Queues

OPAL ships with two separate queues: one for downloads (engines, gems, assets) and one for builds (engine source builds, project builds). They behave the same way from a UX perspective: add, pause, resume, reorder, remove.

What you can do in a queue

• Pause / Resume individual items
• Pause All / Resume All the whole queue
• Move to top / Move to bottom an item
• Cancel an item (asks for confirmation; preserves partial state to a trash area)
• Retry a failed item
• Clear completed to reclaim the list

All of these persist across launches. Close OPAL mid-download, reopen an hour later, and the queue looks exactly like you left it — same items, same order, same progress.

Parallelism

How many downloads run in parallel? How many builds? Configurable — independently — in Settings → Queues.

Good defaults:

• Downloads: 4 concurrent connections
• Builds: 1 concurrent on laptops, 2–3 on workstations

Speed limits

Settings → Queues → Download speed limit sets a cap in MB/s. Set to 0 (default) for unlimited. Useful when OPAL is competing with Zoom calls or a home connection that doesn’t love saturated uploads.

Schedule windows

Settings → Queues → Schedule lets you restrict download activity to a time window — for example, 22:00 to 07:00 so you don’t burn daytime bandwidth. When the window closes, OPAL:

• Allows downloads >90% complete to finish
• Pauses everything else
• Resumes automatically at the next window open

Overnight windows that cross midnight (e.g. 22:00–06:00) are handled correctly.