Sling v1.5.12 (2026-03-09T18:18:58Z)

New Features

• --home-dir flag: New flag across sling run and all sling conns subcommands (list, test, set, unset, exec, discover) to specify a custom sling home directory. Sets SLING_HOME_DIR and reloads connections accordingly.

• Column merge with defaults (+ prefix): Stream-level columns: entries prefixed with + now merge with defaults.columns instead of replacing them. Use +column_name: ~ to unset a default. Without +, legacy replace behavior is preserved.

• Pipeline store variables in replications: {store.xxx} variables set in pipeline steps are now accessible in inline replication where: and sql: fields.

• API spec range_step support: Added range_step to the endpoint context map, enabling three-part range expressions for backfill.

• API spec state variable rendering in jmespath / jq: State variables (e.g. {state.endpoint_name}) are now resolved inside jmespath and jq response record expressions.

Bug Fixes

• SLING_LOGGING env from replication: Moved SLING_LOGGING env handling from per-task to replication-level so it takes effect before stream execution and properly reinitializes the logger.

• Direct insert incremental state: writeToDbDirectly now calls SyncColumns() and SyncStats() so incremental state (e.g. datetime update keys) is correctly captured after direct insert writes.

• Auth token refresh on retry: API retry logic now refreshes HTTP request headers from conn.State.Auth.Headers before resending, fixing stale token issues after server-side token rotation (both single-request and mid-pagination scenarios).

• Windows path handling: CleanWindowsPath applied to local file locations in ParseLocation, API spec file:// paths, env file paths, and SLING_HOME_DIR.

• Oracle chunking with custom SQL: Fixed AS table alias syntax for Oracle (which doesn't support AS for subquery aliases).

Sling v1.5.11 (2026-03-02T19:52:22Z)

• Fix critical issue with API Spec state parsing when using setup

Sling v1.5.10 (2026-03-02T14:00:35Z)

Connectors

• ADBC DuckDB — new ADBC connector with Docker testing
• MongoDB — support ISODate() in filters
• ClickHouse — fix table rename SQL syntax
• SFTP — fix incremental file timestamp filtering
• Google Drive — add context timeout for API calls
• Local files — UNC path support (Windows network paths)

Connections & Environment

• Support setting username in connection URL
• New .env.sling file support for per-project connection definitions

MCP Server

• working_dir parameter on connection, pipeline, and replication actions
• Auto-loads .env.sling from working directory

CDC (Change Data Capture)

• Soft delete now uses _sling_synced_op = 'D' instead of _sling_deleted_at; snapshot rows marked with 'S'
• Updated merge_change_capture_soft templates across all 14 databases

Other

• Updated godbc v0.0.5, purego v0.10.0
• Disable AWS EC2 metadata service to prevent warning messages
• JMESPath/JQ safe rendering with state variables
• Simplified update check logic

Sling v1.5.9 (2026-02-23T15:13:21Z)

Change Data Capture (CDC)

• New change-capture replication mode
• Supports initial full/chunked snapshot then incremental CDC
• New merge strategies: change_capture and change_capture_soft (soft delete)
• CDC merge templates for: Postgres, MySQL, Snowflake, BigQuery, SQL Server, DuckDB, Redshift, Databricks, ClickHouse, SQLite, D1, DB2, Exasol, Oracle, StarRocks
• Pre-release for testing, not ready for production yet

Chunking Improvements

• Optional WHERE clause support added to chunk query functions
• Fix bug where start-date is 0000-01-01

CLI Cleanup

• Removed legacy subcommands
• Centralized execution ID into core/env package (env.ExecID)
• Enhanced file logging: exec ID prefix and log cleanup (added SLING_LOG_DIR env vars)

Proxy Support

• New SLING_PROXY environment variable (or proxy_url per-connection property) for proxy configuration

Bug Fixes

• StreamRowsContext column mapping streamlined; sync issue fixed
• Prometheus connector: consistent float conversion via toFloat method
• Time format strings in NewStreamProcessor clarified
• MySQL/MariaDB primary key handling improved in GenerateDDL
• InferColumnTypes preserves explicit types for empty datasets

Sling v1.5.8 (2026-02-17T11:17:57Z)

• Critical fix for AzureSQL and Fabric merge_strategy templates
• Improve S3 buffering to avoid back-pressure panic.

Sling v1.5.7 (2026-02-16T11:11:59Z)

Schema Migration

• Preserve foreign keys, indexes, column comments, default values, and auto-increment attributes when replicating between databases
• Supported for Oracle, PostgreSQL, Redshift, Snowflake, SQL Server, BigQuery, MySQL, DuckDB, ClickHouse, Databricks, SQLite
• Streams automatically ordered by foreign key dependencies
• Default value translation mappings between database engines

Merge Strategies

• Support for insert, update, update_insert, and delete_insert merge strategies

jq Expressions

• New jq source option for JSON-based data streams
• jq() transform function for column-level transformations
• Works with API sources and database JSON columns
• Compiled expressions cached for performance

Template & Expression Engine

• Nested template expression support for recursive resolution within nested braces (e.g., GraphQL queries)
• Safe rendering methods that keep missing expressions intact instead of erroring

Fixes & Improvements

• File-based logging setup for persistent log output
• Wildcard schema support in Discover method
• Duplicate step ID validation in pipeline configs
• DuckDB HTTP server shutdown fix after batch processing
• Total rows and bytes tracked in pipeline state
• Metadata queries updated to use current_database() for catalog filtering
• Zip file response handling for API sources

Sling v1.5.6 (2026-02-02T10:19:20Z)

• Enhanced delete_missing with configurable source and target WHERE clauses
• Added secret encoding support for HMAC authentication in API specs
• Added EscapeBackslash option for MySQL LOAD DATA operations
• Added row-start-only range format support for Excel

Bug Fixes

• Fixed Fabric ROWTERMINATOR to use hexadecimal representation
• Disabled AWS EC2 metadata retrieval for improved security
• Restored escape character handling in MySQL/MariaDB LOAD DATA INFILE templates

Sling v1.5.5 (2026-01-26T16:09:41Z)

New Features

• DB2 Database Support - Initial support for IBM DB2 with connection templates and full test suite
• definition-only Mode - Create table/file definitions without transferring data (parquet/arrow only for files)
• _sling_synced_at Column - Enable with SLING_SYNCED_AT_COLUMN=true for timestamp tracking
• _sling_synced_op Column - Tracks operation type: I (insert), U (update), D (soft delete)
• slugify Function - Convert strings to URL-friendly slugs

Bug Fixes

• DDL primary key with WITH clauses - Fixed incorrect placement when table options present (#694)
• Prometheus streaming deadlock - Fixed stall on large time ranges (#700)
• MySQL boolean CSV streaming - Fixed boolean handling in LOAD DATA LOCAL INFILE
• delete_missing with transforms - Fixed errors in PK-only queries when transforms present
• Connection caching - Fixed hash method and ODBC initialization

Improvements

• Go 1.25 - Upgraded build toolchain
• Docker ODBC packages - Added unixodbc and odbcinst
• Oracle XMLTYPE - Support for BigQuery transfers
• MySQL LOAD DATA LOCAL - Enhanced NULL value handling
• S3 multi-bucket access - Improved support in replications
• Schema discovery - Thread-safe schemata merging, column-level support

Sling v1.5.4 (2026-01-05T20:59:07Z)

ODBC Connection Support

• New ODBCConn type for generic ODBC database connections

Environment Variable Expansion in Env Files

• Environment variables can now be used within ~/.sling/env.yaml files
• Variables are expanded before YAML unmarshalling
• Loaded env vars are set into the OS environment if not already present

Enhanced Boolean Type Handling

• Boolean columns now cast to SmallIntType instead of IntegerType for better compatibility
• Improved boolean handling for MySQL, MariaDB, and StarRocks databases

Pipeline Step Order Preservation

• Updated YAML handling to use v3
• Pipeline steps now maintain their defined order during execution

Bug Fixes

• ADBC Safety Check: Ensure ADBC connection is initialized before use (conn.adbc != nil check)
• Google API Auth: Fixed "multiple credential options provided" error with google.golang.org/api >= v0.258.0
• Windows Build Dynamic Linking issue

Sling v1.5.3 (2025-12-23T14:49:39Z)

Fix for boolean casting logic for v1.5.2

• Added CastBoolColumnForSelect method to cast boolean columns when target expects integer or string
  • Boolean → Integer: true→1, false→0
  • Boolean → String: true→"true", false→"false"
• Enhanced CastColumnsForSelect to detect boolean/integer or boolean/string mismatches and apply casting

API Incremental Sync Improvements

• New GetSyncUpdateKey function - Automatically detects sync key and update key from API endpoint configuration when:
  • Endpoint has a sync array defined
  • A processor uses aggregation: maximum that outputs to state.<sync_key>
  • update_key is defined in response records
• DB-based incremental fallback - When SLING_STATE is not set, API replications can now fetch the incremental value directly from the target database