Improve installer updates and dependency checks and add command aliases

internal/config/config.go

@@ -4,12 +4,14 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"regexp"
 	"strings"
 
 	"github.com/spf13/viper"
 )
 
 type Config struct {
+	Shell     ShellConfig     `mapstructure:"shell"`
 	NetBox    NetBoxConfig    `mapstructure:"netbox"`
 	Resolver  ResolverConfig  `mapstructure:"resolver"`
 	Cache     CacheConfig     `mapstructure:"cache"`
@@ -17,6 +19,10 @@ type Config struct {
 	Shortcuts ShortcutsConfig `mapstructure:"shortcuts"`
 }
 
+type ShellConfig struct {
+	Alias string `mapstructure:"alias"`
+}
+
 type NetBoxConfig struct {
 	URL          string `mapstructure:"url"`
 	Token        string `mapstructure:"token"`
@@ -71,7 +77,7 @@ func Load() (*Config, error) {
 	v.SetEnvPrefix("NETSSH")
 	v.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
 	v.AutomaticEnv()
-	for _, key := range []string{"netbox.url", "netbox.token", "netbox.token_version", "resolver.strategies", "resolver.management_subnets", "resolver.interface_name", "cache.ttl", "cache.path", "ssh.default_user", "ssh.default_port", "shortcuts.domains", "shortcuts.strip_hyphens"} {
+	for _, key := range []string{"netbox.url", "netbox.token", "netbox.token_version", "resolver.strategies", "resolver.management_subnets", "resolver.interface_name", "cache.ttl", "cache.path", "ssh.default_user", "ssh.default_port", "shortcuts.domains", "shortcuts.strip_hyphens", "shell.alias"} {
 		if err := v.BindEnv(key); err != nil {
 			return nil, err
 		}
@@ -88,6 +94,10 @@ func Load() (*Config, error) {
 		return nil, fmt.Errorf("parsing config: %w", err)
 	}
 
+	if err := ValidateCommandAlias(cfg.Shell.Alias); err != nil {
+		return nil, err
+	}
+
 	if cfg.NetBox.TokenVersion == 0 && cfg.NetBox.Token != "" {
 		if strings.HasPrefix(cfg.NetBox.Token, "nbt_") {
 			cfg.NetBox.TokenVersion = 2
@@ -106,3 +116,18 @@ func Load() (*Config, error) {
 
 	return &cfg, nil
 }
+
+// ValidateCommandAlias restricts aliases to portable shell identifiers.
+func ValidateCommandAlias(name string) error {
+	if name == "" {
+		return nil
+	}
+	if !regexp.MustCompile(`^[a-zA-Z_][a-zA-Z0-9_]*$`).MatchString(name) {
+		return fmt.Errorf("shell.alias must be a shell identifier (e.g. j)")
+	}
+	switch name {
+	case "netssh", "alias", "unalias", "source", "eval", "exec", "command", "builtin", "if", "then", "else", "elif", "fi", "for", "while", "until", "do", "done", "case", "esac", "in", "function", "select", "time", "coproc", "end", "begin", "switch", "set", "export", "return", "break", "continue", "not", "and", "or":
+		return fmt.Errorf("shell.alias %q is reserved; choose another name", name)
+	}
+	return nil
+}