feat: add WASI Preview 1 stubs for wasip1-targeting languages#4641
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djgilcrease wants to merge 2 commits intoclockworklabs:masterfrom
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feat: add WASI Preview 1 stubs for wasip1-targeting languages#4641djgilcrease wants to merge 2 commits intoclockworklabs:masterfrom
djgilcrease wants to merge 2 commits intoclockworklabs:masterfrom
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Add minimal WASI function stubs (fd_write, clock_time_get, random_get, etc.) so that modules compiled to `wasip1` (e.g. Go with `-buildmode=c-shared`) can run in SpacetimeDB's wasmtime runtime. This includes: - wasi_stubs.rs: stub implementations for wasi_snapshot_preview1 imports - Linking the stubs into the wasmtime linker - Calling `_initialize`/`_start` exports before other module exports to initialize the language runtime (WASI reactor/command convention) These changes are additive — existing Rust/C# modules are unaffected since they don't import WASI functions or export `_initialize`/`_start`.
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Description of Changes
Summary
Add minimal WASI Preview 1 stub implementations so that modules compiled to
wasip1(e.g. Go with-buildmode=c-shared) can be instantiated and run in SpacetimeDB's wasmtimeruntime.
wasi_stubs.rswith stub implementations forwasi_snapshot_preview1imports (fd_write,clock_time_get,random_get,proc_exit,args_sizes_get,environ_sizes_get,sched_yield, etc.)_initialize/_startexports (WASI reactor/command convention) before preinit functions to initialize the guest language runtimeWhy
Languages like Go use
//go:wasmimportfor WASI functions, which must be satisfied by the host. Without these stubs, wasmtime fails to instantiatewasip1-targeting modules becausethe
wasi_snapshot_preview1imports are unresolved. The C++ SDK handles this differently by embedding shims in the compiled module itself(
crates/bindings-cpp/src/abi/wasi_shims.cpp), but Go (and potentially other languages) require host-side stubs.This is a prerequisite for the Go server SDK but is language-agnostic — any
wasip1-targeting language benefits from these stubs.This can also replace the stubs that were added separately for C # and C++, so those and Go can all share the same stubs. I did not update the C# and cpp modules to use these stubs in this MR as I want it to be as minimal as possible so I could start using my go server module asap.
What the stubs do
fd_writelog::info!/log::warn!)clock_time_getrandom_getargs_sizes_get/args_getenviron_sizes_get/environ_getpoll_oneoffproc_exit/sched_yieldfd_close/fd_seek/fd_read/fd_fdstat_get/fd_fdstat_set_flags/fd_prestat_get/fd_prestat_dir_nameERRNO_BADForERRNO_NOSYSImpact on existing modules
None. These changes are purely additive:
wasi_snapshot_preview1namespace, which existing Rust/C# modules don't import_initialize/_startdetection is a no-op for modules that don't export themAPI and ABI breaking changes
None
Expected complexity level and risk
1 - very low complexity and risk, the stubs are not used by anything, BUT will enable me to externalize a go-sdk for server modules
Testing
ran the full test suite locally