Enable migration generation in modules

[senekor]

Adds

Generating a new migration no works even if migrations are not at the root of their own crate.

I didn't want to have an entire separate crate just for migrations. So I put them into a module in my regular crate. sea-orm-cli migrate generate accepts a flag --migration-dir, which seemed perfect for my use case. However, that flag still assumes there is a directory src/ and that the migrator definition is in lib.rs.

If there is a directory src/ and a file lib.rs, this PR doesn't change anything, so I don't think it's a breaking change. If src/ doesn't exist, it will look in the parent directory instead. If there is no lib.rs, it will look for a mod.rs instead.

For reference, this is what my file structure looks like:

my-app/
├─ src/
│  ├─ db/
│  │  ├─ migration/
│  │  │  ├─ mod.rs/
│  │  │  ├─ m20220101_000001_create_table.rs/
│  │  ├─ migration_cli.rs
│  │  ├─ mod.rs
│  ├─ main.rs
├─ Cargo.toml

Both db/mod.rs and db/migration_cli.rs contain mod migration;. That way, both binaries (main.rs, the main app, and migration_cli.rs, a thin wrapper around the migration cli api) can access my migrations.

I'm looking forward to discussions and suggestions!

[billy1624]

Hey @remlse, welcome! And thanks for the great contributions!

I think we should document the updated behaviour on the get_full_migration_dir and get_migrator_filepath method because the logic is getter more complex it's not easy to understand at a glance.

Which directory/file be checked for existence then what's the fallback?

Thoughts? :)

[billy1624]

Hey @remlse, just notice a problem. Before updating the migrator file mod.rs/lib.rs. A backup file will be created with file extension of .bak.

• sea-orm/sea-orm-cli/src/commands/migrate.rs

  Lines 143 to 144 in 1a2090f

  	// create a backup of the migrator file in case something goes wrong
  	let migrator_backup_filepath = migrator_filepath.with_file_name("lib.rs.bak");

However, now that migrator can be either reside in mod.rs/lib.rs. We should change the line to:

let migrator_backup_filepath = migrator_filepath.with_extension("rs.bak");

[senekor]

@billy1624 thanks for having a look! I think I'll get around to it on the weekend, I'll add some documentation and fix the backup filename.

[senekor]

@billy1624 I've added some documentation. Some internally and some to be displayed by sea-orm-cli migrate -h. Let me know if I can improve something, I haven't done much documentation before.

[billy1624]

Thanks! @remlse The documentation looks great :)

[tyt2y3]

Thank you for the contribution. Too bad for the delay, I am surprised this patch still applies