Override config with enviroment variable parameters root-gg#337

README.md

@@ -55,7 +55,7 @@ apt-get update
 apt-get install plikd plik
 ```
 
-Edit server configuration at /etc/plikd.cfg and start the server 
+Edit server configuration at /etc/plikd.cfg and start the server
 ```
 service plikd start
 ```
@@ -376,4 +376,18 @@ See : https://github.com/golang/go/wiki/GoArm
     server/plikd: ELF 32-bit LSB executable, ARM, EABI5 version 1 (GNU/Linux), statically linked, for GNU/Linux 3.2.0, Go ...
 
     Then either copy the binary from the docker or play with releaser/releaser.sh to generate a release archive
+```
+
+* Defining configuration parameters using environment variables
+
+One can specify configuration parameters using env variable with the configuration parameter in screaming snake case  
+```
+    PLIKD_DEBUG_REQUESTS=true ./plikd
+```
+
+For Arrays and config maps they must be provided in json format.
+Arrays are overriden but maps are merged
+
+```
+    PLIKD_DATA_BACKEND_CONFIG='{"Directory":"/var/files"}' ./plikd
 ```

go.mod

@@ -16,7 +16,7 @@ require (
 	github.com/google/uuid v1.1.2 // indirect
 	github.com/gorilla/mux v1.7.1
 	github.com/hashicorp/golang-lru v0.5.1 // indirect
-	github.com/iancoleman/strcase v0.0.0-20191112232945-16388991a334 // indirect
+	github.com/iancoleman/strcase v0.1.2
 	github.com/jinzhu/copier v0.0.0-20190924061706-b57f9002281a
 	github.com/jinzhu/gorm v1.9.13-0.20200126152832-7180bd0f27d1
 	github.com/kardianos/osext v0.0.0-20190222173326-2bc1f35cddc0
@@ -31,7 +31,7 @@ require (
 	github.com/olekukonko/ts v0.0.0-20171002115256-78ecb04241c0
 	github.com/pilagod/gorm-cursor-paginator v1.2.0
 	github.com/root-gg/logger v0.0.0-20150501173826-5d9a47a35312
-	github.com/root-gg/utils v0.0.0-20151025161626-38f45ede2ce2
+	github.com/root-gg/utils v0.0.0-20201113182430-4cef83d8cdcf
 	github.com/spf13/cobra v0.0.6-0.20200106181057-89c7ffb5129b
 	github.com/spf13/pflag v1.0.5 // indirect
 	github.com/stretchr/testify v1.4.0

go.sum

@@ -104,8 +104,8 @@ github.com/hashicorp/golang-lru v0.5.1/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ
 github.com/hashicorp/hcl v1.0.0/go.mod h1:E5yfLk+7swimpb2L/Alb/PJmXilQ/rhwaUYs4T20WEQ=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/iancoleman/strcase v0.0.0-20180726023541-3605ed457bf7/go.mod h1:SK73tn/9oHe+/Y0h39VT4UCxmurVJkR5NA7kMEAOgSE=
-github.com/iancoleman/strcase v0.0.0-20191112232945-16388991a334 h1:VHgatEHNcBFEB7inlalqfNqw65aNkM1lGX2yt3NmbS8=
-github.com/iancoleman/strcase v0.0.0-20191112232945-16388991a334/go.mod h1:SK73tn/9oHe+/Y0h39VT4UCxmurVJkR5NA7kMEAOgSE=
+github.com/iancoleman/strcase v0.1.2 h1:gnomlvw9tnV3ITTAxzKSgTF+8kFWcU/f+TgttpXGz1U=
+github.com/iancoleman/strcase v0.1.2/go.mod h1:SK73tn/9oHe+/Y0h39VT4UCxmurVJkR5NA7kMEAOgSE=
 github.com/inconshreveable/mousetrap v1.0.0 h1:Z8tu5sraLXCXIcARxBp/8cbvlwVa7Z1NHg9XEKhtSvM=
 github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANytuPF1OarO4DADm73n8=
 github.com/jinzhu/copier v0.0.0-20190924061706-b57f9002281a h1:zPPuIq2jAWWPTrGt70eK/BSch+gFAGrNzecsoENgu2o=
@@ -216,6 +216,8 @@ github.com/root-gg/logger v0.0.0-20150501173826-5d9a47a35312 h1:gLYLMWhdoU02+VLb
 github.com/root-gg/logger v0.0.0-20150501173826-5d9a47a35312/go.mod h1:SZ5sf0POVtIvp+vNCGYwJp1/ZT6/nShOau6aVMGgtGU=
 github.com/root-gg/utils v0.0.0-20151025161626-38f45ede2ce2 h1:2IC5+HunAKLL0GxcXtqbsQxEOmDcFTf8gn34mxpTs20=
 github.com/root-gg/utils v0.0.0-20151025161626-38f45ede2ce2/go.mod h1:XF39UJcqum+uYclrw+wB0V1qg9vgglJ8gz8AMrVJ/AQ=
+github.com/root-gg/utils v0.0.0-20201113182430-4cef83d8cdcf h1:Qx8jlCUW4X3+W+k14GCr33IBh/jYt+kaV/AzZWrl4vk=
+github.com/root-gg/utils v0.0.0-20201113182430-4cef83d8cdcf/go.mod h1:XF39UJcqum+uYclrw+wB0V1qg9vgglJ8gz8AMrVJ/AQ=
 github.com/rs/xid v1.2.1 h1:mhH9Nq+C1fY2l1XIpgxIiUOfNpRBYH1kKcr+qfKgjRc=
 github.com/rs/xid v1.2.1/go.mod h1:+uKXf+4Djp6Md1KODXJxgGQPKngRmWyn10oCKFzNHOQ=
 github.com/russross/blackfriday/v2 v2.0.1/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=

server/cmd/root.go

@@ -94,13 +94,9 @@ func initConfig() {
 		}
 	}
 
-	if configPath != "" {
-		config, err = common.LoadConfiguration(configPath)
-		if err != nil {
-			fmt.Printf("Unable to read config file : %s\n", err)
-		}
-	} else {
-		config = common.NewConfiguration()
+	config, err = common.LoadConfiguration(configPath)
+	if err != nil {
+		fmt.Printf("Unable to load config : %s\n", err)
 	}
 }
 

server/common/config.go

@@ -4,15 +4,21 @@ import (
 	"fmt"
 	"net"
 	"net/url"
+	"os"
 	"strings"
 	"time"
 
+	"github.com/root-gg/utils"
+
 	"github.com/BurntSushi/toml"
 	"github.com/dustin/go-humanize"
+	"github.com/iancoleman/strcase"
 
 	"github.com/root-gg/logger"
 )
 
+const envPrefix = "PLIKD_"
+
 // Configuration object
 type Configuration struct {
 	Debug         bool   `json:"-"`
@@ -96,11 +102,18 @@ func NewConfiguration() (config *Configuration) {
 // LoadConfiguration creates a new empty configuration
 // and try to load specified file with toml library to
 // override default params
-func LoadConfiguration(file string) (config *Configuration, err error) {
+func LoadConfiguration(path string) (config *Configuration, err error) {
 	config = NewConfiguration()
 
-	if _, err := toml.DecodeFile(file, config); err != nil {
-		return nil, fmt.Errorf("unable to load config file %s : %s", file, err)
+	if path != "" {
+		if _, err := toml.DecodeFile(path, config); err != nil {
+			return nil, fmt.Errorf("unable to load config file %s : %s", path, err)
+		}
+	}
+
+	err = config.EnvironmentOverride()
+	if err != nil {
+		return nil, err
 	}
 
 	err = config.Initialize()
@@ -111,6 +124,15 @@ func LoadConfiguration(file string) (config *Configuration, err error) {
 	return config, nil
 }
 
+// EnvironmentOverride override config from environment variables
+// Environment variables must match config params in screaming snake case ( DebugRequests -> PLIKD_DEBUG_REQUESTS )
+func (config *Configuration) EnvironmentOverride() (err error) {
+	getEnvOverride := func(fieldName string) (string, bool) {
+		return os.LookupEnv(envPrefix + strcase.ToScreamingSnake(fieldName))
+	}
+	return utils.AssignStrings(config, getEnvOverride)
+}
+
 // Initialize config internal parameters
 func (config *Configuration) Initialize() (err error) {
 

server/common/config_test.go

@@ -2,11 +2,20 @@ package common
 
 import (
 	"net"
+	"os"
 	"testing"
 
+	"github.com/iancoleman/strcase"
+
 	"github.com/stretchr/testify/require"
 )
 
+func TestToScreamingSnakeCase(t *testing.T) {
+	require.Equal(t, "DEBUG_REQUESTS", strcase.ToScreamingSnake("DebugRequests"))
+	require.Equal(t, "DEFAULT_TTL", strcase.ToScreamingSnake("DefaultTTL"))
+	require.Equal(t, "GOOGLE_API_CLIENT_ID", strcase.ToScreamingSnake("GoogleAPIClientID"))
+}
+
 // Test new configuration
 func TestNewConfig(t *testing.T) {
 	config := NewConfiguration()
@@ -116,3 +125,38 @@ func TestString(t *testing.T) {
 	config := NewConfiguration()
 	require.NotEmpty(t, config.String())
 }
+
+func TestConfiguration_EnvironmentOverride(t *testing.T) {
+	defer func() {
+		_ = os.Unsetenv(envPrefix + "DEBUG")
+		_ = os.Unsetenv(envPrefix + "LISTEN_ADDRESS")
+		_ = os.Unsetenv(envPrefix + "MAX_FILE_SIZE")
+		_ = os.Unsetenv(envPrefix + "UPLOAD_WHITELIST")
+		_ = os.Unsetenv(envPrefix + "METADATA_BACKEND_CONFIG")
+	}()
+
+	err := os.Setenv(envPrefix+"DEBUG", "true")
+	require.NoError(t, err)
+
+	err = os.Setenv(envPrefix+"LISTEN_ADDRESS", "1.2.3.4")
+	require.NoError(t, err)
+
+	err = os.Setenv(envPrefix+"MAX_FILE_SIZE", "42")
+	require.NoError(t, err)
+
+	err = os.Setenv(envPrefix+"UPLOAD_WHITELIST", "[\"127.0.0.1\"]")
+	require.NoError(t, err)
+
+	err = os.Setenv(envPrefix+"METADATA_BACKEND_CONFIG", "{\"path\": \"files\"}")
+	require.NoError(t, err)
+
+	config := NewConfiguration()
+	err = config.EnvironmentOverride()
+	require.NoError(t, err)
+
+	require.True(t, config.Debug)
+	require.Equal(t, "1.2.3.4", config.ListenAddress)
+	require.Equal(t, int64(42), config.MaxFileSize)
+	require.EqualValues(t, []string{"127.0.0.1"}, config.UploadWhitelist)
+	require.EqualValues(t, map[string]interface{}{"path": "files"}, config.MetadataBackendConfig)
+}