🐞 Multiple prebid server endpoints - too strict validations

[muuki88]

Type of issue

🐞Bug
⚡Feature

Description

Configuring multiple prebid server instances is surprisingly tricky. I stumbled upon multiple layers of validation and unexpected side effects. Here's a quick summary with more details below.

1. TCF restrictions for server-side bidders  #12084 , gvlMapping or vendorExceptions are necessary when the tcfConsentModule is active
2. If you have multiple s2sConfig entries and set one to enabled: false, no requests will be sent to any s2sConfig instance
3. If there's no client adapter, but the bid params a configured client-side, additional params and bid config properties need to be added

At the end I hope to finish prebid/prebid.github.io#5033

(1) TCF Mapping

#12084 sums it up perfectly. gvlMapping is a valid solution, while I need to document this more.

(2) Disabling a single entry, disables all entries

If you have two entries

{
                s2sConfig: [
                    {
                        enabled: true, // !! turn this false, and not pbs request are sent !!
                        bidders: ['bidderB'],

                        accountId: '123456',
                        endpoint: {
                            p1Consent: 'https://prebid.adnxs.com/pbs/v1/auction'
                        }
                    },
                    {
                        enabled: true,
                        bidders: ['bidderA'],

                        accountId: '123456',
                        endpoint: {
                            p1Consent: 'https://mp.4dex.io/pbs/openrtb2/auction',
                        }
                    }
                ]
}

and set enabled: false for one of them, no requests for both of them are sent. This because

Prebid.js/modules/prebidServerBidAdapter/index.js

Lines 177 to 181 in 5864b98

	const optionsValid = normalizedOptions.every((option, i, array) => {
	formatUrlParams(option);
	const updateSuccess = updateConfigDefaultVendor(option);
	if (updateSuccess !== false) {
	const valid = validateConfigRequiredProps(option);

yield false due to no default vendor being set

Prebid.js/modules/prebidServerBidAdapter/index.js

Lines 128 to 129 in 5864b98

	// this is how we can know if user / defaultVendor has set it, or if we should default to false
	return option.enabled = typeof option.enabled === 'boolean' ? option.enabled : false;

I think this is a bug. If you want to have different prebid servers or pbs hosting companies, then disabling one should disable everything. Use cases are

1. performance testing two vendors
2. enabling different configs depending on geo
3. run different subsets of bidders on different pbs instances

I know, that one could filter the array on the publisher side, but why is there an enabled flag then 😛 The demo page below can be used to test this.

(3) client-side adapter requirement

TASK FOR MUKI TO DOCUMENT

If you run a pbs auction on the server, there should be no client-side adapter necessary. There has been great progress:

• Improve client-side footprint for server-side adapters #6361
• client-side adapter code should not be required for server-side bidders #6388
• Support Prebid Server stored impression scenario #7027
• Prebid Core: Restore use of server-side adapter without client-side adapter #7662

I think it's working as shown on the test page. It seems the bid.params.configName and bid.module = 'pbsBidAdapter' are not necessary. Even though I had a certain state where it wasn't working, I thought I pinned it down to this

Prebid.js/src/adapterManager.js

Lines 177 to 181 in 5864b98

	const s2sBids = adUnit.bids.filter((b) => b.module === PBS_ADAPTER_NAME && b.params?.configName === s2sConfig.configName);
	if (s2sBids.length === 1) {
	adUnit.s2sBid = s2sBids[0];
	hasModuleBids = true;
	adUnit.ortb2Imp = mergeDeep({}, adUnit.s2sBid.ortb2Imp, adUnit.ortb2Imp);

Test page

https://jsbin.com/legafiwoqe/edit?html,console

Expected results

If I set enable: false for one s2sConfig , the others are still enabled.

Actual results

All are disabled.

Platform details

Prebid 9.x

Other information

• Improve client-side footprint for server-side adapters #6361
• client-side adapter code should not be required for server-side bidders #6388
• Support Prebid Server stored impression scenario #7027
• Prebid Core: Restore use of server-side adapter without client-side adapter #7662

[dgirardi]

The test page generates "missing undefined" errors for me because the PBS adapter expects each config's adapter option to be set. With #12727 those default to "prebidServer".

It seems the bid.params.configName and bid.module = 'pbsBidAdapter' are not necessary

They only affect "module" bids for stored impression scenarios, to decide which instance to route them to - since there's no bidders to use for that purpose. There's an example here