Merge pull request #102 from brendandburns/main

Add the ability to call specific modules in wasmtime.

crates/containerd-shim-wasmtime/src/instance.rs

@@ -87,7 +87,7 @@ pub fn prepare_module(
  stdin_path: String,
  stdout_path: String,
  stderr_path: String,
-) -> Result<(WasiCtx, Module), WasmtimeError> {
+) -> Result<(WasiCtx, Module, String), WasmtimeError> {
  debug!("opening rootfs");
  let rootfs = oci_wasmtime::get_rootfs(spec)?;
  let args = oci::get_args(spec);
@@ -121,19 +121,25 @@ pub fn prepare_module(
  let wctx = wasi_builder.build();
  debug!("wasi context ready");
 
- let mut cmd = args[0].clone();
- let stripped = args[0].strip_prefix(std::path::MAIN_SEPARATOR);
+ let start = args[0].clone();
+ let mut iterator = start.split('#');
+ let mut cmd = iterator.next().unwrap().to_string();
+
+ let stripped = cmd.strip_prefix(std::path::MAIN_SEPARATOR);
  if let Some(strpd) = stripped {
  cmd = strpd.to_string();
  }
+ let method = match iterator.next() {
+ Some(f) => f,
+ None => "_start",
+ };
 
  let mod_path = oci::get_root(spec).join(cmd);
-
  debug!("loading module from file");
  let module = Module::from_file(&engine, mod_path)
  .map_err(|err| Error::Others(format!("could not load module from file: {}", err)))?;
 
- Ok((wctx, module))
+ Ok((wctx, module, method.to_string()))
 }
 
 impl Instance for Wasi {
@@ -168,15 +174,15 @@ impl Instance for Wasi {
  let m = prepare_module(engine.clone(), &spec, stdin, stdout, stderr)
  .map_err(|e| Error::Others(format!("error setting up module: {}", e)))?;
 
- let mut store = Store::new(&engine, m.0);
+ let mut store = Store::new(&engine, m.0); 
 
- debug!("instantiating instnace");
+ debug!("instantiating instance");
  let i = linker
  .instantiate(&mut store, &m.1)
  .map_err(|err| Error::Others(format!("error instantiating module: {}", err)))?;
 
  debug!("getting start function");
- let f = i.get_func(&mut store, "_start").ok_or_else(|| {
+ let f = i.get_func(&mut store, &m.2).ok_or_else(|| {
  Error::InvalidArgument("module does not have a wasi start function".to_string())
  })?;