External Table Access for Cross-Account Analytics

Question

Pulumi · Accepted Answer

To enable cross-account analytics, you can define external tables in a data warehouse such as Snowflake that reference data stored in an external storage location like an Amazon S3 bucket belonging to another AWS account. This setup allows you to perform analytics across different AWS accounts without having to move or copy the data.

I'll guide you through the process of creating a Pulumi program to set up an external table in Snowflake that references data in an S3 bucket from another account. This involves several steps:

1. Provisioning an Amazon S3 bucket in the other AWS account and setting the appropriate permissions.
2. Creating a Snowflake external table that references the S3 bucket's data.

For the purpose of this example, let's assume that the S3 bucket and necessary permissions are already provisioned in the other AWS account, since Pulumi cannot manage resources across AWS accounts in a single program.

The code below will focus on creating an external table in Snowflake using the `pulumi_snowflake` package. Please ensure that you have the necessary permissions and Snowflake credentials configured before running this Pulumi program.

Here's how you can create an External Table in Snowflake for cross-account analytics using Pulumi:

```python
import pulumi
import pulumi_snowflake as snowflake

# Assuming you have the following information:
# - The name of your S3 bucket (e.g., 'my-external-data-bucket')
# - The external stage name (e.g., 'my_stage')
# - The database and schema where your table will be created (e.g., 'MY_DB', 'PUBLIC')
# - Snowflake role with access to create external tables (e.g., 'MY_ROLE')

# Snowflake credentials are being used from the environment variables or Pulumi config.
# Create an external stage referencing the S3 bucket in the other AWS account.
external_stage = snowflake.Stage("MyExternalStage",
    database="MY_DB",
    schema="PUBLIC",
    url="s3://my-external-data-bucket",
    # You must have the appropriate IAM role ARN that provides Snowflake access to the S3 bucket
    credentials=snowflake.StageCredentialsArgs(
        aws_role_arn="arn:aws:iam::123456789012:role/MySnowflakeS3AccessRole"
    ),
    file_format=snowflake.StageFileFormatArgs(
        type="JSON"
    ),
    comment="External stage for cross-account analytics"
)

# Define the columns and data types for the external table.
# Replace this with the actual columns of your JSON files in S3.
columns = [
    snowflake.ExternalTableColumnArgs(
        name="user_id",
        type="VARCHAR"
    ),
    snowflake.ExternalTableColumnArgs(
        name="purchase",
        type="FLOAT"
    ),
    # Add more columns as needed
]

# Create an external table that references the external stage.
external_table = snowflake.ExternalTable("MyExternalTable",
    database="MY_DB",
    schema="PUBLIC",
    external_stage=external_stage.name.apply(lambda stage_name: f"@{stage_name}"),
    file_format="JSON",
    columns=columns,
    comment="External table for cross-account analytics"
)

# Output the fully qualified external table name
pulumi.export("external_table_fqn", external_table.name.apply(
    lambda name: f"{external_table.database.get()}." + \
                 f"{external_table.schema.get()}." + \
                 f"{name}"
))
```

This program does the following:

- It creates an external stage in Snowflake with the name `MyExternalStage`, which references an S3 bucket in another AWS account. The S3 bucket URL is given along with the AWS IAM role ARN that Snowflake will use to access the S3 bucket.
- It defines the structure of an external table, `MyExternalTable`, which includes the columns expected in the data stored in the S3 bucket. The data format is specified as `JSON`.
- It references the external stage in the external table definition.
- Finally, the program exports the fully qualified name of the external table which can be used for running queries.

For the above code to work, ensure:

- You've installed the `pulumi_snowflake` package with `pip install pulumi_snowflake`.
- Your Pulumi and AWS CLI configurations are correctly set up with the necessary permissions.
- You've provided the correct AWS IAM role ARN which Snowflake should assume to access the S3 bucket in the other account.

Please replace the placeholders like `MY_DB`, `PUBLIC`, `my-external-data-bucket`, `MySnowflakeS3AccessRole`, and the column definitions with the actual values corresponding to your setup.