Crate harmonizer
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Harmonizer
This harmonizer offers the ability to invoke a bundled version of the
JavaScript library, @apollo/composition, which composes multiple subgraphs
into a supergraph.
The bundled version of the federation library that is included is a JavaScript
Immediately Invoked Function Expression (IIFE) that is created by running the
esbuild bundler on the @apollo/composition package.
When the harmonize function that this crate provides is called with a
[ServiceList] (which is synonymous with the terminology and service list
notion that exists within the JavaScript composition library), this crate uses
deno_core to invoke the JavaScript within V8. This is ultimately
accomplished using rusty_v8’s V8 bindings to V8.
While we intend for a future version of composition to be done natively within Rust, this allows us to provide a more stable transition using an already stable composition implementation while we work toward something else.
Functions
The harmonize function receives a Vec<SubgraphDefinition> and invokes JavaScript
composition on it, either returning the successful output, or a list of error messages.