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Krishna Tangudu
Krishna Tangudu

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Part 3: Solving Permissions and RBAC in Cloned Databases

#snowflake #cloning #datawarehouse #lakehouse

Previously: In Part 2, we fixed all the broken database references. But even with correct references, you still can't access anything without proper permissions!

In this post: Learn how to programmatically manage permissions in cloned databases with dynamic role creation, ownership transfers, and automated RBAC provisioning.

The Permission Problem (Recap)

After cloning:

CREATE DATABASE dev_project_db CLONE production_db;
SHOW GRANTS ON DATABASE dev_project_db;
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Result:

| privilege | grantee_name   |
|-----------|----------------|
| OWNERSHIP | PROD_ADMIN     |  ⚠️ Wrong environment!
| USAGE     | PROD_READ_ONLY |  ⚠️ Dev needs different roles
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This creates three immediate problems:

  1. Wrong Roles - Production roles shouldn't access dev
  2. No Access - Dev team roles aren't granted anything
  3. Ownership Lock - Can't modify without PROD_ADMIN privileges

The Solution: Four-Stage Automation

Our approach automates permission management in four stages:

Stage 1: Temporary Ownership Transfer
   ↓
Stage 2: Permission Cleanup
   ↓
Stage 3: Dynamic Role Creation
   ↓
Stage 4: RBAC Mapping Application
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Let's dive into each.

Stage 1: Temporary Ownership Transfer

First, we need control. Grant temporary ownership to a privileged service account:

// Pseudocode for understanding
for each schema in clone_database:
    GRANT OWNERSHIP ON SCHEMA to SERVICE_ROLE COPY CURRENT GRANTS

    for each object_type in [TABLES, VIEWS, PROCEDURES, ...]:
        GRANT OWNERSHIP ON ALL object_type to SERVICE_ROLE COPY CURRENT GRANTS
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Key insight: COPY CURRENT GRANTS preserves existing permissions while changing ownership.

Usage 

CALL sp_grant_temp_ownership('dev_project_db');

-- Result:
-- {
--   "schemas_granted": 4,
--   "objects_transferred": 1250,
--   "errors": []
-- }
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Now we have control to make changes.

Stage 2: Permission Cleanup

Revoke production-specific grants, especially future grants that auto-apply to new objects:

-- Example: Revoke future ownership from production roles
REVOKE OWNERSHIP ON FUTURE TABLES IN SCHEMA dev_db.analytics 
  FROM ROLE PROD_ANALYTICS_OWNER;
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For multiple schemas and object types, we automate this:

// Pseudocode
for each schema in schemas:
    prod_role = source_database + schema_owner_suffix

    for each object_type in [TABLES, VIEWS, PROCEDURES, ...]:
        REVOKE OWNERSHIP ON FUTURE object_type IN SCHEMA 
          FROM ROLE prod_role
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Stage 3: Dynamic Role Creation

Instead of hardcoding role names, we generate them dynamically based on:

  • Database name (environment-specific)
  • Schema name (domain-specific)
  • Access level (READ, READ_WRITE, ADMIN)

The Pattern 

<DATABASE>_<SCHEMA>_<LEVEL>

Examples:
DEV_PROJECT_DB_ANALYTICS_READ
DEV_PROJECT_DB_ANALYTICS_READ_WRITE
DEV_PROJECT_DB_DATA_ADMIN
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The Logic 

// Simplified version for understanding
for each schema in schemas:
    for each access_level in [READ, READ_WRITE, ADMIN]:
        role_name = clone_db + "_" + schema + "_" + access_level

        CREATE ROLE IF NOT EXISTS role_name
        GRANT USAGE ON DATABASE to role_name
        GRANT USAGE ON SCHEMA to role_name

        if (access_level == READ):
            GRANT SELECT ON ALL TABLES to role_name
            GRANT SELECT ON FUTURE TABLES to role_name
        else if (access_level == READ_WRITE):
            GRANT SELECT, INSERT, UPDATE, DELETE ON ALL TABLES to role_name
        else if (access_level == ADMIN):
            GRANT ALL ON SCHEMA to role_name
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Why this scales: From 3 schemas to 300, the pattern stays the same.

Full implementation: sql/04_clone_rbac.sql#L97-L185

Example Usage 

CALL sp_create_clone_roles(
    'DEV_PROJECT_DB',
    ARRAY_CONSTRUCT('ADMINISTRATION', 'ANALYTICS', 'DATA')
);

-- Result:
-- {
--   "roles_created": [
--     "DEV_PROJECT_DB_ADMINISTRATION_READ",
--     "DEV_PROJECT_DB_ADMINISTRATION_READ_WRITE",
--     "DEV_PROJECT_DB_ADMINISTRATION_ADMIN",
--     "DEV_PROJECT_DB_ANALYTICS_READ",
--     "DEV_PROJECT_DB_ANALYTICS_READ_WRITE",
--     "DEV_PROJECT_DB_ANALYTICS_ADMIN",
--     "DEV_PROJECT_DB_DATA_READ",
--     "DEV_PROJECT_DB_DATA_READ_WRITE",
--     "DEV_PROJECT_DB_DATA_ADMIN"
--   ],
--   "total_created": 9
-- }
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Stage 4: RBAC Mapping

The final piece: map clone-specific roles to functional roles that users actually have:

CLONE ROLE                           FUNCTIONAL ROLE
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
DEV_PROJECT_DB_ANALYTICS_READ   →    DATA_ANALYST_ROLE
DEV_PROJECT_DB_ANALYTICS_WRITE  →    DATA_ENGINEER_ROLE  
DEV_PROJECT_DB_ANALYTICS_ADMIN  →    PROJECT_ADMIN_ROLE
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Configuration Table

Store mappings in a table (not hardcoded):

CREATE TABLE rbac_mapping (
    schema_role VARCHAR(255),         -- Clone-specific role
    environment VARCHAR(40),           -- DEV, QA, STAGING
    functional_role VARCHAR(255),     -- User's actual role
    operation VARCHAR(40),            -- GRANT or REVOKE
    execute_indicator VARCHAR DEFAULT 'Y'
);

-- Example mappings with placeholder
INSERT INTO rbac_mapping (schema_role, environment, functional_role, operation)
VALUES 
    ('{{CLONE_DB}}_ANALYTICS_READ', 'DEV', 'DATA_ANALYST_ROLE', 'GRANT'),
    ('{{CLONE_DB}}_ANALYTICS_WRITE', 'DEV', 'DATA_ENGINEER_ROLE', 'GRANT'),
    ('{{CLONE_DB}}_ANALYTICS_ADMIN', 'DEV', 'PROJECT_ADMIN_ROLE', 'GRANT');
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Note: {{CLONE_DB}} is replaced dynamically at runtime.

The Mapping Logic 

// Pseudocode
mappings = SELECT * FROM rbac_mapping WHERE environment = target_env

for each mapping in mappings:
    schema_role = mapping.schema_role.replace('{{CLONE_DB}}', actual_clone_db)

    if mapping.operation == 'GRANT':
        GRANT ROLE schema_role TO ROLE mapping.functional_role
    else:
        REVOKE ROLE schema_role FROM ROLE mapping.functional_role
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Full implementation: sql/04_clone_rbac.sql#L187-L245

Result 

CALL sp_apply_rbac_mapping('DEV_PROJECT_DB', 'DEV');

-- Now developers can use their normal roles:
USE ROLE DATA_ANALYST_ROLE;
SELECT * FROM dev_project_db.analytics.customer_summary;  -- ✅ Works!
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Putting It All Together

Complete permission setup in one command:

CALL sp_setup_clone_permissions(
    clone_db => 'DEV_PROJECT_DB',
    source_db => 'PRODUCTION_DB',
    environment => 'DEV'
);

-- Behind the scenes:
-- ✅ Temporary ownership transferred
-- ✅ Production grants revoked
-- ✅ 9 new environment-specific roles created
-- ✅ RBAC mappings applied
-- ✅ Developers have appropriate access
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Key Design Principles

1. Configuration Over Code 

-- ❌ Hardcoded in procedures
GRANT ROLE dev_analytics_read TO ROLE data_analyst;

-- ✅ Configuration-driven
INSERT INTO rbac_mapping VALUES (...);
CALL sp_apply_rbac_mapping(...);
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Benefits:

  • Non-developers can manage permissions
  • Different mappings per environment
  • Audit trail of changes

2. Dynamic Role Generation 

// This scales from 3 schemas to 300
role_name = database + "_" + schema + "_" + access_level
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3. Temporary Ownership Pattern 

User requests clone
   ↓
Service role takes ownership
   ↓
Service role makes all changes
   ↓
Service role transfers ownership to target roles
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Never make permission changes as the requesting user.

4. Future Grants Are Critical 

-- ❌ Only current objects
GRANT SELECT ON ALL TABLES IN SCHEMA analytics TO ROLE analyst;

-- ✅ Current AND future objects
GRANT SELECT ON ALL TABLES IN SCHEMA analytics TO ROLE analyst;
GRANT SELECT ON FUTURE TABLES IN SCHEMA analytics TO ROLE analyst;
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Common Pitfalls (And How We Avoid Them)

Pitfall 1: Not Using COPY CURRENT GRANTS 

-- ❌ Drops all existing grants during ownership transfer
GRANT OWNERSHIP ON SCHEMA my_schema TO ROLE new_owner;

-- ✅ Preserves grants during transfer
GRANT OWNERSHIP ON SCHEMA my_schema TO ROLE new_owner COPY CURRENT GRANTS;
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Our code: Always uses COPY CURRENT GRANTS

Pitfall 2: Forgetting Object Types

Don't forget:

  • DYNAMIC TABLES
  • ICEBERG TABLES
  • EVENT TABLES
  • STAGES, FILE FORMATS, SEQUENCES

Our code: Comprehensive object type list in sql/04_clone_rbac.sql

Pitfall 3: Not Handling Missing Roles 

// ❌ Fails if role doesn't exist
execSQL("GRANT ROLE clone_role TO ROLE functional_role");

// ✅ Graceful error handling (in our procedures)
try {
    execSQL("GRANT ROLE ...");
    success_count++;
} catch (e) {
    errors.push({error: e.message});
}
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Our code: Try-catch blocks around all grant operations

Production Metrics

After implementing automated RBAC:

Metric Before After
Time to grant permissions 45-90 min < 2 min
Permission errors per clone 8-12 0-1
Security audit failures 4/mo 0/mo
Developer self-service No Yes
Concurrent clone setup 1 at a time 10+ parallel

What's Next?

We've solved both major challenges:

  • ✅ Database reference repointing (Part 2)
  • ✅ Permissions and RBAC (Part 3)

But our solution still processes schemas sequentially. In Part 4, we'll make it production-ready with:

  • Parallel processing with ASYNC/AWAIT (73% faster)
  • Resume-from-failure capabilities
  • Audit logging and observability
  • Task suspension for cost control
  • Production-grade orchestration

Next: Part 4: Parallelization and Production Features →
Previous: Part 2: Repointing Database References

About This Series

This is Part 3 of a 4-part series on production-grade Snowflake database cloning. All code is available in the GitHub repository with complete documentation and examples.

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