WIP: Module Improvements / Fixes for Schema Reversion

[lcatlett]

1. Implement Proper Core Reload Functionality

Changes:

• Add explicit core reload calls after schema updates.
• Verify core reload success.
• Add retry mechanism for failed reloads.

Architecture Review:

• Core Reload Calls: Ensure that after any schema update, the Solr core is explicitly reloaded to apply changes.
• Verification: Implement a method to verify the success of the core reload by checking the core status.
• Retry Mechanism: Introduce a retry mechanism with exponential backoff to handle transient failures during core reloads.

Code Changes:

• Modify PantheonSolrConnector.php to include core reload calls and verification.
• Add retry logic in the reloadCore method.

2. Improve Configuration Persistence

Changes:

• Store complete Solr configuration in Drupal's config system.
• Implement proper config update hooks.
• Add configuration validation.

Architecture Review:

• Configuration Storage: Utilize Drupal's configuration management system to store and retrieve Solr configurations.
• Update Hooks: Implement hooks to handle configuration updates and ensure they are applied correctly.
• Validation: Add validation logic to ensure the configuration is correct before applying it.

Code Changes:

• Update PantheonSolrConnector.php to store configuration in Drupal's config system.
• Implement hook_update_N functions to handle configuration updates.
• Add validation methods in SchemaValidator.php.

3. Add Safeguards

Changes:

• Validate schema compatibility before updates.
• Implement rollback mechanism for failed updates.
• Add configuration version tracking.

Architecture Review:

• Schema Validation: Before applying any schema updates, validate the schema to ensure compatibility.
• Rollback Mechanism: Implement a mechanism to rollback to the previous schema if an update fails.
• Version Tracking: Track the version of the configuration to detect and handle mismatches.

Code Changes:

• Add schema validation in SchemaValidator.php.
• Implement rollback logic in SchemaPoster.php.
• Track configuration versions in CoreStatusMonitor.php.

4. Improve Error Handling

Changes:

• Add proper exception handling.
• Implement retry mechanisms.
• Add detailed logging.
• Provide better user feedback.

Architecture Review:

• Exception Handling: Ensure all critical operations have proper exception handling to catch and log errors.
• Retry Mechanisms: Implement retry logic for operations that can fail transiently.
• Logging: Enhance logging to provide detailed information about errors and operations.
• User Feedback: Provide clear and actionable feedback to users when errors occur.

Code Changes:

• Update SolariumClient.php and PantheonSolrConnector.php to include detailed logging and exception handling.
• Implement retry logic in methods that interact with Solr.

5. Add Monitoring

Changes:

• Track schema versions.
• Monitor core status.
• Alert on configuration mismatches.

Architecture Review:

• Schema Version Tracking: Track the current schema version and compare it with the expected version.
• Core Status Monitoring: Regularly check the status of the Solr core to ensure it is running correctly.
• Alerts: Implement alerts to notify administrators of configuration mismatches or other issues.

Code Changes:

• Add schema version tracking in CoreStatusMonitor.php.
• Implement core status monitoring in CoreStatusMonitor.php.
• Add alerting logic to notify administrators of issues.

WIP #### 6. Migrate to new Pantheon config-set (vs jumpstart):

• Create an update hook to migrate existing installations to new pantheon default config-set
• Modifies SchemaPoster to use the new config-set structure
• Handles merging of default and custom configurations
• Maintains backward compatibility

[stovak]

/admin/cores is inaccessible from the standard pantheon environment. We have a process for reloading the core.