unkinben
02e3e0315d
RFC2136 dynamic-DNS updater. Watches a records file (inotify) and new interface addresses and pushes TSIG-signed updates to BIND per zone, sending only the delta. Native miekg/dns (structured per-zone RCODEs), local status API + facter fact, systemd unit, nfpm RPM, Woodpecker CI. Replaces the puppet dns-update shell script; keeps the same records-file and TSIG-key contract.
89 lines
3.4 KiB
Go
89 lines
3.4 KiB
Go
// Package config holds dns-updater's runtime configuration, sourced from flags
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// with environment-variable fallbacks so it works as a systemd unit with an
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// EnvironmentFile.
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package config
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import (
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"flag"
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"fmt"
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"os"
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"time"
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)
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// Config is the daemon configuration.
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type Config struct {
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Server string // authoritative write endpoint host[:port]
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KeyFile string // BIND-style TSIG key file
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RecordsFile string // desired records (zone|name|type|ttl|value)
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StateFile string // last-applied state
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ResyncEvery time.Duration // periodic reconcile safety net
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Debounce time.Duration // coalesce bursts of watch events
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Timeout time.Duration // per-update network timeout
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WatchIface bool // subscribe to interface address changes
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Oneshot bool // reconcile once and exit (no watching)
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APIAddr string // status API address (unix socket path or host:port; empty disables)
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LogLevel string // debug|info|warn|error
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}
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const defaultPort = "53"
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// Parse builds a Config from args (typically os.Args[1:]).
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func Parse(args []string) (*Config, error) {
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fs := flag.NewFlagSet("dns-updater", flag.ContinueOnError)
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c := &Config{}
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fs.StringVar(&c.Server, "server", env("DNS_UPDATER_SERVER", ""), "authoritative write endpoint host[:port]")
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fs.StringVar(&c.KeyFile, "key-file", env("DNS_UPDATER_KEY_FILE", "/etc/dns-updater/key"), "BIND-style TSIG key file")
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fs.StringVar(&c.RecordsFile, "records-file", env("DNS_UPDATER_RECORDS_FILE", "/var/lib/dns-updater/records"), "desired records file")
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fs.StringVar(&c.StateFile, "state-file", env("DNS_UPDATER_STATE_FILE", "/var/lib/dns-updater/applied"), "last-applied state file")
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fs.DurationVar(&c.ResyncEvery, "resync", envDur("DNS_UPDATER_RESYNC", 10*time.Minute), "periodic reconcile interval (0 disables)")
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fs.DurationVar(&c.Debounce, "debounce", envDur("DNS_UPDATER_DEBOUNCE", 2*time.Second), "coalesce watch events for this long")
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fs.DurationVar(&c.Timeout, "timeout", envDur("DNS_UPDATER_TIMEOUT", 10*time.Second), "per-update network timeout")
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fs.BoolVar(&c.WatchIface, "watch-interfaces", envBool("DNS_UPDATER_WATCH_INTERFACES", true), "reconcile on interface address changes")
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fs.BoolVar(&c.Oneshot, "oneshot", envBool("DNS_UPDATER_ONESHOT", false), "reconcile once and exit")
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fs.StringVar(&c.APIAddr, "api", env("DNS_UPDATER_API", "/run/dns-updater/api.sock"), "status API address (unix path or host:port; empty disables)")
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fs.StringVar(&c.LogLevel, "log-level", env("DNS_UPDATER_LOG_LEVEL", "info"), "log level: debug|info|warn|error")
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if err := fs.Parse(args); err != nil {
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return nil, err
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}
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if c.Server == "" {
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return nil, fmt.Errorf("server is required (-server or DNS_UPDATER_SERVER)")
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}
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c.Server = withPort(c.Server)
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return c, nil
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}
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func withPort(s string) string {
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for i := len(s) - 1; i >= 0; i-- {
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if s[i] == ':' {
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return s // already has a port
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}
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if s[i] == ']' {
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break // IPv6 literal without port
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}
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}
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return s + ":" + defaultPort
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}
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func env(k, def string) string {
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if v, ok := os.LookupEnv(k); ok {
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return v
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}
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return def
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}
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func envDur(k string, def time.Duration) time.Duration {
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if v, ok := os.LookupEnv(k); ok {
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if d, err := time.ParseDuration(v); err == nil {
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return d
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}
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}
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return def
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}
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func envBool(k string, def bool) bool {
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if v, ok := os.LookupEnv(k); ok {
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return v == "1" || v == "true" || v == "yes"
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}
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return def
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}
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