Merge pull request #74 from thin-edge/feat-config-data-dir

feat(config): add data_dir config setting

Author: reubenmiller

cli/container_group/install.go

@@ -61,8 +61,7 @@ func (c *InstallCommand) RunE(cmd *cobra.Command, args []string) error {
 	// Run docker compose down before up
 	// TODO: Move to settings file
 	downFirst := false
-	baseDir := "/var/tedge-container-plugin/compose"
-	workingDir := filepath.Join(baseDir, projectName)
+	workingDir := filepath.Join(c.CommandContext.PersistentDir(true), "compose", projectName)
 
 	// Stop project
 	if downFirst && utils.PathExists(workingDir) {

packaging/config.toml

@@ -4,6 +4,10 @@ log_level = "info"
 # Service name used to show the status of the service
 service_name = "tedge-container-plugin"
 
+# Data directory used to store state such as docker compose project files
+# The first writable directory will be used
+data_dir = ["/var/tedge-container-plugin", "/data/tedge-container-plugin"]
+
 # Remove the legacy tedge-container-monitor service
 delete_legacy = true
 

pkg/cli/cli.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"log/slog"
 	"os"
+	"path/filepath"
 	"sort"
 	"strings"
 	"time"
@@ -27,6 +28,7 @@ func (c *Cli) OnInit() {
 	// Set shared config
 	viper.SetDefault("container.network", "tedge")
 	viper.SetDefault("delete_legacy", true)
+	viper.SetDefault("data_dir", []string{"/var/tedge-container-plugin", "/data/tedge-container-plugin"})
 
 	if c.ConfigFile != "" && utils.PathExists(c.ConfigFile) {
 		// Use config file from the flag.
@@ -165,6 +167,25 @@ func (c *Cli) GetDeviceTarget() tedge.Target {
 	}
 }
 
+func (c *Cli) PersistentDir(check_writable bool) string {
+	paths := viper.GetStringSlice("data_dir")
+	defaultDir := filepath.Join(os.TempDir(), c.GetServiceName())
+
+	if !check_writable {
+		if len(paths) > 0 {
+			return paths[0]
+		}
+		return defaultDir
+	}
+
+	for _, p := range paths {
+		if ok, _ := utils.IsDirWritable(p, 0755); ok {
+			return p
+		}
+	}
+	return defaultDir
+}
+
 func getExpandedStringSlice(key string) []string {
 	v := viper.GetStringSlice(key)
 	out := make([]string, 0, len(v))

pkg/utils/utils.go

@@ -2,6 +2,7 @@ package utils
 
 import (
 	"errors"
+	"io/fs"
 	"os"
 	"os/exec"
 )
@@ -26,3 +27,20 @@ func CommandExists(cmd string) bool {
 	_, err := exec.LookPath(cmd)
 	return err == nil
 }
+
+// Check if a directory is writable.
+// It tries to create a dummy file in the directory to verify
+func IsDirWritable(d string, perm fs.FileMode) (bool, error) {
+	dirErr := os.MkdirAll(d, 0755)
+	if dirErr != nil {
+		return false, dirErr
+	}
+
+	file, err := os.CreateTemp(d, ".write-test")
+	if err != nil {
+		return false, err
+	}
+	defer os.Remove(file.Name())
+	defer file.Close()
+	return true, nil
+}