feat(postgres): Add list DBs command

cmd/cmd.go

@@ -7,6 +7,7 @@ import (
 	_ "github.com/sikalabs/slut/cmd/postgres"
 	_ "github.com/sikalabs/slut/cmd/postgres/create"
 	_ "github.com/sikalabs/slut/cmd/postgres/drop"
+	_ "github.com/sikalabs/slut/cmd/postgres/list"
 	"github.com/sikalabs/slut/cmd/root"
 	_ "github.com/sikalabs/slut/cmd/version"
 	"github.com/spf13/cobra"

cmd/postgres/list/list.go

@@ -0,0 +1,26 @@
+package drop
+
+import (
+	postgrescmd "github.com/sikalabs/slut/cmd/postgres"
+	"github.com/sikalabs/slut/utils/postgres"
+
+	"github.com/spf13/cobra"
+)
+
+var PostgresListCmd = &cobra.Command{
+	Use:   "list",
+	Short: "list Postgres databases",
+	Args:  cobra.NoArgs,
+	Run: func(c *cobra.Command, args []string) {
+		postgres.ListText(
+			postgrescmd.PostgresCmdFlagHost,
+			postgrescmd.PostgresCmdFlagPort,
+			postgrescmd.PostgresCmdFlagUser,
+			postgrescmd.PostgresCmdFlagPassword,
+		)
+	},
+}
+
+func init() {
+	postgrescmd.PostgresCmd.AddCommand(PostgresListCmd)
+}

utils/postgres/list.go

@@ -0,0 +1,58 @@
+package postgres
+
+import (
+	"database/sql"
+	"fmt"
+
+	_ "github.com/lib/pq"
+)
+
+func List(
+	host string,
+	port int,
+	user string,
+	password string,
+) ([]string, error) {
+	db, err := sql.Open(
+		"postgres", fmt.Sprintf(
+			"host=%s port=%d user=%s password=%s sslmode=disable",
+			host, port, user, password,
+		))
+	if err != nil {
+		return nil, err
+	}
+	defer db.Close()
+
+	rows, err := db.Query("SELECT datname FROM pg_database;")
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var dbNames []string
+	var dbName string
+
+	for rows.Next() {
+		err := rows.Scan(&dbName)
+		if err != nil {
+			return nil, err
+		}
+		dbNames = append(dbNames, dbName)
+	}
+	return dbNames, err
+}
+
+func ListText(
+	host string,
+	port int,
+	user string,
+	password string,
+) {
+	dbNames, err := List(host, port, user, password)
+	if err != nil {
+		panic(err)
+	}
+	for _, dbName := range dbNames {
+		fmt.Println(dbName)
+	}
+}