Subscription Policy Access Types

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Write policies are only available to select accounts. Contact your Immuta representative to enable this feature.

Immuta offers two types of subscription policies to manage read and write access in a single system:

Read access policies manage who can read data.
Write access policies manage who can modify data.

Both of these access types can be enforced at any of the restriction levels outlined in the Subscription policies reference guide.

The table below illustrates the access types supported by each integration.

Integration	Read access policies	Write access policies
Snowflake
Databricks Unity Catalog
Databricks Spark		Write access is controlled through workspaces and scratch paths
Starburst
Redshift		View-based integrations are read-only
Azure Synapse Analytics		View-based integrations are read-only
Amazon S3
Google BigQuery		View-based integrations are read-only

To create a read or write access policy, see the Author a subscription policy guide.

Policy enforcement

Once a read or write access policy is enforced on an Immuta data source, it translates to the relevant privileges on the table, view, or object in the remote platform. The sections below detail how these access types are enforced for each integration.

Granting Snowflake privileges

The Snowflake integration supports read and write access subscription policies. However, when applying read and write access policies to Snowflake data sources, the privileges granted by Immuta vary depending on the object type. For example, users can register Snowflake views as Immuta data sources and apply read and write policies to them, but when a write policy is applied to a view only the SELECT privilege will take effect in Snowflake, as views are read-only objects.

Users can register any object stored in Snowflake’s information_schema.tables view as an Immuta data source. The table below outlines the Snowflake privileges Immuta issues when read and write policies are applied to various object types in Snowflake. Beyond the privileges listed, Immuta always grants the USAGE privilege on the parent schema and database for any object that access is granted to for a particular user.

Snowflake object	Read policy applied	Write policy applied
Table	SELECT	SELECT, INSERT, UPDATE, DELETE, TRUNCATE
View	SELECT	SELECT, INSERT, UPDATE, DELETE, TRUNCATE ¹
Materialized view	SELECT	SELECT, INSERT, UPDATE, DELETE, TRUNCATE ¹
External table	SELECT	SELECT, INSERT, UPDATE, DELETE, TRUNCATE ¹
Event table	SELECT	SELECT, INSERT, UPDATE, DELETE, TRUNCATE ¹
Dynamic table	SELECT	No privileges issued by Immuta ²
Iceberg table	SELECT	SELECT, INSERT, UPDATE, DELETE, TRUNCATE ³
Data object from an incoming Data Share	No privileges issued by Immuta ⁴	No privileges issued by Immuta ⁴

^{1. Snowflake views, materialized views, external tables, and event tables are read-only. Consequently, if a write policy gets applied to a data source of these types, only the SELECT privilege has an effect on users' ability to operate on data.}

^{2. Snowflake dynamic tables are not a supported object type for write policies in Immuta. If a write policy gets applied to a data source of that type, no privileges are issued by Immuta.}

^{3. Iceberg tables using a catalog integration are read-only. Consequently, if a write policy gets applied to a data source of that type, only the SELECT privilege has an effect on users ability to operate on data.}

^{4. Snowflake only supports granting access privileges at the level of a Data Share, but not on individual objects within a Data Share. Therefore, data objects from an incoming Data Share are not supported for subscription policies in Immuta. If a read or write policy gets applied to a data source of that type, no privileges are issued by Immuta.}

Granting Databricks Unity Catalog privileges

The Databricks Unity Catalog integration supports read and write access subscription policies. When users create a subscription policy in Immuta, Immuta uses the Unity Catalog API to issue GRANTS or REVOKES against the catalog, schema, or table in Databricks for every user affected by that subscription policy.

Users can register any object stored in Databricks Unity Catalog’s information_schema.tables view as an Immuta data source. However, when applying read and write access policies to these data sources, the privileges granted by Immuta vary depending on the object type. For example, users can register federated tables as Immuta data sources and apply read and write policies to them, but only a read policy will take effect in Databricks and allow users to SELECT those tables. If a write policy is applied, Immuta will not issue SELECT or MODIFY privileges in Databricks.

The table below outlines the Databricks privileges Immuta issues when read and write policies are applied to various object types in Databricks Unity Catalog. Beyond the privileges listed, Immuta always grants the USAGE privilege on the parent schema and catalog for any object that access is granted to for a particular user.

Databricks Unity Catalog object	Read policy applied	Write policy applied
Table	SELECT	SELECT, MODIFY
View	No privileges issued by Immuta ¹	No privileges issued by Immuta ¹
Materialized view	No privileges issued by Immuta ¹	No privileges issued by Immuta ¹
External table	SELECT	SELECT, MODIFY
Streaming table	SELECT	SELECT, MODIFY
Federated table	SELECT	No privileges issued by Immuta ²
Data object from incoming Delta Share	No privileges issued by Immuta ³	No privileges issued by Immuta ³

^{1. Databricks Unity Catalog views and materialized views are not supported object types for subscription policies in Immuta. If a read or write policy gets applied to a data source of these types, no privileges are issued by Immuta.}

^{2. Databricks Unity Catalog federated tables are not a supported object type for write policies in Immuta. If a write policy gets applied to a data source of that type, no privileges are issued by Immuta.}

^{3. Data objects from an incoming Delta Share are not supported for subscription policies in Immuta. If a read or write policy gets applied to a data source of that type, no privileges are issued by Immuta.}

Granting Databricks Spark privileges

The Databricks Spark integration supports read access subscription policies. When a read access policy is applied to a data source, Immuta modifies the logical plan that Spark builds when a user queries data to enforce policies that apply that user. If the user is subscribed to the data source, the user is granted SELECT on the object in Databricks. If the user does not have read access to the object, they are denied access.

Granting Starburst privileges

The Starburst integration supports read and write access subscription policies. In the Starburst integration's default configuration, the following access values grant read and write access to Starburst data when a user is granted access through a subscription policy:

READ: When a user is granted read access to a data source, they can SELECT on tables or views and SHOW on tables, views, or columns in Starburst. This setting in enabled by default when you configure the Starburst integration.
WRITE: In its default setting, the Starburst integration's write access value controls the authorization of SQL operations that perform data modification (such as INSERT, UPDATE, DELETE, MERGE, and TRUNCATE). When users are granted write access to a data source through a subscription policy, they can INSERT, UPDATE, DELETE, MERGE, and TRUNCATE on tables and REFRESH on materialized views. This setting is enabled by default when you configure the Starburst integration.

Administrators can customize write access configuration to grant additional Starburst table modification privileges. See the Custom configuration section below for an overview and example configurations.

Custom configuration

Because Starburst can govern certain table modification operations (like ALTER) separately from data modification operations (like INSERT), Immuta allows users to specify what modification operations are permitted on data in Starburst. Administrators can allow table modification operations (such as ALTER and DROP tables) to be authorized as write operations through advanced configuration in the Immuta web service or Starburst cluster with the following access values:

OWN: When mapped via advanced configuration to Immuta write policies, users who are granted write access to Starburst data can ALTER and DROP tables and SET comments and properties on a data source.
CREATE: When this privilege is granted on Starburst data, an Immuta user can create catalogs, schemas, tables, or views on a Starburst cluster. CREATE is a Starburst privilege that is not controlled by Immuta policies, and this property can only be set in the access-control.properties file on the Starburst cluster.

Administrators can customize table and data modification settings in one or both of the following places; however, the access-control.properties overrides the settings configured in the Immuta web service:

Immuta web service: Configuring write policies in the Immuta web service allows all Starburst clusters targeting that Immuta tenant to receive the same write policy configuration for Immuta data sources. This configuration only affects tables or views registered as Immuta data sources. Use the option below to control how unregistered data is affected.
Starburst cluster: Configuring write policies using the access-control.properties file on a Starburst cluster allows access to be broadly customized for Immuta users on that cluster. This configuration file takes precedence over write policies passed from the Immuta web service. Use this option if all Immuta users should have the same level of access to data regardless of the configuration in the Immuta web service.

Immuta web service access grants mapping

Customizing read and write access in the Immuta web service affects operations on all Starburst data registered as Immuta data sources in that Immuta tenant. This configuration method should be used when all Starburst data source operations should be affected identically across Starburst clusters connected to the Immuta web service. Example configurations are provided below. Contact your Immuta representative to customize the mapping of read or write access policies for your Immuta tenant.

Default configurationCustom configuration

Default configuration

The default setting shown below maps WRITE to READ and WRITE permissions and maps READ to READ. Both the READ and WRITE permission should always include READ.

In this example, if a user is granted write access to a data source through a subscription policy, that user can perform data modification operations (INSERT, UPDATE, MERGE, etc.) on the data.

accessGrantMapping:
  WRITE: ['READ', 'WRITE']
  READ: ['READ']

Custom configuration

The following configuration example maps WRITE to READ, WRITE, and OWN permissions and maps READ to READ. Both READ and WRITE permissions should always include READ.

In this example, if a user gets write access to a data source through a subscription policy, that user can perform both data (INSERT, UPDATE, MERGE, etc.) and table (ALTER, DROP, etc.) modification operations on the data.

accessGrantMapping:
  WRITE: ['READ', 'WRITE', 'OWN']
  READ: ['READ']

Starburst cluster access grants mapping

The Starburst integration can also be configured to allow read and write policies to apply to any data source (registered or unregistered in Immuta) on a specific Starburst cluster.

Two properties customize the behavior of read or write access for all Immuta users on that Starburst cluster:

immuta.allowed.immuta.datasource.operations: This property governs objects (catalogs, schemas, tables, etc.) that are registered as data sources in Immuta. For these permissions to apply, the user must be subscribed in Immuta and not be an administrator (who gets all permissions).
immuta.allowed.non.immuta.datasource.operations: This property governs objects (catalogs, schemas, tables, etc.) that are not registered as data sources in Immuta. This is the only property that allows the CREATE permission, since CREATE is enforced on new objects that do not exist in Starburst or Immuta yet (such as a new table being created with CREATE TABLE).

The default configuration and an example of a custom configuration are provided below. See the Customize read and write access policies in Starburst page for guidance on configuring these properties in your Starburst cluster.

Default configurationCustom configuration

Default configuration

By default, Immuta allows READ and WRITE operations to be authorized on data registered in Immuta, while all operations are permitted for data sources that are not registered in Immuta.

immuta.allowed.immuta.datasource.operations=READ,WRITE
immuta.allowed.non.immuta.datasource.operations=READ,WRITE,CREATE,OWN

Custom configuration

In the example below, the configuration allows READ, WRITE, and OWN operations to be authorized on data sources registered in Immuta and all operations are permitted on data that is not registered in Immuta. If a user gets write access to data registered in Immuta through a subscription policy, that user can perform both data (INSERT, UPDATE, MERGE, etc.) and table (ALTER, DROP, etc.) modification operations on the data.

immuta.allowed.immuta.datasource.operations=READ,WRITE,OWN
immuta.allowed.non.immuta.datasource.operations=READ,WRITE,CREATE,OWN

Granting Redshift privileges

The Redshift integration supports read access subscription policies. Immuta grants the SELECT Redshift privilege to the PUBLIC role when the integration is configured, which allows all users who meet the conditions of a subscription policy to access the Immuta-managed view. When a data source is created, Immuta creates a corresponding dynamic view of the table with a join to a secure view that contains all Immuta users, their entitlements, their projects, and a list of the tables they have access to. When a read policy is created or updated (or when a user's entitlements change, they switch projects, or when their data source access is approved or revoked), Immuta updates the secure view to grant or revoke users' access to the data source. If a user is granted access to the data source, they can access the view. If a user does not have read access to the view, zero rows are returned when they attempt to query the view.

Granting Azure Synapse Analytics privileges

The Azure Synapse Analytics integration supports read access subscription policies. Immuta grants the SELECT privilege to the PUBLIC role when the integration is configured, which allows all users who meet the conditions of a subscription policy to access the Immuta-managed view. When a read policy is created or removed (or when a user's entitlements change, they switch projects, or when their data source access is approved or revoked), Immuta updates the view that contains the users' entitlements, projects, and a list of tables they have access to grant or revoke their access to the dynamic view. Users' read access is enforced through an access check function in each individual view. If a user is granted access to the data source, they can access the view. If a user does not have read access to the view, they receive an Access denied: you are not subscribed to the data source error when they attempt to query the view.

Granting Google BigQuery privileges

The Google BigQuery integration supports read access subscription policies. In this integration, Immuta creates views that contain all policy logic. Each view has a 1-to-1 relationship with the original table, and read access controls are applied in the view. After data sources are registered, Immuta uses the custom user and role, created before the integration is enabled, to push the Immuta data sources as views into a mirrored dataset of the original table. Immuta manages grants on the created view to ensure only users subscribed to the Immuta data source will see the data.

Granting Amazon S3 privileges

The Amazon S3 integration supports read and write access subscription policies. Users can apply read and write access policies to data in S3 to restrict what prefixes, buckets, or objects users can access or modify. To enforce access controls on this data, Immuta creates S3 grants that are administered by S3 Access Grants, an AWS feature that defines access permissions to data in S3. To query a data source they are subscribed to, users request temporary credentials from their Access Grants instance. These just-in-time access credentials provide access to a prefix, bucket, or object with a permission level of READ or READWRITE in S3. When a user or application requests temporary credentials to access S3 data, the S3 Access Grants instance evaluates the request against the grants Immuta has created for that user. If a matching grant exists, S3 Access Grants assumes the IAM role associated with the location of the matching grant and scopes the permissions of the IAM session to the S3 prefix, bucket, or object specified by the grant and vends these temporary credentials to the requester. If the grant does not exist for the user, they receive an Access denied error.

S3 Access Grants `READ` and `READWRITE` access levels

Immuta read policies translate to the READ access level in S3 Access Grants and Immuta write policies translate to the READWRITE access level. The table below outlines the Amazon S3 actions granted on an S3 data source when users meet the restrictions specified in an Immuta read or write access subscription policy that is applied to the data source. See the AWS documentation for more details about grants, access levels, and actions.

Immuta policy S3 Access Grants access level Amazon S3 action

Read

READ

GetObject

GetObjectVersion

GetObjectAcl

GetObjectVersionAcl

ListMultipartUploadParts

ListObjects

ListObjectsVersions

ListBucketMultipartUploads

KmsDecrypt

Write

READWRITE