diff --git a/README.md b/README.md index 9f236b2..690228c 100644 --- a/README.md +++ b/README.md @@ -98,12 +98,13 @@ Aliases permit a single value to be referenced by multiple keys ### Working with Environment Variables Viper has full support for environment variables. This enables 12 factor -applications out of the box. There are three methods that exist to aid +applications out of the box. There are four methods that exist to aid with working with ENV: * AutomaticEnv() * BindEnv(string...) : error * SetEnvPrefix(string) + * SetEnvReplacer(string...) *strings.Replacer _When working with ENV variables it’s important to recognize that Viper treats ENV variables as case sensitive._ @@ -131,6 +132,11 @@ any time a viper.Get request is made. It will apply the following rules. It will check for a environment variable with a name matching the key uppercased and prefixed with the EnvPrefix if set. +SetEnvReplacer allows you to use a `strings.Replacer` object to rewrite Env keys +to an extent. This is useful if you want to use `-` or something in your Get() +calls, but want your environmental variables to use `_` delimiters. An example +of using it can be found in `viper_test.go` + #### Env example SetEnvPrefix("spf") // will be uppercased automatically diff --git a/viper.go b/viper.go index e808887..2d51b9b 100644 --- a/viper.go +++ b/viper.go @@ -77,6 +77,7 @@ type viper struct { envPrefix string automaticEnvApplied bool + envKeyReplacer *strings.Replacer config map[string]interface{} override map[string]interface{} @@ -153,6 +154,20 @@ func (v *viper) mergeWithEnvPrefix(in string) string { return strings.ToUpper(in) } +// TODO: should getEnv logic be moved into find(). Can generalize the use of +// rewriting keys many things, Ex: Get('someKey') -> some_key +// (cammel case to snake case for JSON keys perhaps) + +// getEnv s a wrapper around os.Getenv which replaces characters in the original +// key. This allows env vars which have different keys then the config object +// keys +func (v *viper) getEnv(key string) string { + if v.envKeyReplacer != nil { + key = v.envKeyReplacer.Replace(key) + } + return os.Getenv(key) +} + // Return the config file used func ConfigFileUsed() string { return v.ConfigFileUsed() } func (v *viper) ConfigFileUsed() string { return v.configFile } @@ -427,7 +442,7 @@ func (v *viper) find(key string) interface{} { if v.automaticEnvApplied { // even if it hasn't been registered, if automaticEnv is used, // check any Get request - if val = os.Getenv(v.mergeWithEnvPrefix(key)); val != "" { + if val = v.getEnv(v.mergeWithEnvPrefix(key)); val != "" { jww.TRACE.Println(key, "found in environment with val:", val) return val } @@ -436,7 +451,7 @@ func (v *viper) find(key string) interface{} { envkey, exists := v.env[key] if exists { jww.TRACE.Println(key, "registered as env var", envkey) - if val = os.Getenv(envkey); val != "" { + if val = v.getEnv(envkey); val != "" { jww.TRACE.Println(envkey, "found in environment with val:", val) return val } else { @@ -479,6 +494,12 @@ func (v *viper) AutomaticEnv() { v.automaticEnvApplied = true } +// SetEnvKeyReplacer sets the strings.Replacer on the viper object +func SetEnvKeyReplacer(r *strings.Replacer) { v.SetEnvKeyReplacer(r) } +func (v *viper) SetEnvKeyReplacer(r *strings.Replacer) { + v.envKeyReplacer = r +} + // Aliases provide another accessor for the same key. // This enables one to change a name without breaking the application func RegisterAlias(alias string, key string) { v.RegisterAlias(alias, key) } diff --git a/viper_test.go b/viper_test.go index 2c665ec..a9ba70f 100644 --- a/viper_test.go +++ b/viper_test.go @@ -10,6 +10,7 @@ import ( "fmt" "os" "sort" + "strings" "testing" "time" @@ -221,6 +222,7 @@ func TestEnv(t *testing.T) { AutomaticEnv() assert.Equal(t, "crunk", Get("name")) + } func TestEnvPrefix(t *testing.T) { @@ -260,6 +262,18 @@ func TestAutoEnvWithPrefix(t *testing.T) { assert.Equal(t, "13", Get("bar")) } +func TestSetEnvReplacer(t *testing.T) { + Reset() + + AutomaticEnv() + os.Setenv("REFRESH_INTERVAL", "30s") + + replacer := strings.NewReplacer("-", "_") + SetEnvKeyReplacer(replacer) + + assert.Equal(t, "30s", Get("refresh-interval")) +} + func TestAllKeys(t *testing.T) { initConfigs()