More precise .pgpass handling

* localhost matches unix sockets too
* use OS user as default username
* use username as default database
* ignore comment lines

pgpass.go

@@ -9,7 +9,7 @@ import (
 	"strings"
 )
 
-func parsepgpass(cfg *ConnConfig, line string) *string {
+func parsepgpass(line, cfgHost, cfgPort, cfgDatabase, cfgUsername string) *string {
 	const (
 		backslash = "\r"
 		colon     = "\n"
@@ -21,6 +21,9 @@ func parsepgpass(cfg *ConnConfig, line string) *string {
 		username
 		pw
 	)
+	if strings.HasPrefix(line, "#") {
+		return nil
+	}
 	line = strings.Replace(line, `\:`, colon, -1)
 	line = strings.Replace(line, `\\`, backslash, -1)
 	parts := strings.Split(line, `:`)
@@ -34,23 +37,19 @@ func parsepgpass(cfg *ConnConfig, line string) *string {
 		parts[i] = strings.Replace(strings.Replace(parts[i], backslash, `\`, -1), colon, `:`, -1)
 		switch i {
 		case host:
-			if parts[i] != cfg.Host {
+			if parts[i] != cfgHost {
 				return nil
 			}
 		case port:
-			portstr := fmt.Sprintf(`%v`, cfg.Port)
-			if portstr == "0" {
-				portstr = "5432"
-			}
-			if parts[i] != portstr {
+			if parts[i] != cfgPort {
 				return nil
 			}
 		case database:
-			if parts[i] != cfg.Database {
+			if parts[i] != cfgDatabase {
 				return nil
 			}
 		case username:
-			if parts[i] != cfg.User {
+			if parts[i] != cfgUsername {
 				return nil
 			}
 		}
@@ -72,10 +71,32 @@ func pgpass(cfg *ConnConfig) (found bool) {
 		return
 	}
 	defer f.Close()
+
+	host := cfg.Host
+	if _, err := os.Stat(host); err == nil {
+		host = "localhost"
+	}
+	port := fmt.Sprintf(`%v`, cfg.Port)
+	if port == "0" {
+		port = "5432"
+	}
+	username := cfg.User
+	if username == "" {
+		user, err := user.Current()
+		if err != nil {
+			return
+		}
+		username = user.Username
+	}
+	database := cfg.Database
+	if database == "" {
+		database = username
+	}
+
 	scanner := bufio.NewScanner(f)
 	var pw *string
 	for scanner.Scan() {
-		pw = parsepgpass(cfg, scanner.Text())
+		pw = parsepgpass(scanner.Text(), host, port, database, username)
 		if pw != nil {
 			cfg.Password = *pw
 			return true

pgpass_test.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"os/user"
 	"strings"
 	"testing"
 )
@@ -20,6 +21,8 @@ var passfile = [][]string{
 	{"test1", "5432", "curlydb", "curly", "nyuknyuknyuk"},
 	{"test2", "5432", "*", "shemp", "heymoe"},
 	{"test2", "5432", "*", "*", `test\\ing\:`},
+	{"localhost", "*", "*", "*", "sesam"},
+	{"test3", "*", "", "", "swordfish"}, // user will be filled later
 }
 
 func TestPGPass(t *testing.T) {
@@ -27,9 +30,20 @@ func TestPGPass(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	user, err := user.Current()
+	if err != nil {
+		t.Fatal(err)
+	}
+	passfile[len(passfile)-1][2] = user.Username
+	passfile[len(passfile)-1][3] = user.Username
+
 	defer tf.Close()
 	defer os.Remove(tf.Name())
 	os.Setenv("PGPASSFILE", tf.Name())
+	_, err = fmt.Fprintln(tf, "#some comment\n\n#more comment")
+	if err != nil {
+		t.Fatal(err)
+	}
 	for _, l := range passfile {
 		_, err := fmt.Fprintln(tf, strings.Join(l, `:`))
 		if err != nil {
@@ -48,9 +62,28 @@ func TestPGPass(t *testing.T) {
 		if cfg.Password != unescape(l[4]) {
 			t.Fatalf(`Password mismatch entry %v want %s got %s`, i, unescape(l[4]), cfg.Password)
 		}
+		if l[0] == "localhost" {
+			// using some existing path as socket
+			cfg := ConnConfig{Host: tf.Name(), Database: l[2], User: l[3]}
+			found := pgpass(&cfg)
+			if !found {
+				t.Fatalf("Entry %v not found", i)
+			}
+			if cfg.Password != unescape(l[4]) {
+				t.Fatalf(`Password mismatch entry %v want %s got %s`, i, unescape(l[4]), cfg.Password)
+			}
+		}
 	}
-	cfg := ConnConfig{Host: "derp", Database: "herp", User: "joe"}
+	cfg := ConnConfig{Host: "test3"}
 	found := pgpass(&cfg)
+	if !found {
+		t.Fatalf("Entry for default user name")
+	}
+	if cfg.Password != "swordfish" {
+		t.Fatalf(`Password mismatch for default user entry, want %s got %s`, "swordfish", cfg.Password)
+	}
+	cfg = ConnConfig{Host: "derp", Database: "herp", User: "joe"}
+	found = pgpass(&cfg)
 	if found {
 		t.Fatal("bad found")
 	}