feat: support automatic MongoDB database cleanup on stack destroy

[baotn166]

Overview

When mongoDbDestroyDatabase: true is set in cloudExtras of a stack client config, the provisioner will automatically drop the corresponding MongoDB database before the Pulumi stack is destroyed.

Changes

pkg/clouds/pulumi/mongodb/drop_db.go (new file)

• Adds DropDatabase(ctx, mongoUri, dbName) helper that connects to MongoDB (with a 30s timeout) and drops the target database
• The URI must include credentials with dbAdmin privileges on the target database

pkg/clouds/pulumi/destroy.go

• Extends destroyStack signature to accept variadic preDestroyHooks ...func(auto.Stack)
• Hooks are executed after stack refresh but before the actual destroy (skipped on preview runs)

pkg/clouds/pulumi/provisioner.go

• Adds dropMongoDbIfEnabled method called as a preDestroyHook in DestroyChildStack
• Reads cloudExtras.mongoDbDestroyDatabase from the stack's client config
• Fetches stack outputs and finds MongoDB service-user credentials (stack output keys ending in -service-user)
• Parses the DbUserOutput JSON to extract dbUri, userName, and password
• Constructs the full MongoDB URI and calls DropDatabase; failures are logged as warnings (non-fatal) so the destroy proceeds regardless

go.mod / go.sum

• Adds go.mongodb.org/mongo-driver and its transitive dependencies

Configuration example

# stack client config
cloudExtras:
  mongoDbDestroyDatabase: true

Behavior notes

• If mongoDbDestroyDatabase is absent or false, no MongoDB operation is performed
• If the database drop fails (e.g. wrong credentials, network issue), the error is logged as a warning and the stack destroy continues normally
• Only stack outputs whose key ends with -service-user are used to discover MongoDB databases to drop