This makes clock source configuration more clear about the timestamps
returned. Specifically, that realtime is UTC and the most common
consumers.
Signed-off-by: Adrian Cole <adrian@tetrate.io>
This implements WASI `sched_yield` with `sys.Osyield` that defaults to
return immediately. This is intentionally left without a built-in
alternative as common platforms such as darwin implement
`runtime.osyield` by sleeping for a microsecond. If we implemented that,
user code would be slowed down without a clear reason why.
Signed-off-by: Adrian Cole <adrian@tetrate.io>
We originally had a `context.Context` for anything that might be
traced, but it turned out to be only useful for lifecycle and host functions.
For instruction-scoped aspects like memory updates, a context parameter is too
fine-grained and also invisible in practice. For example, most users will use
the compiler engine, and its memory, global or table access will never use go's
context.
Signed-off-by: Adrian Cole <adrian@tetrate.io>
This changes the AssemblyScript abort handler and WASI proc_exit
implementation to panic the caller which eventually invoked close.
This ensures no code executes afterwards, For example, LLVM inserts
unreachable instructions after calls to exit.
See https://github.com/emscripten-core/emscripten/issues/12322
See #601
Signed-off-by: Adrian Cole <adrian@tetrate.io>
This implements wasi_snapshot_preview1.poll_oneoff for relative clock events,
and in doing so stubs `Nanosleep` which defaults to noop, but can be configured
to `time.Sleep`.
Signed-off-by: Adrian Cole <adrian@tetrate.io>
This adds two clock interfaces: sys.Walltime and sys.Nanotime to
allow implementations to override readings for purposes of security or
determinism.
The default values of both are a fake timestamp, to avoid the sandbox
break we formerly had by returning the real time. This is similar to how
we don't inherit OS Env values.
I researched what is available for improving godoc. Notably, this does
the following on every non-internal go file (tests excluded).
* consolidates links where there's a better single one
* wraps See where there are multiple relevant links
* reduces use of Note: where possible
* Uses preformatting for bullets similar to gob
* Uses titles where appropriate
I looked into it and while there are many ways to re-render godoc into
markdown, there are limited options on what to do in godoc itself. There
are tricks implicitly used where preformatting (tab indent) is used to
avoid having to add extra lines everywhere. This is done in gob, for
example.
See https://go.dev/src/encoding/gob/doc.go
See https://github.com/fluhus/godoc-tricks/blob/master/doc.go
See #426
Signed-off-by: Adrian Cole <adrian@tetrate.io>
Before, we tested the examples/ directory using "ExampleXX", but this is
not ideal because it literally embeds the call to `main` into example
godoc output. This stops doing that for a different infrastructure.
This also makes sure there's a godoc example for both the main package
and wasi, so that people looking at https://pkg.go.dev see something and
also a link to our real examples directory.
Signed-off-by: Adrian Cole <adrian@tetrate.io>
During #425, @neilalexander gave constructive feedback that the API is
both moving fast, and not good enough yet. This attempts to reduce the
incidental complexity at the cost of a little conflation.
### odd presence of `wasm` and `wasi` packages -> `api` package
We had public API packages in wasm and wasi, which helped us avoid
leaking too many internals as public. That these had names that look
like there should be implementations in them cause unnecessary
confusion. This squashes both into one package "api" which has no
package collission with anything.
We've long struggled with the poorly specified and non-uniformly
implemented WASI specification. Trying to bring visibility to its
constraints knowing they are routinely invalid taints our API for no
good reason. This removes all `WASI` commands for a default to invoke
the function `_start` if it exists. In doing so, there's only one path
to start a module.
Moreover, this puts all wasi code in a top-level package "wasi" as it
isn't re-imported by any internal types.
### Reuse of Module for pre and post instantiation to `Binary` -> `Module`
Module is defined by WebAssembly in many phases, from decoded to
instantiated. However, using the same noun in multiple packages is very
confusing. We at one point tried a name "DecodedModule" or
"InstantiatedModule", but this is a fools errand. By deviating slightly
from the spec we can make it unambiguous what a module is.
This make a result of compilation a `Binary`, retaining `Module` for an
instantiated one. In doing so, there's no longer any name conflicts
whatsoever.
### Confusion about config -> `ModuleConfig`
Also caused by splitting wasm into wasm+wasi is configuration. This
conflates both into the same type `ModuleConfig` as it is simpler than
trying to explain a "will never be finished" api of wasi snapshot-01 in
routine use of WebAssembly. In other words, this further moves WASI out
of the foreground as it has been nothing but burden.
```diff
--- a/README.md
+++ b/README.md
@@ -49,8 +49,8 @@ For example, here's how you can allow WebAssembly modules to read
-wm, err := r.InstantiateModule(wazero.WASISnapshotPreview1())
-defer wm.Close()
+wm, err := wasi.InstantiateSnapshotPreview1(r)
+defer wm.Close()
-sysConfig := wazero.NewSysConfig().WithFS(os.DirFS("/work/home"))
-module, err := wazero.StartWASICommandWithConfig(r, compiled, sysConfig)
+config := wazero.ModuleConfig().WithFS(os.DirFS("/work/home"))
+module, err := r.InstantiateModule(binary, config)
defer module.Close()
...
```
