Moved and fixed postgres migration

pkg/db/postgres/README.md

+# Postgres
+
+### Using Config
+
+```golang
+// config.go
+pkg config
+
+type Config struct {
+    cfgPkg.BaseConfig `mapstructure:",squash"`
+    Postgres postgresPkg.Config `mapstructure:"postgres"`
+}
+
+// main.go
+var conf config.Config
+config.LoadConfig("WELLKNOWN", &conf, nil)
+
+pgDb, err := postgresPkg.ConnectRetry(ctx, conf.Postgres, time.Minute)
+```
+
+### Using ConnectRetry
+
+`ConnectRetry` is a function that tries to establish a db connection for the given
+`maxDuration time.Duration`. It will periodically retry, using a fibonacci backoff
+pattern.
+
+For usage example, see above.
+
+### Using MigrateUp
+
+Given the following folder structure:
+
+```
+src/
+├─ postgres/
+│  ├─ postgres.go
+│  ├─ migrations/
+│  │  ├─ 001_init.down.sql
+│  │  ├─ 001_init.up.sql
+├─ main.go     
+```
+
+First, create a variable of type `embed.FS` and annotate it with `//go:embed relative-path`,
+pointing to the folder containing the migration files (no `.` or `..` allowed):
+```golang
+// postgres/postgres.go
+pkg postgres 
+
+//go:embed migrations
+var Migrations embed.FS
+```
+
+Then, when you established the DB connection (here in `main.go`), pass
+the variable and path to `MigrateUP()` 
+
+```golang
+// main.go
+pkg main
+
+func main() {
+	// ...
+	pgDb, _ := postgresPkg.ConnectRetry(...)
+	postgres.MigrateUP(pgDb, postgres.Migrations, "migrations")
+} 
+```
+
+The last parameter is the path relative to the embedded file system.
\ No newline at end of file

pkg/db/postgres/migration/migrate.go

-package migration
-
-import (
-	"embed"
-	"errors"
-	"fmt"
-	"net/http"
-
-	"github.com/golang-migrate/migrate/v4"
-	"github.com/golang-migrate/migrate/v4/source/httpfs"
-	"github.com/jackc/pgx/v5/pgxpool"
-)
-
-func MigrateUP(pool *pgxpool.Pool, migrations embed.FS, migrationsPath string) error {
-	source, err := httpfs.New(http.FS(migrations), migrationsPath)
-	if err != nil {
-		return nil
-	}
-
-	m, err := migrate.NewWithSourceInstance("httpfs", source, pool.Config().ConnString())
-	if err != nil {
-		return fmt.Errorf("failed to init migration: %w", err)
-	}
-
-	if err := m.Up(); err != nil && errors.Is(err, migrate.ErrNoChange) {
-		return err
-	}
-
-	return nil
-}

pkg/db/postgres/postgres.go

@@ -2,8 +2,15 @@ package postgres
 
 import (
 	"context"
+	"embed"
+	"errors"
+	"fmt"
+	"net/http"
 	"time"
 
+	"github.com/golang-migrate/migrate/v4"
+	_ "github.com/golang-migrate/migrate/v4/database/postgres"
+	"github.com/golang-migrate/migrate/v4/source/httpfs"
 	"github.com/jackc/pgx/v5/pgconn"
 	"github.com/jackc/pgx/v5/pgxpool"
 	"github.com/sethvargo/go-retry"
@@ -48,6 +55,24 @@ func ConnectRetry(ctx context.Context, conf Config, maxDuration time.Duration, e
 	return
 }
 
+func MigrateUP(pool *pgxpool.Pool, migrations embed.FS, migrationsPath string) error {
+	source, err := httpfs.New(http.FS(migrations), migrationsPath)
+	if err != nil {
+		return fmt.Errorf("could not initialize source: %w", err)
+	}
+
+	m, err := migrate.NewWithSourceInstance("httpfs", source, pool.Config().ConnString())
+	if err != nil {
+		return fmt.Errorf("failed to init migration: %w", err)
+	}
+
+	if err := m.Up(); err != nil && !errors.Is(err, migrate.ErrNoChange) {
+		return err
+	}
+
+	return nil
+}
+
 func isRetryableError(err error) bool {
 	if _, ok := err.(*pgconn.ConnectError); ok {
 		return true