Fixed getting tokens from metadata with no options provided

[ilyutov]

A tiny fix for shorthand metadata source configuration:

{Goth, name: MyApp.Goth} - broken {Goth, name: MyApp.Goth, source: :metadata} - broken {Goth, name: MyApp.Goth, source: {:metadata, []}} - works

Got this issue while migrating my app from using credentials file to Workload Identity.

Stacktrace:

(CaseClauseError) no case clause matching: %Goth{http_client: {#Function<3.71762554/1 in Goth."-fun.__finch__/1-">, []}, max_retries: 10, name: MyApp.Goth, refresh_before: 300, retries: 0, retry_after: nil, retry_delay: #Function<4.71762554/1 in Goth."-fun.exp_backoff/1-">, source: {:metadata, []}}
    (goth 1.3.0) lib/goth.ex:194: Goth.prefetch/1
    (goth 1.3.0) lib/goth.ex:187: Goth.handle_continue/2
    (stdlib 3.17.2) gen_server.erl:695: :gen_server.try_dispatch/4
    (stdlib 3.17.2) gen_server.erl:437: :gen_server.loop/7
    (stdlib 3.17.2) proc_lib.erl:226: :proc_lib.init_p_do_apply/3
Last message: {:continue, :async_prefetch}

I couldn't find a way to write a test for this with the current setup. I hope it's simple enough to go untested.

[wojtekmach]

Good catch, thank you!

{Goth, name: MyApp.Goth} - broken

What's the error you're getting? Does this patch fix that one too?

[ilyutov]

What's the error you're getting? Does this patch fix that one too?

Same error. I believe it checks for env variables and default json file location when you don't specify source. If none of those exist it falls back to metadata which was broken.