github.com/caos/orbos@v1.5.14-0.20221103111702-e6cd0cea7ad4/internal/operator/nodeagent/dep/swap/dep.go (about)

     1  package swap
     2  
     3  import (
     4  	"bytes"
     5  
     6  	"fmt"
     7  	"io"
     8  	"os/exec"
     9  	"strings"
    10  
    11  	"github.com/caos/orbos/internal/operator/common"
    12  	"github.com/caos/orbos/internal/operator/nodeagent"
    13  	"github.com/caos/orbos/internal/operator/nodeagent/dep"
    14  	"github.com/caos/orbos/internal/operator/nodeagent/dep/middleware"
    15  )
    16  
    17  type Installer interface {
    18  	isSwap()
    19  	nodeagent.Installer
    20  }
    21  
    22  type swapDep struct {
    23  	fstabFilePath string
    24  }
    25  
    26  func New(fstabFilePath string) Installer {
    27  	return &swapDep{fstabFilePath: fstabFilePath}
    28  }
    29  
    30  func (swapDep) Is(other nodeagent.Installer) bool {
    31  	_, ok := middleware.Unwrap(other).(Installer)
    32  	return ok
    33  }
    34  
    35  func (swapDep) isSwap() {}
    36  
    37  func (swapDep) String() string { return "Swap" }
    38  
    39  func (*swapDep) Equals(other nodeagent.Installer) bool {
    40  	_, ok := other.(*swapDep)
    41  	return ok
    42  }
    43  
    44  func (*swapDep) InstalledFilter() []string { return nil }
    45  
    46  func (s *swapDep) Current() (pkg common.Package, err error) {
    47  
    48  	buf := new(bytes.Buffer)
    49  	defer buf.Reset()
    50  
    51  	swapon := exec.Command("swapon", "--summary")
    52  	swapon.Stdout = buf
    53  	if err := swapon.Run(); err != nil {
    54  		return pkg, err
    55  	}
    56  
    57  	pkg.Version = "disabled"
    58  	var lines uint8
    59  	var line string
    60  	for {
    61  		if err != nil && err != io.EOF {
    62  			return pkg, err
    63  		}
    64  		line, err = buf.ReadString('\n')
    65  		if len(line) > 0 {
    66  			lines++
    67  		}
    68  		if lines >= 2 {
    69  			pkg.Version = "enabled"
    70  			return
    71  		}
    72  		if err == io.EOF {
    73  			return pkg, nil
    74  		}
    75  	}
    76  }
    77  
    78  func (s *swapDep) Ensure(remove common.Package, ensure common.Package, _ bool) error {
    79  	buf := new(bytes.Buffer)
    80  	defer buf.Reset()
    81  
    82  	swapoff := exec.Command("swapoff", "--all")
    83  	swapoff.Stderr = buf
    84  	if err := swapoff.Run(); err != nil {
    85  		return fmt.Errorf("disabling swap failed with standard error: %s: %w", buf.String(), err)
    86  	}
    87  
    88  	return dep.ManipulateFile(s.fstabFilePath, nil, nil, func(line string) *string {
    89  		if !strings.Contains(line, "swap") {
    90  			return &line
    91  		}
    92  		switch {
    93  		case strings.HasPrefix(line, "#") && ensure.Version == "enabled" && remove.Version == "disabled":
    94  			line = strings.Replace(line, "#", "", 1)
    95  		case !strings.HasPrefix(line, "#") && ensure.Version == "disabled" && remove.Version == "enabled":
    96  			line = "#" + line
    97  		}
    98  		return &line
    99  	})
   100  }