# Env Source The env source reads config from environment variables ## Format We expect environment variables to be in the standard format of FOO=bar Keys are converted to lowercase and split on underscore. ### Example ``` DATABASE_ADDRESS=127.0.0.1 DATABASE_PORT=3306 ``` Becomes ```json { "database": { "address": "127.0.0.1", "port": 3306 } } ``` ## Prefixes Environment variables can be namespaced so we only have access to a subset. Two options are available: ``` WithPrefix(p ...string) WithStrippedPrefix(p ...string) ``` The former will preserve the prefix and make it a top level key in the config. The latter eliminates the prefix, reducing the nesting by one. #### Example: Given ENVs of: ``` APP_DATABASE_ADDRESS=127.0.0.1 APP_DATABASE_PORT=3306 VAULT_ADDR=vault:1337 ``` and a source initialized as follows: ``` src := env.NewSource( env.WithPrefix("VAULT"), env.WithStrippedPrefix("APP"), ) ``` The resulting config will be: ``` { "database": { "address": "127.0.0.1", "port": 3306 }, "vault": { "addr": "vault:1337" } } ``` ## New Source Specify source with data ```go src := env.NewSource( // optionally specify prefix env.WithPrefix("MICRO"), ) ``` ## Load Source Load the source into config ```go // Create new config conf := config.NewConfig() // Load env source conf.Load(src) ```