added support for config by environment variable, resolved #3

Dockerfile

@@ -22,15 +22,13 @@ LABEL BUILD=${buildnum}
 
 WORKDIR /home
 COPY --from=builder /home/thing-directory .
-COPY sample_conf/thing-directory.json /conf/
-COPY wot/wot_td_schema.json /conf/
+COPY sample_conf/thing-directory.json /home/conf/
+COPY wot/wot_td_schema.json /home/conf/
 
-ENV SC_DNSSDENABLED=false
-ENV SC_STORAGE_TYPE=leveldb
-ENV SC_STORAGE_DSN=/data
+ENV TD_STORAGE_DSN=/data
 
-VOLUME /conf /data
+VOLUME /data
 EXPOSE 8081
 
 ENTRYPOINT ["./thing-directory"]
-CMD ["--conf", "/conf/thing-directory.json", "--schema", "/conf/wot_td_schema.json"]
+# Note: this loads the default config files from /home/conf/. Use --help to to learn about CLI arguments.

config.go

@@ -9,6 +9,7 @@ import (
 	"io/ioutil"
 	"net/url"
 
+	"github.com/kelseyhightower/envconfig"
 	"github.com/linksmart/go-sec/authz"
 )
 
@@ -19,22 +20,23 @@ const (
 )
 
 type Config struct {
-	ServiceID      string          `json:"serviceID"`
-	Description    string          `json:"description"`
-	PublicEndpoint string          `json:"publicEndpoint"`
-	BindAddr       string          `json:"bindAddr"`
-	BindPort       int             `json:"bindPort"`
-	DnssdEnabled   bool            `json:"dnssdEnabled"`
-	Storage        StorageConfig   `json:"storage"`
-	ServiceCatalog *ServiceCatalog `json:"serviceCatalog"`
-	Auth           ValidatorConf   `json:"auth"`
+	ServiceID      string         `json:"serviceID"`
+	Description    string         `json:"description"`
+	PublicEndpoint string         `json:"publicEndpoint"`
+	BindAddr       string         `json:"bindAddr"`
+	BindPort       int            `json:"bindPort"`
+	DnssdEnabled   bool           `json:"dnssdEnabled"`
+	Storage        StorageConfig  `json:"storage"`
+	ServiceCatalog ServiceCatalog `json:"serviceCatalog"`
+	Auth           ValidatorConf  `json:"auth"`
 }
 
 type ServiceCatalog struct {
-	Discover bool          `json:"discover"`
-	Endpoint string        `json:"endpoint"`
-	Ttl      int           `json:"ttl"`
-	Auth     *ObtainerConf `json:"auth"`
+	Enabled  bool         `json:"enabled"`
+	Discover bool         `json:"discover"`
+	Endpoint string       `json:"endpoint"`
+	Ttl      int          `json:"ttl"`
+	Auth     ObtainerConf `json:"auth"`
 }
 
 type StorageConfig struct {
@@ -64,14 +66,14 @@ func (c *Config) Validate() error {
 		err = fmt.Errorf("Unsupported storage backend")
 	}
 
-	if c.ServiceCatalog != nil {
+	if c.ServiceCatalog.Enabled {
 		if c.ServiceCatalog.Endpoint == "" && c.ServiceCatalog.Discover == false {
 			err = fmt.Errorf("All ServiceCatalog entries must have either endpoint or a discovery flag defined")
 		}
 		if c.ServiceCatalog.Ttl <= 0 {
 			err = fmt.Errorf("All ServiceCatalog entries must have TTL >= 0")
 		}
-		if c.ServiceCatalog.Auth != nil {
+		if c.ServiceCatalog.Auth.Enabled {
 			// Validate ticket obtainer config
 			err = c.ServiceCatalog.Auth.Validate()
 			if err != nil {
@@ -97,16 +99,22 @@ func loadConfig(path string) (*Config, error) {
 		return nil, err
 	}
 
-	c := new(Config)
-	err = json.Unmarshal(file, c)
+	var config Config
+	err = json.Unmarshal(file, &config)
 	if err != nil {
 		return nil, err
 	}
 
-	if err = c.Validate(); err != nil {
+	// Override loaded values with environment variables
+	err = envconfig.Process("td", &config)
+	if err != nil {
+		return nil, err
+	}
+
+	if err = config.Validate(); err != nil {
 		return nil, err
 	}
-	return c, nil
+	return &config, nil
 }
 
 // Ticket Validator Config
@@ -158,6 +166,8 @@ func (c ValidatorConf) Validate() error {
 
 // Ticket Obtainer Client Config
 type ObtainerConf struct {
+	// Auth switch
+	Enabled bool `json:"enabled"`
 	// Authentication provider name
 	Provider string `json:"provider"`
 	// Authentication provider URL

go.mod

@@ -8,6 +8,7 @@ require (
 	github.com/gorilla/context v1.1.1
 	github.com/gorilla/mux v1.7.3
 	github.com/justinas/alice v0.0.0-20160512134231-052b8b6c18ed
+	github.com/kelseyhightower/envconfig v1.4.0
 	github.com/linksmart/go-sec v1.0.1
 	github.com/linksmart/service-catalog/v3 v3.0.0-beta.1.0.20200302143206-92739dd2a511
 	github.com/oleksandr/bonjour v0.0.0-20160508152359-5dcf00d8b228

go.sum

@@ -30,6 +30,8 @@ github.com/justinas/alice v0.0.0-20160512134231-052b8b6c18ed h1:Ab4XhecWusSSeIfQ
 github.com/justinas/alice v0.0.0-20160512134231-052b8b6c18ed/go.mod h1:oLH0CmIaxCGXD67VKGR5AacGXZSMznlmeqM8RzPrcY8=
 github.com/kelseyhightower/envconfig v1.3.0 h1:IvRS4f2VcIQy6j4ORGIf9145T/AsUB+oY8LyvN8BXNM=
 github.com/kelseyhightower/envconfig v1.3.0/go.mod h1:cccZRl6mQpaq41TPp5QxidR+Sa3axMbJDNb//FQX6Gg=
+github.com/kelseyhightower/envconfig v1.4.0 h1:Im6hONhd3pLkfDFsbRgu68RDNkGF1r3dvMUtDTo2cv8=
+github.com/kelseyhightower/envconfig v1.4.0/go.mod h1:cccZRl6mQpaq41TPp5QxidR+Sa3axMbJDNb//FQX6Gg=
 github.com/linksmart/go-sec v1.0.1 h1:UNeRj81/KHCy4hkFcZn7x5N/nM+uNxe+xsLBQzNF7kg=
 github.com/linksmart/go-sec v1.0.1/go.mod h1:bTksBzP6fCEwIM43z8m3jSRa4YIAWdUwMBYjcoftm1c=
 github.com/linksmart/service-catalog/v3 v3.0.0-beta.1.0.20200302143206-92739dd2a511 h1:JNHuaKtZUDsgbGJ5bdFBZ4vIUlJB7EBvjLdSaNOFatQ=

main.go

@@ -126,7 +126,7 @@ func main() {
 	}
 
 	// Register in the LinkSmart Service Catalog
-	if config.ServiceCatalog != nil {
+	if config.ServiceCatalog.Enabled {
 		unregisterService, err := registerInServiceCatalog(config)
 		if err != nil {
 			panic("Error registering service:" + err.Error())

registration.go

@@ -41,7 +41,7 @@ func registerInServiceCatalog(conf *Config) (func() error, error) {
 
 	var ticket *obtainer.Client
 	var err error
-	if cat.Auth != nil {
+	if cat.Auth.Enabled {
 		// Setup ticket client
 		ticket, err = obtainer.NewClient(cat.Auth.Provider, cat.Auth.ProviderURL, cat.Auth.Username, cat.Auth.Password, cat.Auth.ServiceID)
 		if err != nil {

sample_conf/thing-directory.json

@@ -6,7 +6,7 @@
   "bindPort": 8081,
   "storage": {
     "type": "leveldb",
-    "dsn": "/data"
+    "dsn": "./data"
   },
   "serviceCatalog": null,
   "auth": {