Add database migrations and handle leaving private chat portals. Fixes #7

database/upgrades/2018-09-01-initial-schema.go

@@ -0,0 +1,74 @@
+package upgrades
+
+import (
+	"database/sql"
+	"fmt"
+)
+
+func init() {
+	upgrades[0] = upgrade{"Initial schema", func(dialect Dialect, tx *sql.Tx) error {
+		var byteType string
+		if dialect == SQLite {
+			byteType = "BLOB"
+		} else {
+			byteType = "bytea"
+		}
+		_, err := tx.Exec(`CREATE TABLE IF NOT EXISTS portal (
+			jid      VARCHAR(255),
+			receiver VARCHAR(255),
+			mxid     VARCHAR(255) UNIQUE,
+	
+			name   VARCHAR(255) NOT NULL,
+			topic  VARCHAR(255) NOT NULL,
+			avatar VARCHAR(255) NOT NULL,
+	
+			PRIMARY KEY (jid, receiver)
+		)`)
+		if err != nil {
+			return err
+		}
+
+		_, err = tx.Exec(`CREATE TABLE IF NOT EXISTS puppet (
+			jid          VARCHAR(255) PRIMARY KEY,
+			avatar       VARCHAR(255),
+			displayname  VARCHAR(255),
+			name_quality SMALLINT
+		)`)
+		if err != nil {
+			return err
+		}
+
+		_, err = tx.Exec(fmt.Sprintf(`CREATE TABLE IF NOT EXISTS "user" (
+			mxid VARCHAR(255) PRIMARY KEY,
+			jid  VARCHAR(255)  UNIQUE,
+
+			management_room VARCHAR(255),
+
+			client_id    VARCHAR(255),
+			client_token VARCHAR(255),
+			server_token VARCHAR(255),
+			enc_key      %[1]s,
+			mac_key      %[1]s
+		)`, byteType))
+		if err != nil {
+			return err
+		}
+
+		_, err = tx.Exec(fmt.Sprintf(`CREATE TABLE IF NOT EXISTS message (
+			chat_jid      VARCHAR(255),
+			chat_receiver VARCHAR(255),
+			jid           VARCHAR(255),
+			mxid          VARCHAR(255) NOT NULL UNIQUE,
+			sender        VARCHAR(255) NOT NULL,
+			content       %[1]s        NOT NULL,
+
+			PRIMARY KEY (chat_jid, chat_receiver, jid),
+			FOREIGN KEY (chat_jid, chat_receiver) REFERENCES portal(jid, receiver)
+		)`, byteType))
+		if err != nil {
+			return err
+		}
+
+		return nil
+	}}
+}

database/upgrades/2019-05-16-message-delete-cascade.go

@@ -0,0 +1,25 @@
+package upgrades
+
+import (
+	"database/sql"
+)
+
+func init() {
+	upgrades[1] = upgrade{"Add ON DELETE CASCADE to message table", func(dialect Dialect, tx *sql.Tx) error {
+		if dialect == SQLite {
+			// SQLite doesn't support constraint updates, but it isn't that careful with constraints anyway.
+			return nil
+		}
+		_, err := tx.Exec("ALTER TABLE message DROP CONSTRAINT message_chat_jid_fkey")
+		if err != nil {
+			return err
+		}
+		_, err = tx.Exec(`ALTER TABLE message ADD CONSTRAINT message_chat_jid_fkey
+				FOREIGN KEY (chat_jid, chat_receiver) REFERENCES portal(jid, receiver)
+				ON DELETE CASCADE`)
+		if err != nil {
+			return err
+		}
+		return nil
+	}}
+}

database/upgrades/upgrades.go

@@ -0,0 +1,87 @@
+package upgrades
+
+import (
+	"database/sql"
+	"fmt"
+	"strings"
+
+	log "maunium.net/go/maulogger/v2"
+)
+
+type Dialect int
+
+const (
+	Postgres Dialect = iota
+	SQLite
+)
+
+type upgradeFunc func(Dialect, *sql.Tx) error
+
+type upgrade struct {
+	message string
+	fn upgradeFunc
+}
+
+var upgrades [2]upgrade
+
+func getVersion(dialect Dialect, db *sql.DB) (int, error) {
+	_, err := db.Exec("CREATE TABLE IF NOT EXISTS version (version INTEGER)")
+	if err != nil {
+		return -1, err
+	}
+
+	version := 0
+	row := db.QueryRow("SELECT version FROM version LIMIT 1")
+	if row != nil {
+		_ = row.Scan(&version)
+	}
+	return version, nil
+}
+
+func setVersion(dialect Dialect, tx *sql.Tx, version int) error {
+	_, err := tx.Exec("DELETE FROM version")
+	if err != nil {
+		return err
+	}
+	_, err = tx.Exec("INSERT INTO version (version) VALUES ($1)", version)
+	return err
+}
+
+func Run(log log.Logger, dialectName string, db *sql.DB) error {
+	var dialect Dialect
+	switch strings.ToLower(dialectName) {
+	case "postgres":
+		dialect = Postgres
+	case "sqlite3":
+		dialect = SQLite
+	default:
+		return fmt.Errorf("unknown dialect %s", dialectName)
+	}
+
+	version, err := getVersion(dialect, db)
+	if err != nil {
+		return err
+	}
+
+	log.Infofln("Database currently on v%d, latest: v%d", version, len(upgrades))
+	for i, upgrade := range upgrades[version:] {
+		log.Infofln("Upgrading database to v%d: %s", i+1, upgrade.message)
+		tx, err := db.Begin()
+		if err != nil {
+			return err
+		}
+		err = upgrade.fn(dialect, tx)
+		if err != nil {
+			return err
+		}
+		err = setVersion(dialect, tx, i+1)
+		if err != nil {
+			return err
+		}
+		err = tx.Commit()
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}