[Question]Do we need a lock if we use a cache?

[caibirdme]

Didn't find any docs about the running model of envoy wasm. Does a plugin just like a single thread redis server, that we don't need to take care of the data race, or do we should protect the data by lock?
For example: I want to implement a http plugin that if url matches some regex, add coresponding pre-configured value to its request header, so that VirtualService can leverage this header to do some traffic splitting.

{
"^/a/\\d+": "us_east",
"/x/.*/y/z$": "us_west"
}

Because regex matching consumes too much cpu time, I want to cache the result

// fast path
if head_val, ok := self.cache.get(url); ok {
  // set request header
  return Continue
}
// slow path
head_val, ok :=self.do_regexp_match(url)
if ok {
  self.cache.set(url, head_val)
}
// set request header
return Continue

I don't know if I should add a rwlock to protect the cache object?

type pluginContext struct {
  cache ThreadSafeMap[string,string] // does this map need to be thread safe? Or a builtin map is ok?
}

func (ctx *pluginContext) NewHttpContext(contextID uint32) types.HttpContext {
	return &myRegexMatchPlugin{cache: ctx.cache}
}

[mathetake]

no since Proxy-Wasm is single-threaded (and Wasm is in a general single thread). Please search the GitHub repo before asking questions on the issues #368