Add RuntimeParams to ConnConfig

conn.go

@@ -36,6 +36,7 @@ type ConnConfig struct {
 	Logger            Logger
 	LogLevel          int
 	Dial              DialFunc
+	RuntimeParams     map[string]string // Run-time parameters to set on connection as session default values (e.g. search_path or application_name)
 }
 
 // Conn is a PostgreSQL connection handle. It is not safe for concurrent usage.
@@ -219,6 +220,12 @@ func (c *Conn) connect(config ConnConfig, network, address string, tlsConfig *tl
 	c.mr.reader = c.reader
 
 	msg := newStartupMessage()
+
+	// Copy default run-time params
+	for k, v := range config.RuntimeParams {
+		msg.options[k] = v
+	}
+
 	msg.options["user"] = c.config.User
 	if c.config.Database != "" {
 		msg.options["database"] = c.config.Database

conn_test.go

@@ -258,6 +258,39 @@ func TestConnectCustomDialer(t *testing.T) {
 	}
 }
 
+func TestConnectWithRuntimeParams(t *testing.T) {
+	t.Parallel()
+
+	connConfig := *defaultConnConfig
+	connConfig.RuntimeParams = map[string]string{
+		"application_name": "pgxtest",
+		"search_path":      "myschema",
+	}
+
+	conn, err := pgx.Connect(connConfig)
+	if err != nil {
+		t.Fatalf("Unable to establish connection: %v", err)
+	}
+	defer conn.Close()
+
+	var s string
+	err = conn.QueryRow("show application_name").Scan(&s)
+	if err != nil {
+		t.Fatalf("QueryRow Scan unexpectedly failed: %v", err)
+	}
+	if s != "pgxtest" {
+		t.Errorf("Expected application_name to be %s, but it was %s", "pgxtest", s)
+	}
+
+	err = conn.QueryRow("show search_path").Scan(&s)
+	if err != nil {
+		t.Fatalf("QueryRow Scan unexpectedly failed: %v", err)
+	}
+	if s != "myschema" {
+		t.Errorf("Expected search_path to be %s, but it was %s", "myschema", s)
+	}
+}
+
 func TestParseURI(t *testing.T) {
 	t.Parallel()