Running with the Backend

Time to see it all work together: we'll start the backend locally, log in from Play-In-Editor, and get into a server that the backend started for us.

Launching the Backend

Locally, the whole backend runs in a single process called the Dev Initiator. It starts the Director, each deployed realm's services, ticketing, and an in-memory Redis stub, and it creates local SQLite databases. Game servers are started on demand with your Unreal editor executable.

Standard License

Open a terminal in the RedwoodBackend directory and run the below command after replacing <your-config-env> with the name of the config environment you created in Installing:

./dev-initiator-win.exe <your-config-env>

macOS and Linux users can use ./dev-initiator-mac and ./dev-initiator-lin instead, respectively. Always run it from the RedwoodBackend directory, since it looks for the config folder and the installed dependencies relative to where you run it.

Custom License

In the RedwoodBackend directory, run:

yarn dev <your-config-env>

For example: yarn dev project-name.

Several logs will print to the console as the backend initializes; wait until you see All services ready.

Your local data is wiped on every start

By default, the Dev Initiator deletes the local databases each time it starts (environment.clean-db-on-dev-initiator-start: true), so accounts, characters, and servers don't survive a restart. This keeps development predictable, but if you'd rather keep your data, add this to your config environment's _index.yaml:

environment:
  clean-db-on-dev-initiator-start: false

The databases are the director-dev.db and realm-default-dev.db files in the RedwoodBackend directory.

If the Dev Initiator exits right away with an error about the config environment, double check the name you passed matches your folder (and that the folder is in config/node or one of your extraDirs). You can't run it with the default environment.

Your First Login

1. Make sure Use Backend in PIE is enabled (Setting Up Unreal).
2. Open your title map.
3. In the Play button's dropdown, set Net Mode to Play Standalone. Your title map runs as a normal client; the backend starts the actual servers.
4. Press Play.
5. Your menu should connect to the Director. If it's stuck connecting, see Troubleshooting.
6. Register an account. Any username and password works locally; we use test and test for quick iteration. Then log in.
7. Connect to the realm and create a character.

You can watch all of this happen in the Dev Initiator's console.

Testing with multiple players

Set Number of Players in the Play dropdown to open several PIE windows; each one is a separate client that can log in as a different account. You can also launch extra clients outside the editor with Standalone Game mode, which always uses the backend.

Getting into a Server

How you get into a server depends on the kind of game you configured in your game.yaml.

Match-based game

Use your play screen to either:

• Join Matchmaking with your profile ID (e.g. deathmatch). With min-players-for-matchmaking: 1, a match is made with just you after max-wait-until-make-shallow-match-ms.
• Create Proxy with bJoinSession enabled to host a lobby, or List Proxies and Join Proxy with Single Instance to join one another client created.

The backend then starts a game server for the match by running your project with UnrealEditor.exe -server. The server boots into your idle server map, Redwood tells it which map and game mode to load, and once it's ready your client travels there automatically.

Note: the first server start can take a while (shaders, asset compilation, and an uncooked editor process). If your ticket goes stale or you see a timeout, increase ticket-stale-time-ms and game-servers.ready-timeout-seconds in your realm instance config and restart the Dev Initiator. Cooked servers on Kubernetes start much faster, especially with Agones keeping warm servers ready.

Persistent world

Persistent worlds are expected to already be running before players join, so you need to create the world's GameServerProxy first. There are two ways to do that.

Option 1: Let the realm create it on boot (recommended for local development). Add this to your realm/instances/default.yaml:

default-proxy:
  create-on-first-boot:
    enabled: true
    name: "World"
  profile-id: "overworld" # your persistent profile's id
  start-on-boot: true

When the realm starts, it creates a proxy named World if one doesn't exist yet and starts its servers (after start-proxies-on-boot-delay-seconds, 15 seconds by default). Since the Dev Initiator wipes the database on every start, the world is recreated fresh each time. See Default Proxy for the other options.

Option 2: Use the CLI. With the Dev Initiator running, open another terminal in the RedwoodBackend directory and run:

yarn cli create-proxy overworld World --env project-name --start-on-boot --proxy-ends

The first argument is the profile ID and the second is the proxy's name. The CLI logs in as the backend's admin user, which is created automatically. --start-on-boot starts the proxy right away (and on future boots, if you keep your data), and --proxy-ends ends the proxy when its servers stop so you get a clean world next time. Wait for Proxy created successfully: <proxy-id>.

Either way, the backend starts one server per zone (each zone runs its own UnrealEditor.exe -server process, using roughly 1 to 2 GB of RAM each with uncooked content). Then use List Proxies to find the proxy's ID and Join Queue with that ID and the zone to enter (e.g. town). You'll be admitted and travel to the zone's server.

To stop the world's servers (e.g. so you can edit assets they have loaded), run:

yarn cli stop-proxy World --name --env project-name

--name tells the CLI the argument is the proxy's name rather than its ID. If you created the proxy with --proxy-ends, stopping its servers also ends the proxy, so you'll create a new one next time. Otherwise (including the default proxy from Option 1, which doesn't end by default), start it again with yarn cli start-proxy World --name --env project-name.

When you're in, you're playing on a dedicated server that Redwood started, authenticated against, and loaded your character on. 🎉

info

The servers run your uncooked content through the editor executable, which locks the assets they've loaded. Stop the servers (or let the match end) before saving changes to assets they're using.

Where to Find Logs

What	Where
Backend (Director, realm, ticketing, and sidecars)	The Dev Initiator's console. Set logging.level to debug or trace in your config environment for more detail, or enable logging.log-file.
Game servers	YourProject/Saved/Logs/YourProject*.log (search for LogRedwood). Add -log to game-servers.local.arguments to open a log window per server, or set game-servers.local.log-to-terminal: true to print server output in the Dev Initiator's console.
Game client	The Output Log in the editor (filter by LogRedwood)

Troubleshooting

The menu is stuck connecting to the Director

• Make sure the Dev Initiator is running and printed All services ready. If you pressed Play before it finished, the client retries on its own, but the retry delay grows each time; restart PIE if you don't want to wait.
• Make sure nothing else is using port 3001 (the Director Frontend) on your machine.
• Make sure the Director Uri in Project Settings > Plugins > Redwood is ws://localhost:3001 or ws://director.localhost:3001, and if you're using the latter, that your hosts file has director.localhost.
• Make sure Use Backend in PIE is enabled. Without it, Redwood doesn't connect at all (it pretends to succeed).

Logging in works but connecting to the realm hangs

• Make sure nothing else is using port 3011 (the Realm Frontend).
• Make sure your hosts file has realm-default.localhost.

Matchmaking or joining never gets you into a server

• Check the Dev Initiator's console for errors. Executable not found at path or Project not found at path means the game-servers.local paths in your realm instance config are wrong.
• Make sure your hosts file has realm-default-backend.localhost; the game server's sidecar uses it to connect to the realm.
• Check the game server's log. If it never finishes starting, the most common causes are a missing Asset Manager entry, a profile id or map ID in game.yaml that doesn't match a Data Asset's Redwood Id (Invalid ModeId or MapId), or a slow first start (increase game-servers.ready-timeout-seconds).
• If your ticket goes stale before the server is ready, increase ticketing.matchmaking.ticket-stale-time-ms.

You get kicked right after joining

• Could not load player character data means a URedwoodCharacterComponent is looking for data variables that don't exist. See Saving Player Data.
• Sidecar is not connected means the server's Servers Auto Connect to Sidecar setting is off.

There's a longer list of symptoms and fixes on the Troubleshooting page.

success

You're using Redwood to start your servers and route clients into them! Next, let's save the player's character data.