Improve error messages when server misconfigured

[jameshiew]

Motivation

Relates to #1435

This PR is trying out a way to improve the error message shown when something is misconfigured.

Currently running the server binary (cargo run in the svix-server/ folder) panics when some needed config is missing.

e.g. listen_address not set

thread 'main' panicked at svix-server/src/cfg.rs:550:10:
Error loading configuration: Error { tag: Tag::Default, profile: Some(Profile(Uncased { string: "default" })), metadata: None, path: [], kind: MissingField("listen_address"), prev: None }
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

e.g. jwt_secret not set - in this case the error message doesn't indicate the missing field due to an issue with it coming from an inlined struct inside ConfigurationInner - SergioBenitez/Figment#80

thread 'main' panicked at svix-server/src/cfg.rs:550:10:
Error loading configuration: Error { tag: Tag::Default, profile: Some(Profile(Uncased { string: "default" })), metadata: None, path: [], kind: Message("data did not match any variant of untagged enum JwtSigningConfig"), prev: None }

Solution

If cfg::load() errors out, terminate with exit code 1 and print the formatted error to stderr. I tried switching to using anyhow::Result for main() and cfg::load() to make propagating errors with human friendly context easier.

Error: failed to extract configuration

Caused by:
    missing field `listen_address`

Check upfront that jwt_secret is set and override the error message to be more helpful due to SergioBenitez/Figment#80

Error: failed to extract configuration

Caused by:
    missing field `jwt_secret`

[jameshiew]

Thanks for reviewing! I've updated to bail! with the wait_for_dsn err

 > SVIX_JWT_SECRET='a' SVIX_REDIS_DSN='redis://redis:6379' cargo run -- --wait-for 1
   Compiling svix-server v1.40.0 (/opt/workspace/3p/svix-webhooks/server/svix-server)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 6.00s
     Running `/opt/workspace/caches/cargo/debug/svix-server --wait-for 1`
2024-11-18T18:21:00.138658Z ERROR svix_server: Waiting for service PostgreSQL host=pgbouncer port=5432 timed out
Error: Waiting for service PostgreSQL host=pgbouncer port=5432 timed out

[svix-jplatte]

Thanks!