Usage of futures::executor::block_on

[paologallinaharbur]

We are trying to call async method hiding calls to k8s from no-async methods:

Es:

    fn get(&self, agent_id: &str) -> Result<Option<DataStored>, StorerError> {
        futures::executor::block_on(self.async_get(agent_id))
    }

    async fn async_get(&self, agent_id: &str) -> Result<Option<DataStored>, StorerError> {
       [...]
        let data_res = self
            .k8s_executor
            .get_configmap_key()
            .await?;

and we are in a Tokio runtime marked with #[tokio::main]

I initially had some issues, but now it seems to be working. However, while researching I found the following comment in an old issue from @nightkr

It states:

You can use tokio::Runtime::block_on, but not futures::block_on 
(at least not without doing a bunch of extra setups to make sure that you still have a Tokio runtime in scope).

Are there any issues I am not seeing? are they compatible?

[nightkr]

So there are several issues going on here, some of which hide the others...

1. Tokio features largely need to have a Tokio runtime available. futures::block_on does not provide this by itself, however in your case it would be inherited from the tokio::main. tokio::Runtime::block_on does provide this. You can also use tokio::Runtime::enter yourself to install one if you want to use a different executor.
2. Running blocking IO code in an async context blocks the entire thread, which prevents other futures from progressing (either ones that are explicitly joined using something like futures::future::{select,join}, ones running in a single-threaded runtime, or ones that are tokio::spawned but happen to be scheduled for the same thread). tokio::Runtime::block_on will detect this case and panic, while futures::block_on will apparently leave you to glue your foot back on yourself.
3. Frankly, trying to hide futures like this makes your code much less clear. block_on should only be used when trying to run a piece of async code in an otherwise async-unaware application.

All in all, this smells like a case of the XY problem. What is the actual goal that you are trying to accomplish here?