Snowflake Data Clean Rooms: Register a developer API clean room in the web app¶

Set up the environment¶

Before using the Developer APIs, you need to assume the SAMOOHA_APP_ROLE role and specify which warehouse you want to use to execute the APIs. If you don’t have the SAMOOHA_APP_ROLE role, contact your account administrator.

Assuming you want to use the app_wh as your warehouse, execute the following commands to set up your environment:

USE ROLE samooha_app_role;
USE WAREHOUSE app_wh;

Create the clean room¶

Before creating a clean room, you need to specify an alphanumeric name for the clean room. The name cannot contain special characters except spaces and underscores. Make sure that the name of the clean room does not duplicate an existing clean room.

To specify the name of the clean room, execute the following command:

SET cleanroom_name = 'UI Registration ML Clean room';

You are now ready to execute the provider.cleanroom_init command to create the clean room. The second argument defines the distribution of the clean room. For this example, you’ll set this to INTERNAL to bypass the automated security scan that takes place before the clean room can be released to collaborators. The provider and consumer accounts must be in the same organization to use the INTERNAL distribution method. For clean rooms being distributed to an account in a different organization, you must use an EXTERNAL distribution.

To create the clean room, execute the following command:

CALL samooha_by_snowflake_local_db.provider.cleanroom_init($cleanroom_name, 'INTERNAL');

After you create a clean room, you must set its release directive before it can be shared with a collaborator.

CALL samooha_by_snowflake_local_db.provider.view_cleanroom_scan_status($cleanroom_name);

To set the release directive for the clean room, execute the following command:

CALL samooha_by_snowflake_local_db.provider.set_default_release_directive($cleanroom_name, 'V1_0', '0');

Cross-region sharing¶

In order to share a clean room with a Snowflake customer whose account is in a different region than your account, you must enable Cross-Cloud Auto-Fulfillment. For information about the additional costs associated with collaborating with consumers in other regions, see Cross-Cloud Auto-Fulfillment costs.

When using developer APIs, enabling cross-region sharing is a two-step process:

1. A Snowflake administrator with the ACCOUNTADMIN role enables Cross-Cloud Auto-Fulfillment for your Snowflake account. For instructions, see Collaborate with accounts in different regions.

2. You execute the provider.enable_laf_for_cleanroom command to enable Cross-Cloud Auto-Fulfillment for the clean room. For example:

   CALL samooha_by_snowflake_local_db.provider.enable_laf_for_cleanroom($cleanroom_name);
   

   Copy

After you have enabled Cross-Cloud Auto-Fulfillment for the clean room, you can add consumers to your listing as usual using the provider.create_cleanroom_listing command. The listing is automatically replicated to remote clouds and regions as needed.

Link the dataset, and set the join policy for the dataset¶

Link Snowflake tables into the clean room, browse through the list of tables in your Snowflake account and enter the fully qualified table names (Database.Schema.Table) as an array. The procedure automatically makes the table accessible to the clean room by creating a secure view of the table from within the clean room, thereby avoiding any need to make a copy of your table.

CALL samooha_by_snowflake_local_db.provider.link_datasets($cleanroom_name, ['samooha_provider_sample_database.lookalike_modeling.customers']);

USE ROLE accountadmin;
CALL samooha_by_snowflake_local_db.provider.register_db('<DATABASE_NAME>');
USE ROLE samooha_app_role;

You can view the dataset names linked to the clean room by calling the following procedure.

CALL samooha_by_snowflake_local_db.provider.view_provider_datasets($cleanroom_name);

You can see the datasets linked to the clean room using the following procedure:

SELECT * FROM <PROVIDER_TABLE> LIMIT 10;

Specify which columns the consumer is allowed to join on when running templates within the clean room. This procedure should be called on identity columns like email. The join policy is “replace only”, so if the function is called again, then the previously set join policy is completely replaced by the new one.

CALL samooha_by_snowflake_local_db.provider.set_join_policy($cleanroom_name, ['samooha_provider_sample_database.lookalike_modeling.customers:hashed_email']);

If you want to view all the columns to decide the join policy columns, call the following procedure.

CALL samooha_by_snowflake_local_db.provider.view_join_policy($cleanroom_name);

Add confidential Machine Learning Python code to the clean room¶

Load some python functions into the clean room for the lookalike ML work. All python functions installed in the clean room remain completely confidential. They cannot be seen by the consumer.

The following API allows you to define your Python functions directly as inline functions into the clean room. Alternatively you can load Python from staged files you’ve uploaded into the clean room stage. See the API reference guide for an example.

CALL samooha_by_snowflake_local_db.provider.load_python_into_cleanroom(
    $cleanroom_name,
    'lookalike_train',
    ['input_data variant', 'labels variant'],
    ['pandas', 'numpy', 'xgboost'],
    'variant',
    'train',
$$
import numpy as np
import pandas as pd
import xgboost
from sklearn import preprocessing
import sys
import os
import pickle
import codecs
import threading


class TrainXGBoostClassifier(object):
    def __init__(self):
        self.model = None
        self._params = {
            "objective": "binary:logistic",
            "max_depth": 3,
            "nthread": 1,
            "eval_metric": "auc",
        }
        self.num_boosting_rounds = 10

    def get_params(self):
        if self.model is not None and "updater" not in self._params:
            self._params.update(
                {"process_type": "update", "updater": "refresh", "refresh_leaf": True}
            )
        return self._params

    def train(self, X, y):
        # Train the model in a threadsafe way

        # pick only the categorical attributes
        categorical = X.select_dtypes(include=[object])

        # fit a one-hot-encoder to convert categorical features to binary features (required by XGBoost)
        ohe = preprocessing.OneHotEncoder()
        categorical_ohe = ohe.fit_transform(categorical)
        self.ohe = ohe

        # get the rest of the features and add them to the binary features
        non_categorical = X.select_dtypes(exclude=[object])
        train_x = np.concatenate((categorical_ohe.toarray(), non_categorical.to_numpy()), axis=1)

        xg_train = xgboost.DMatrix(train_x, label=y)

        params = self.get_params()
        params["eval_metric"] = "auc"
        evallist = [(xg_train, "train")]
        evals_result = {}

        self.model = xgboost.train(
            params, xg_train, self.num_boosting_rounds, evallist, evals_result=evals_result
        )

        self.evals_result = evals_result

    def __dump_model(self, model):
        # Save down the model as a json string to load up for scoring/inference

        pickle_jar = codecs.encode(pickle.dumps([model, self.ohe]), "base64").decode()
        return pickle_jar

    def dump_model(self):
        # Save down the model as a json string to load up for scoring/inference
        if self.model is not None:
            return self.__dump_model(self.model)
        else:
            raise ValueError("Model needs to be trained first")


def train(d1, l1):
    # get take training features and put them in a pandas dataframe
    X = pd.DataFrame(d1)

    # get the labels into a Numpy array
    y = np.array(l1)

    trainer = TrainXGBoostClassifier()
    trainer.train(X, y)

    # return training stats, accuracy, and the pickled model and pickled one-hot-encoder
    return {
        "total_rows": len(d1),
        "total_bytes_in": sys.getsizeof(d1),
        "model": trainer.dump_model(),
        "iteration": trainer.num_boosting_rounds,
        "auc": np.max(trainer.evals_result["train"]["auc"]),
        "error": 1 - np.max(trainer.evals_result["train"]["auc"])
    }   
$$);

Now install a scoring function into the clean room:

CALL samooha_by_snowflake_local_db.provider.load_python_into_cleanroom(
    $cleanroom_name,
    'lookalike_score',
    ['pickle_jar variant', 'emails variant', 'features variant'],
    ['pandas', 'numpy', 'xgboost'],
    'string',
    'score',
$$
import numpy as np
import pandas as pd
import xgboost as xgb
import pickle
import codecs
import json


def score(model, emails, features):
    # load model
    model = model[0] if not isinstance(model, str) else model
    model = pickle.loads(codecs.decode(model.encode(), "base64"))

    # retrieve the XGBoost trainer from the pickle jar
    bst = model[0]

    # retrieve the fitted one-hot-encoder from the pickle jar
    ohe2 = model[1]

    # create pandas dataframe from the inference features
    Y = pd.DataFrame(features)

    # select the categorical attributes and one-hot-encode them
    Y1 = Y.select_dtypes(include=[object])
    Y2 = ohe2.transform(Y1)

    # select the non-categorical attributes
    Y3 = Y.select_dtypes(exclude=[object])

    # join the results of the one-hot encoding to the rest of the attributes
    Y_pred = np.concatenate((Y2.toarray(), Y3.to_numpy()), axis=1)

    # inference
    dscore = xgb.DMatrix(Y_pred)
    pred = bst.predict(dscore)

    retval = list(zip(np.array(emails), list(map(str, pred))))
    retval = [{"email": r[0], "score": r[1]} for r in retval]
    return json.dumps(retval)  
$$);

-- See the versions available inside the cleanroom
SHOW VERSIONS IN APPLICATION PACKAGE samooha_cleanroom_UI_Registration_ML_clean_room;

-- Once the security scan is approved, update the release directive to the latest version
CALL samooha_by_snowflake_local_db.provider.set_default_release_directive($cleanroom_name, 'V1_0', '2');

Add a Custom Lookalike Modeling template¶

To add a custom analysis template to the clean room you need a placeholder for table names on both the provider and consumer sides, along with join columns from the provider side. In SQL Jinja templates, these placeholders must always be:

• source_table: an array of table names from the provider

• my_table: an array of table names from the consumer

Table names can be made dynamic through using these variables, but they can also be hardcoded into the template if desired using the name of the view linked to the clean room. Column names can either be hardcoded into the template, if desired, or set dynamically through parameters. If they are set through parameters, remember that you need to call the parameters dimensions or measure_column, which need to be arrays, in order for them to be checked against the column policy. You add these as SQL Jinja parameters in the template that will be passed in later by the consumer when querying. The join policies ensure that the consumer cannot join on columns other than the authorized ones.

Alternatively, any argument in a custom SQL Jinja template can be checked for compliance with the join and column policies using the following filters:

• join_policy: checks if a string value or filter clause is compliant with the join policy

• column_policy: checks if a string value or filter clause is compliant with the column policy

• join_and_column_policy: checks if columns used for a join in a filter clause are compliant with the join policy, and that columns used as a filter are compliant with the column policy

For example, in the clause {{ provider_id | sqlsafe | join_policy }}, an input of p.HEM will be parsed to check if p.HEM is in the join policy. Note: Only use the sqlsafe filter with caution as it allows collaborators to put pure SQL into the template.

Note that this function overrides any existing template with the same name. If you want to update any existing template, you can simply call this function again with the updated template.

A set of features is selected from the provider dataset, and a set of labels is selected from the consumer dataset, along with a “high value” flag (called label_value). These 2 tables are then inner-joined on email and passed to the Random Forest training algorithm. Lastly, the output of the model training step is passed to an inference function, which uses the trained model to “infer” which of the provider customers NOT in the consumer datasets could be “high value”. The count of such individuals is then returned, along with the model error.

The threshold for determining the score beyond which a customer is “likely high value” is manually set in the template as 0.5. This can be easily changed when adding the template to the clean room.

CALL samooha_by_snowflake_local_db.provider.add_custom_sql_template($cleanroom_name, 'prod_custom_lookalike_template',
$$
WITH
features AS (
    SELECT
        identifier({{ provider_join_col | join_policy }}) AS joincol,
        array_construct({{ dimensions[0] | sqlsafe }} {% for feat in dimensions[1:] %} , {{ feat | sqlsafe }} {% endfor %}) AS features
    FROM
        identifier({{ source_table[0] }}) AS p
),
labels AS (
    SELECT
        c.{{ consumer_join_col | sqlsafe }} AS joincol,
        c.{{ filter_column | default('SALES_DLR') | sqlsafe }} {{ operator | default('>=') | sqlsafe }} {{ filter_value | default(2000) | sqlsafe }} AS label_value
    FROM
        identifier({{ my_table[0] }}) AS c
),
trained_model AS (
    SELECT
        train_out:model::varchar AS model,
        train_out:error::float AS error
    FROM (
      SELECT
        cleanroom.{{ lookalike_train_function | default('lookalike_train') | sqlsafe }}(array_agg(f.features), array_agg(l.label_value)) AS train_out
      FROM features f, labels l
      WHERE f.joincol = l.joincol
    )
),
inference_output AS (
    SELECT
        MOD(seq4(), 100) AS batch,
        cleanroom.{{ lookalike_score_function | default('lookalike_score') | sqlsafe }}(
            array_agg(distinct t.model), 
            array_agg(identifier({{ provider_join_col | join_policy }})), 
            array_agg(array_construct( identifier({{ dimensions[0] }}) {% for feat in dimensions[1:] %} , identifier({{ feat }}) {% endfor %}) )
        ) AS scores
    FROM trained_model t, identifier({{ source_table[0] }}) p
    WHERE identifier({{ provider_join_col | join_policy }}) NOT IN (SELECT c.{{ consumer_join_col | sqlsafe }} FROM identifier({{ my_table[0] }}) c)
    GROUP BY batch
),
processed_output AS (
    SELECT value:email::string as id, value:score::float AS score FROM (select scores from inference_output), lateral flatten(input => parse_json(scores))
), train_results AS (
    SELECT {{ num_boosting_rounds | sqlsafe }} AS num_boosting_rounds, {{ trim_extremes | sqlsafe }} AS trim_extremes, p.audience_size AS audience_size, t.error AS error FROM (SELECT count(distinct id) AS audience_size FROM processed_output WHERE score > 0.5) p, trained_model t
), seed_size AS (
    select count(*) AS seed_audience_size FROM features f, labels l WHERE f.joincol = l.joincol
)
SELECT s.seed_audience_size, t.audience_size AS num_lookalikes_found, t.error FROM train_results t, seed_size s
$$);

If you want to view the templates that are currently active in the clean room, call the following procedure. You can make the modifications to enable Differential Privacy guarantees on your analysis. A similar pattern can be incorporated into any custom template that you choose to write.

CALL samooha_by_snowflake_local_db.provider.view_added_templates($cleanroom_name);

Set the column policy on each table¶

Display the data linked to see the columns present inside the table. To view the top 10 rows, call the following procedure.

SELECT * FROM <PROVIDER_TABLE> LIMIT 10;

Set the columns on which you want to group, aggregate (e.g. SUM/AVG) and generally use in an analysis for every table and template combination. This gives flexibility so that the same table can allow different column selections depending on the underlying template. This should be called only after adding the template.

Note that the column policy is replace only, so if the function is called again, then the previously set column policy is completely replaced by the new one.

Column policy should not be used on identity columns like email, HEM, RampID, etc. since you don’t want the consumer to be able to group by these columns. In the production environment, the system will intelligently infer PII columns and block this operation, but this feature is not available in the sandbox environment. It should only be used on columns that you want the consumer to be able to aggregate and group by, like Status, Age Band, Region Code, Days Active, etc.

Note that for the “column_policy” and “join_policy” to carry out checks on the consumer analysis requests, all column names MUST be referred to as dimensions or measure_columns in the SQL Jinja template. Make sure you use these tags to refer to columns you want to be checked in custom SQL Jinja templates.

CALL samooha_by_snowflake_local_db.provider.set_column_policy($cleanroom_name, [
    'prod_custom_lookalike_template:samooha_provider_sample_database.lookalike_modeling.customers:status', 
    'prod_custom_lookalike_template:samooha_provider_sample_database.lookalike_modeling.customers:age', 
    'prod_custom_lookalike_template:samooha_provider_sample_database.lookalike_modeling.customers:region_code', 
    'prod_custom_lookalike_template:samooha_provider_sample_database.lookalike_modeling.customers:days_active', 
    'prod_custom_lookalike_template:samooha_provider_sample_database.lookalike_modeling.customers:income_bracket'
]);

If you want to view the column policy that has been added to the clean room, call the following procedure.

CALL samooha_by_snowflake_local_db.provider.view_column_policy($cleanroom_name);

Share with a consumer¶

Finally, add a data consumer to the clean room by adding their Snowflake account locator and account names as shown below. The Snowflake account name must be of the form <ORGANIZATION>.<ACCOUNT_NAME>.

SHOW VERSIONS IN APPLICATION PACKAGE samooha_cleanroom_UI_Registration_ML_clean_room;

CALL samooha_by_snowflake_local_db.provider.add_consumers($cleanroom_name, '<CONSUMER_ACCOUNT_LOCATOR>', '<CONSUMER_ACCOUNT_NAME>');
CALL samooha_By_snowflake_local_db.provider.create_cleanroom_listing($cleanroom_name, '<CONSUMER_ACCOUNT_NAME>');

Register clean room with the web app¶

Now that the clean room has been shared with the consumer, you can register the custom template so it is available to the consumer in the web app. This means the consumer can run custom analyses, including those backed by complex machine learning code, through a user interface without the need to use developer APIs.

Registering a clean room so the consumer can access it in the web app is a three-step process. You need to do the following:

1. Call the provider.add_ui_form_customizations command to define how the template appears in the web app.

2. Call the provider.register_cleanroom_in_ui command to register the template.

3. Sign in to the web as the provider.

CALL samooha_by_snowflake_local_db.provider.add_ui_form_customizations(
    $cleanroom_name,
    'prod_custom_lookalike_template',
    {
        'display_name': 'Custom Lookalike Template',
        'description': 'Use our customized ML techniques to find lookalike audiences.',
        'methodology': 'Specify your own seed audience, while matching against our users. Then customize the lookalike model across number of boosting rounds and removing outliers.',
        'warehouse_hints': {
            'warehouse_size': 'medium',
            'snowpark_optimized': TRUE
        }
    },
    {
    'num_boosting_rounds': {
        'display_name': 'Number of Boosting Rounds',
        'type': 'integer',
        'default': 10,
        'order': 7,
        'description': 'How many rounds of boosting should the model do?',
        'size': 'M',
        'group': 'Training & Inference Configuration'
    },
    'trim_extremes': {
        'display_name': 'Trim Extremes',
        'type': 'boolean',
        'default': False,
        'order': 8,
        'description': 'Remove outliers by default?',
        'size': 'M',
        'group': 'Training & Inference Configuration'
    },
    'lookalike_train_function': {
        'display_name': 'Training Function',
        'choices': ['lookalike_train'],
        'type': 'dropdown',
        'order': 9,
        'description': 'Which function do you want to use for training?',
        'size': 'M',
        'group': 'Training & Inference Configuration'
    },
    'lookalike_score_function': {
        'display_name': 'Scoring Function',
        'choices': ['lookalike_score'],
        'type': 'dropdown',
        'order': 10,
        'description': 'Which function do you want to use for scoring?',
        'size': 'M',
        'group': 'Training & Inference Configuration'
    },    
    'provider_join_col': {
        'display_name': 'Provider Join Column',
        'choices': ['p.HASHED_EMAIL'],
        'type': 'dropdown',
        'order': 4,
        'description': 'Select the provider column to join users on.',
        'infoMessage': 'We recommend using HASHED_EMAIL.',
        'size': 'M',
        'group': 'Enable Provider Features'
    },
    'consumer_join_col': {
        'display_name': 'Consumer Join Column',
        'description': 'Specify column in your table that matches the providers (i.e. HASHED_EMAIL).',
        'size': 'M',
        'default': 'HASHED_EMAIL',
        'infoMessage': 'We recommend using HASHED_EMAIL.',
        'order': 5,
        'group': 'Enable Provider Features'
    },
    'dimensions': {
        'display_name': 'Feature Selection',
        'choices': ['p.STATUS', 'p.AGE', 'p.REGION_CODE', 'p.DAYS_ACTIVE'],
        'type': 'multiselect',
        'order': 6,
        'description': 'What features do you want to train on?',
        'infoMessage': 'We recommend selecting all features for maximum signal.',
        'size': 'M',
        'group': 'Enable Provider Features'
    },
    'filter_column': {
        'display_name': 'Filter Column',
        'type': 'any',
        'order': 1,
        'description': 'Specify column in your table to filter for high value users (i.e. SALES_DLR)',
        'size': 'S',
        'default': 'SALES_DLR',
        'infoMessage': 'We recommend you input SALES_DLR over here.',
        'group': 'Seed Audience Selection'
    },
    'operator': {
        'display_name': 'Operator',
        'choices': ['>=', '=', '<='],
        'type': 'dropdown',
        'order': 2,
        'description': 'What is the operator your want to use for the filter?',
        'size': 'S',
        'group': 'Seed Audience Selection'
    },
    'filter_value': {
        'display_name': 'Filter Value',
        'order': 3,
        'description': 'What value do you want to filter to?',
        'default': 2000,        
        'size': 'S',
        'group': 'Seed Audience Selection'
    }
}, {
    'measure_columns': ['seed_audience_size', 'audience_size', 'num_lookalikes_found', 'error'],
    'default_output_type': 'BAR'
});

CALL samooha_by_snowflake_local_db.provider.register_cleanroom_in_ui($cleanroom_name, 'prod_custom_lookalike_template', '<CONSUMER_ACCOUNT_IDENTIFIER>', '<CONSUMER_USER_EMAIL>');

CALL samooha_by_snowflake_local_db.provider.view_ui_registration_request_log();

Helper methods¶

Multiple consumer account locators can be passed into the provider.add_consumers function as a comma separated string, or as separate calls to provider.add_consumers.

If you want to view the consumers who have been added to this clean room, call the following procedure.

CALL samooha_by_snowflake_local_db.provider.view_consumers($cleanroom_name);

If you want to view the clean rooms that have been created recently, use the following procedure.

CALL samooha_by_snowflake_local_db.provider.view_cleanrooms();

If you want to get more insights about the clean room that you have created, use the following procedure.

CALL samooha_by_snowflake_local_db.provider.describe_cleanroom($cleanroom_name);

Any clean room created can also be deleted. The following command drops the clean room entirely, so any consumers who previously had access to the clean room will no longer be able to use it. If a clean room with the same name is desired in the future, it must be re-initialized using the above flow.

CALL samooha_by_snowflake_local_db.provider.drop_cleanroom($cleanroom_name);

Access the consumer account on the Web App¶

To sign in to the clean room as the consumer:

1. Sign in to the web app of the Snowflake Data Clean Room. For details, see Snowflake Data Clean Room: Web app.

2. Enter your email address, and select Continue.

3. Enter your password.

4. Select the Snowflake account associated with the consumer account.

Install the clean room¶

On the Clean Rooms page, find the tile that corresponds to the clean room you just created, and select Install. The tile might look like the following:

Run an analysis¶

To run an analysis in the clean room:

1. On the Analyses & Queries page, select New Analysis & Query.

2. Select the tile that corresponds to the Custom Lookalike Template you created, then select Next.

3. Select the clean room, then select Next.

4. Fill in the custom form that you created for the clean room.