go: allow choosing db type, setting connstr

app/settings/settings.go

@@ -16,6 +16,8 @@ type Settings struct {
 	assetsPath          string
 	templatesPath       string
 	version             string
+	dbConnstring        string
+	dbType              string
 	dbIsSetUp           bool
 }
 
@@ -125,6 +127,16 @@ func (s *Settings) DbIsSetUp() bool {
 	return s.dbIsSetUp
 }
 
+// DbConnstring returns the dbConnString.
+func (s *Settings) DbConnstring() string {
+	return s.dbConnstring
+}
+
+// DbType returns the dbType.
+func (s *Settings) DbType() string {
+	return s.dbType
+}
+
 // SetHost sets the host.
 func (s *Settings) SetHost(host string) {
 	s.host = host
@@ -175,6 +187,16 @@ func (s *Settings) SetVersion(version string) {
 	s.version = version
 }
 
+// SetDbConnstring sets the dbConnString.
+func (s *Settings) SetDbConnstring(connstring string) {
+	s.dbConnstring = connstring
+}
+
+// SetDbType sets the dbType.
+func (s *Settings) SetDbType(dbType string) {
+	s.dbType = dbType
+}
+
 // SetDbIsSetUp sets the dbIsSetUp.
 func (s *Settings) SetDbIsSetUp(is bool) {
 	s.dbIsSetUp = is

devenv.nix

@@ -2,6 +2,8 @@
 
 {
   env.CGO_ENABLED = 0;
+  env.PCMT_DBTYPE = "postgres";
+  env.PCMT_CONNSTRING = "host=127.0.0.1 sslmode=disable port=5432 user=postgres dbname=postgres password=postgres";
 
   packages = with pkgs; [ 
     git 

go.mod

@@ -8,6 +8,7 @@ require (
 	github.com/gorilla/sessions v1.2.1
 	github.com/labstack/echo-contrib v0.14.1
 	github.com/labstack/echo/v4 v4.10.2
+	github.com/lib/pq v1.10.7
 	github.com/microcosm-cc/bluemonday v1.0.23
 	github.com/philandstuff/dhall-golang/v6 v6.0.2
 	github.com/xiaoqidun/entps v0.0.0-20230328150929-94b1b92d8c03

go.sum

@@ -62,6 +62,8 @@ github.com/labstack/gommon v0.4.0 h1:y7cvthEAEbU0yHOf4axH8ZG2NH8knB9iNSoTO8dyIk8
 github.com/labstack/gommon v0.4.0/go.mod h1:uW6kP17uPlLJsD3ijUYn3/M5bAxtlZhMI6m3MFxTMTM=
 github.com/leanovate/gopter v0.2.5-0.20190402064358-634a59d12406 h1:+OUpk+IVvmKU0jivOVFGtOzA6U5AWFs8HE4DRzWLOUE=
 github.com/leanovate/gopter v0.2.5-0.20190402064358-634a59d12406/go.mod h1:gNcbPWNEWRe4lm+bycKqxUYoH5uoVje5SkOJ3uoLer8=
+github.com/lib/pq v1.10.7 h1:p7ZhMD+KsSRozJr34udlUrhboJwWAgCg34+/ZZNvZZw=
+github.com/lib/pq v1.10.7/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
 github.com/mattn/go-colorable v0.1.11/go.mod h1:u5H1YNBxpqRaxsYJYSkiCWKzEfiAb1Gb520KVy5xxl4=
 github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
 github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=

run.go

@@ -11,6 +11,8 @@ import (
 	"syscall"
 	"time"
 
+	// pure go postgres driver.
+	_ "github.com/lib/pq"
 	// ent pure go sqlite3 driver instead of "github.com/mattn/go-sqlite3".
 	_ "github.com/xiaoqidun/entps"
 
@@ -89,13 +91,27 @@ func run() error {
 		return err
 	}
 
-	// for "github.com/xiaoqidun/entps".
-	connstr := "file:ent?mode=memory&cache=shared&_fk=1"
+	setting := settings.New()
+
+	setting.Consolidate(
+		conf, host, port, devel, version,
+	)
+
+	// expected connstring form for "github.com/xiaoqidun/entps":
+	// "file:ent?mode=memory&cache=shared&_fk=1"
+	// and for the postgres driver "github.com/lib/pq":
+	// "host=127.0.0.1 sslmode=disable port=5432 user=postgres dbname=postgres password=postgres".
+
+	connstr := os.Getenv("PCMT_CONNSTRING")
+	dbtype := os.Getenv("PCMT_DBTYPE")
+
+	setting.SetDbConnstring(connstr)
+	// type can be one of "postgres" or "sqlite3".
+	setting.SetDbType(dbtype)
 
 	log.Infof("connecting to db at '%s'", connstr)
 
-	// TODO: conditionally set db type.
-	db, err := ent.Open("sqlite3", connstr)
+	db, err := ent.Open(setting.DbType(), setting.DbConnstring())
 	if err != nil {
 		return fmt.Errorf("failed to open a connection to sqlite: %v", err)
 	}
@@ -116,14 +132,8 @@ func run() error {
 		return fmt.Errorf("failed creating schema resources: %v", err)
 	}
 
-	setting := settings.New()
-
 	setting.SetDbIsSetUp(true)
 
-	setting.Consolidate(
-		conf, host, port, devel, version,
-	)
-
 	a := &app.App{}
 
 	err = a.Init(setting, log, db)