feat: Add SQL Server CDC support to Datastream-to-BigQuery template

[mahendrarathore1742]

Closes #3410

Add SQL Server as a supported source database for the Datastream to BigQuery Flex template, enabling CDC replication from SQL Server to BigQuery.

Changes:

• DataStreamClient: Add SQL Server schema discovery, primary key extraction, and type conversion (20+ SQL Server types to BigQuery)
• FormatDatastreamRecordToJson: Handle SQL Server CDC metadata (_metadata_schema, _metadata_lsn, _metadata_tx_id) for Avro format
• FormatDatastreamJsonToJson: Handle SQL Server CDC metadata for JSON format. Also fix pre-existing bug where _metadata_lsn was reading from 'database' instead of 'lsn'
• DatastreamRow: Add SQL Server sort fields for CDC event ordering
• BigQueryDefaultSchemas: Add _metadata_lsn to default schema
• DataStreamToBigQuery: Update template requirements and parameter docs to include SQL Server
• DataStreamClientTest: Add unit tests for SQL Server type conversion

Tested:

• Maven compile: SUCCESS (datastream-common + datastream-to-bigquery)
• Checkstyle: 0 violations
• Unit tests: 11 run, 0 failures

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[gemini-code-assist]

Summary of Changes

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This pull request significantly expands the capabilities of the Datastream-to-BigQuery Flex template by introducing full support for SQL Server as a source for Change Data Capture (CDC) replication. The changes enable seamless data streaming from SQL Server instances to BigQuery, encompassing schema mapping, metadata processing, and proper data type conversions. This enhancement allows users to leverage the template for a broader range of enterprise data sources, facilitating real-time analytics and data warehousing solutions.

Highlights

• SQL Server CDC Support: Added comprehensive support for SQL Server as a source database for Datastream-to-BigQuery CDC replication, including schema discovery, primary key extraction, and type conversion for over 20 SQL Server data types to BigQuery.
• CDC Metadata Handling: Implemented handling for SQL Server CDC metadata (_metadata_schema, _metadata_lsn, _metadata_tx_id) in both Avro and JSON record formatting, ensuring proper data ingestion and processing.
• Metadata LSN Bug Fix: Corrected a pre-existing bug in JSON record formatting where _metadata_lsn was incorrectly reading from the 'database' field instead of the 'lsn' field for certain source types.
• Data Ordering and Schema Updates: Integrated SQL Server specific sort fields for CDC event ordering and updated the default BigQuery schema to include the _metadata_lsn field.
• Documentation and Testing: Updated template requirements and parameter documentation to reflect SQL Server support, and added dedicated unit tests for SQL Server type conversion to ensure correctness.

Changelog

• v2/common/src/main/java/com/google/cloud/teleport/v2/cdc/mappers/BigQueryDefaultSchemas.java
  • Added _metadata_lsn field for SQL Server specific metadata.
• v2/datastream-common/src/main/java/com/google/cloud/teleport/v2/datastream/transforms/FormatDatastreamJsonToJson.java
  • Added handling for SQL Server specific CDC metadata (_metadata_schema, _metadata_lsn, _metadata_tx_id).
  • Fixed a bug where _metadata_lsn was incorrectly read from 'database' instead of 'lsn'.
• v2/datastream-common/src/main/java/com/google/cloud/teleport/v2/datastream/transforms/FormatDatastreamRecordToJson.java
  • Added handling for SQL Server specific CDC metadata (_metadata_schema, _metadata_lsn, _metadata_tx_id).
• v2/datastream-common/src/main/java/com/google/cloud/teleport/v2/datastream/utils/DataStreamClient.java
  • Imported SQL Server model classes.
  • Integrated SQL Server into schema discovery and primary key extraction logic.
  • Implemented methods for discovering SQL Server table schemas and primary keys.
  • Added a comprehensive type conversion utility for mapping SQL Server data types to BigQuery Standard SQL types.
• v2/datastream-common/src/main/java/com/google/cloud/teleport/v2/datastream/values/DatastreamRow.java
  • Included SQL Server as a source type for determining CDC event sort fields.
• v2/datastream-common/src/test/java/com/google/cloud/teleport/v2/datastream/utils/DataStreamClientTest.java
  • Imported SqlServerColumn and StandardSQLTypeName.
  • Added extensive unit tests for SQL Server to BigQuery column type conversion, covering various data types.
• v2/datastream-to-bigquery/README_Cloud_Datastream_to_BigQuery.md
  • Updated documentation for the 'datastreamSourceType' parameter to include 'sqlserver' as a valid value.
• v2/datastream-to-bigquery/src/main/java/com/google/cloud/teleport/v2/templates/DataStreamToBigQuery.java
  • Updated template requirements to explicitly list SQL Server as a supported source database.
  • Modified the 'datastreamSourceType' parameter's help text to include 'sqlserver'.

Activity

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