Support reading client/server secret from an environment variable

[orhun]

This PR adds env feature to clap for defining custom variables to read the values of --secret arguments from the environment.

• BORE_SECRET: sets the client/server secret

closes #17

[ekzhang]

Thank you for doing this! Is there a reason why the environment variable names are different between client and server though, rather than just BORE_SECRET? I can't think of any case where a user would set these two environment variables to different values, since the secret is intended to be the same on both ends.

[orhun]

Thank you for doing this! Is there a reason why the environment variable names are different between client and server though, rather than just BORE_SECRET? I can't think of any case where a user would set these two environment variables to different values, since the secret is intended to be the same on both ends.

Good point, I guess I haven't thought of that 🐻

Updated the PR.

[praveenperera]

Thank you for doing this! Is there a reason why the environment variable names are different between client and server though, rather than just BORE_SECRET? I can't think of any case where a user would set these two environment variables to different values, since the secret is intended to be the same on both ends.

Could someone maybe use bore to hope traffic between a few servers? That's the only reason I could see both bore client and server being used on the same machine.

[gngeorgiev]

@praveenperera You can just reassign the env variable per each instance:

BORE_SECRET=$BORE_CLIENT_SECRET ./client
BORE_SECRET=$BORE_SERVER_SECRET ./server

[ekzhang]

Thank you!