Dotenv (.env) Provider

FromDotEnv reads a 12-factor-style .env file into the configuration pipeline. It is built into the core package (no extra dependency) and uses the same reactive file-watching as the File provider — including followSymlinks: true for Kubernetes ConfigMap / Secret mounts.

builder.AddCocoarConfiguration(c => c
    .UseConfiguration(rules =>
    [
        rules.For<AppSettings>().FromDotEnv(),          // defaults to ".env"
        rules.For<AppSettings>().FromDotEnv("local.env"),
    ]));

Format

# comments and blank lines are ignored
NAME=myapp
export TOKEN=abc123        # an optional `export` prefix is stripped

DQ="hello world"           # double quotes; supports \n \t \" \\ escapes
SQ='literal $x'            # single quotes are literal
INLINE=value # trailing comment   (stripped — needs a leading space)

# Nested keys with : or __  (like environment variables)
Db__Port=5432              # → { "Db": { "Port": "5432" } }
Db:Host=localhost

Values are emitted as strings; the binder coerces them to the target type (e.g. Db__Port=5432 binds to an int). Keys nest on : or __, matching the Environment Variables provider.

Reactivity & per-tenant paths

Editing the file triggers a recompute. A config-aware overload resolves the path per recompute:

rules.For<Secrets>().FromDotEnv(a => $"tenants/{a.Tenant}/.env").TenantScoped()

YAML?

For .yaml / .yml files see the YAML provider (Cocoar.Configuration.Yaml).