config: Allow setting config path via TMKMS_CONFIG_FILE

[tarcieri]

This is nice for using tmkms interactively via the command line (e.g. tmkms yubihsm) in cases where tmkms.toml is not in the current working directory.

[liamsi]

I did not test this but the changes look good to me!

[liamsi]

This should probably come with a test.

[liamsi]

Huh, how did we not see this before?

error[E0308]: match arms have incompatible types
  --> src/commands/mod.rs:58:22
   |
58 |           let config = match self {
   |  ______________________^
59 | |             KmsCommand::Start(run) => run.config.as_ref(),
60 | |             #[cfg(feature = "yubihsm")]
61 | |             KmsCommand::Yubihsm(yubihsm) => yubihsm.config_path(),
   | |                                             --------------------- match arm with an incompatible type
62 | |             _ => return None,
63 | |         };
   | |_________^ expected struct `std::string::String`, found str

Update: OK, the changes in the latest commit should fix this!

[liamsi]

Merging. I wonder if adding a code-coverage report to circle-ci is sth. we should consider for this repo?

[tarcieri]

@liamsi it'd be a bit tricky, because the tests are largely black box as opposed to unit tests, and as such would probably thwart a coverage tool.

It'd be good to improve unit testing, but that'd require hoisting more of the code into library-level constructions.

I can make an issue about improving the testing situation (or you can, either way)

[tarcieri]

Re:

Huh, how did we not see this before?

...because I was testing locally without the --features=yubihsm flag 🤦‍♂️

Perhaps we should add a Makefile with a make test option that runs cargo test --all --all-features -- --test-threads 1. The testing situation has definitely gotten... trickier.

[tarcieri]

An alternative to the above is to eliminate the need for --test-threads 1. This can be accomplished by adding a lazy_static Mutex around the tests that need to run single-threaded (e.g. this mutex could be acquired any time tmkms is run as an external command)