# `Trogon.Proto.Env`
[🔗](https://github.com/straw-hat-team/beam-monorepo/blob/trogon_proto@v0.13.1/apps/trogon_proto/lib/trogon/proto/env.ex#L1)

Compile-time macro for generating environment variable loaders from proto definitions.

Reads field-level `trogon_proto.env.v1_alpha1.field` extensions to generate:
- Typed struct with proper field definitions
- `from_env/0` function that returns `{:ok, t()} | {:error, LoadError.t()}`
- `from_env!/0` function that returns the struct or raises `LoadError`
- Inspect implementation that masks secret fields automatically

## Usage

Define your configuration message in a proto file with env var options:

    syntax = "proto3";

    package myapp.config.v1;

    import "trogon/env/v1alpha1/options.proto";

    message AppConfig {
      string database_url = 1 [(trogon.env.v1alpha1.field).env_var = {
        visibility: VISIBILITY_SECRET
      }];

      string port = 2 [(trogon.env.v1alpha1.field).env_var = {
        visibility: VISIBILITY_PLAINTEXT,
        default_value: "5432"
      }];
    }

Then use the macro in a module:

    defmodule MyApp.Config do
      use Trogon.Proto.Env, message: Myapp.Config.V1.AppConfig
    end

At runtime, load the configuration:

    # Requires DATABASE_URL env var, uses PORT default of 5432
    config = MyApp.Config.from_env!()

    # Or handle failures without rescuing (CLI / Mix tasks / health checks):
    case MyApp.Config.from_env() do
      {:ok, config} -> config
      {:error, %Trogon.Proto.Env.LoadError{errors: errors}} -> handle(errors)
    end

    # Secrets are automatically masked when inspecting/logging
    Logger.info(inspect(config))

## Type Conversions

Environment variables are always strings. This module converts them to the
appropriate Elixir types based on the proto field type:

- `string` - No conversion
- `int32`, `int64` - Parsed via `String.to_integer/1`
- `float`, `double` - Parsed via `Float.parse/1` (accepts both "1.5" and "1")
- `bool` - Case-insensitive, truthy values: `"true"`, `"1"`, `"yes"`, `"on"`;
  all other values are considered `false`
- `enum` - Exact enum name match (for example `"LOG_LEVEL_DEBUG"`)

# `field_config`

```elixir
@type field_config() :: %{
  env_var_name: String.t(),
  visibility: non_neg_integer(),
  default_value: String.t() | nil,
  field_type: atom() | {:enum, module()},
  is_repeated: boolean(),
  split_delimiter: String.t(),
  trim: TrogonProto.Env.V1Alpha1.Trim.t() | nil
}
```

# `__using__`
*macro* 

Defines an environment variable loader struct from a protobuf message.

## Options

- `:message` (required) - The protobuf message module to extract env vars from

# `get_env`

# `get_env`

---

*Consult [api-reference.md](api-reference.md) for complete listing*