Add support for hostaddr

Fixes #860

Author: arp242

CHANGELOG.md

@@ -1,6 +1,6 @@
 unreleased
 ----------
-This version of kq requires Go 1.18 or newer.
+This version of pq requires Go 1.18 or newer.
 
 pq now supports only maintained PostgreSQL releases, which is PostgreSQL 14 and
 newer. Previously PostgreSQL 8.4 and newer were supported.
@@ -33,6 +33,8 @@ newer. Previously PostgreSQL 8.4 and newer were supported.
 - Add `Config`, `NewConfig()`, and `NewConnectorConfig()` to supply connection
   details in a more structured way ([#1240]).
 
+- Support `hostaddr` and `$PGHOSTADDR` ([#1243]).
+
 - Add `PQGO_DEBUG=1` print the communication with PostgreSQL to stderr, to aid
   in debugging, testing, and bug reports ([#1223]).
 
@@ -104,6 +106,7 @@ newer. Previously PostgreSQL 8.4 and newer were supported.
 [#1238]: https://github.com/lib/pq/pull/1238
 [#1239]: https://github.com/lib/pq/pull/1239
 [#1240]: https://github.com/lib/pq/pull/1240
+[#1243]: https://github.com/lib/pq/pull/1243
 
 
 v1.10.9 (2023-04-26)

conn.go

@@ -1077,7 +1077,7 @@ func (cn *conn) ssl(o values) error {
 // startup packet.
 func isDriverSetting(key string) bool {
 	switch key {
-	case "host", "port", "password", "fallback_application_name",
+	case "host", "hostaddr", "port", "password", "fallback_application_name",
 		"sslmode", "sslcert", "sslkey", "sslrootcert", "sslinline", "sslsni",
 		"connect_timeout", "binary_parameters", "disable_prepared_binary_result",
 		"krbsrvname", "krbspn":

conn_test.go

@@ -69,20 +69,34 @@ func TestCommitInFailedTransaction(t *testing.T) {
 	}
 }
 
-func TestOpenURL(t *testing.T) {
-	t.Parallel()
-	testURL := func(url string) {
-		db := pqtest.MustDB(t, url)
-		// database/sql might not call our Open at all unless we do something with
-		// the connection
-		txn, err := db.Begin()
-		if err != nil {
-			t.Fatal(err)
-		}
-		txn.Rollback()
+func TestOpen(t *testing.T) {
+	tests := []struct {
+		dsn, wantErr string
+	}{
+		{"postgres://", ""},
+		{"postgresql://", ""},
+		{"host=doesnotexist hostaddr=127.0.0.1", ""}, // Should ignore the host
+
+		{"hostaddr=255.255.255.255", "dial tcp 255.255.255.255"},
+	}
+
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.dsn, func(t *testing.T) {
+			t.Parallel()
+
+			db, err := pqtest.DB(tt.dsn)
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer db.Close()
+
+			err = db.Ping()
+			if !pqtest.ErrorContains(err, tt.wantErr) {
+				t.Errorf("wrong error:\nhave: %s\nwant: %s", err, tt.wantErr)
+			}
+		})
 	}
-	testURL("postgres://")
-	testURL("postgresql://")
 }
 
 func TestPgpass(t *testing.T) {

connector.go

@@ -5,6 +5,7 @@ import (
 	"database/sql/driver"
 	"fmt"
 	"net"
+	"net/netip"
 	neturl "net/url"
 	"os"
 	"path/filepath"
@@ -104,6 +105,25 @@ type Config struct {
 	// for unix domain sockets. Defaults to localhost.
 	Host string `postgres:"host" env:"PGHOST"`
 
+	// IPv4 or IPv6 address to connect to. Using hostaddr allows the application
+	// to avoid a host name lookup, which might be important in applications
+	// with time constraints. A hostname is required for sslmode=verify-full and
+	// the GSSAPI or SSPI authentication methods.
+	//
+	// The following rules are used:
+	//
+	// - If host is given without hostaddr, a host name lookup occurs.
+	//
+	// - If hostaddr is given without host, the value for hostaddr gives the
+	//   server network address. The connection attempt will fail if the
+	//   authentication method requires a host name.
+	//
+	// - If both host and hostaddr are given, the value for hostaddr gives the
+	//   server network address. The value for host is ignored unless the
+	//   authentication method requires it, in which case it will be used as the
+	//   host name.
+	Hostaddr netip.Addr `postgres:"hostaddr" env:"PGHOSTADDR"`
+
 	// The port to connect to. Defaults to 5432.
 	Port uint16 `postgres:"port" env:"PGPORT"`
 
@@ -302,6 +322,9 @@ func newConfig(dsn string, env []string) (Config, error) {
 }
 
 func (cfg Config) network() (string, string) {
+	if cfg.Hostaddr != (netip.Addr{}) {
+		return "tcp", net.JoinHostPort(cfg.Hostaddr.String(), strconv.Itoa(int(cfg.Port)))
+	}
 	// UNIX domain sockets are either represented by an (absolute) file system
 	// path or they live in the abstract name space (starting with an @).
 	if filepath.IsAbs(cfg.Host) || strings.HasPrefix(cfg.Host, "@") {
@@ -319,7 +342,7 @@ func (cfg *Config) fromEnv(env []string) error {
 			continue
 		}
 		switch k {
-		case "PGHOSTADDR", "PGREQUIREAUTH", "PGCHANNELBINDING", "PGSERVICE", "PGSERVICEFILE", "PGREALM",
+		case "PGREQUIREAUTH", "PGCHANNELBINDING", "PGSERVICE", "PGSERVICEFILE", "PGREALM",
 			"PGSSLCERTMODE", "PGSSLCOMPRESSION", "PGREQUIRESSL", "PGSSLCRL", "PGREQUIREPEER",
 			"PGSYSCONFDIR", "PGLOCALEDIR", "PGSSLCRLDIR", "PGSSLMINPROTOCOLVERSION", "PGSSLMAXPROTOCOLVERSION",
 			"PGGSSENCMODE", "PGGSSDELEGATION", "PGTARGETSESSIONATTRS", "PGLOADBALANCEHOSTS", "PGMINPROTOCOLVERSION",
@@ -468,7 +491,17 @@ func (cfg *Config) setFromTag(o map[string]string, tag string) error {
 			}
 			switch rt.Type.Kind() {
 			default:
-				return fmt.Errorf("don't know how to set %s: unknown type %s", rt.Name, rt.Type)
+				return fmt.Errorf("don't know how to set %s: unknown type %s", rt.Name, rt.Type.Kind())
+			case reflect.Struct:
+				if rt.Type == reflect.TypeOf(netip.Addr{}) {
+					ip, err := netip.ParseAddr(v)
+					if err != nil {
+						return fmt.Errorf(f+"%w", k, err)
+					}
+					rv.Set(reflect.ValueOf(ip))
+				} else {
+					return fmt.Errorf("don't know how to set %s: unknown type %s", rt.Name, rt.Type)
+				}
 			case reflect.String:
 				if ((tag == "postgres" && k == "sslmode") || (tag == "env" && k == "PGSSLMODE")) &&
 					!pqutil.Contains(sslModes, SSLMode(v)) &&
@@ -545,7 +578,11 @@ func (cfg Config) tomap() values {
 		if !rv.IsZero() || pqutil.Contains(cfg.set, k) {
 			switch rt.Type.Kind() {
 			default:
-				o[k] = rv.String()
+				if s, ok := rv.Interface().(fmt.Stringer); ok {
+					o[k] = s.String()
+				} else {
+					o[k] = rv.String()
+				}
 			case reflect.Uint16:
 				n := rv.Uint()
 				o[k] = strconv.FormatUint(n, 10)

connector_test.go

@@ -357,6 +357,11 @@ func TestNewConfig(t *testing.T) {
 		{"port=5s", nil, "", `pq: wrong value for "port": strconv.ParseUint: parsing "5s": invalid syntax`},
 		{"", []string{"PGPORT=5s"}, "", `pq: wrong value for $PGPORT: strconv.ParseUint: parsing "5s": invalid syntax`},
 
+		// hostaddr
+		{"hostaddr=127.1.2.3", nil, "hostaddr=127.1.2.3", ""},
+		{"hostaddr=::1", nil, "hostaddr=::1", ""},
+		{"", []string{"PGHOSTADDR=2a01:4f9:3081:5413::2"}, "hostaddr=2a01:4f9:3081:5413::2", ""},
+
 		// Runtime
 		{"user=u search_path=abc", nil, "search_path=abc user=u", ""},
 		{"database=db", nil, "dbname=db", ``},

deprecated.go

@@ -75,6 +75,10 @@ func ParseURL(url string) (string, error) { return convertURL(url) }
 type values map[string]string
 
 func (o values) network() (string, string) {
+	if ho := o["hostaddr"]; ho != "" {
+		return "tcp", net.JoinHostPort(ho, o["port"])
+	}
+
 	host := o["host"]
 	// UNIX domain sockets are either represented by an (absolute) file system
 	// path or they live in the abstract name space (starting with an @).