abiosoft/colima · error

cannot read file '%s': %w

Error message

cannot read file '%s': %w

What it means

limaVM.Read is the environment's file-read primitive: it runs `sudo cat <fileName>` inside the guest over SSH and wraps any failure as 'cannot read file'. The wrapped error typically includes the non-zero exit of cat (file missing, permission issues even under sudo, I/O errors) or the underlying SSH/guest execution failure. Any Colima feature that reads a guest file (certs, runtime config detection) funnels through here.

Source

Thrown at environment/vm/lima/file.go:19

package lima

import (
	"bytes"
	"fmt"
	"io/fs"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"time"

	"github.com/abiosoft/colima/environment"
)

func (l limaVM) Read(fileName string) (string, error) {
	s, err := l.RunOutput("sudo", "cat", fileName)
	if err != nil {
		return "", fmt.Errorf("cannot read file '%s': %w", fileName, err)
	}
	return s, err
}

func (l *limaVM) Write(fileName string, body []byte) error {
	var stdin = bytes.NewReader(body)
	dir := filepath.Dir(fileName)
	if err := l.RunQuiet("sudo", "mkdir", "-p", dir); err != nil {
		return fmt.Errorf("error creating directory '%s': %w", dir, err)
	}
	return l.RunWith(stdin, nil, "sudo", "sh", "-c", "cat > "+fileName)
}

func (l *limaVM) Stat(fileName string) (os.FileInfo, error) {
	return newFileInfo(l, fileName)
}

var _ os.FileInfo = (*fileInfo)(nil)

View on GitHub (pinned to c3a5f9184d)

Solutions

1. Confirm the VM is actually running (`colima status`) before issuing reads.
2. Check the exact guest path exists via `colima ssh -- sudo ls -la <path>` and create/fix it if missing.
3. Retry after a full stop/start if the guest was in a transient state.
4. In caller code, treat ENOENT-style wrapped errors for optional files as non-fatal rather than aborting.

Example fix

// before
body, err := vm.Read("/etc/containerd/config.toml")
if err != nil { return err } // aborts on missing optional file

// after
body, err := vm.Read("/etc/containerd/config.toml")
if err != nil {
    if strings.Contains(err.Error(), "No such file") { body = "" } else { return err }
}

// guard reads: vm must be running, and optional files tolerated as absent
if !vm.Running(ctx) { return errors.New("vm not running") }
if _, err := vm.Stat(fileName); err != nil && isOptional(fileName) { return "", nil }

Go: read, then on error inspect the chain; for optional configs treat ENOENT-like messages ("No such file") as empty result, propagate the rest.

When it happens

Trigger: Reading a guest path that does not exist (e.g. a config file not yet created by the runtime); calling Read while the VM is stopping/stopped so the SSH command fails; guest disk I/O errors.

Common situations: Automation scripts probing optional files in the guest; races where a file is read before the guest service creates it; profile in a broken half-started state.

Related errors

• error creating directory '%s': %w
• error reading ssh config: %w
• error modifying %s: %w
• failed to create dnsmasq config directory: %w
• failed to write dnsmasq config: %w

AI-assisted analysis of abiosoft/colima@c3a5f9184d (2026-08-15). Data as JSON: /api/errors/177e3521823e65da. Report an issue: GitHub.