Add support for specifying sslmode in connection strings

Add tests for sslmode parameter when calling ParseURI.  Fix existing tests to work since default sslmode is 'prefer'

Make sure we default to prefer if sslmode is not provided in ParseDSN

Fix existing tests for ParseDSN to expect TLS configuration for prefer since prefer is the default sslmode; also, add tests for ParseDSN when specifying sslmode parameter on connection string

conn.go

@@ -296,6 +296,11 @@ func ParseURI(uri string) (ConnConfig, error) {
 	}
 	cp.Database = strings.TrimLeft(url.Path, "/")
 
+	err = configSSL(url.Query().Get("sslmode"), &cp)
+	if err != nil {
+		return cp, err
+	}
+
 	return cp, nil
 }
 
@@ -303,12 +308,14 @@ var dsn_regexp = regexp.MustCompile(`([a-z]+)=((?:"[^"]+")|(?:[^ ]+))`)
 
 // ParseDSN parses a database DSN (data source name) into a ConnConfig
 //
-// e.g. ParseDSN("user=username password=password host=1.2.3.4 port=5432 dbname=mydb")
+// e.g. ParseDSN("user=username password=password host=1.2.3.4 port=5432 dbname=mydb sslmode=disable")
 func ParseDSN(s string) (ConnConfig, error) {
 	var cp ConnConfig
 
 	m := dsn_regexp.FindAllStringSubmatch(s, -1)
 
+	var sslmode string
+
 	for _, b := range m {
 		switch b[1] {
 		case "user":
@@ -325,9 +332,16 @@ func ParseDSN(s string) (ConnConfig, error) {
 			}
 		case "dbname":
 			cp.Database = b[2]
+		case "sslmode":
+			sslmode = b[2]
 		}
 	}
 
+	err := configSSL(sslmode, &cp)
+	if err != nil {
+		return cp, err
+	}
+
 	return cp, nil
 }
 
@@ -380,6 +394,15 @@ func ParseEnvLibpq() (ConnConfig, error) {
 
 	sslmode := os.Getenv("PGSSLMODE")
 
+	err := configSSL(sslmode, &cc)
+	if err != nil {
+		return cc, err
+	}
+
+	return cc, nil
+}
+
+func configSSL(sslmode string, cc *ConnConfig) error {
 	// Match libpq default behavior
 	if sslmode == "" {
 		sslmode = "prefer"
@@ -399,10 +422,10 @@ func ParseEnvLibpq() (ConnConfig, error) {
 			ServerName: cc.Host,
 		}
 	default:
-		return cc, errors.New("sslmode is invalid")
+		return errors.New("sslmode is invalid")
 	}
 
-	return cc, nil
+	return nil
 }
 
 // Prepare creates a prepared statement with name and sql. sql can contain placeholders