charmbracelet/glow · error

unable to get cache dir: %w

Error message

unable to get cache dir: %w

What it means

On startup glow resolves a log-file directory with go-app-paths (gap.NewScope(gap.User, "glow").CacheDir(), i.e. ~/.cache/glow on Linux). This error means the user cache directory could not be determined - typically because HOME and XDG_CACHE_HOME are unset or unusable. main() treats it as fatal: it prints the error and exits 1, so glow does not start at all.

Source

Thrown at log.go:16

package main

import (
	"fmt"
	"io"
	"os"
	"path/filepath"

	"github.com/charmbracelet/log"
	gap "github.com/muesli/go-app-paths"
)

func getLogFilePath() (string, error) {
	dir, err := gap.NewScope(gap.User, "glow").CacheDir()
	if err != nil {
		return "", fmt.Errorf("unable to get cache dir: %w", err)
	}
	return filepath.Join(dir, "glow.log"), nil
}

func setupLog() (func() error, error) {
	log.SetOutput(io.Discard)
	// Log to file, if set
	logFile, err := getLogFilePath()
	if err != nil {
		return nil, err
	}
	if err := os.MkdirAll(filepath.Dir(logFile), 0o755); err != nil { //nolint:gosec
		// log disabled
		return func() error { return nil }, nil //nolint:nilerr
	}
	f, err := os.OpenFile(logFile, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0o644) //nolint:gosec
	if err != nil {
		// log disabled

View on GitHub (pinned to e3970c813d)

Solutions

1. Set HOME to a writable directory: export HOME=/tmp
2. Or set XDG_CACHE_HOME=/tmp/cache on Linux so the cache dir resolves
3. For service units, add Environment="HOME=/var/lib/glow" to the unit file
4. Verify writability afterwards: mkdir -p ~/.cache/glow

func cacheDirResolvable() bool {
	if dir := os.Getenv("XDG_CACHE_HOME"); dir != "" {
		fi, err := os.Stat(dir)
		return err == nil && fi.IsDir()
	}
	return os.Getenv("HOME") != ""
}

When it happens

Trigger: HOME unset and XDG_CACHE_HOME unset (gap cannot compute the cache path); HOME pointing to a path that cannot be resolved; running in an environment where neither variable exists.

Common situations: Docker/OCI scratch or distroless images, systemd units without Environment="HOME=...", cron jobs, CI runners that scrub the environment, minimal sandboxes.

Related errors

• missing markdown source
• unable to set config file: %w
• could not write configuration file: %w
• unable create directory: %w
• unable to create config file: %w

AI-assisted analysis of charmbracelet/glow@e3970c813d (2026-08-15). Data as JSON: /api/errors/5f7785d08957ba54. Report an issue: GitHub.