Add Support for Custom Dev Container Initialization (#1441)

[ljluestc]

Add Support for Custom Dev Container Initialization (#1441)

Description

This PR resolves Issue #1441 by adding a --dev-init flag to the Atlas CLI, enabling users to customize development database containers (e.g., Docker-based PostgreSQL instances) before database initialization. The feature supports use cases such as creating directories for PostgreSQL tablespaces and copying files (e.g., for PGXN extensions) into the container.

Changes

• CLI Update: Introduced the --dev-init flag to atlas schema apply, atlas migrate diff, and atlas migrate apply commands when using a Docker-based --dev-url (e.g., docker://postgres/15/test). The flag accepts a file path to a shell script (e.g., file://init-dev.sh).
• Dev Container Logic: Updated Docker container initialization in atlas/sql/postgres to:
  • Mount the user-provided script to /docker-entrypoint-initdb.d/init-dev.sh.
  • Mount an optional directory (via --dev-files) for copying files (e.g., extension files) to /tmp/extensions.
  • Execute the script during container startup, before database initialization.
• Validation: Added checks for script existence and executability, with descriptive error messages.
• Documentation: Updated docs/cli-reference.md to document --dev-init and --dev-files flags, including examples.
• Example Script: Included a sample init-dev.sh in the documentation for creating tablespace directories and copying extension files.

Example Usage

atlas migrate diff "my_migration" \
  --dir "file://migrations" \
  --to "file://schema.hcl" \
  --dev-url "docker://postgres/15/test" \
  --dev-init "file://init-dev.sh" \
  --dev-files "file://extensions"