db initialization

server/cmd/main.go

@@ -4,11 +4,13 @@ import (
 	"database/sql"
 	_ "embed"
 	"encoding/json"
+	"errors"
 	"flag"
 	"fmt"
 	"io"
 	"net/http"
 	"os"
+	"strings"
 
 	_ "github.com/mattn/go-sqlite3"
 )
@@ -38,10 +40,12 @@ type Opts struct {
 	Logf       func(string, ...interface{})
 	Config     Config
 	DB         *sql.DB
+	Reset      bool
 }
 
 func main() {
 	var configFlag = flag.String("config", "config.yml", "A path to a config file.")
+	var resetFlag = flag.Bool("reset", false, "reset the database. WARNING this wipes everything.")
 	flag.Parse()
 	io := iostreams{
 		Err: os.Stderr,
@@ -49,6 +53,7 @@ func main() {
 	}
 	opts := &Opts{
 		ConfigPath: *configFlag,
+		Reset:      *resetFlag,
 		IO:         io,
 		// TODO use real logger
 		Log: func(s string) {
@@ -92,7 +97,7 @@ func _main(opts *Opts) error {
 	}
 	defer teardown()
 
-	err = ensureSchema(*opts, "1.0.0")
+	err = ensureSchema(*opts)
 	if err != nil {
 		return err
 	}
@@ -108,10 +113,34 @@ func _main(opts *Opts) error {
 	return nil
 }
 
-func ensureSchema(opts Opts, version string) error {
-	// TODO make idempotent
-	// TODO actually respect version
-	_, err := opts.DB.Exec(schemaSQL)
+func ensureSchema(opts Opts) error {
+	db := opts.DB
+
+	if opts.Reset {
+		err := os.Remove(opts.Config.DBPath)
+		if err != nil {
+			return fmt.Errorf("failed to delete database: %w", err)
+		}
+	}
+	rows, err := db.Query("select version from meta")
+	if err == nil {
+		//defer rows.Close()
+		rows.Next()
+		var version string
+		err = rows.Scan(&version)
+		if err != nil {
+			return fmt.Errorf("failed to check database schema version: %w", err)
+		} else if version == "" {
+			return errors.New("database is in unknown state")
+		}
+		return nil
+	}
+
+	if !strings.Contains(err.Error(), "no such table") {
+		return fmt.Errorf("got error checking database state: %w", err)
+	}
+
+	_, err = db.Exec(schemaSQL)
 	if err != nil {
 		return fmt.Errorf("failed to initialize database schema: %w", err)
 	}

server/cmd/schema.sql

@@ -2,6 +2,8 @@ create table meta (
   version text      -- schema version
 );
 
+insert into meta values ("1.0.0");
+
 create table users (
   user_id text,     -- string (uuid1)
   user_name text,   -- string