Simplify connection string configuration

cmd/timescaledb-parallel-copy/main.go

@@ -51,8 +51,9 @@ var (
 
 // Parse args
 func init() {
+	// Documented https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNSTRING
 	flag.StringVar(&postgresConnect, "connection", "host=localhost user=postgres sslmode=disable", "PostgreSQL connection url")
-	flag.StringVar(&dbName, "db-name", "", "Database where the destination table exists")
+	flag.StringVar(&dbName, "db-name", "", "(deprecated) Database where the destination table exists")
 	flag.StringVar(&tableName, "table", "test_table", "Destination table for insertions")
 	flag.StringVar(&schemaName, "schema", "public", "Destination table's schema")
 	flag.BoolVar(&truncate, "truncate", false, "Truncate the destination table before insert")
@@ -86,13 +87,16 @@ func (l csvCopierLogger) Infof(msg string, args ...interface{}) {
 
 func main() {
 	if showVersion {
-		fmt.Printf("%s %s (%s %s)\n", binName, version, runtime.GOOS, runtime.GOARCH)
+		log.Printf("%s %s (%s %s)\n", binName, version, runtime.GOOS, runtime.GOARCH)
 		os.Exit(0)
 	}
 
+	if dbName != "" {
+		log.Fatalf("Error: Deprecated flag -db-name is being used. Update -connection to connect to the given database")
+	}
+
 	copier, err := csvcopy.NewCopier(
 		postgresConnect,
-		dbName,
 		schemaName,
 		tableName,
 		copyOptions,

internal/db/db.go

@@ -4,151 +4,15 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"os"
-	"regexp"
-	"strconv"
-	"strings"
 
-	"github.com/jackc/pgx/v5/pgconn"
 	"github.com/jackc/pgx/v5/stdlib"
 	"github.com/jmoiron/sqlx"
 )
 
-// minimalConnConfig is the minimal settings we need for connection. More
-// unusual options are currently not supported.
-type minimalConnConfig struct {
-	host     string
-	user     string
-	password string
-	db       string
-	port     uint16
-	sslmode  string
-}
-
-// DSN returns the PostgreSQL compatible DSN string that corresponds to mcc.
-// This is expressed as a string of <key>=<value> separated by spaces.
-func (mcc *minimalConnConfig) DSN() string {
-	var s strings.Builder
-	writeNonempty := func(key, val string) {
-		if val != "" {
-			_, err := s.WriteString(key + "=" + val + " ")
-			if err != nil {
-				panic(err)
-			}
-		}
-	}
-	writeNonempty("host", mcc.host)
-	writeNonempty("user", mcc.user)
-	writeNonempty("password", mcc.password)
-	writeNonempty("dbname", mcc.db)
-	if mcc.port != 0 {
-		writeNonempty("port", strconv.FormatUint(uint64(mcc.port), 10))
-	}
-	writeNonempty("sslmode", mcc.sslmode)
-	writeNonempty("application_name", "timescaledb-parallel-copy")
-
-	return strings.TrimSpace(s.String())
-}
-
-// Overrideable is an interface for defining ways to override PG settings
-// outside of the usual manners (through the connection string/URL or env vars).
-// An example would be having specific flags that can be used to set database
-// connect parameters.
-type Overrideable interface {
-	Override() string
-}
-
-// OverrideDBName is a type for overriding the database name used to connect.
-// To use it, one casts a string of the database name as an OverrideDBName
-type OverrideDBName string
-
-func (o OverrideDBName) Override() string {
-	return string(o)
-}
-
-// parseConnStr uses an external lib (that backs pgx) to take care of parsing
-// connection parameters for connecting to PostgreSQL. It handles the connStr
-// being in DSN or URL form, as well as reading env vars for additional settings.
-func parseConnStr(connStr string, overrides ...Overrideable) (*minimalConnConfig, error) {
-	config, err := pgconn.ParseConfig(connStr)
-	if err != nil {
-		return nil, err
-	}
-	sslmode, err := determineTLS(connStr)
-	if err != nil {
-		return nil, err
-	}
-
-	mcc := &minimalConnConfig{
-		host:     config.Host,
-		user:     config.User,
-		password: config.Password,
-		db:       config.Database,
-		port:     config.Port,
-		sslmode:  sslmode,
-	}
-
-	for _, o := range overrides {
-		switch o.(type) {
-		case OverrideDBName:
-			mcc.db = o.Override()
-		default:
-			return nil, fmt.Errorf("unknown overrideable: %T=%s", o, o.Override())
-		}
-	}
-
-	return mcc, nil
-}
-
-// ErrInvalidSSLMode is the error when the provided SSL mode is not one of the
-// values that PostgreSQL supports.
-type ErrInvalidSSLMode struct {
-	given string
-}
-
-func (e *ErrInvalidSSLMode) Error() string {
-	return "invalid SSL mode: " + e.given
-}
-
-const (
-	// envSSLMode is the environment variable key for SSL mode.
-	envSSLMode = "PGSSLMODE"
-)
-
-var sslmodeRegex = regexp.MustCompile("sslmode=([a-zA-Z-]+)")
-
-// determineTLS attempts to match SSL mode to a known PostgreSQL supported value.
-func determineTLS(connStr string) (string, error) {
-	res := sslmodeRegex.FindStringSubmatch(connStr)
-	var sslmode string
-	if len(res) == 2 {
-		sslmode = res[1]
-	} else {
-		sslmode = os.Getenv(envSSLMode)
-	}
-
-	if sslmode == "" {
-		return "", nil
-	}
-
-	switch sslmode {
-	case "require", "disable", "allow", "prefer", "verify-ca", "verify-full":
-		return sslmode, nil
-	default:
-		return "", &ErrInvalidSSLMode{given: sslmode}
-	}
-}
-
 // Connect returns a SQLX database corresponding to the provided connection
 // string/URL, env variables, and any provided overrides.
-func Connect(connStr string, overrides ...Overrideable) (*sqlx.DB, error) {
-	mcc, err := parseConnStr(connStr, overrides...)
-	if err != nil {
-		return nil, fmt.Errorf("could not connect: %v", err)
-	}
-	// It is required to connect using pgx/v5
-	// otherwise it may use pgx/v4 if that librariy is registered first
-	db, err := sqlx.Connect("pgx/v5", mcc.DSN())
+func Connect(connStr string) (*sqlx.DB, error) {
+	db, err := sqlx.Connect("pgx/v5", connStr)
 	if err != nil {
 		return nil, fmt.Errorf("could not connect: %v", err)
 	}