Dfyjkt

I have 2 Postgres databases each in their own CloudSQL instance and a .NET web app running in GKE.

Goal: Connect web app utilizing EntityFramework Core to both CloudSQL instances using a single CloudSQL proxy.

I followed this setup and modified it following this S.O. answer.

There is an EF Core DbContext for each CloudSQL Instance.
The context connections are set using 2 environment variables:

new Context1(

optionsBuilder.UseNpgsql(Environment.GetEnvironmentVariable("CONNECTION_1"));
);

new Context2(

optionsBuilder.UseNpgsql(Environment.GetEnvironmentVariable("CONNECTION_2"));
);

The environment variables are set as:

CONNECTION_1 = "Host=127.0.0.1;Port=5432;Database=postgres;Username=postgres;Password=password"

CONNECTION_2 = "Host=127.0.0.1;Port=5432;Database=postgres;Username=postgres;Password=password2"

Current Behavior:

Context1 interacts with CloudSQL instance1 as normal.

Context2 throws PostgresException "42P01: relation my_Table_Name does not exist." when trying to access a table.

Note: "my_Table_Name" is a table in CloudSQL instance2

This leads me to believe Context2 is trying to access CloudSQL instance1 instead of instance2.

How can I point Context2 through the SQL Proxy to CloudSQL instance2?

Basically this:

CONNECTION_1 = "Host=127.0.0.1;Port=5432;Database=postgres;Username=postgres;Password=password"
CONNECTION_2 = "Host=127.0.0.1;Port=5432;Database=postgres;Username=postgres;Password=password2"

means that you are connecting to the exact same Cloud SQL instance, with just two different passwords (same username). Not sure how CONNECTION_2 might even connect to the Cloud SQL instance1 though.

You would want to have something like this:

CONNECTION_1 = "Host=127.0.0.1;Port=5432;Database=postgres;Username=postgres;Password=password"
CONNECTION_2 = "Host=127.0.0.1;Port=5433;Database=postgres;Username=postgres;Password=password2"

and on your cloud-proxy command line (running on the same pod):

-instances=project:region:sqlinstance1=tcp:5432,project:region:sqlinstance2=tcp:5433