Passing relative (and especially sub-board) URLs to be invoked later

[dglazkov]

There are cases where we pass boards as relative URLs to be invoked later. In these cases, the base URL is no longer valid. A good example is Repeater, which is a graph that pretends to be a node in the Agent Kit. This graph takes in a "worker" input, which is a board. This input is then used to repeatedly invoke the graph, specified by the input.

When a user passes a relative URL to this graph, their expectation is that this URL is resolved relative to the graph in which Repeater is situated. However, since it is passed inside of the graph, by the time it reaches the invoke node, the base URL is now the URL of the Repeater graph.

This is especially relevant for subgraphs, because the only workaround right now is to only specify absolute URLs, which means that we could find ourselves encoding various provider-specific URLs into boards:

Which is no good.

Need to figure out what to do here.

[dglazkov]

One simple solution might be to lean into the BoardCapability and use it as a runtime wrapper around a board URL, supplying the base URL with it.

[paullewis]

There's a related issue with the Board selector. If I load a board using – say – the FS API, and I select /graphs/gemini-generator.json from the list we will try and resolve to the FS API, which will fail.

Options I can think of:

1. Expand the URL in the board selector, which has the same "we could find ourselves encoding various provider-specific URLs into boards" problem mentioned above.
2. Denote which provider offered the board to begin with... which I guess might be a similar approach to the BoardCapability option.

[dglazkov]

Yeah, the approach i will try to day is separating compose-time and run-time URL resolution. Basically, we will use relative URLs at compose-time and resolve them into absolute URLs at run-time.

[paullewis]

So we don't forget, this currently expands the URL in place: https://github.com/breadboard-ai/breadboard/blob/main/packages/breadboard-ui/src/elements/node-info/board-selector.ts#L182-L189

For any absolute URLs it works out because they don't get changed. For the /graph/foo.json ones, they get the current origin popped on the front.

[dglazkov]

The relative URLs should now work, as long as we're not linking them across different GraphProviders. This part is trickier and still needs to be implemented.

[dglazkov]

Some incomplete notes to self on the trickier part:

• always resolving the path to url may not always be the right thing. When I run the graph locally, the "examples"-provided URLs will resolve to localhost, which is clearly not what I want when I want to save the BGL file. Similarly, simply resolving the idb or fsapi URLs seems wrong. These aren't portable.
• In the case of "examples", it seems like maybe there needs to be a notion of a "canonical" URL? Or maybe to simplify, example URLs need to point to github, rather than locally?
• What is the solution that enables the user to not have to think about URLs?
• There does seem to be some sort of bundling that will need to happen eventually. If I want to publish a BGL file, and it depends on some other files in my idb, I would probably expect Breadboard to just figure it out, and bundle those graphs when saving... right?