Limit the number of ping upload requests per minute

[brizental]

Related to Bug 1543612

I wanted to get some feedback on my approach to this problem before I continued. My goal here was to try and replicate what Firefox does to rate limit ping uploads, specifically:

Only allow up to 10 ping uploads per minute.

This turned out to be tricky. The challenges on the current implementation and how I decided to solve them are:

• It doesn't really know exactly when the ping is uploaded.
  • My solution here was to ignore this fact and just try to limit the number of times get_upload_task can be called per minute.
• It sends pings to upload one at a time, not in batches.
  • I created a counter to know how many pings have been sent out in the past minute.

NOTE: I am aware this breaks the ffi code and all the bindings, I'll deal with that after.

[Dexterp37]

I'm fine with this approach, but I'd like @badboy input on it as well.

[badboy]

Indeed that looks like a good start.
I have some comments, but not much against the approach by itself.

[Dexterp37]

This looks good to me overall. Before merging this, can we please add a documentation page describing it? I'm fine with it living within the Glean internal docs. I'd like to see some documentation explaining:

• the overview of how this is supposed to work;
• how are we enforcing the rate limitation;
• what are the default choices.

[badboy]

Looks good, see one comment.
Once we got the docs that Dexter asked for we should be good to go.

[Dexterp37]

Great work! r+wc :)