There are two instances of the following line in the code:
let _ = sem_clone.acquire().await.unwrap();
This will acquire the semaphore permit and immediately drop it, as let _ does not actually bind the value (it's ignored). This means that may be more concurrent downloads happening than planned.
A quick fix would be let _permit = sem_clone.acquire().await.unwrap();, then it'd be dropped at the end of the scope. Note that you may need to increment the batch size to keep the current download speed.
Also, I personally find it better to name ignored variables, such as let _result = download_album [..] (line 61) and let _count = io::copy [...] (line 127), making it easier (when reading) to know what's being ignored.
evan-sm
commented
2 years ago
Hey!
There are two instances of the following line in the code:
This will acquire the semaphore permit and immediately drop it, as
let _does not actually bind the value (it's ignored). This means that may be more concurrent downloads happening than planned.A quick fix would be
let _permit = sem_clone.acquire().await.unwrap();, then it'd be dropped at the end of the scope. Note that you may need to increment the batch size to keep the current download speed.Also, I personally find it better to name ignored variables, such as
let _result = download_album [..](line 61) andlet _count = io::copy [...](line 127), making it easier (when reading) to know what's being ignored.References on _ not binding:
The Rust Programming Language: Ignoring an Entire Value with _ https://github.com/rust-lang/rust/issues/40096