Implementing role-based access control for PostgreSQL databases in Azure

Question

Pulumi · Accepted Answer

To implement role-based access control (RBAC) for PostgreSQL databases in Azure using Pulumi, we can utilize the `azure-native` package, which interacts directly with Azure resources. We will define a PostgreSQL server and a database, and then set up RBAC by defining a role assignment on that PostgreSQL server.

Azure RBAC is used to define who has access to Azure resources and what they can do with those resources. In the context of Azure Database for PostgreSQL, RBAC allows us to define custom roles or utilize built-in roles, assigning them to users or groups to control access to the database at a coarse granularity. Fine-grained permissions within the database (e.g., table-level access) must be managed through PostgreSQL's own user and permissions system using SQL commands after the database is deployed.

We'll create a PostgreSQL server, a database within that server, and then demonstrate how to assign a built-in Azure role to a hypothetical user or group. Note, you will need to have the object ID of the user or service principal (or any security principal) to assign roles to them using Pulumi.

Below is the explanatory TypeScript program to set up a PostgreSQL server with role-based access control:

```typescript
import * as azure from "@pulumi/azure-native";

const resourceGroupName = 'myResourceGroup';
const postgreSqlName = 'myPostgreSqlServer';
const databaseName = 'myDatabase';
const userName = 'myUserName';
const password = 'myPassword123'; // Remember to secure your password appropriately.

// Create an Azure Resource Group
const resourceGroup = new azure.resources.ResourceGroup(resourceGroupName);

// Create an Azure PostgreSQL server.
const postgreSqlServer = new azure.dbforpostgresql.Server(postgreSqlName, {
    resourceGroupName: resourceGroup.name,
    sku: {
        name: 'B_Gen5_1',
        tier: 'Basic',
        capacity: 1,
        family: 'Gen5',
    },
    properties: {
        version: '11', // Specify the version of PostgreSQL you want to deploy.
        sslEnforcement: 'Enabled',
        administratorLogin: userName,
        administratorLoginPassword: password,
    },
    location: resourceGroup.location,
});

// Create a PostgreSQL database within the PostgreSQL server.
const postgreSqlDatabase = new azure.dbforpostgresql.Database(databaseName, {
    resourceGroupName: resourceGroup.name,
    serverName: postgreSqlServer.name,
    charset: 'UTF8',
    collation: 'English_United States.1252',
});

// To set RBAC for the PostgreSQL server, assign a role to a user or group.
// Here we will assign the "Reader" role as an example.
const roleAssignmentId = 'some-guid'; // GUIDs are unique identifiers for role assignments; use a UUID generator.
const principalId = 'the-object-id-of-the-user-or-service-principal'; // Replace with the actual ID.

// Create a role assignment for the PostgreSQL server.
const roleAssignment = new azure.authorization.RoleAssignment(roleAssignmentId, {
    scope: postgreSqlServer.id,
    roleDefinitionId: `/subscriptions/${azure.config.subscriptionId}/providers/Microsoft.Authorization/roleDefinitions/7f951dda-4ed3-4680-a7ca-43fe172d538d`, // Reader role definition ID.
    principalId: principalId,
});

export const postgresServerName = postgreSqlServer.name;
export const postgresDatabaseName = postgreSqlDatabase.name;
export const postgresRoleId = roleAssignment.id;

```

In this program:
- We're creating a resource group to contain our PostgreSQL server.
- We instantiate a PostgreSQL server with basic configuration options such as version and admin credentials. 
- We're creating a PostgreSQL database named `myDatabase` associated with our server.
- We assign the Azure "Reader" role to a user or service principal, allowing that security principal to read resources within the PostgreSQL server's scope. The role definition ID for Reader is a constant value defined by Azure.

When you want specific roles managing the PostgreSQL database itself or more granular control inside the PostgreSQL server (like database roles for reading or writing to tables), you'd need to connect to the database using the PostgreSQL client and manage it using SQL statements.

Please make sure to change `the-object-id-of-the-user-or-service-principal` to the actual object ID of the Azure Active Directory user or service principal you want to assign the role to, and generate a unique GUID for `roleAssignmentId`. Additionally, manage