Limit number of impressions in auction request

[linux019]

Some bots or page crawlers send a request containing tens or hundred imps, eg 32...150. This is a useless traffic and it makes extra requests to bidder servers because some adapters send an impression as a separate HTTP request.
This is an example of their windows size, huge width

   "device": {
        "w": 1366,
        "h": 128810,
        "dnt": 0,
        "ua": "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36",
        "language": "en",
    },

https://developers.google.com/publisher-tag/guides/publisher-console-messages#TOO_MANY_SLOTS_IN_SRA_REQUEST
It doesn't allow more than 30 ad slots.

Do you consider a PR that will add a impressions limit and a metric (counter with account_id label)?

[bretg]

Discussed in committee. We agreed that having an opt-in impression limit would be fine. Set this at the default account level that can be overridden by specific accounts.

auction.impression_limit: 50

• 0 means no limit
• Defaults to no limit
• impression objects after this count are dropped
• add a warning to the debug output

@linux019 - do you have a suggestion for what kind of metric you're looking for? We already have a top-level "imps_requested", perhaps a top-level "imps_dropped" metric?

[linux019]

I'm good with any name. The metric of type counter is ok to use rate() on it. ( https://prometheus.io/docs/prometheus/latest/querying/functions/#rate )

[bretg]

Discussed in committee. We agreed the metric can be called "imps_dropped" and that it should count the number of imps dropped.

Ready-for-Dev.

[bretg]

@linux019 - is this a feature you guys might be willing to contribute?

[linux019]

Hi @bretg I'll submit a PR