refactor(pkg): rename internals so their names actually make sense

A "program" was in fact a plugin, while a "plugin" represented the
plugin's results.

cmd/sslcert/main.go

@@ -16,7 +16,7 @@ import (
 
 	"nocternity.net/gomonop/pkg/perfdata"
 	"nocternity.net/gomonop/pkg/plugin"
-	"nocternity.net/gomonop/pkg/program"
+	"nocternity.net/gomonop/pkg/results"
 )
 
 //--------------------------------------------------------------------------------------------------------
@@ -167,7 +167,7 @@ type programFlags struct {
 // Program data including configuration and runtime data.
 type checkProgram struct {
 	programFlags                   // Flags from the command line
-	plugin       *plugin.Plugin    // Plugin output state
+	plugin       *results.Results  // Plugin output state
 	certificate  *x509.Certificate // X.509 certificate from the server
 }
 
@@ -207,16 +207,16 @@ func (flags *programFlags) parseArguments() {
 }
 
 // Initialise the monitoring check program.
-func NewProgram() program.Program {
+func NewProgram() plugin.Plugin {
 	program := &checkProgram{
-		plugin: plugin.New("Certificate check"),
+		plugin: results.New("Certificate check"),
 	}
 	program.parseArguments()
 	return program
 }
 
 // Return the program's output value.
-func (program *checkProgram) Output() *plugin.Plugin {
+func (program *checkProgram) Results() *results.Results {
 	return program.plugin
 }
 
@@ -224,20 +224,20 @@ func (program *checkProgram) Output() *plugin.Plugin {
 // if the arguments made sense.
 func (program *checkProgram) CheckArguments() bool {
 	if program.hostname == "" {
-		program.plugin.SetState(plugin.StatusUnknown, "no hostname specified")
+		program.plugin.SetState(results.StatusUnknown, "no hostname specified")
 		return false
 	}
 	if program.port < 1 || program.port > 65535 {
-		program.plugin.SetState(plugin.StatusUnknown, "invalid or missing port number")
+		program.plugin.SetState(results.StatusUnknown, "invalid or missing port number")
 		return false
 	}
 	if program.warn != -1 && program.crit != -1 && program.warn <= program.crit {
-		program.plugin.SetState(plugin.StatusUnknown, "nonsensical thresholds")
+		program.plugin.SetState(results.StatusUnknown, "nonsensical thresholds")
 		return false
 	}
 	if _, ok := certGetters[program.startTLS]; !ok {
 		errstr := "unsupported StartTLS protocol " + program.startTLS
-		program.plugin.SetState(plugin.StatusUnknown, errstr)
+		program.plugin.SetState(results.StatusUnknown, errstr)
 		return false
 	}
 	program.hostname = strings.ToLower(program.hostname)
@@ -262,13 +262,13 @@ func (program *checkProgram) getCertificate() error {
 // matches the requested host name.
 func (program *checkProgram) checkSANlessCertificate() bool {
 	if !program.ignoreCnOnly || len(program.extraNames) != 0 {
-		program.plugin.SetState(plugin.StatusWarning,
+		program.plugin.SetState(results.StatusWarning,
 			"certificate doesn't have SAN domain names")
 		return false
 	}
 	dn := strings.ToLower(program.certificate.Subject.String())
 	if !strings.HasPrefix(dn, fmt.Sprintf("cn=%s,", program.hostname)) {
-		program.plugin.SetState(plugin.StatusCritical, "incorrect certificate CN")
+		program.plugin.SetState(results.StatusCritical, "incorrect certificate CN")
 		return false
 	}
 	return true
@@ -298,7 +298,7 @@ func (program *checkProgram) checkNames() bool {
 		certificateIsOk = program.checkHostName(name) && certificateIsOk
 	}
 	if !certificateIsOk {
-		program.plugin.SetState(plugin.StatusCritical, "names missing from SAN domain names")
+		program.plugin.SetState(results.StatusCritical, "names missing from SAN domain names")
 	}
 	return certificateIsOk
 }
@@ -306,26 +306,26 @@ func (program *checkProgram) checkNames() bool {
 // Check a certificate's time to expiry against the warning and critical
 // thresholds, returning a status code and description based on these
 // values.
-func (program *checkProgram) checkCertificateExpiry(tlDays int) (plugin.Status, string) {
+func (program *checkProgram) checkCertificateExpiry(tlDays int) (results.Status, string) {
 	if tlDays <= 0 {
-		return plugin.StatusCritical, "certificate expired"
+		return results.StatusCritical, "certificate expired"
 	}
 
 	var limitStr string
-	var state plugin.Status
+	var state results.Status
 
 	switch {
 	case program.crit > 0 && tlDays <= program.crit:
 		limitStr = fmt.Sprintf(" (<= %d)", program.crit)
-		state = plugin.StatusCritical
+		state = results.StatusCritical
 
 	case program.warn > 0 && tlDays <= program.warn:
 		limitStr = fmt.Sprintf(" (<= %d)", program.warn)
-		state = plugin.StatusWarning
+		state = results.StatusWarning
 
 	default:
 		limitStr = ""
-		state = plugin.StatusOK
+		state = results.StatusOK
 	}
 
 	statusString := fmt.Sprintf("certificate will expire in %d days%s",
@@ -351,7 +351,7 @@ func (program *checkProgram) setPerfData(tlDays int) {
 func (program *checkProgram) RunCheck() {
 	err := program.getCertificate()
 	if err != nil {
-		program.plugin.SetState(plugin.StatusUnknown, err.Error())
+		program.plugin.SetState(results.StatusUnknown, err.Error())
 	} else if program.checkNames() {
 		timeLeft := time.Until(program.certificate.NotAfter)
 		tlDays := int((timeLeft + 86399*time.Second) / (24 * time.Hour))

cmd/zoneserial/main.go

@@ -14,7 +14,7 @@ import (
 
 	"nocternity.net/gomonop/pkg/perfdata"
 	"nocternity.net/gomonop/pkg/plugin"
-	"nocternity.net/gomonop/pkg/program"
+	"nocternity.net/gomonop/pkg/results"
 )
 
 //-------------------------------------------------------------------------------------------------------
@@ -56,7 +56,7 @@ type programFlags struct {
 // Program data including configuration and runtime data.
 type checkProgram struct {
 	programFlags                  // Flags from the command line
-	plugin       *plugin.Plugin // Plugin output state
+	plugin       *results.Results // Plugin output state
 }
 
 // Parse command line arguments and store their values. If the -h flag is present,
@@ -77,39 +77,39 @@ func (flags *programFlags) parseArguments() {
 }
 
 // Initialise the monitoring check program.
-func NewProgram() program.Program {
+func NewProgram() plugin.Plugin {
 	program := &checkProgram{
-		plugin: plugin.New("DNS zone serial match check"),
+		plugin: results.New("DNS zone serial match check"),
 	}
 	program.parseArguments()
 	return program
 }
 
 // Return the program's output value.
-func (program *checkProgram) Output() *plugin.Plugin {
+func (program *checkProgram) Results() *results.Results {
 	return program.plugin
 }
 
 // Check the values that were specified from the command line. Returns true if the arguments made sense.
 func (program *checkProgram) CheckArguments() bool {
 	if program.hostname == "" {
-		program.plugin.SetState(plugin.StatusUnknown, "no DNS hostname specified")
+		program.plugin.SetState(results.StatusUnknown, "no DNS hostname specified")
 		return false
 	}
 	if program.port < 1 || program.port > 65535 {
-		program.plugin.SetState(plugin.StatusUnknown, "invalid DNS port number")
+		program.plugin.SetState(results.StatusUnknown, "invalid DNS port number")
 		return false
 	}
 	if program.zone == "" {
-		program.plugin.SetState(plugin.StatusUnknown, "no DNS zone specified")
+		program.plugin.SetState(results.StatusUnknown, "no DNS zone specified")
 		return false
 	}
 	if program.rsHostname == "" {
-		program.plugin.SetState(plugin.StatusUnknown, "no reference DNS hostname specified")
+		program.plugin.SetState(results.StatusUnknown, "no reference DNS hostname specified")
 		return false
 	}
 	if program.rsPort < 1 || program.rsPort > 65535 {
-		program.plugin.SetState(plugin.StatusUnknown, "invalid reference DNS port number")
+		program.plugin.SetState(results.StatusUnknown, "invalid reference DNS port number")
 		return false
 	}
 	program.hostname = strings.ToLower(program.hostname)
@@ -176,12 +176,12 @@ func (program *checkProgram) RunCheck() {
 	cOk, cSerial := program.getSerial("checked", checkResponse)
 	rOk, rSerial := program.getSerial("reference", refResponse)
 	if !(cOk && rOk) {
-		program.plugin.SetState(plugin.StatusUnknown, "could not read serials")
+		program.plugin.SetState(results.StatusUnknown, "could not read serials")
 		return
 	}
 	if cSerial == rSerial {
-		program.plugin.SetState(plugin.StatusOK, "serials match")
+		program.plugin.SetState(results.StatusOK, "serials match")
 	} else {
-		program.plugin.SetState(plugin.StatusCritical, "serials mismatch")
+		program.plugin.SetState(results.StatusCritical, "serials mismatch")
 	}
 }

main.go

@@ -8,33 +8,33 @@ import (
 	"nocternity.net/gomonop/cmd/sslcert"
 	"nocternity.net/gomonop/cmd/zoneserial"
 	"nocternity.net/gomonop/pkg/plugin"
-	"nocternity.net/gomonop/pkg/program"
+	"nocternity.net/gomonop/pkg/results"
 	"nocternity.net/gomonop/pkg/version"
 )
 
 var (
-	programs map[string]program.Builder = map[string]program.Builder{
+	plugins map[string]plugin.Builder = map[string]plugin.Builder{
 		"check_ssl_certificate": sslcert.NewProgram,
 		"check_zone_serial":     zoneserial.NewProgram,
 	}
 )
 
-func getProgram() program.Program {
+func getPlugin() plugin.Plugin {
 	ownName := filepath.Base(os.Args[0])
 
-	if builder, ok := programs[ownName]; ok {
+	if builder, ok := plugins[ownName]; ok {
 		return builder()
 	}
 
 	if len(os.Args) < 2 {
-		fmt.Printf("Syntax: %s <program> [arguments]\n", ownName)
+		fmt.Printf("Syntax: %s <plugin> [arguments]\n", ownName)
-		fmt.Printf("        %s --programs|-p\n", ownName)
+		fmt.Printf("        %s --plugin|-p\n", ownName)
 		fmt.Printf("        %s --version|-v", ownName)
 	}
 
 	switch os.Args[1] {
-	case "--programs", "-p":
+	case "--plugins", "-p":
-		for name := range programs {
+		for name := range plugins {
 			fmt.Println(name)
 		}
 		os.Exit(0)
@@ -44,30 +44,30 @@ func getProgram() program.Program {
 		os.Exit(0)
 	}
 
-	if builder, ok := programs[os.Args[1]]; ok {
+	if builder, ok := plugins[os.Args[1]]; ok {
 		os.Args = os.Args[1:]
 		return builder()
 	}
 
-	fmt.Printf("Unknown program: %s\n", os.Args[1])
+	fmt.Printf("Unknown plugin: %s\n", os.Args[1])
 	os.Exit(1)
 	return nil
 }
 
 func main() {
-	program := getProgram()
+	runPlugin := getPlugin()
 
-	output := program.Output()
+	output := runPlugin.Results()
 	defer func() {
 		if r := recover(); r != nil {
-			output.SetState(plugin.StatusUnknown, "Internal error")
+			output.SetState(results.StatusUnknown, "Internal error")
 			output.AddLinef("Error info: %v", r)
 		}
 		fmt.Println(output.String())
 		os.Exit(output.ExitCode())
 	}()
 
-	if program.CheckArguments() {
+	if runPlugin.CheckArguments() {
-		program.RunCheck()
+		runPlugin.RunCheck()
 	}
 }

pkg/plugin/plugin.go

@@ -1,106 +1,20 @@
-// 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/plugin
 
-import (
+import "nocternity.net/gomonop/pkg/results"
-	"container/list"
-	"fmt"
-	"strings"
 
-	"nocternity.net/gomonop/pkg/perfdata"
+// Plugin represents the interface to a monitoring plugin.
-)
+type Plugin interface {
+	// Results accesses the results of the monitoring plugin.
+	Results() *results.Results
 
-// Plugin represents the monitoring plugin's state, including its name,
+	// CheckArguments ensures that the arguments that were passed to the plugin
-// return status and message, additional lines of text, and performance
+	// actually make sense. Errors should be stored in the plugin's results.
-// data to be encoded in the output.
+	CheckArguments() bool
-type Plugin struct {
+
-	name      string
+	// RunCheck actually runs whatever checks are implemented by the plugin and
-	status    Status
+	// updates the results accordingly.
-	message   string
+	RunCheck()
-	extraText *list.List
-	perfData  map[string]*perfdata.PerfData
 }
 
-// New creates the plugin with `name` as its name and an unknown status.
+// Builder is a function that can be called in order to instantiate a plugin.
-func New(name string) *Plugin {
+type Builder func() Plugin
-	p := new(Plugin)
-	p.name = name
-	p.status = StatusUnknown
-	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
-}
-
-// String generates the plugin's text output from its name, status, text data
-// and performance data.
-func (p *Plugin) String() string {
-	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))
-		}
-	}
-	return strBuilder.String()
-}
-
-// ExitCode returns the plugin's exit code.
-func (p *Plugin) ExitCode() int {
-	return int(p.status)
-}

pkg/program/program.go

@@ -1,11 +0,0 @@
-package program // import nocternity.net/gomonop/pkg/program
-
-import "nocternity.net/gomonop/pkg/plugin"
-
-type Program interface {
-	Output() *plugin.Plugin
-	CheckArguments() bool
-	RunCheck()
-}
-
-type Builder func() Program

pkg/results/results.go

@@ -0,0 +1,107 @@
+// Package results implements a helper that can be used to store the results of
+// a Nagios, Centreon, Icinga... service monitoring plugin, and convert them to
+// text which can be sent to the monitoring server.
+package results // import nocternity.net/gomonop/pkg/results
+
+import (
+	"container/list"
+	"fmt"
+	"strings"
+
+	"nocternity.net/gomonop/pkg/perfdata"
+)
+
+// Results represents the monitoring plugin's results, including its name,
+// return status and message, additional lines of text, and performance
+// data to be encoded in the output.
+type Results 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) *Results {
+	p := new(Results)
+	p.name = name
+	p.status = StatusUnknown
+	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 *Results) SetState(status Status, message string) {
+	p.status = status
+	p.message = message
+}
+
+// AddLine adds the specified string to the extra output text buffer.
+func (p *Results) 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 *Results) AddLinef(format string, data ...interface{}) {
+	p.AddLine(fmt.Sprintf(format, data...))
+}
+
+// AddLines add the specified `lines` to the output text.
+func (p *Results) 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 *Results) AddPerfData(pd *perfdata.PerfData) {
+	_, exists := p.perfData[pd.Label]
+	if exists {
+		panic("duplicate performance data " + pd.Label)
+	}
+	p.perfData[pd.Label] = pd
+}
+
+// String generates the plugin's text output from its name, status, text data
+// and performance data.
+func (p *Results) String() string {
+	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))
+		}
+	}
+	return strBuilder.String()
+}
+
+// ExitCode returns the plugin's exit code.
+func (p *Results) ExitCode() int {
+	return int(p.status)
+}

pkg/results/results_test.go

@@ -1,4 +1,4 @@
-package plugin // import nocternity.net/gomonop/pkg/plugin
+package results // import nocternity.net/gomonop/pkg/results
 
 import (
 	"container/list"
@@ -19,7 +19,7 @@ func TestNew(t *testing.T) {
 }
 
 func TestSetState(t *testing.T) {
-	p := Plugin{}
+	p := Results{}
 
 	p.SetState(StatusWarning, "test")
 
@@ -28,7 +28,7 @@ func TestSetState(t *testing.T) {
 }
 
 func TestAddLineFirst(t *testing.T) {
-	p := Plugin{}
+	p := Results{}
 
 	p.AddLine("test")
 
@@ -38,7 +38,7 @@ func TestAddLineFirst(t *testing.T) {
 }
 
 func TestAddLineNext(t *testing.T) {
-	p := Plugin{}
+	p := Results{}
 	p.extraText = list.New()
 
 	p.AddLine("test")
@@ -48,7 +48,7 @@ func TestAddLineNext(t *testing.T) {
 }
 
 func TestAddLinef(t *testing.T) {
-	p := Plugin{}
+	p := Results{}
 
 	p.AddLinef("test %d", 123)
 
@@ -57,7 +57,7 @@ func TestAddLinef(t *testing.T) {
 }
 
 func TestAddLines(t *testing.T) {
-	p := Plugin{}
+	p := Results{}
 
 	p.AddLines([]string{"test", "test2"})
 
@@ -67,7 +67,7 @@ func TestAddLines(t *testing.T) {
 }
 
 func TestAddPerfData(t *testing.T) {
-	p := Plugin{}
+	p := Results{}
 	p.perfData = make(map[string]*perfdata.PerfData)
 
 	p.AddPerfData(&perfdata.PerfData{Label: "test"})
@@ -78,7 +78,7 @@ func TestAddPerfData(t *testing.T) {
 }
 
 func TestAddPerfDataDuplicate(t *testing.T) {
-	p := Plugin{}
+	p := Results{}
 	p.perfData = make(map[string]*perfdata.PerfData)
 	p.perfData["test"] = &perfdata.PerfData{Label: "test"}
 
@@ -87,14 +87,14 @@ func TestAddPerfDataDuplicate(t *testing.T) {
 
 func TestString(t *testing.T) {
 	type Test struct {
-		Plugin
+		Results
 		expected string
 	}
 
 	pdat := perfdata.PerfData{Label: "test"}
 	tests := []Test{
 		{
-			Plugin{
+			Results{
 				name:     "test",
 				status:   StatusWarning,
 				message:  "test",
@@ -103,8 +103,8 @@ func TestString(t *testing.T) {
 			"test WARNING: test",
 		},
 		{
-			func() Plugin {
+			func() Results {
-				p := Plugin{
+				p := Results{
 					name:      "test",
 					status:    StatusWarning,
 					message:   "test",
@@ -118,8 +118,8 @@ func TestString(t *testing.T) {
 			"test WARNING: test\ntest 1\ntest 2",
 		},
 		{
-			func() Plugin {
+			func() Results {
-				p := Plugin{
+				p := Results{
 					name:     "test",
 					status:   StatusWarning,
 					message:  "test",
@@ -133,8 +133,8 @@ func TestString(t *testing.T) {
 				pdat.String(),
 		},
 		{
-			func() Plugin {
+			func() Results {
-				p := Plugin{
+				p := Results{
 					name:      "test",
 					status:    StatusWarning,
 					message:   "test",
@@ -153,13 +153,13 @@ func TestString(t *testing.T) {
 	}
 
 	for _, test := range tests {
-		result := test.Plugin.String()
+		result := test.Results.String()
 		assert.Equal(t, test.expected, result, "Expected '%s', got '%s'", test.expected, result)
 	}
 }
 
 func TestExitCode(t *testing.T) {
-	p := Plugin{}
+	p := Results{}
 
 	p.status = StatusOK
 	assert.Equal(t, int(StatusOK), p.ExitCode())

pkg/results/status.go

@@ -1,4 +1,4 @@
-package plugin // import nocternity.net/gomonop/pkg/plugin
+package results // import nocternity.net/gomonop/pkg/results
 
 // Status represents the return status of the monitoring plugin. The
 // corresponding integer value will be used as the program's exit code,

pkg/results/status_test.go

@@ -1,4 +1,4 @@
-package plugin // import nocternity.net/gomonop/pkg/plugin
+package results // import nocternity.net/gomonop/pkg/results
 
 import (
 	"testing"