mpundlik / cassandra-schema

Cassandra Schema Migration Tool

Goals

• Create tools that generate SQL DDL scripts for Cassandra according to design
• Use generated SQL DDL scripts during upgrade procedure with one of following migration tools:
  • https://github.com/mattes/migrate/
  • https://github.com/db-journey/journey

Concept

• Developer writes GO structures with metadata (field tags & helper methods)
• SQL DDL scrips are generated from the GO structures
• Connectivity to existing schema is needed to generate alter statements but tool needs to work also without connecitivity (then it generates new schema with tables, UDTs etc.)

Iterations

Iteration 1 - struct -> DDL

• Generating new schema (in this iteration there is no need to connect to existing cassandra schema because no alter statments are calulated yet)
• Primary Keys
• Default mapping for go types to cassandra types

Iteration 2 - struct -> DDL

• Indexes
• UDTs
• customizable mapping of go types to cassandra types using new GO structure field tags

Iteration 3 - diff DDLs

• Alter table/type statements

Iteration 4 - integration & doc

• showcase how all four tools work together during upgrade procedure (deploying new version of microservice)
• describe everything in documentation with example/tutorial