Allow env expansion in config file

example.config.yaml

@@ -1,9 +1,9 @@
 redis:
-  address: 127.0.0.1:6379
+  address: ${REDIS_HOST:-127.0.0.1}:${REDIS_PORT:number:-6379}
 limits:
-  interval: 10
-  anonymous: 10
-  identified: 60
+  interval: ${LIMIT_INTERVAL:number:-10}
+  anonymous: ${LIMIT_ANONYMOUS:number:-10}
+  identified: ${LIMIT_IDENTIFIED:number:-60}
   other:
     system: 0
 identifiers:

go.mod

@@ -3,22 +3,19 @@ module github.com/airfocusio/rate-limit-proxy
 go 1.17
 
 require (
+	github.com/airfocusio/go-expandenv v0.1.0-alpha.2
 	github.com/go-redis/redis/v8 v8.11.4
 	github.com/golang-jwt/jwt/v4 v4.2.0
 	github.com/google/go-cmp v0.5.6
-	github.com/stretchr/testify v1.5.1
+	github.com/stretchr/testify v1.7.0
 	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b
 )
 
 require (
 	github.com/cespare/xxhash/v2 v2.1.2 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
-	github.com/kr/text v0.2.0 // indirect
-	github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	golang.org/x/net v0.0.0-20210520170846-37e1c6afe023 // indirect
 	golang.org/x/sys v0.0.0-20211019181941-9d821ace8654 // indirect
-	gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f // indirect
-	gopkg.in/yaml.v2 v2.4.0 // indirect
 )

go.sum

@@ -1,3 +1,5 @@
+github.com/airfocusio/go-expandenv v0.1.0-alpha.2 h1:by1LmIeCHPlVVN1gb0OoP6FnDmQGDCdtv+lGjKBHWk4=
+github.com/airfocusio/go-expandenv v0.1.0-alpha.2/go.mod h1:UB5QYHJ7klVI34hnK9G3xtveYnKUAIC94hpP9rvzl2o=
 github.com/cespare/xxhash/v2 v2.1.2 h1:YRXhKfTDauu4ajMg1TPgFO5jnlC2HCbmLXMcTG5cbYE=
 github.com/cespare/xxhash/v2 v2.1.2/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
@@ -50,8 +52,9 @@ github.com/onsi/gomega v1.16.0/go.mod h1:HnhC7FXeEQY45zxNK3PPoIUhzk/80Xly9PcubAl
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.5.1 h1:nOGnQDM7FYENwehXlg/kFVnos3rEvtKTjRvOWSzb6H4=
 github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
@@ -113,5 +116,6 @@ gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b h1:h8qDotaEPuJATrMmW04NCwg7v22aHH28wwpauUhK9Oo=
 gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

internal/proxy-config.go

@@ -3,6 +3,7 @@ package internal
 import (
 	"fmt"
 
+	"github.com/airfocusio/go-expandenv"
 	"github.com/google/go-cmp/cmp"
 	"gopkg.in/yaml.v3"
 )
@@ -38,7 +39,21 @@ type RateLimitProxyConfig struct {
 }
 
 // LoadRateLimitProxyConfig ...
-func LoadRateLimitProxyConfig(bytes []byte) (*RateLimitProxyConfig, *[]Identifier, error) {
+func LoadRateLimitProxyConfig(bytesRaw []byte) (*RateLimitProxyConfig, *[]Identifier, error) {
+	var expansionTemp interface{}
+	err := yaml.Unmarshal(bytesRaw, &expansionTemp)
+	if err != nil {
+		return nil, nil, err
+	}
+	expansionTemp, err = expandenv.ExpandEnv(expansionTemp)
+	if err != nil {
+		return nil, nil, err
+	}
+	bytes, err := yaml.Marshal(expansionTemp)
+	if err != nil {
+		return nil, nil, err
+	}
+
 	config := &RateLimitProxyConfig{}
 	if err := yaml.Unmarshal(bytes, config); err != nil {
 		return nil, nil, err