v1.0.0

internal/config/config.go

@@ -0,0 +1,115 @@
+// Package config loads est tunnel configuration and command-line options.
+package config
+
+import (
+	"errors"
+	"os"
+	"time"
+
+	"github.com/BurntSushi/toml"
+)
+
+// ProxyDirection identifies the direction of an SSH port forward.
+type ProxyDirection string
+
+const (
+	// RemoteToLocal creates a local SSH forward with the -L option.
+	RemoteToLocal ProxyDirection = "rtl"
+	// LocalToRemote creates a remote SSH forward with the -R option.
+	LocalToRemote ProxyDirection = "ltr"
+)
+
+const (
+	// DefaultRetryCount is the number of reconnect attempts used when retry is
+	// not specified.
+	DefaultRetryCount = 5
+	// DefaultRetryDelay is the wait between reconnect attempts when retry is
+	// not specified.
+	DefaultRetryDelay = 5 * time.Second
+)
+
+var (
+	// ErrInvalidRetryCount is returned when retry count is less than -1.
+	ErrInvalidRetryCount = errors.New("retry count must be -1 or greater")
+	// ErrInvalidRetryDelay is returned when retry delay is invalid or not positive.
+	ErrInvalidRetryDelay = errors.New("retry delay must be a positive duration")
+)
+
+// RetryConfig configures tunnel reconnection behavior.
+// Count is the number of attempts after the initial SSH process exits; -1
+// retries indefinitely. Delay uses time.ParseDuration syntax, such as "5s".
+type RetryConfig struct {
+	Count *int   `toml:"count"`
+	Delay string `toml:"delay"`
+}
+
+// RetrySettings is a validated retry configuration ready for execution.
+type RetrySettings struct {
+	Count int
+	Delay time.Duration
+}
+
+// Settings resolves RetryConfig fields with est's default retry values.
+func (retry RetryConfig) Settings() (RetrySettings, error) {
+	settings := RetrySettings{Count: DefaultRetryCount, Delay: DefaultRetryDelay}
+	if retry.Count != nil {
+		settings.Count = *retry.Count
+	}
+	if settings.Count < -1 {
+		return RetrySettings{}, ErrInvalidRetryCount
+	}
+	if retry.Delay != "" {
+		delay, err := time.ParseDuration(retry.Delay)
+		if err != nil || delay <= 0 {
+			return RetrySettings{}, ErrInvalidRetryDelay
+		}
+		settings.Delay = delay
+	}
+	return settings, nil
+}
+
+// ProxyEntry defines one SSH tunnel.
+type ProxyEntry struct {
+	Direction  ProxyDirection `toml:"direction"`
+	RemotePort uint16         `toml:"remotePort"`
+	RemoteIP   string         `toml:"remoteIP"`
+	LocalPort  uint16         `toml:"localPort"`
+	LocalIP    string         `toml:"localIP"`
+	Host       string         `toml:"host"`
+
+	IdentityFile string       `toml:"identityFile,omitempty"`
+	Retry        *RetryConfig `toml:"retry"`
+}
+
+// Config is the TOML configuration used by est.
+type Config struct {
+	SSHConfig string       `toml:"sshConfig"`
+	Retry     *RetryConfig `toml:"retry"`
+	Entries   []ProxyEntry `toml:"entry"`
+}
+
+// RetrySettings resolves the retry configuration for entry. An entry retry
+// block fully overrides the top-level retry block.
+func (cfg Config) RetrySettings(entry ProxyEntry) (RetrySettings, error) {
+	if entry.Retry != nil {
+		return entry.Retry.Settings()
+	}
+	if cfg.Retry != nil {
+		return cfg.Retry.Settings()
+	}
+	return RetryConfig{}.Settings()
+}
+
+// LoadConfig decodes a TOML configuration file from path.
+func LoadConfig(path string) (Config, error) {
+	var config Config
+	file, err := os.Open(path)
+	if err != nil {
+		return config, err
+	}
+	defer file.Close()
+	if _, err := toml.NewDecoder(file).Decode(&config); err != nil {
+		return config, err
+	}
+	return config, nil
+}