feat: docker compose backup

internal/config/config.go

@@ -0,0 +1,143 @@
+package config
+
+import (
+	"fmt"
+	"os"
+	"strings"
+)
+
+// Config is the top-level configuration.
+type Config struct {
+	Global   GlobalConfig   `mapstructure:"global"`
+	Projects []ProjectConfig `mapstructure:"projects"`
+	Remote   *RemoteConfig  `mapstructure:"remote"`
+}
+
+// GlobalConfig holds global settings.
+type GlobalConfig struct {
+	BackupDir string `mapstructure:"backup_dir"`
+	TempDir   string `mapstructure:"temp_dir"`
+}
+
+// ProjectConfig defines one Docker Compose project to back up.
+type ProjectConfig struct {
+	Name        string          `mapstructure:"name"`
+	Path        string          `mapstructure:"path"`
+	ComposeFile string          `mapstructure:"compose_file"`
+	Cron        string          `mapstructure:"cron"`
+	Exclude     []string        `mapstructure:"exclude"`
+	Retention   RetentionConfig `mapstructure:"retention"`
+}
+
+// RetentionConfig controls backup cleanup policy.
+type RetentionConfig struct {
+	Count int `mapstructure:"count"`
+	Days  int `mapstructure:"days"`
+}
+
+// RemoteConfig holds optional remote upload targets.
+type RemoteConfig struct {
+	S3     *S3Config     `mapstructure:"s3"`
+	WebDAV *WebDAVConfig `mapstructure:"webdav"`
+}
+
+// S3Config is the S3-compatible storage backend config.
+type S3Config struct {
+	Endpoint   string `mapstructure:"endpoint"`
+	Bucket     string `mapstructure:"bucket"`
+	AccessKey  string `mapstructure:"access_key"`
+	SecretKey  string `mapstructure:"secret_key"`
+	Region     string `mapstructure:"region"`
+	PathPrefix string `mapstructure:"path_prefix"`
+}
+
+// WebDAVConfig is the WebDAV storage backend config.
+type WebDAVConfig struct {
+	URL      string `mapstructure:"url"`
+	Username string `mapstructure:"username"`
+	Password string `mapstructure:"password"`
+}
+
+// DefaultRetentionCount is used when no retention count is specified.
+const DefaultRetentionCount = 7
+
+// Validate checks the configuration and fills in defaults.
+func (c *Config) Validate() error {
+	if c.Global.BackupDir == "" {
+		return fmt.Errorf("global.backup_dir is required")
+	}
+	if c.Global.TempDir == "" {
+		c.Global.TempDir = os.TempDir()
+	}
+
+	if len(c.Projects) == 0 {
+		return fmt.Errorf("at least one project must be configured")
+	}
+
+	for i := range c.Projects {
+		p := &c.Projects[i]
+		if p.Name == "" {
+			return fmt.Errorf("projects[%d]: name is required", i)
+		}
+		if p.Path == "" {
+			return fmt.Errorf("projects[%d] (%s): path is required", i, p.Name)
+		}
+		if p.ComposeFile == "" {
+			p.ComposeFile = "docker-compose.yml"
+		}
+		if p.Retention.Count <= 0 {
+			p.Retention.Count = DefaultRetentionCount
+		}
+	}
+
+	// Expand environment variable placeholders in remote configs and validate required fields.
+	if c.Remote != nil {
+		if c.Remote.S3 != nil {
+			c.Remote.S3.AccessKey = expandEnv(c.Remote.S3.AccessKey)
+			c.Remote.S3.SecretKey = expandEnv(c.Remote.S3.SecretKey)
+			if strings.TrimSpace(c.Remote.S3.Bucket) == "" {
+				return fmt.Errorf("remote.s3.bucket is required")
+			}
+			if strings.TrimSpace(c.Remote.S3.Region) == "" {
+				return fmt.Errorf("remote.s3.region is required")
+			}
+			if strings.TrimSpace(c.Remote.S3.AccessKey) == "" {
+				return fmt.Errorf("remote.s3.access_key is required")
+			}
+			if strings.TrimSpace(c.Remote.S3.SecretKey) == "" {
+				return fmt.Errorf("remote.s3.secret_key is required")
+			}
+		}
+		if c.Remote.WebDAV != nil {
+			c.Remote.WebDAV.Username = expandEnv(c.Remote.WebDAV.Username)
+			c.Remote.WebDAV.Password = expandEnv(c.Remote.WebDAV.Password)
+			if strings.TrimSpace(c.Remote.WebDAV.URL) == "" {
+				return fmt.Errorf("remote.webdav.url is required")
+			}
+		}
+	}
+
+	return nil
+}
+
+// expandEnv replaces ${VAR} or $VAR placeholders with environment values.
+func expandEnv(s string) string {
+	return os.Expand(s, func(key string) string {
+		return os.Getenv(key)
+	})
+}
+
+// HasRemote returns true if at least one remote backend is configured.
+func (c *Config) HasRemote() bool {
+	return c.Remote != nil && (c.Remote.S3 != nil || c.Remote.WebDAV != nil)
+}
+
+// HasCron returns true if at least one project has a cron expression.
+func (c *Config) HasCron() bool {
+	for _, p := range c.Projects {
+		if strings.TrimSpace(p.Cron) != "" {
+			return true
+		}
+	}
+	return false
+}