Bobcat rate limit

[droidkfx]

What happened

When using this exporter it seems to rather regularly fail to fetch temperature data because it receives a 429 response. I can reproduce this issue at polling intervals all the way up to 1m so I am pretty sure it is not the scraping frequency that is the culprit.

time="2022-07-08T00:08:26Z" level=error msg="Can't scrape /temp.json: HTTP status 429" source="main.go:205"
time="2022-07-08T00:09:26Z" level=error msg="Can't scrape /temp.json: HTTP status 429" source="main.go:205"
time="2022-07-08T00:10:26Z" level=error msg="Can't scrape /temp.json: HTTP status 429" source="main.go:205"
time="2022-07-08T00:11:26Z" level=error msg="Can't scrape /temp.json: HTTP status 429" source="main.go:205"

Debugging

I did some debugging and I think the issue is the tight loop that this exporter uses. I think, and this is sorta ironic, that the code executes the call to /temp.json too soon after calling /status.json.

In some cases, 429 errors come with a Retry-After header that could be used to space out the requests but I don't see that in the response from the miner.

I went looking for documentation from bobcat but I can't seem to find any details on the miner HTTP server or how it is configured...

By testing, I found the limit, at least on my miner, could be as low as 1 request per 1.5s!

Possible solution

I think there are a couple of things that could be done:

• The fetch routine could be improved to have a retry with a back-off
• There could be a configurable constant sleep time for requests (seems questionable to me)
• The fetching could be done in the background instead of on-demand. I think this is "best" but does not really fit with what you had going here. It also adds a lot of complexity.

I mention the above because I am happy to do any of them but since this is not my project, and I don't wanna fork it, I wanted to see what you the author thought.

Let me know and if I have some time I may send a PR your way.

Take care!

[droidkfx]

Also just learned that as of the time of writing the status.json endpoint is being removed. As of:

Bobcat Firmware version updated to 1.0.3.1 Helium Firmware version updated to 2022.07.14.0_GA

Bobcat miners will be lite so they will not have a sync status. Syncing will be done by validators I guess... So the above might be a non-issue. The only metric you can really track without impacting the bobcat would be the temperature.

Details if interested: https://shop.bobcatminer.com/blogs/all/bobcat-ota-update-blockchain-sync-turned-off-7-15-2022