Stream: git-wasmtime

Topic: wasmtime / issue #10638 [wasmtime]: Construct CacheConfig...

Wasmtime GitHub notifications bot (Apr 22 2025 at 13:10):

benbrandt opened issue #10638:

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.

Wasmtime GitHub notifications bot (Apr 22 2025 at 13:11):

benbrandt commented on issue #10638:

I forgot to mention, but I am open to doing the implementation (with any necessary pointers), but wanted to get feedback on the idea before submitting the PR

Wasmtime GitHub notifications bot (Apr 22 2025 at 14:36):

alexcrichton commented on issue #10638:

I think this'd be a great idea to have, thanks for filing an issue and working on this!

The only thing I'd suggest is that we wouldn't want users to have to depend on the wasmtime-cache crate itself, so we'd reexport as wasmtime::CacheConfig to have accessible from the main wasmtime crate. Otherwise though definitley agreed it'd be best to support progammatic configuration instead of exclusively file-based configuration.

Wasmtime GitHub notifications bot (Apr 29 2025 at 18:58):

benbrandt closed issue #10638:

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.

Last updated: Dec 06 2025 at 07:03 UTC