add DryRun() method for instruction common interface | add DryRun() method to all instructions | TODO: tests + install/delete

internal/buildfile/reader.go

@@ -112,7 +112,13 @@ func NewReader(ctx *instruction.ExecutionContext, buildfile io.Reader) (*Reader,
 }
 
 // Execute the current buildfile instruction by instruction
-func (r *Reader) Execute() error {
+// if <dryRun> is set to TRUE, run on dry-run mode
+func (r *Reader) Execute(_dryRun ...bool) error {
+
+	dryRun := true
+	if len(_dryRun) < 1 || !_dryRun[0] {
+		dryRun = false
+	}
 
 	// 1. update package list
 	// err := r.Context.PackageManager.Fetch()
@@ -168,7 +174,7 @@ func (r *Reader) Execute() error {
 
 	// 3. launch [pre] (it set)
 	if pre != nil {
-		execSection(pre, *r.Context, preTable, refresh, wg)
+		execSection(pre, *r.Context, preTable, dryRun, refresh, wg)
 		time.Sleep(time.Second * 2)
 	}
 
@@ -182,7 +188,7 @@ func (r *Reader) Execute() error {
 		if !ok {
 			continue
 		}
-		go execSection(sec, *r.Context, &table[i], refresh, wg)
+		go execSection(sec, *r.Context, &table[i], dryRun, refresh, wg)
 	}
 
 	wg.Wait()
@@ -192,11 +198,17 @@ func (r *Reader) Execute() error {
 	return nil
 }
 
-func execSection(section *[]instruction.T, ctx instruction.ExecutionContext, tsec *tableSection, refresher chan<- bool, wg *sync.WaitGroup) {
+func execSection(section *[]instruction.T, ctx instruction.ExecutionContext, tsec *tableSection, dryRun bool, refresher chan<- bool, wg *sync.WaitGroup) {
 
 	for i, inst := range *section {
 		tsec.instructions[i].start = time.Now()
-		_, err := inst.Exec(ctx)
+		var err error = nil
+		if dryRun {
+			_, err = inst.DryRun(ctx)
+		} else {
+			_, err = inst.Exec(ctx)
+
+		}
 		tsec.instructions[i].stop = time.Now()
 		tsec.instructions[i].stopped = true
 		tsec.instructions[i].err = err

internal/instruction/alias.go

@@ -39,3 +39,7 @@ func (d alias) Exec(ctx ExecutionContext) ([]byte, error) {
 	ctx.Alias[d.Name] = d.Value
 	return nil, nil
 }
+
+func (d alias) DryRun(ctx ExecutionContext) ([]byte, error) {
+	return d.Exec(ctx)
+}

internal/instruction/common.go

@@ -15,6 +15,8 @@ type T interface {
 	Build(string) error
 	// Exec the given instruction
 	Exec(ExecutionContext) ([]byte, error)
+	// DryRun checks the success of the given instruction without actually running it (non-destructive)
+	DryRun(ExecutionContext) ([]byte, error)
 }
 
 // ExecutionContext contains system-specific drivers to manage the host

internal/instruction/copy.go

@@ -45,3 +45,38 @@ func (d copy) Exec(ctx ExecutionContext) ([]byte, error) {
 	return nil, nil
 
 }
+
+func (d copy) DryRun(ctx ExecutionContext) ([]byte, error) {
+
+	// 1. fail if source file not found
+	if _, err := os.Stat(d.Src); os.IsNotExist(err) {
+		return nil, fmt.Errorf("cannot find file '%s'", d.Src)
+	}
+
+	// 2. if destination to create : try to create (then remove)
+	if _, err := os.Stat(d.Src); os.IsNotExist(err) {
+
+		file, err := os.OpenFile(d.Dst, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0600)
+		if err != nil {
+			return nil, fmt.Errorf("cannot copy '%s' to '%s' | %s", d.Src, d.Dst, err)
+		}
+		file.Close()
+
+		if err := os.Remove(d.Dst); err != nil {
+			return nil, fmt.Errorf("cannot tmp file at '%s' | %s", d.Dst, err)
+		}
+
+		return nil, nil
+
+	}
+
+	// 3. if destination exists : check write permission
+	file, err := os.OpenFile(d.Dst, os.O_APPEND|os.O_WRONLY, 0600)
+	if err != nil {
+		return nil, fmt.Errorf("cannot copy '%s' to '%s' | %s", d.Src, d.Dst, err)
+	}
+	file.Close()
+
+	return nil, nil
+
+}

internal/instruction/delete.go

@@ -33,3 +33,7 @@ func (d delete) Exec(ctx ExecutionContext) ([]byte, error) {
 	return nil, nil
 
 }
+
+func (d delete) DryRun(ctx ExecutionContext) ([]byte, error) {
+	return nil, nil
+}

internal/instruction/install.go

@@ -33,3 +33,7 @@ func (d install) Exec(ctx ExecutionContext) ([]byte, error) {
 	return nil, nil
 
 }
+
+func (d install) DryRun(ctx ExecutionContext) ([]byte, error) {
+	return nil, nil
+}

internal/instruction/run.go

@@ -40,3 +40,21 @@ func (d run) Exec(ctx ExecutionContext) ([]byte, error) {
 	return nil, nil
 
 }
+func (d run) DryRun(ctx ExecutionContext) ([]byte, error) {
+
+	// 1. get file / alias
+	path := d.raw
+	if !strings.Contains(path, "/") {
+		if p, exists := ctx.Alias[path]; exists {
+			path = p
+		}
+	}
+
+	// 1. fail if file not found
+	if _, err := os.Stat(path); os.IsNotExist(err) {
+		return nil, fmt.Errorf("cannot find script '%s'", path)
+	}
+
+	return nil, nil
+
+}

internal/instruction/service.go

@@ -60,3 +60,17 @@ func (d service) Exec(ctx ExecutionContext) ([]byte, error) {
 	return nil, nil
 
 }
+func (d service) DryRun(ctx ExecutionContext) ([]byte, error) {
+
+	// fail if a service does not exist
+	for _, service := range d.Services {
+
+		if err := ctx.ServiceManager.Exec("status", service); err != nil {
+			return nil, fmt.Errorf("cannot find service '%s' | %s", service, err)
+		}
+
+	}
+
+	return nil, nil
+
+}

internal/instruction/set.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"github.com/xdrm-brackets/nix-amer/internal/cnf"
 	"os"
+	"path/filepath"
 	"strings"
 )
 
@@ -94,3 +95,57 @@ func (d set) Exec(ctx ExecutionContext) ([]byte, error) {
 	return nil, nil
 
 }
+func (d set) DryRun(ctx ExecutionContext) ([]byte, error) {
+
+	// 1. get file / alias
+	path := d.File
+	if !strings.Contains(path, "/") {
+		if p, exists := ctx.Alias[path]; exists {
+			path = p
+		}
+	}
+
+	// 2. fail if file not found
+	if _, err := os.Stat(path); os.IsNotExist(err) {
+		return nil, fmt.Errorf("cannot find file '%s'", path)
+	}
+
+	// 3. try to load format
+	format, err := cnf.Load(path)
+	if err != nil {
+		return nil, err
+	}
+
+	// 4. try to update value
+	if !format.Set(d.Path, d.Value) {
+		return nil, ErrCannotSet
+	}
+
+	// 5. fail on missing write permission
+	file, err := os.OpenFile(path, os.O_APPEND|os.O_WRONLY, os.FileMode(0775))
+	if err != nil {
+		return nil, fmt.Errorf("cannot update '%s' | %s", path, err)
+	}
+	file.Close()
+
+	// 6. create non-destructive dry-run folder
+	dryRunFolder := "/tmp/dry-run"
+	if err := os.MkdirAll(dryRunFolder, os.FileMode(0777)); err != nil {
+		return nil, fmt.Errorf("cannot create dry-run folder | %s", err)
+
+	}
+
+	// 7. create updated file inside .dry-run
+	tmpout := filepath.Join(dryRunFolder, strings.Replace(path, "/", "-", -1))
+	file, err = os.Create(tmpout)
+	if err != nil {
+		return nil, fmt.Errorf("cannot create dry-run file '%s' | %s", tmpout, err)
+	}
+	defer file.Close()
+	if _, err = format.WriteTo(file); err != nil {
+		return nil, fmt.Errorf("cannot write dry-run file '%s' | %s", tmpout, err)
+	}
+
+	return nil, nil
+
+}

internal/ser/systemd.go

@@ -7,7 +7,7 @@ import (
 type systemd struct{ exec exec.Executor }
 
 // available actions
-var actions = []string{"enable", "disable", "start", "stop", "reload", "restart"}
+var actions = []string{"enable", "disable", "status", "start", "stop", "reload", "restart"}
 
 func (d *systemd) SetExecutor(_exec exec.Executor) {
 	d.exec = _exec

main.go

@@ -43,13 +43,10 @@ func main() {
 	fmt.Printf("%s\n", clifmt.Color(32, "valid"))
 
 	// stop here if dry run
-	if dryRun {
-		return
-	}
 
 	// 3. Execute
 	fmt.Printf("------\n")
-	err = instructions.Execute()
+	err = instructions.Execute(dryRun)
 	if err != nil {
 		fmt.Printf("%s\n", clifmt.Warn(err.Error()))
 		return
@@ -58,4 +55,8 @@ func main() {
 	clifmt.Align("finished in")
 	fmt.Printf("%ss\n", clifmt.Color(32, fmt.Sprintf("%.2f", time.Now().Sub(start).Seconds())))
 
+	if dryRun {
+		fmt.Printf("\n%s %s\n", clifmt.Info("updated configurations are inside"), clifmt.Color(32, "/tmp/dry-run"))
+	}
+
 }