PSC-based connections should use the DNS name in TLS config

[enocom]

Feature Description

When connecting to a PSC endpoint, we should use the PSC DNS name as the server name in the TLS configuration here:

cloud-sql-go-connector/internal/cloudsql/refresh.go

Line 234 in aeb4de1

ServerName: inst.String(),

.

That should also allow us to remove InsecureSkipVerify for PSC-based connections.

Sample code

No response

Alternatives Considered

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Additional Details

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[jackwotherspoon]

@hessjcg can we close this now?