Initial structure

internal/config/node.go

@@ -0,0 +1,67 @@
+package config
+
+import (
+	"fmt"
+	"os"
+
+	"gopkg.in/yaml.v3"
+)
+
+// NodeConfig is the per-node, never-replicated identity file.
+type NodeConfig struct {
+	// NodeID is a stable UUID generated at `qu init`. Used by all peers
+	// to refer to this node across restarts and IP changes.
+	NodeID string `yaml:"node_id"`
+
+	// BindAddr is the address the daemon listens on for inter-node
+	// traffic. Defaults to 0.0.0.0.
+	BindAddr string `yaml:"bind_addr"`
+
+	// BindPort is the port the daemon listens on. Default 9001.
+	BindPort int `yaml:"bind_port"`
+
+	// Advertise is the address other nodes use to reach us. May differ
+	// from BindAddr when behind NAT. Set explicitly via `qu init --advertise`.
+	Advertise string `yaml:"advertise"`
+}
+
+// AdvertiseAddr returns the address peers should dial. Falls back to
+// BindAddr:BindPort if Advertise is empty.
+func (n *NodeConfig) AdvertiseAddr() string {
+	if n.Advertise != "" {
+		return n.Advertise
+	}
+	bind := n.BindAddr
+	if bind == "" || bind == "0.0.0.0" || bind == "::" {
+		bind = "127.0.0.1"
+	}
+	return fmt.Sprintf("%s:%d", bind, n.BindPort)
+}
+
+// LoadNodeConfig reads node.yaml from the data dir.
+func LoadNodeConfig() (*NodeConfig, error) {
+	raw, err := os.ReadFile(NodeFilePath())
+	if err != nil {
+		return nil, err
+	}
+	cfg := &NodeConfig{}
+	if err := yaml.Unmarshal(raw, cfg); err != nil {
+		return nil, fmt.Errorf("parse node.yaml: %w", err)
+	}
+	if cfg.BindPort == 0 {
+		cfg.BindPort = 9001
+	}
+	if cfg.BindAddr == "" {
+		cfg.BindAddr = "0.0.0.0"
+	}
+	return cfg, nil
+}
+
+// Save writes node.yaml atomically.
+func (n *NodeConfig) Save() error {
+	out, err := yaml.Marshal(n)
+	if err != nil {
+		return err
+	}
+	return AtomicWrite(NodeFilePath(), out, 0o600)
+}