Multiple DB support

[crusty-dave]

I need to support two different PSQL DBs, one of which might end up running in a separate cluster some day.

What is the idiomatic way to support this correctly using diesel?

i.e. I need to ensure that migrations are kept in isolated directories.

I am hoping that I don't have to create a library for one of them, but diesel.toml seems to be restricted to a single DB in a project

TIA, -Dave

[weiznich]

but diesel.toml seems to be restricted to a single DB in a project

That's literally the only place where there is an assumption about a single database connection and that's the only place where it's reasonable to assume such thing.

Generally speaking: If you use diesel-cli for managing stuff, you just want to use the command line options to set different connections/migration dirs. If you use diesel, it's even easier as different connections can point to different databases. How you actually setup and manage them, that's part of your implementation.

[crusty-dave]

FYI: I wasn't worried about diesel, only the CLI and the migrations dir. I wanted to know the idiomatic way to do this.

What I am going to try is the following:

embed_migrations!("./db/db1/migrations");
embed_migrations!("./db/db2/migrations");

And I am going to try moving diesel.toml to db1/db1.toml & create a new db2/db2.toml and then use the command line arguments.

OPTIONS:
        --config-file <CONFIG_FILE>      The location of the configuration file to use. Falls back to the
                                         `DIESEL_CONFIG_FILE` environment variable if unspecified. Defaults to
                                         `diesel.toml` in your project root. See diesel.rs/guides/configuring-diesel-cli
                                         for documentation on this file.
        --database-url <DATABASE_URL>    Specifies the database URL to connect to. Falls back to the DATABASE_URL
                                         environment variable if unspecified.

Thanks

[crusty-dave]

@weiznich - it seems that I had some confusion about migrations.

The following documentation is misleading, mod embedded_migrations is actually created by the embed_migrations macro, it would be helpful if the documentation actually stated that to avoid confusion:

https://docs.rs/diesel_migrations/1.4.0/diesel_migrations/macro.embed_migrations.html

Based on the example, I thought I would need to add a use statement that included both the embed_migrations! macro as well as the embedded_migrations module.

TIA, -Dave