default_test option

[mgibowski]

Hi, cool library :)

It would be great to have a default_test option, similar to default_dev.

[emadalam]

@mgibowski Thanks for trying it out and giving the feedback 🙌

Currently the default_dev works for both :dev and :test mix environments. The name might have been a little confusing but the idea was to have a default that can work for local development (that includes both :dev and :test).

Having said that, I'm still contemplating what could be the best way to allow setting mix environment specific defaults since mix environments can be any number of custom values. I'm thinking of introducing a unified defaults keyword list option to allow this flexibility. Any other suggestions are more than welcome.

[mgibowski]

In my case, I just need a different default value for test, different for dev, and no default for prod (always set from env variable).

defaults: [dev: “a”, test: “b”]would be fine for my use case.

[emadalam]

@mgibowski I have added the configuration option defaults as part of a new feature branch. Have a look at this PR #5 and see if it serves the purpose. I'd make a release tomorrow if you don't have any further comments to the approach.

Side note: I have also soft deprecated the default_dev option with warnings to prefer using the new defaults option.

[mgibowski]

thanks @emadalam just tried the feature branch, and it works great for me!

[mgibowski]

@emadalam I was a bit too quick.

Something doesn't work.

Here is the code fragment:

  use Mahaul,
    REDPANDA_NUM_PARTITIONS: [type: :int, defaults: [dev: 1]]

When I invoke MyApp.Env.redpanda_num_partitions()

I get the error:

** (FunctionClauseError) no function clause matching in Integer.parse/2    
    
    The following arguments were given to Integer.parse/2:
    
        # 1
        1
    
        # 2
        10
    
    Attempted function clauses (showing 2 out of 2):
    
        def parse(_binary, base) when not (is_integer(base) and (base >= 2 and base <= 36))
        def parse(binary, base) when is_binary(binary)
    
    (elixir 1.14.3) lib/integer.ex:275: Integer.parse/2
    (mahaul 0.4.0) lib/mahaul/helpers.ex:226: Mahaul.Helpers.parse/2

Is it a bug in mahaul, or did I make some mistake?

[emadalam]

@mgibowski For consistency reasons, the parsing of values to correct data types happen only from string values like how you set in the actual environment variables. So the correct way to set any defaults is to set the string values exactly like how you would do while setting the environment variables. So in your example you should do,

  use Mahaul,
    REDPANDA_NUM_PARTITIONS: [
      type: :int,
      defaults: [dev: "1"]
    ]

Regardless of the type, you always should set string values for defaults, I have it in the documentation, but maybe I'd need to reemphasize that and improve documentation. Also I could improve this through a compile time validation in future.

[mgibowski]

Alright, makes sense - thanks!

[emadalam]

Also I could improve this through a compile time validation in future.

@mgibowski In retrospect, this should have been implemented with the new defaults option, as we already had compile time checks for invalid default and default_dev options.

Nonetheless I have added those compile time checks in v0.4.1 🙌