Multi-tenancy: How to set user properties before tracking events? Alternatives without user property?

Hi Yuanyuan, thanks for your swift response.

Would it help your case if it is configured to be dynamic?

I am not entirely sure what you mean here. Based on your response, I checked out page-view-tracking.ts in the Amplitude-TypeScript library. From my testing, it appears that the function I provide to trackOn is evaluated each time I navigate within the browser, meaning it re-evaluates, not just on the initial load.

I tried using trackOn since I could not find any other options. Ideally, I would like tenant to work similarly to amplitude.setUserId(), where userId is set before the session initialises. Do you happen to know of any way to set a user property before Amplitude begins tracking?

Thanks again for your help.

Hi Yuanyuan, we are using Amplitude in a Next.js application, which means Amplitude is initialised only once. Subsequent URL changes will not reinitialise Amplitude, as the view updates without a full page reload. Hope this answers your question.

Hi Yuanyang, thank you for your reply the other day. I have applied the code on our staging environment to first call identify and then amplitude.init. However, the traffic still shows events being sent without a tenant value.

We are using the 'Any Active Event' option provided by Amplitude.

Is there anything I might be missing? During local testing, I also noticed events are sent without a tenant, even when the init call is placed after identify

Here’s my code

useEffect(() => {
  if (!userId) {
    return;
  }

  const identifyEvent = new amplitude.Identify();
  identifyEvent.setOnce('tenant', tenant);
  amplitude.identify(identifyEvent);
  amplitude.init(AMPLITUDE_ID, {
    userId,
  });
}, [userId, tenant]);

And here are the results

The result is similar to what I share with you earlier a week ago

Would you be able to share any additional insights or check with the engineering team? I would greatly appreciate it. Thank you!

Thank you Yuanyuan for your support. Looking forward to your response. For now, have a great weekend!

Hi @Trung Vo !
I haven’t tested it, but I think it could work.
https://github.com/amplitude/Amplitude-TypeScript/blob/main/examples/plugins/page-view-tracking-enrichment/index.ts
By adding a "pageViewTrackingEnrichment" plugin, you could perform an identify only when event.event_type == 'Start session'

Thank you, Yuanyuan and Roque, for your input—it looks very promising. I have pushed the changes to our staging environment for testing and will monitor them over the next few days. I will keep you updated on the results.

Hi ​@Yuanyuan Zhang, apologies for the very late update. We deployed the changes you suggested in early November, and the number of page titles with empty tenants has now dropped to 0, confirming that the fix works on PROD.

Here is my final plugin code:

const tenantPropertyPlugin = (
  tenant: string,
): EnrichmentPlugin => {
  return {
    execute: async (event) => {
      event.user_properties = {
        ...event.user_properties,
        $setOnce: {
          tenant,
          domain: 'client',
        },
      };
      return event;
    },
  };
};

 However, on staging, we started using the Experiment package.

import { Experiment, ExperimentClient } from '@amplitude/experiment-js-client';

const tenantPropertyPlugin = (
  tenant: string,
): EnrichmentPlugin => {
  return {
    execute: async (event) => {
      event.user_properties = {
        ...event.user_properties,
        $setOnce: {
          tenant,
          domain: 'client',
        },
      };
      return event;
    },
  };
};


const experiment = Experiment.initializeWithAmplitudeAnalytics(AMPLITUDE_ID, {
  debug: true,
  automaticExposureTracking: true, // Default to true for now, but let's set to true to ensure we don't lose exposure props for variant value
  exposureTrackingProvider: {
    track: (exposure) => {
      amplitude.track('$exposure', exposure);
    },
  },
});

amplitude.add(
  tenantPropertyPlugin(
    bootstrapData.tenant
  ),
);
amplitude.init(AMPLITUDE_ID, {
  userId,
});

experiment?.start({
  user_properties: {
    platform: 'rc-us', // TODO - need to make this dynamic and easy to determine from 'rc-in' later on
    environment: appEnv as string,
    tenant: bootstrapData.tenantId,
  },
});

Noted that on my code, experiment?.start is called after amplitude.init. Upon tracking, staging began showing events without tenant data. This behaviour makes sense based on the code, as we only added the tenantPropertyPlugin using amplitude.add, but not for the Experiment package. As a result, any Experiment event is missing the user properties set by tenantPropertyPlugin.

My follow-up question is: is there a way to apply the same plugin when using the Experiment SDK?

Thank you so much for your support so far, Yuanyuan.

Hello ​@Yuanyuan Zhang , we have implemented the tenantEnrichmentPlugin as mentioned

const tenantUserPropertyPlugin = (): EnrichmentPlugin => {
  return {
    execute: async (event: Event) => {
      event.user_properties = {
        ...event.user_properties,
        "$setOnce": {
          "tenant": "tenant-id"
          // Other properties
        },
      };
      return event;
    },
  }
}

However, we recently discovered that it does not seem to correctly send the user property to Amplitude. 

Specifically, Amplitude is receiving $setOnce.<custom_user_property> instead of <custom_user_property>. 

Can I check we should be doing the following instead?

const tenantUserPropertyPlugin = (): EnrichmentPlugin => {
  return {
    execute: async (event: Event) => {
      event.user_properties = {
        ...event.user_properties,
        "tenant": "tenant-id"
        // Other properties
      };
      return event;
    },
  }
}

Can I also clarify how does the amplitude.Identify() object work? From the Chrome extension, I see that it triggers a $identity event containing the $setOnce object. Does Amplitude only read from this object when it detects an $identity event? I’m wondering if this is why Amplitude does not recognise the $setOnce object when we set it via the plugin.