Track DB migrations

src/main/db.zig

@@ -1,6 +1,7 @@
 const std = @import("std");
 const sql = @import("sql");
 const models = @import("./db/models.zig");
+const migrations = @import("./db/migrations.zig");
 const util = @import("util");
 
 const Uuid = util.Uuid;
@@ -151,88 +152,11 @@ fn getAlloc(row: sql.Row, comptime T: type, idx: u15, alloc: std.mem.Allocator)
 pub const Database = struct {
     db: sql.Sqlite,
 
-    const init_sql_stmts = [_][]const u8{
-        \\CREATE TABLE IF NOT EXISTS
-        \\user(
-        \\  id TEXT NOT NULL PRIMARY KEY,
-        \\  username TEXT NOT NULL,
-        \\
-        \\  created_at INTEGER NOT NULL DEFAULT CURRENT_TIMESTAMP
-        \\) STRICT;
-        ,
-        \\CREATE TABLE IF NOT EXISTS
-        \\actor(
-        \\  user_id TEXT NOT NULL PRIMARY KEY REFERENCES user(id),
-        \\  public_id TEXT NOT NULL
-        \\) STRICT;
-        ,
-        \\CREATE TABLE IF NOT EXISTS
-        \\local_user(
-        \\  user_id TEXT NOT NULL PRIMARY KEY REFERENCES user(id),
-        \\
-        \\  email TEXT,
-        \\
-        \\  hashed_password TEXT NOT NULL,
-        \\  password_changed_at INTEGER NOT NULL
-        \\) STRICT;
-        ,
-        \\CREATE TABLE IF NOT EXISTS
-        \\note(
-        \\  id TEXT NOT NULL,
-        \\
-        \\  content TEXT NOT NULL,
-        \\  author_id TEXT NOT NULL REFERENCES actor(id),
-        \\
-        \\  created_at INTEGER NOT NULL DEFAULT CURRENT_TIMESTAMP
-        \\) STRICT;
-        ,
-        \\CREATE TABLE IF NOT EXISTS
-        \\reaction(
-        \\  id TEXT NOT NULL PRIMARY KEY,
-        \\
-        \\  reactor_id TEXT NOT NULL REFERENCES actor(id),
-        \\  note_id TEXT NOT NULL REFERENCES note(id),
-        \\
-        \\  created_at INTEGER NOT NULL DEFAULT CURRENT_TIMESTAMP
-        \\) STRICT;
-        ,
-        \\CREATE TABLE IF NOT EXISTS
-        \\token(
-        \\  id TEXT NOT NULL PRIMARY KEY,
-        \\
-        \\  hash BLOB UNIQUE NOT NULL,
-        \\  user_id TEXT NOT NULL REFERENCES local_user(id),
-        \\
-        \\  issued_at INTEGER NOT NULL DEFAULT CURRENT_TIMESTAMP
-        \\) STRICT;
-        ,
-        \\CREATE TABLE IF NOT EXISTS
-        \\invite(
-        \\  id TEXT NOT NULL PRIMARY KEY,
-        \\
-        \\  name TEXT NOT NULL,
-        \\  invite_code TEXT NOT NULL UNIQUE,
-        \\  created_by TEXT NOT NULL REFERENCES local_user(id),
-        \\
-        \\  max_uses INTEGER,
-        \\
-        \\  created_at INTEGER NOT NULL DEFAULT CURRENT_TIMESTAMP,
-        \\  expires_at INTEGER
-        \\) STRICT;
-        ,
-        \\ALTER TABLE local_user ADD COLUMN invite_id TEXT REFERENCES invite(id);
-    };
-
     pub fn init() !Database {
         var db = try sql.Sqlite.open("./test.db");
         errdefer db.close();
 
-        for (init_sql_stmts) |stmt_sql| {
+        try migrations.up(&db);
-            var stmt = try db.prepare(stmt_sql);
-            defer stmt.finalize();
-
-            while (try stmt.step()) |_| {}
-        }
 
         return Database{ .db = db };
     }

src/main/db/migrations.zig

@@ -0,0 +1,175 @@
+const sql = @import("sql");
+const DateTime = @import("util").DateTime;
+
+pub const Migration = struct {
+    name: []const u8,
+    up: []const u8,
+    down: []const u8,
+};
+
+fn firstIndexOf(str: []const u8, char: u8) ?usize {
+    for (str) |ch, i| {
+        if (ch == char) return i;
+    }
+
+    return null;
+}
+
+fn execStmt(db: *sql.Sqlite, stmt_sql: []const u8) !void {
+    const stmt = try db.prepare(stmt_sql);
+    defer stmt.finalize();
+    while (try stmt.step()) |_| {}
+}
+
+fn execScript(db: *sql.Sqlite, script: []const u8) !void {
+    try execStmt(db, "BEGIN;");
+    errdefer {
+        _ = execStmt(db, "ROLLBACK;") catch unreachable;
+    }
+
+    var remaining = script;
+    while (firstIndexOf(remaining, ';')) |last| {
+        try execStmt(db, remaining[0 .. last + 1]);
+
+        remaining = remaining[last + 1 ..];
+    }
+
+    try execStmt(db, "COMMIT;");
+}
+
+fn wasMigrationRan(db: *sql.Sqlite, name: []const u8) !bool {
+    const stmt = try db.prepare("SELECT COUNT(*) FROM migration WHERE name = ?;");
+    defer stmt.finalize();
+
+    try stmt.bindText(1, name);
+    const result = (try stmt.step()).?;
+
+    const count = try result.getI64(0);
+    return count != 0;
+}
+
+fn markMigrationAsRan(db: *sql.Sqlite, name: []const u8) !void {
+    const stmt = try db.prepare("INSERT INTO migration(name) VALUES(?);");
+    defer stmt.finalize();
+
+    try stmt.bindText(1, name);
+    _ = try stmt.step();
+}
+
+pub fn up(db: *sql.Sqlite) !void {
+    try execScript(db, create_migration_table);
+
+    for (migrations) |migration| {
+        if (!try wasMigrationRan(db, migration.name)) {
+            try execScript(db, migration.up);
+            try markMigrationAsRan(db, migration.name);
+        }
+    }
+}
+
+const create_migration_table =
+    \\CREATE TABLE IF NOT EXISTS
+    \\migration(
+    \\  name TEXT NOT NULL PRIMARY KEY,
+    \\  applied_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP
+    \\) STRICT;
+;
+
+// NOTE: Until the first public release, i may collapse multiple
+// migrations into a single one. this will require db recreation
+const migrations: []const Migration = &.{
+    .{
+        .name = "users and actors",
+        .up = 
+        \\CREATE TABLE user(
+        \\  id TEXT NOT NULL PRIMARY KEY,
+        \\  username TEXT NOT NULL,
+        \\
+        \\  created_at INTEGER NOT NULL DEFAULT CURRENT_TIMESTAMP
+        \\) STRICT;
+        \\
+        \\CREATE TABLE actor(
+        \\  user_id TEXT NOT NULL PRIMARY KEY REFERENCES user(id),
+        \\  public_id TEXT NOT NULL
+        \\) STRICT;
+        \\
+        \\CREATE TABLE local_user(
+        \\  user_id TEXT NOT NULL PRIMARY KEY REFERENCES user(id),
+        \\
+        \\  email TEXT,
+        \\
+        \\  hashed_password TEXT NOT NULL,
+        \\  password_changed_at INTEGER NOT NULL
+        \\) STRICT;
+        ,
+        .down = 
+        \\DROP TABLE local_user;
+        \\DROP TABLE actor;
+        \\DROP TABLE user;
+        ,
+    },
+    .{
+        .name = "notes",
+        .up = 
+        \\CREATE TABLE note(
+        \\  id TEXT NOT NULL,
+        \\
+        \\  content TEXT NOT NULL,
+        \\  author_id TEXT NOT NULL REFERENCES actor(id),
+        \\
+        \\  created_at INTEGER NOT NULL DEFAULT CURRENT_TIMESTAMP
+        \\) STRICT;
+        ,
+        .down = "DROP TABLE note;",
+    },
+    .{
+        .name = "note reactions",
+        .up = 
+        \\CREATE TABLE reaction(
+        \\  id TEXT NOT NULL PRIMARY KEY,
+        \\
+        \\  reactor_id TEXT NOT NULL REFERENCES actor(id),
+        \\  note_id TEXT NOT NULL REFERENCES note(id),
+        \\
+        \\  created_at INTEGER NOT NULL DEFAULT CURRENT_TIMESTAMP
+        \\) STRICT;
+        ,
+        .down = "DROP TABLE reaction;",
+    },
+    .{
+        .name = "user tokens",
+        .up = 
+        \\CREATE TABLE token(
+        \\  id TEXT NOT NULL PRIMARY KEY,
+        \\
+        \\  hash BLOB UNIQUE NOT NULL,
+        \\  user_id TEXT NOT NULL REFERENCES local_user(id),
+        \\
+        \\  issued_at INTEGER NOT NULL DEFAULT CURRENT_TIMESTAMP
+        \\) STRICT;
+        ,
+        .down = "DROP TABLE token;",
+    },
+    .{
+        .name = "user invites",
+        .up = 
+        \\CREATE TABLE invite(
+        \\  id TEXT NOT NULL PRIMARY KEY,
+        \\
+        \\  name TEXT NOT NULL,
+        \\  invite_code TEXT NOT NULL UNIQUE,
+        \\  created_by TEXT NOT NULL REFERENCES local_user(id),
+        \\
+        \\  max_uses INTEGER,
+        \\
+        \\  created_at INTEGER NOT NULL DEFAULT CURRENT_TIMESTAMP,
+        \\  expires_at INTEGER
+        \\) STRICT;
+        \\ALTER TABLE local_user ADD COLUMN invite_id TEXT REFERENCES invite(id);
+        ,
+        .down = 
+        \\ALTER TABLE local_user DROP COLUMN invite_id;
+        \\DROP TABLE invite;
+        ,
+    },
+};