Summary

Implementation for #24716

This PR implements broker-level metrics for tracking non-recoverable data skips in Apache Pulsar, providing operational visibility for data loss events.

Key Features Added

• NonRecoverableDataMetricsCallback Interface: New callback interface in managed-ledger module to avoid cross-module dependencies
• ManagedLedger Integration: Updated ManagedLedgerImpl.skipNonRecoverableLedger() to trigger callback when ledgers are skipped
• ManagedCursor Integration: Updated ManagedCursorImpl.skipNonRecoverableEntries() to count and report skipped entries
• BrokerService Configuration: Automatic callback setup during managed ledger creation for topics
• Dual Metrics Support: Both Prometheus and OpenTelemetry metrics implementation

New Metrics

1. pulsar.broker.non.recoverable.ledgers.skipped.count - Tracks the number of entire ledgers skipped due to non-recoverable issues
2. pulsar.broker.non.recoverable.entries.skipped.count - Tracks the number of individual entries skipped due to non-recoverable issues

Design Decisions

• Callback Pattern: Uses callback interface to avoid introducing dependencies between managed-ledger and broker modules
• Automatic Setup: Callbacks are automatically configured by BrokerService during topic creation
• Null-Safe: All implementations handle null callback gracefully

Testing Coverage

• 7 Unit Tests: Comprehensive testing of callback integration in NonRecoverableDataCallbackTest
• 3 Integration Tests: End-to-end validation including real topic/subscription creation in OpenTelemetryBrokerOperabilityStatsTest

Implementation Details

The implementation uses a callback pattern where:

1. BrokerService sets up the NonRecoverableDataMetricsCallback during managed ledger configuration
2. ManagedLedgerImpl calls the callback when skipNonRecoverableLedger() is invoked
3. ManagedCursorImpl calls the callback when skipNonRecoverableEntries() is invoked with actual entry counts
4. The callback updates BrokerOperabilityMetrics which maintains both Prometheus and OpenTelemetry counters

Test plan

• Unit tests pass (7/7 in managed-ledger module)
• Integration tests pass (3/3 in broker module)
• Checkstyle validation passes (0 violations)
• End-to-end testing with real topics, subscriptions, and message positions
• Callback integration verified through actual broker service topic creation

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete