refactor: create check.go, use flagrun and seferio

Makefile

@@ -1,10 +1,9 @@
 VERSION=0.0.7
-GITCOMMIT?=$(shell git describe --dirty --always)
-LDFLAGS=-ldflags "-w -s -X main.version=${VERSION} -X main.commit=${GITCOMMIT}"
+LDFLAGS=-ldflags "-w -s -X main.version=${VERSION}"
 
 all: check-diff
 
-.PHONY: check-diff
+.PHONY: check-diff lint check linux
 
 check-diff: *.go
 	go build $(LDFLAGS) -o check-diff

check.go

@@ -0,0 +1,97 @@
+package main
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"fmt"
+	"os"
+	"os/exec"
+	"os/user"
+	"path/filepath"
+	"strings"
+
+	"github.com/mackerelio/checkers"
+	"github.com/monitoring-forge/saferio"
+)
+
+func (opt *Opt) cmd(file *os.File) error {
+	cmd := exec.Command(opt.Command, opt.Args...)
+	var stderr bytes.Buffer
+	cmd.Stdout = file
+	cmd.Stderr = &stderr
+	if err := cmd.Start(); err != nil {
+		return err
+	}
+	err := cmd.Wait()
+	if err != nil {
+		return fmt.Errorf("%w - %s", err, stderr.String())
+	}
+	return nil
+}
+
+func (opt *Opt) check() *checkers.Checker {
+
+	hasher := sha256.New()
+	fmt.Fprintf(hasher, "%s\x00%s\x00%s", opt.Identifier, opt.Command, strings.Join(opt.Args, "\x00"))
+
+	curUser, err := user.Current()
+	if err != nil {
+		return checkers.Critical(err.Error())
+	}
+
+	prevFileName := fmt.Sprintf("check-diff-%s-%x", curUser.Uid, hasher.Sum(nil))
+	newFile, err := os.CreateTemp(opt.Workdir, "check-diff-")
+	if err != nil {
+		return checkers.Critical(err.Error())
+	}
+
+	defer func() {
+		_ = newFile.Close()
+		_ = os.Remove(newFile.Name())
+	}()
+
+	err = opt.cmd(newFile)
+	if err != nil {
+		return checkers.Critical(err.Error())
+	}
+
+	err = newFile.Close()
+	if err != nil {
+		return checkers.Critical(err.Error())
+	}
+
+	if !saferio.FileExists(opt.Workdir, prevFileName) {
+		err = os.Rename(newFile.Name(), filepath.Join(opt.Workdir, prevFileName))
+		if err != nil {
+			return checkers.Critical(err.Error())
+		}
+		if len(opt.Args) > 0 {
+			return checkers.Ok(fmt.Sprintf("first time execution command: '%s %s'", opt.Command, strings.Join(opt.Args, " ")))
+		}
+		return checkers.Ok(fmt.Sprintf("first time execution command: '%s'", opt.Command))
+	}
+
+	diff, err := diff(filepath.Join(opt.Workdir, prevFileName), newFile.Name())
+	if err != nil {
+		return checkers.Critical(err.Error())
+	}
+
+	err = os.Rename(newFile.Name(), filepath.Join(opt.Workdir, prevFileName))
+	if err != nil {
+		return checkers.Critical(err.Error())
+	}
+
+	if diff == "" {
+		msg, err := buildNoDifferenceMsg(filepath.Join(opt.Workdir, prevFileName))
+		if err != nil {
+			return checkers.Critical(err.Error())
+		}
+		return checkers.Ok(msg)
+	}
+
+	diffMsg := buildDiffMsg(diff)
+	if opt.Warn {
+		return checkers.Warning(diffMsg)
+	}
+	return checkers.Critical(diffMsg)
+}

main_test.go → check_test.go

@@ -84,19 +84,19 @@ func createTempFile(t *testing.T, content string) (*os.File, func()) {
 	}
 }
 
-func TestRun(t *testing.T) {
+func TestCheck(t *testing.T) {
 	opt, file := getCmdOpt(t, "echo", []string{"Hello, World!"})
 	defer file.Close()
-	ckr := opt.run()
+	ckr := opt.check()
 	if ckr.Status != checkers.OK {
 		t.Errorf("Expected OK status, got %v", ckr.Status)
 	}
 	if !strings.Contains(ckr.Message, "first time execution command") {
 		t.Errorf("Expected first time execution message, got %q", ckr.Message)
 	}
 
-	// Run again to check for no difference
-	ckr = opt.run()
+	// Check again to check for no difference
+	ckr = opt.check()
 	if ckr.Status != checkers.OK {
 		t.Errorf("Expected OK status, got %v", ckr.Status)
 	}
@@ -105,16 +105,16 @@ func TestRun(t *testing.T) {
 	}
 }
 
-func TestRunWithDifference(t *testing.T) {
+func TestCheckWithDifference(t *testing.T) {
 	opt, file := getCmdOpt(t, "date", []string{})
 	defer file.Close()
-	// First run to create the initial state
-	opt.run()
+	// First check to create the initial state
+	opt.check()
 
 	// Change the command to produce a different output
 	time.Sleep(2 * time.Second) // Ensure the date command produces a different output
 	opt.Command = "date"
-	ckr := opt.run()
+	ckr := opt.check()
 	if ckr.Status != checkers.CRITICAL {
 		t.Errorf("Expected CRITICAL status, got %v", ckr.Status)
 	}

diff.go

@@ -2,15 +2,17 @@ package main
 
 import (
 	"bufio"
+	"errors"
 	"fmt"
 	"io"
 	"strings"
 
 	"github.com/cubicdaiya/gonp"
+	"github.com/monitoring-forge/saferio"
 )
 
 func getLines(filename string) ([]string, error) {
-	file, err := openRD(filename)
+	file, err := saferio.OpenRD(filename)
 	if err != nil {
 		return nil, err
 	}
@@ -29,23 +31,23 @@ func getLines(filename string) ([]string, error) {
 }
 
 func diff(prev, current string) (string, error) {
-    prevLines, err := getLines(prev)
-    if err != nil {
-        return "", err
-    }
-    newLines, err := getLines(current)
-    if err != nil {
-        return "", err
-    }
+	prevLines, err := getLines(prev)
+	if err != nil {
+		return "", err
+	}
+	newLines, err := getLines(current)
+	if err != nil {
+		return "", err
+	}
 
-    d := gonp.New(prevLines, newLines)
-    d.Compose()
+	d := gonp.New(prevLines, newLines)
+	d.Compose()
 
-    return d.SprintUniHunks(d.UnifiedHunks()), nil
+	return d.SprintUniHunks(d.UnifiedHunks()), nil
 }
 
 func buildNoDifferenceMsg(filename string) (string, error) {
-	file, err := openRD(filename)
+	file, err := saferio.OpenRD(filename)
 	if err != nil {
 		return "", err
 	}
@@ -57,7 +59,7 @@ func buildNoDifferenceMsg(filename string) (string, error) {
 	}
 	b := make([]byte, 128)
 	count, err := file.Read(b)
-	if err != nil && err != io.EOF {
+	if err != nil && !errors.Is(err, io.EOF) {
 		return "", err
 	}
 	o := string(strings.TrimRight(string(b[0:count]), "\r\n"))

go.mod

@@ -11,5 +11,7 @@ require github.com/cubicdaiya/gonp v1.0.4
 
 require (
 	github.com/mackerelio/golib v1.2.2
+	github.com/monitoring-forge/flagrun v0.0.7
+	github.com/monitoring-forge/saferio v0.0.2
 	golang.org/x/sys v0.47.0 // indirect
 )

go.sum

@@ -6,5 +6,9 @@ github.com/mackerelio/checkers v0.2.1 h1:vRXzAT+CEyaLjSrHVxKUBjyWq1kfo8QcI8ZoSKZ
 github.com/mackerelio/checkers v0.2.1/go.mod h1:CW3k/5bvHhxDrfKgWvMvNH0R51zco141ZVxlI7o/KAc=
 github.com/mackerelio/golib v1.2.2 h1:fQfW1o2KvPyIsAH/7+M2J0gpf2jLu+NyYpDCN79zxW4=
 github.com/mackerelio/golib v1.2.2/go.mod h1:itcSOfrsT5XvkzflFPebT43RrliaKDz2T6YGYt3jclw=
+github.com/monitoring-forge/flagrun v0.0.7 h1:6UpM8waZzN0KiZJJ2xHP64TncdmMKHE6W2HBxJwhAZA=
+github.com/monitoring-forge/flagrun v0.0.7/go.mod h1:yAwxGIEx81wU4JOMp6hz7SdSYWgT/Hr4JXEdHlEn1mw=
+github.com/monitoring-forge/saferio v0.0.2 h1:DJ4D4e7tBuMze4Ez7N7l7pGPAJ/oFsC0mwh+dg5UkwE=
+github.com/monitoring-forge/saferio v0.0.2/go.mod h1:N2nfAMrgYrax2CdwKIIWIjy5tIrlQFtJJWzKess30KY=
 golang.org/x/sys v0.47.0 h1:o7XGOvZQCADBQQ4Y7VNq2dRWQR7JmOUW8Kxx4ZsNgWs=
 golang.org/x/sys v0.47.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=