on_vm_start is called multiple times when multiple plugins exist in a single VM.

[mathetake]

WasmBase::start is called for every plugin;

proxy-wasm-cpp-host/src/wasm.cc

Line 593 in 668bc99

auto plugin_context = wasm_handle->wasm()->start(plugin);

and inside of it ContextBase::onStart is called:

proxy-wasm-cpp-host/src/wasm.cc

Line 395 in 668bc99

if (!context_ptr->onStart(plugin)) {

that results in calling on_vm_start:

proxy-wasm-cpp-host/src/context.cc

Lines 137 to 142 in 668bc99

	if (wasm_->on_vm_start_) {
	// Do not set plugin_ as the on_vm_start handler should be independent of the plugin since the
	// specific plugin which ends up calling it is not necessarily known by the Wasm module.
	result =
	wasm_->on_vm_start_(this, id_, static_cast<uint32_t>(wasm()->vm_configuration().size()))
	.u64_ != 0;

[PiotrSikora]

I think it was done deliberately to retain some backward compatibility, since otherwise only on_vm_start from one plugin would be called, which might result in skipped global initializations, etc.

Having said that, do you have any use for this? I was thinking about completely removing on_vm_start (and vm_configuration) from the ABI, since everything should be scoped to plugins and their configuration.

[mathetake]

Having said that, do you have any use for this? I was thinking about completely removing on_vm_start (and vm_configuration) from the ABI, since everything should be scoped to plugins and their configuration.

actually I don't use this, and +1 to the idea that everything should be scoped to plugins. Btw what's your current thoughts on multiple plugins per 1 VM thing? That is somewhat related to that ABI change.