# Calculate your first attributes in real time with Signals
> Use Snowplow Console to define a Signals attribute group and service that calculate session metrics in real time, then retrieve them with the Python SDK.
> Source: https://docs.snowplow.io/docs/signals/get-started/quickstart-tutorial/
> Documentation index: https://docs.snowplow.io/llms.txt

[![Open in Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/snowplow-incubator/signals-notebooks/blob/main/quickstart.ipynb)

[Snowplow Signals](/docs/signals/introduction/) computes attributes from your behavioral data in real time and serves them to your applications over an API. In this tutorial you calculate three session attributes from page views in your event stream, then retrieve them for your current session.

You define the attributes in Snowplow Console. If you'd rather define them in code, the **Open in Colab** notebook has the same steps for the [Signals Python SDK](https://pypi.org/project/snowplow-signals/). To have a coding agent do this for you instead, follow the [quickstart with your coding agent](/docs/signals/quickstart/).

## What you'll build

This tutorial takes less than 10 minutes, from enabling Signals to retrieving calculated attributes.

You'll create:

- An [attribute group](/docs/signals/attributes/attribute-groups/) called `quickstart_group` that calculates, for each session:

  - `page_view_count`: how many page views in the last 15 minutes
  - `most_recent_browser`: the last seen browser name
  - `first_referrer`: the first seen page referrer

- A [service](/docs/signals/applications/services/) called `quickstart_service` that serves the attribute group to applications

You'll finish by retrieving the attribute values for your own browsing session with the Python SDK.

## Requirements

You'll need:

- A web application where you can add the JavaScript tracker
- A Python notebook environment, such as Google Colab or Jupyter

What else you need depends on where you're starting from:

**New to Snowplow:**

1. Sign up for the [Signals free tier](https://signals.snowplow.io/start?utm_source=docs.snowplow.io\&utm_medium=referral). It comes with event collection and with Signals already enabled.
2. Add the JavaScript tracker to your web application and send page views, by following [Track your first events](/docs/get-started/tracking/). It shows where to find your Collector URL.
3. Continue from [Create the attribute group](#create-the-attribute-group).

**Already tracking with Snowplow:**

1. Check that your web application sends page views with the [JavaScript tracker](/docs/sources/web-trackers/). This tutorial calculates attributes per session, from the `domain_sessionid` the tracker sets.
2. Make sure Signals is enabled on your account. If it isn't, follow [Set up Signals](/docs/signals/setup/).
3. Continue from [Create the attribute group](#create-the-attribute-group).

***

## Steps

Each step builds on the one before it. Keep your web application open in another tab, so that you can generate page views as you go.

### Enable Signals

Log in to [Console](https://console.snowplowanalytics.com) and go to the **Signals** section.

If Signals isn't enabled for your organization yet, follow [Set up Signals](/docs/signals/setup/) first.

### Track page views

Signals calculates these attributes from page views. If your web application doesn't send Snowplow page views yet, follow [Track your first events](/docs/get-started/tracking/) to add the JavaScript tracker, then come back. Open a few pages and check the page views in the [Snowplow Inspector](/docs/testing/snowplow-inspector/) before you continue.

### Create the attribute group

To create an attribute group, go to **Signals** > **Attribute groups** in Console and click **Create attribute group**.

![Create attribute group form for quickstart tutorial](/assets/images/attribute-group-create-05c9671a86bc1133c6625497bb434064.png)

Specify the basic configuration for your attribute group:

- **Name**: `quickstart_group`
- **Description**: Quick Start tutorial: page view session metrics
- **Source**: stream
- **Primary owner**: your email address

The name is the group's unique identifier. The description and owner are optional.

Under the **Configuration** section, select the following:

- **Attribute key**: `domain_sessionid`
- **TTL**: leave as default

### Add the page view counter

Click **Add attribute** to create each attribute.

![Add attribute button in attribute group configuration](/assets/images/attribute-group-add-attribute-9c768a8601d840dcb5dfc584e5cbbbd3.png)

The first attribute counts page view events within the last 15 minutes. Enter `page_view_count` in the attribute name field.

To set the event to calculate this attribute from:

1. Click the event filter field to bring up the event selection options
2. Page views are a built-in Snowplow event, so they're listed in the default **Snowplow events** tab
3. Click in the search box to find `page_view`
4. Click **Confirm** to add the event to the attribute

![Event selection showing page\_view event in Snowplow events list](/assets/images/attribute1-specify-page-view-cfbc1204a7d596b7c79114f00b078d3e.png)

Leave the aggregation as `Counter`. This aggregation doesn't use a property, so leave the property field blank.

To set the time period, update the **Period** field to 15 minutes.

![Period configuration set to 15 minutes for page view counter](/assets/images/attribute1-set-period-1245a531daa2acb8b7019decfda6c451.png)

![Completed page view counter attribute with time period indicator](/assets/images/attribute1-complete-56da0854f312fdb55434d453ffea8006.png)

### Add the most recent browser

The second attribute is the last seen browser name. The calculation uses the [YAUAA enrichment](/docs/pipeline/enrichments/available-enrichments/yauaa-enrichment/): the browser name is a field in the `yauaa_context` entity.

Create an attribute named `most_recent_browser`, select `page_view` as before, and choose the `Last` aggregation.

To set the property:

1. Click the property selection field
2. Choose the **Entities** tab to search through all schemas that have been tracked as entities with your events
3. Search for `yauaa_context`
4. Select the entity `yauaa_context (nl.basjes)`
5. Select the `agentName` property
6. Click **Confirm** to save

![Property selection showing YAUAA context agentName field for browser attribute](/assets/images/attribute2-property-selector-d2cb6ca2f9acc7207cf1a5eaa5c35f9c.png)

### Add the first referrer

The third attribute stores the first seen referrer host, from the `refr_urlhost` [atomic event property](/docs/fundamentals/canonical-event/#web-specific-fields).

Create an attribute named `first_referrer`, select `page_view` as before, and choose the `First` aggregation.

To set the property:

1. Click the property selection field
2. Stay on the default **Atomic** tab to search through all atomic properties
3. Search for and select `refr_urlhost`
4. Click **Confirm** to save

![Property selection showing refr\_urlhost atomic field for referrer attribute](/assets/images/attribute3-property-selector-cae8bd66bb4c82c99f0c4eb19a856ee8.png)

Add a criteria filter so that the attribute only considers events where the referrer isn't an empty string:

1. Click **More**
2. Click **Add criteria**
3. Choose the `page_referrer` atomic property and click **Confirm**
4. Change the operator to `not equals`
5. Leave the value blank
6. Click **Done** to return to the group details page

![Criteria configuration filtering for non-empty referrer values](/assets/images/attribute3-criteria-c7f348fa7a4d62046e99bb08d56ded51.png)

### Preview and publish the attribute group

If you've connected a warehouse to Signals, click **Run preview** to test your attribute group configuration. The preview needs a warehouse connection. Without one, skip to creating the attribute group, and check the values in the [Snowplow Inspector](/docs/testing/snowplow-inspector/signals-integration/) once it's published.

![Attribute group with three attributes ready for preview testing](/assets/images/attribute-group-ready-to-test-5aa563c932d646a7e65d6d9cd17c665e.png)

The preview calculates the attributes from your atomic events table, using 10 random events from the last hour. The first column shows the attribute key values, in this case `domain_sessionid`.

![Test results showing calculated attributes for sample session IDs](/assets/images/attribute-group-test-results-6d563dd6fffe08fc3f9d74502b2e51e6.png)

When you're satisfied with the preview results, click **Create attribute group** to save it as a draft.

![Draft attribute group page after saving configuration](/assets/images/attribute-group-draft-c1d87d4475afae4157d9f077bd4b0d77.png)

Click **Publish** to push this configuration to Signals and start calculating attributes.

![Published attribute group showing active calculation status](/assets/images/attribute-group-published-2cf1af60f705a14cbe0ba0d61c5390f6.png)

### Create the service

Services group attribute groups together for serving to your applications. Go to **Signals** > **Services** in Console and click **Create service**.

![Create service form for quickstart tutorial service](/assets/images/service-create-85585d669c129ebb7cb30d74209dfc12.png)

Specify the configuration for your service:

- **Name**: `quickstart_service`
- **Description**: Quick Start tutorial service
- **Owner**: your email address

To add the attribute group, click the attribute group selector, then search for and select `quickstart_group (v1)`. If it isn't listed, check that you published it in the previous step.

![Attribute group selector showing quickstart\_group v1 selection](/assets/images/service-choose-groups-3eb324c39c910489d866001bf3cb9cc5.png)

Click **Create service**. Services are published as soon as they're created.

![Published quickstart service ready for attribute retrieval](/assets/images/service-published-5f5116562383bfe95d332ac7fd6b070c.png)

### Find your session ID

Signals calculates the attributes in real time, within the session. To retrieve them, you need the session ID for your own browsing session.

Use the [Snowplow Inspector](/docs/testing/snowplow-inspector/) browser extension on your web application. Click around to generate some page view events, then find the **Domain Session ID** in the Inspector.

![Screenshot showing the session ID in the Snowplow Inspector](/assets/images/inspector-session-8a359813742a08d72749eacb5c4727b5.png)

In your application code, read the session ID from the tracker instead, as described in [getting cookie values](/docs/sources/web-trackers/cookies-and-local-storage/getting-cookie-values/).

### Connect with the Python SDK

Go to **Signals** > **Overview** in Console to find your Signals [connection credentials](/docs/signals/connection/reference/#connection-credentials), and add them to your notebook secrets.

![Screenshot showing how to add secrets](/assets/images/notebook-secrets-0e5fd8ee477440010bd1671d5b6e2908.png)

Install the SDK:

```python
%pip install snowplow-signals
```

Connect to Signals:

```python
from snowplow_signals import Signals
from google.colab import userdata

sp_signals = Signals(
    api_url=userdata.get('SP_API_URL'),
    api_key=userdata.get('SP_API_KEY'),
    api_key_id=userdata.get('SP_API_KEY_ID'),
    org_id=userdata.get('SP_ORG_ID'),
)
```

### Retrieve your session attributes

Use your session ID to retrieve the attributes that Signals has calculated for your session:

**Python:**

```python
import pandas as pd

attributes = sp_signals.get_service_attributes(
    name="quickstart_service",
    attribute_key="domain_sessionid",
    identifier="472f97c1-eec1-45fe-b081-3ff695c30415", # UPDATE THIS
)

pd.DataFrame([attributes])
```

**Node.js:**

To retrieve the attributes from Node.js instead of the notebook, install `@snowplow/signals-node` and create a client from the same credentials, as described in [Connect to Signals](/docs/signals/connection/):

```typescript
import { Signals } from '@snowplow/signals-node';

const signals = new Signals({
  baseUrl: process.env.SIGNALS_API_URL,
  apiKey: process.env.SNOWPLOW_API_KEY,
  apiKeyId: process.env.SNOWPLOW_API_KEY_ID,
  organizationId: process.env.SNOWPLOW_ORG_ID,
});

const attributes = await signals.getServiceAttributes({
  name: "quickstart_service",
  attribute_key: "domain_sessionid",
  identifier: "472f97c1-eec1-45fe-b081-3ff695c30415", // UPDATE THIS
});
console.log(attributes);
```

***

The result looks something like this:

| `page_view_count` | `most_recent_browser` | `first_referrer` |
| ----------------- | --------------------- | ---------------- |
| 2.0               | `Firefox`             | `snowplow.io`    |

To retrieve individual attributes without a service, use the `get_group_attributes()` method:

```python
attributes = sp_signals.get_group_attributes(
    name="quickstart_group",
    version=1,
    attributes=["page_view_count"],
    attribute_key="domain_sessionid",
    identifier="472f97c1-eec1-45fe-b081-3ff695c30415", # UPDATE THIS
)

pd.DataFrame([attributes])
```

If the values are empty, generate a few more page views and try again. Signals only calculates from events received after you published the attribute group.

## Clean up

The tutorial's attribute group keeps calculating attributes while it's published. When you've finished, unpublish and delete `quickstart_service` and `quickstart_group`, in Console or with the Python SDK's `unpublish` and `delete` methods. The [configuration workflow](/docs/signals/attributes/#configuration-workflow) explains how unpublishing and deleting work.

To keep exploring, try calculating the same attributes against `domain_userid` instead of the session, define attributes from other event types, or [retrieve attributes in your application](/docs/signals/applications/retrieve-attributes/). The [interventions tutorial](/tutorials/signals-interventions/start/) and the [prospect scoring tutorial](/tutorials/signals-ml-prospect-scoring/intro/) build on these steps.