yaml configuration is error-prone

[Brendan Linn]

I maintain a Misk-based app. Yesterday, I added a backend to it via Guice injection, and added fake and real Guice modules for the binding. All tests passed. But when I deployed the change to the app's staging environment, it failed:

com.google.inject.ProvisionException: Unable to provision, see the following errors:
        1) Error in custom provider, java.lang.IllegalArgumentException: no client configuration for endpoint [redacted]
          at misk.client.HttpClientModule.configure(HttpClientModule.kt:23) (via modules: [redacted] -> misk.client.TypedHttpClientModule -> misk.client.HttpClientModule)
          while locating okhttp3.OkHttpClient annotated with @com.google.inject.name.Named(value=[redacted])
          at misk.client.TypedHttpClientModule.configure(TypedHttpClientModule.kt:45) (via modules: [redacted] -> misk.client.TypedHttpClientModule)
          while locating [redacted] annotated with @com.google.inject.name.Named(value=[redacted])

After reading Misk docs, I realized I needed to add a line to app-staging.yaml corresponding to this new backend.

Could this error have been surfaced before deploying? I realize that app-staging.yaml is meant for the staging environment, but it should be possible to write a tool that would do some static analysis on the yaml file and realize there's a missing backend. (I'm filing this issue here, rather than against my own app, because it seems like it would be valuable for every Misk app.)

[Ricardo Mariano]

Sorry about the long delay in replying.

I think that a test on the Injector with different envs should have picked this up.

While we've added config-checking via hoplite, that particular error stems from the module trying to pull dynamically from the config, so without changing how the module works, an injector test is probably the way to go.