Use service instead of container

Author: jdetter

.github/workflows/ci.yml

@@ -290,6 +290,9 @@ jobs:
 
   unreal_engine_tests:
     name: Unreal Engine Tests
+    # This can't go on e.g. ubuntu-latest because that runner runs out of disk space. ChatGPT suggested that the general solution tends to be to use
+    # a custom runner.
+    runs-on: spacetimedb-new-runner
     container:
       image: localhost:5000/spacetimedb-ci:latest
       options: >-
@@ -298,24 +301,21 @@ jobs:
         -v /var/run/docker.sock:/var/run/docker.sock
         -v /opt/github-runner/cargo-cache:/home/runner/.cargo/registry
         -v /opt/github-runner/cargo-git:/home/runner/.cargo/git
-
-    # This can't go on e.g. ubuntu-latest because that runner runs out of disk space. ChatGPT suggested that the general solution tends to be to use
-    # a custom runner.
-    runs-on: spacetimedb-new-runner
     # Skip if this is an external contribution. GitHub secrets will be empty, so the step would fail anyway.
     if: ${{ github.event_name != 'pull_request' || !github.event.pull_request.head.repo.fork }}
-    container:
-      image: ghcr.io/epicgames/unreal-engine:dev-5.6
-      credentials:
-        # Note(bfops): I don't think that `github.actor` needs to match the user that the token is for, because I'm using a token for my account and
-        # it seems to be totally happy.
-        # However, the token needs to be for a user that has access to the EpicGames org (see
-        # https://dev.epicgames.com/documentation/en-us/unreal-engine/downloading-source-code-in-unreal-engine?application_version=5.6)
-        username: ${{ github.actor }}
-        password: ${{ secrets.GHCR_TOKEN }}
-      # Run as root because otherwise we get permission denied for various directories inside the container. I tried doing dances to allow it to run
-      # without this (reassigning env vars and stuff), but was unable to get it to work and it felt like an uphill battle.
-      options: --user 0:0
+    services:
+      unreal:
+        image: ghcr.io/epicgames/unreal-engine:dev-5.6
+        credentials:
+          # Note(bfops): I don't think that `github.actor` needs to match the user that the token is for, because I'm using a token for my account and
+          # it seems to be totally happy.
+          # However, the token needs to be for a user that has access to the EpicGames org (see
+          # https://dev.epicgames.com/documentation/en-us/unreal-engine/downloading-source-code-in-unreal-engine?application_version=5.6)
+          username: ${{ github.actor }}
+          password: ${{ secrets.GHCR_TOKEN }}
+          # Run as root because otherwise we get permission denied for various directories inside the container. I tried doing dances to allow it to run
+          # without this (reassigning env vars and stuff), but was unable to get it to work and it felt like an uphill battle.
+          options: --user 0:0
     steps:
 # Uncomment this before merging so that it will run properly if run manually through the GH actions flow. It was playing weird with rolled back
 # commits though.