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.

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 (
-	"container/list"
-	"fmt"
-	"strings"
+import "nocternity.net/gomonop/pkg/results"
 
-	"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,
-// 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
+	// CheckArguments ensures that the arguments that were passed to the plugin
+	// actually make sense. Errors should be stored in the plugin's results.
+	CheckArguments() bool
+
+	// RunCheck actually runs whatever checks are implemented by the plugin and
+	// updates the results accordingly.
+	RunCheck()
 }
 
-// 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 = 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)
-}
+// Builder is a function that can be called in order to instantiate a plugin.
+type Builder func() Plugin

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 {
-				p := Plugin{
+			func() Results {
+				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 {
-				p := Plugin{
+			func() Results {
+				p := Results{
 					name:     "test",
 					status:   StatusWarning,
 					message:  "test",
@@ -133,8 +133,8 @@ func TestString(t *testing.T) {
 				pdat.String(),
 		},
 		{
-			func() Plugin {
-				p := Plugin{
+			func() Results {
+				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"