Feature

wasmtime::Config::cache_config for loading a CacheConfig from a struct instead of a file.

Benefit

Right now, in order to use the cache, you have to provide a path to a file with the needed configuration.

However, there are cases where the wasmtime is embedded, rather than the CLI, where the cache is still helpful. It would be more convenient to create the configuration programmatically rather than loaded from a file, to allow the application to determine the cache setup based on its own configuration.

Implementation

1. Expose wasmtime_cache::CacheConfig from wasmtime

2. Add setters for wasmtime_cache::CacheConfig so individual fields can be configured.

let mut cache_config = wasmtime_cache::CacheConfig::default();
cache_config.with_directory("/path/to/cache");

3. Add cache_config method to set this config on the wasmtime::Config

let mut config = wasmtime::Config::default();
config.cache_config(cache_config);

Alternatives

Based on the implementation for the method to load from a file, this seems like a straightforward way to allow for a wasmtime user to create their own cache.

If there are other ideas, we could explore those instead.