add external milvus database option

[SkyHive]

Adds support for specifying a custom Milvus database.

Problem:

The current implementation hardcodes the "default" database name for Milvus. External Milvus instances may require a different database name.

Solution:

Introduces the MILVUS_DATABASE environment variable to allow users to specify the database to use when connecting to an external Milvus instance.

Details:

• Adds MILVUS_DATABASE to templates/config.tpl.
• Adds externalMilvus.database option in values.yaml

Usage:

Set externalMilvus.database in your values.yaml file to the desired database name.

Benefits:

• Enables Dify to connect to external Milvus instances using custom database names.

[BorisPolonsky]

Thanks for your contribution. However we couldn't find this option in current version of dify. https://github.com/langgenius/dify/blob/4dae0e514e1b149ea74e42056fcc520ad60b8c04/docker/docker-compose.yaml#L137-L141

[SkyHive]

Thanks for your contribution. However we couldn't find this option in current version of dify. https://github.com/langgenius/dify/blob/4dae0e514e1b149ea74e42056fcc520ad60b8c04/docker/docker-compose.yaml#L137-L141

You're right that MILVUS_DATABASE isn't explicitly in the docker-compose files. However,the code actually already supports reading this environment variable to configure the Milvus database connection.
https://github.com/langgenius/dify/blob/main/api/configs/middleware/vdb/milvus_config.py#L32