check

Validates the configuration file and tests connectivity to both databases. Run this first before any other command.

Usage

deepdiffdb check --config deepdiffdb.config.yaml

What It Does

1. Loads and validates the configuration file — checks for required fields, valid driver names, and valid port numbers.
2. Opens a connection to the production database and runs a lightweight ping query.
3. Opens a connection to the development database and runs a lightweight ping query.
4. Verifies that every non-ignored table in both databases has a primary key. Tables without primary keys cannot be diffed and must either be fixed or added to the ignore.tables list.
5. Checks that the output.dir directory exists and is writable (creates it if missing).
6. Prints a summary of the resolved configuration settings.

Flags

Flag	Description
--config	Path to the configuration file (default: deepdiffdb.config.yaml)

Example Output

✓ Config loaded
✓ Production database connected (postgres @ 127.0.0.1:5432/prod_db)
✓ Development database connected (postgres @ 127.0.0.1:5432/dev_db)
✓ All non-ignored tables have primary keys (12 tables checked)
✓ Output directory is writable: ./diff-output

Configuration Summary:
  Ignored tables : audit_logs, sessions
  Ignored columns: *.updated_at, *.created_at
  Batch size     : 10000
  Parallel tables: 1

Check passed.

When to Use

• Before starting any diff — confirm connectivity before investing time in a long operation.
• In CI/CD pipelines — use as a readiness gate before running diff or gen-pack.
• After editing the config file — confirm the new settings are valid before running.

Exit Codes

Code	Meaning
0	All checks passed
1	One or more checks failed (see stderr for details)