Add a force_tls_destination flag for forcing secure connection to destination

[nsobadzhiev]

The use case

• I'm developing an app using gRPC and I'm connecting to a stage/prod service running remotely
• I want to sniff the traffic and forward it to the remote service

The problem

I know that I can import a certificate that my system trusts and establish 2 TLS sessions (app <> grpc-dump and grpc-dump <> remote server), but that's additional hassle. I'd much rather connect insecurely my app to grpc-dump, and then have grpc-dump connect securely to the remote server.

This, ofc, assumes I have the power to change my app's code and allow it to create plain text connections to a server. Whereas I agree that this is not the most correct and black-box way to do it, I think it's much more convenient for a lot of people.

Solution

Add a flag to the cli that forces grpc-dump to establish a TLS connection even if the original connection it is trying to relay is plain text.
Default value: false
If the value is false at runtime, only use TLS if the original request was also TLS secured.

Any input is appreciated, and I'm sorry if the code is not perfect - this is my first Go code :)

I hope you'll find this feature useful or interested. Or not, I'll keep it to myself :)