refactor(db): Make log handling explicit in StorageAPI.setState (#581)

* feat(db): Add appendLog method to storage API

Move the log concatenation logic out of setState and into a separate 
appendLog method.

* feat(master): Don’t persist deltalog in main state object

* feat(db): Revert to using setState but with optional deltalog argument

Author: delucis

src/master/master.ts

@@ -296,10 +296,12 @@ export class Master {
       };
     });
 
+    const { deltalog, ...stateWithoutDeltalog } = state;
+
     if (IsSynchronous(this.storageAPI)) {
-      this.storageAPI.setState(key, state);
+      this.storageAPI.setState(key, stateWithoutDeltalog, deltalog);
     } else {
-      await this.storageAPI.setState(key, state);
+      await this.storageAPI.setState(key, stateWithoutDeltalog, deltalog);
     }
   }
 

src/server/api.test.ts

@@ -19,14 +19,13 @@ class AsyncStorage extends StorageAPI.Async {
 
   constructor(args: any = {}) {
     super();
-    const { createGame, fetch, setState, setMetadata, listGames, wipe } = args;
     this.mocks = {
-      createGame: createGame || jest.fn(),
-      setState: setState || jest.fn(),
-      fetch: fetch || jest.fn(() => ({})),
-      setMetadata: setMetadata || jest.fn(),
-      listGames: listGames || jest.fn(() => []),
-      wipe: wipe || jest.fn(),
+      createGame: args.createGame || jest.fn(),
+      setState: args.setState || jest.fn(),
+      fetch: args.fetch || jest.fn(() => ({})),
+      setMetadata: args.setMetadata || jest.fn(),
+      listGames: args.listGames || jest.fn(() => []),
+      wipe: args.wipe || jest.fn(),
     };
   }
 

src/server/db/base.ts

@@ -73,8 +73,15 @@ export abstract class Async {
 
   /**
    * Update the game state.
+   *
+   * If passed a deltalog array, setState should append its contents to the
+   * existing log for this game.
    */
-  abstract setState(gameID: string, state: State): Promise<void>;
+  abstract setState(
+    gameID: string,
+    state: State,
+    deltalog?: LogEntry[]
+  ): Promise<void>;
 
   /**
    * Update the game metadata.
@@ -130,8 +137,11 @@ export abstract class Sync {
 
   /**
    * Update the game state.
+   *
+   * If passed a deltalog array, setState should append its contents to the
+   * existing log for this game.
    */
-  abstract setState(gameID: string, state: State): void;
+  abstract setState(gameID: string, state: State, deltalog?: LogEntry[]): void;
 
   /**
    * Update the game metadata.

src/server/db/flatfile.test.ts

@@ -88,8 +88,8 @@ describe('FlatFile', () => {
       phase: '',
     };
 
-    await db.setState('gameID', { deltalog: [logEntry1] } as State);
-    await db.setState('gameID', { deltalog: [logEntry2] } as State);
+    await db.setState('gameID', null, [logEntry1]);
+    await db.setState('gameID', null, [logEntry2]);
 
     const result = await db.fetch('gameID', { log: true });
     expect(result.log).toEqual([logEntry1, logEntry2]);

src/server/db/flatfile.ts

@@ -94,13 +94,13 @@ export class FlatFile extends StorageAPI.Async {
     return this.games.clear();
   }
 
-  async setState(id: string, state: State) {
-    let log: LogEntry[] =
-      ((await this.games.getItem(LogKey(id))) as LogEntry[]) || [];
-    if (state.deltalog) {
-      log = log.concat(state.deltalog);
+  async setState(id: string, state: State, deltalog?: LogEntry[]) {
+    if (deltalog && deltalog.length > 0) {
+      const key = LogKey(id);
+      const log: LogEntry[] =
+        ((await this.games.getItem(key)) as LogEntry[]) || [];
+      await this.games.setItem(key, log.concat(deltalog));
     }
-    await this.games.setItem(LogKey(id), log);
     return await this.games.setItem(id, state);
   }
 

src/server/db/inmemory.ts

@@ -48,14 +48,12 @@ export class InMemory extends StorageAPI.Sync {
   /**
    * Write the game state to the in-memory object.
    */
-  setState(gameID: string, state: State): void {
-    this.state.set(gameID, state);
-
-    let log = this.log.get(gameID) || [];
-    if (state.deltalog) {
-      log = log.concat(state.deltalog);
+  setState(gameID: string, state: State, deltalog?: LogEntry[]): void {
+    if (deltalog && deltalog.length > 0) {
+      const log = this.log.get(gameID) || [];
+      this.log.set(gameID, log.concat(deltalog));
     }
-    this.log.set(gameID, log);
+    this.state.set(gameID, state);
   }
 
   /**