fix: limit run command output to 2MB

internal/ioutil/ioutil.go

@@ -2,6 +2,7 @@ package ioutil
 
 import (
 	"bytes"
+	"fmt"
 	"io"
 	"sync"
 	"sync/atomic"
@@ -101,3 +102,25 @@ func (w *SizeTrackingWriter) Write(p []byte) (n int, err error) {
 func (w *SizeTrackingWriter) Size() uint64 {
 	return w.size.Load()
 }
+
+type SizeLimitedWriter struct {
+	SizeTrackingWriter
+	Limit uint64
+}
+
+var _ io.Writer = &SizeLimitedWriter{}
+
+func (w *SizeLimitedWriter) Write(p []byte) (n int, err error) {
+	size := w.Size()
+	if size+uint64(len(p)) > w.Limit {
+		p = p[:w.Limit-size]
+		err = fmt.Errorf("size limit exceeded: %d bytes written, limit is %d bytes", size, w.Limit)
+	}
+
+	var e error
+	n, e = w.Writer.Write(p)
+	if e != nil {
+		err = e
+	}
+	return
+}

internal/orchestrator/tasks/taskruncommand.go

@@ -9,6 +9,8 @@ import (
 	"github.com/garethgeorge/backrest/internal/ioutil"
 )
 
+var DefaultCommandOutputSizeLimit uint64 = 2_000_000 // 2MB
+
 func NewOneoffRunCommandTask(repo *v1.Repo, planID string, flowID int64, at time.Time, command string) Task {
 	return &GenericOneoffTask{
 		OneoffTask: OneoffTask{
@@ -54,9 +56,13 @@ func runCommandHelper(ctx context.Context, st ScheduledTask, taskRunner TaskRunn
 		return fmt.Errorf("get logref writer: %w", err)
 	}
 	defer writer.Close()
-	sizeWriter := &ioutil.SizeTrackingWriter{Writer: writer}
+	sizeWriter := &ioutil.SizeLimitedWriter{
+		SizeTrackingWriter: ioutil.SizeTrackingWriter{Writer: writer},
+		Limit:              DefaultCommandOutputSizeLimit, // 2 MB max output size
+	}
 	defer func() {
-		runCmdOp.OutputSizeBytes = int64(sizeWriter.Size())
+		size := sizeWriter.Size()
+		runCmdOp.OutputSizeBytes = int64(size)
 	}()
 
 	runCmdOp.OutputLogref = id

internal/resticinstaller/resticinstaller.go

@@ -145,7 +145,7 @@ func removeOldVersions(installDir string) {
 
 func installResticHelper(resticInstallPath string) {
 	if _, err := os.Stat(resticInstallPath); err == nil {
-		zap.S().Infof("replacing restic binary in data dir due to failed check: %w", err)
+		zap.S().Infof("replacing restic binary in data dir due to failed check: %v", err)
 		if err := os.Remove(resticInstallPath); err != nil {
 			zap.S().Errorf("failed to remove old restic binary %v: %v", resticInstallPath, err)
 		}
@@ -211,6 +211,7 @@ func tryFindOrInstall() (string, error) {
 
 		// Check again after acquiring the lock.
 		if err := assertResticVersion(resticInstallPath); err != nil {
+			zap.S().Errorf("could not verify version of binary %v: %v", resticInstallPath, err)
 			installResticHelper(resticInstallPath)
 		}
 	}