exhaustruct
+    - forbidigo
+    - forcetypeassert
+    - gochecknoglobals
+    - gochecknoinits
+    - godot
+    - godox
+    - lll
+    - mnd
+    - musttag
+    - nakedret
+    - nlreturn
+    - nolintlint
+    - nonamedreturns
+    - tagliatelle
+    - varnamelen
+    - wrapcheck
+    - funlen
+  settings:
+    wsl_v5:
+      allow-first-in-block: true
+      allow-whole-block: true
+      branch-max-lines: 2
+      disable:
+        - err
+  exclusions:
+    generated: lax
+    presets:
+      - comments
+      - common-false-positives
+      - legacy
+      - std-error-handling
+    paths:
+      - third_party$
+      - builtin$
+      - examples$
+formatters:
+  enable:
+    - gofmt
+    - goimports
+  exclusions:
+    generated: lax
+    paths:
+      - third_party$
+      - builtin$
+      - examples$

Makefile

@@ -0,0 +1,13 @@
+.PHONY: test coverage lint vet
+
+build:
+	CGO_ENABLED=0 go build
+lint:
+	go fmt $(go list ./... | grep -v /vendor/)
+vet:
+	go vet $(go list ./... | grep -v /vendor/)
+test:
+	go test -v -cover ./...
+coverage:
+	go test -v -cover -coverprofile=coverage.out ./... &&\
+	go tool cover -html=coverage.out -o coverage.html

README.md

@@ -1,36 +1,31 @@
-check_sms3status
-================
+# check_sms3status
 
-This plugin checks the status of an SMS modem using the regular_run functionality
-provided in smstools3
+A check plugin for SMS modem using the regular_run functionality provided by [smstools3](https://smstools3.kekekasvi.com/)
 
-It does not directly access the modem, but instead reads a status file generated
-by smstools3.
+It does not directly access the modem, instead it reads the status file generated by smstools3.
 
-In order to work the following options need to be set in smsd.conf
+In order to work the following options need to be set in `smsd.conf`:
 
-    regular_run_interval = 60
-    regular_run_cmd = AT+CREG?;+CSQ;+COPS?
-    regular_run_statfile = F<status_file>
+```
+regular_run_interval = 60
+regular_run_cmd = AT+CREG?;+CSQ;+COPS?
+regular_run_statfile = F<status_file>
+```
 
+## Usage
 
-### Requirements
+```
+Flags:
+  -a, --age int             The maximum age of the file in seconds (default 300) (default 300)
+  -c, --critical string     Critical threshold for signal strength in percent (default "20:")
+  -h, --help                help for check_sms3status
+  -s, --statusfile string   Path to the status file
+  -v, --version             version for check_sms3status
+  -w, --warning string      Warning threshold for signal strength in percent (default "40:")
+```
 
-* Perl library: `Nagios::Plugins utils.pm`
-
-### Usage
-
-    check_sms3status [options] status_file
-
-    --warning
-        warning level for percentage signal strength (default 40)
-
-    --critical
-        critical level for percentage signal strength (default 20)
-
-    --timeout
-        how long to wait for the file (default 30)
-
-    --age
-        the maximum age of the file in seconds (default 300)
+## Examples
 
+```bash
+check_sms3status --warning 30 --critical 50 --statusfile /path/to/statusfile
+```

cmd/root.go

@@ -0,0 +1,195 @@
+package cmd
+
+import (
+	"fmt"
+	"math"
+	"os"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/NETWAYS/go-check"
+	"github.com/NETWAYS/go-check/result"
+	"github.com/spf13/cobra"
+)
+
+var warning, critical, statusfilePath string
+var maxFileAge int64
+
+var csqRe = regexp.MustCompile(`\+CSQ:\s*(\d+),(\d+)`)
+var copsReQuoted = regexp.MustCompile(`\+COPS:\s*\d+,\d+,"([^"]*)"`)
+var copsReUnquoted = regexp.MustCompile(`\+COPS:\s*\d+,\d+,([^"]+)`)
+var cregRe = regexp.MustCompile(`\+CREG:\s*(\d,(?:1|5))`)
+
+var rootCmd = &cobra.Command{
+	Use:   "check_sms3status",
+	Short: "This plugin checks the status of an SMS modem using the regular_run functionality provided in smstools3",
+	Long:  `This plugin checks the status of an SMS modem using the regular_run functionality provided in smstools3a. It does not directly access the modem, but instead reads a status file generated by smstools3.`,
+	Example: `
+check_sms3status --warning 30 --critical 50 --statusfile /path/to/statusfile
+`,
+	Run: func(_ *cobra.Command, _ []string) {
+		// Parse the thresholds add exit if there's an issue
+		warnThreshold, warningThresholdErr := check.ParseThreshold(warning)
+
+		if warningThresholdErr != nil {
+			check.ExitError(warningThresholdErr)
+		}
+
+		critThreshold, critThresholdErr := check.ParseThreshold(critical)
+
+		if critThresholdErr != nil {
+			check.ExitError(critThresholdErr)
+		}
+
+		// Get the file content and info
+		content, fileInfo, contentErr := getFileContentAndInfo(statusfilePath)
+
+		if contentErr != nil {
+			check.ExitError(contentErr)
+		}
+
+		var overall result.Overall
+
+		overall.AddSubcheck(checkFileAge(fileInfo))
+		overall.AddSubcheck(checkContent(string(content), *warnThreshold, *critThreshold))
+
+		check.Exit(overall.GetStatus(), overall.GetOutput())
+	},
+}
+
+func Execute(version string) {
+	defer check.CatchPanic()
+
+	rootCmd.Version = version
+	rootCmd.VersionTemplate()
+
+	err := rootCmd.Execute()
+	if err != nil {
+		check.ExitError(err)
+	}
+}
+
+func init() {
+	rootCmd.Flags().StringVarP(&statusfilePath, "statusfile", "s", "", "Path to the status file")
+	rootCmd.Flags().StringVarP(&warning, "warning", "w", "40:", "Warning threshold for signal strength in percent")
+	rootCmd.Flags().StringVarP(&critical, "critical", "c", "20:", "Critical threshold for signal strength in percent")
+	rootCmd.Flags().Int64VarP(&maxFileAge, "age", "a", 300, "The maximum age of the file in seconds (default 300)")
+
+	_ = rootCmd.MarkFlagRequired("statusfile")
+}
+
+func Usage(cmd *cobra.Command, _ []string) {
+	_ = cmd.Usage()
+
+	os.Exit(3)
+}
+
+// getFileContentAndInfo returns the files content and file info
+func getFileContentAndInfo(filePath string) ([]byte, os.FileInfo, error) {
+	content, contentErr := os.ReadFile(filePath)
+
+	var fileInfo os.FileInfo
+
+	if contentErr != nil {
+		return content, fileInfo, contentErr
+	}
+
+	fileInfo, fileInfoErr := os.Stat(filePath)
+	if fileInfoErr != nil {
+		return content, fileInfo, fileInfoErr
+	}
+
+	return content, fileInfo, nil
+}
+
+// checkFileAge compares the given file into with the requested maximum file age
+func checkFileAge(fileInfo os.FileInfo) *result.PartialResult {
+	nowSec := time.Now().Unix()
+	fileSec := fileInfo.ModTime().Unix()
+	fileAge := nowSec - fileSec
+
+	tmpResult := &result.PartialResult{
+		Output: fmt.Sprintf("Status file was last updated %d seconds ago", fileAge),
+	}
+
+	tmpResult.SetState(check.OK)
+
+	if fileAge > maxFileAge {
+		tmpResult.SetState(check.Critical)
+	}
+
+	return tmpResult
+}
+
+// checkContent compares the file content against the given thresholds
+func checkContent(fileContent string, warningThreshold check.Threshold, criticalThreshold check.Threshold) *result.PartialResult {
+	var signal, sigber int
+
+	var network string
+
+	isRegistered := true
+
+	lines := strings.SplitSeq(fileContent, "\n")
+
+	for line := range lines {
+		if matches := csqRe.FindStringSubmatch(line); matches != nil {
+			val, err := strconv.Atoi(matches[1])
+			if err == nil {
+				signal = val
+			}
+
+			val, err = strconv.Atoi(matches[2])
+			if err == nil {
+				sigber = val
+			}
+		} else if matches := copsReQuoted.FindStringSubmatch(line); matches != nil {
+			network = matches[1]
+		} else if matches := copsReUnquoted.FindStringSubmatch(line); matches != nil {
+			network = matches[1]
+		}
+
+		if strings.Contains(line, "+CREG:") && !cregRe.MatchString(line) {
+			isRegistered = false
+		}
+	}
+
+	sigdb := (2 * signal) - 113
+	sigproc := float64(signal*100) / 31.0
+	result := result.NewPartialResult()
+
+	if !isRegistered {
+		result.Output = "Modem not registered on network"
+		result.SetState(check.Critical)
+
+		return result
+	} else if signal > 31 {
+		result.Output = "Signal strength returned an invalid value"
+		result.SetState(check.Unknown)
+	}
+
+	result.Perfdata.Add(&check.Perfdata{Label: "dbm", Value: sigdb, Uom: "", Warn: nil, Crit: nil, Min: nil, Max: nil})
+	result.Perfdata.Add(&check.Perfdata{Label: "signal", Value: math.Round(sigproc), Uom: "%", Warn: &warningThreshold, Crit: &criticalThreshold})
+
+	msg := fmt.Sprintf("Registered on network '%s' with signal strength %0.f%%", network, sigproc)
+
+	result.Output = msg
+
+	// bit error rate 99 means unknown
+	if sigber != 99 {
+		result.Perfdata.Add(&check.Perfdata{Label: "bit_error_rate", Value: sigber})
+	}
+
+	//nolint: gocritic
+	if criticalThreshold.DoesViolate(sigproc) {
+		result.SetState(check.Critical)
+	} else if warningThreshold.DoesViolate(sigproc) {
+		result.SetState(check.Warning)
+		result.Output = msg
+	} else {
+		result.SetState(check.OK)
+	}
+
+	return result
+}