Support configuration files (#462)

* Support configuration files

Signed-off-by: Pavol Loffay <ploffay@redhat.com>

* Fix review comments

Signed-off-by: Pavol Loffay <ploffay@redhat.com>

* rename to AddConfigFileFlag

Signed-off-by: Pavol Loffay <ploffay@redhat.com>

* Add config file name to logs

Signed-off-by: Pavol Loffay <ploffay@redhat.com>

Author: pavolloffay

cmd/agent/main.go

@@ -23,6 +23,7 @@ import (
 	"go.uber.org/zap"
 
 	"github.com/uber/jaeger/cmd/agent/app"
+	"github.com/uber/jaeger/cmd/flags"
 	"github.com/uber/jaeger/pkg/config"
 	"github.com/uber/jaeger/pkg/metrics"
 )
@@ -35,6 +36,8 @@ func main() {
 		Short: "Jaeger agent is a local daemon program which collects tracing data.",
 		Long:  `Jaeger agent is a daemon program that runs on every host and receives tracing data submitted by Jaeger client libraries.`,
 		RunE: func(cmd *cobra.Command, args []string) error {
+			flags.TryLoadConfigFile(v, logger)
+
 			builder := &app.Builder{}
 			builder.InitFromViper(v)
 			runtime.GOMAXPROCS(runtime.NumCPU())
@@ -58,6 +61,7 @@ func main() {
 	config.AddFlags(
 		v,
 		command,
+		flags.AddConfigFileFlag,
 		app.AddFlags,
 		metrics.AddFlags,
 	)

cmd/collector/main.go

@@ -61,13 +61,15 @@ func main() {
 		Long: `Jaeger collector receives traces from Jaeger agents and agent and runs them through
 				a processing pipeline.`,
 		Run: func(cmd *cobra.Command, args []string) {
+			flags.TryLoadConfigFile(v, logger)
+
+			sFlags := new(flags.SharedFlags).InitFromViper(v)
 			casOptions.InitFromViper(v)
 			esOptions.InitFromViper(v)
 
 			baseMetrics := xkit.Wrap(serviceName, expvar.NewFactory(10))
 
 			builderOpts := new(builder.CollectorOptions).InitFromViper(v)
-			sFlags := new(flags.SharedFlags).InitFromViper(v)
 
 			hc, err := healthcheck.Serve(http.StatusServiceUnavailable, builderOpts.CollectorHealthCheckHTTPPort, logger)
 			if err != nil {
@@ -130,6 +132,7 @@ func main() {
 	config.AddFlags(
 		v,
 		command,
+		flags.AddConfigFileFlag,
 		flags.AddFlags,
 		builder.AddFlags,
 		casOptions.AddFlags,

cmd/flags/flags.go

@@ -22,6 +22,7 @@ import (
 	"time"
 
 	"github.com/spf13/viper"
+	"go.uber.org/zap"
 )
 
 const (
@@ -34,8 +35,25 @@ const (
 	spanStorageType                = "span-storage.type"
 	logLevel                       = "log-level"
 	dependencyStorageDataFrequency = "dependency-storage.data-frequency"
+	configFile                     = "config-file"
 )
 
+// AddConfigFileFlag adds flags for ExternalConfFlags
+func AddConfigFileFlag(flagSet *flag.FlagSet) {
+	flagSet.String(configFile, "", "Configuration file in JSON, TOML, YAML, HCL, or Java properties formats (default none). See spf13/viper for precedence.")
+}
+
+// TryLoadConfigFile initializes viper with config file specified as flag
+func TryLoadConfigFile(v *viper.Viper, logger *zap.Logger) {
+	if file := v.GetString(configFile); file != "" {
+		v.SetConfigFile(file)
+		err := v.ReadInConfig()
+		if err != nil {
+			logger.Fatal("Error loading config file", zap.Error(err), zap.String(configFile, file))
+		}
+	}
+}
+
 // SharedFlags holds flags configuration
 type SharedFlags struct {
 	// SpanStorage defines common settings for Span Storage.

cmd/query/main.go

@@ -54,10 +54,12 @@ func main() {
 		Short: "Jaeger query is a service to access tracing data",
 		Long:  `Jaeger query is a service to access tracing data and host UI.`,
 		Run: func(cmd *cobra.Command, args []string) {
+			flags.TryLoadConfigFile(v, logger)
+
+			sFlags := new(flags.SharedFlags).InitFromViper(v)
 			casOptions.InitFromViper(v)
 			esOptions.InitFromViper(v)
 			queryOpts := new(builder.QueryOptions).InitFromViper(v)
-			sFlags := new(flags.SharedFlags).InitFromViper(v)
 
 			hc, err := healthcheck.Serve(http.StatusServiceUnavailable, queryOpts.QueryHealthCheckHTTPPort, logger)
 			if err != nil {
@@ -123,6 +125,7 @@ func main() {
 	config.AddFlags(
 		v,
 		command,
+		flags.AddConfigFileFlag,
 		flags.AddFlags,
 		casOptions.AddFlags,
 		esOptions.AddFlags,

cmd/standalone/main.go

@@ -59,10 +59,11 @@ func main() {
 		Long: `Jaeger all-in-one distribution with agent, collector and query. Use with caution this version
 		 uses only in-memory database.`,
 		RunE: func(cmd *cobra.Command, args []string) error {
-			runtime.GOMAXPROCS(runtime.NumCPU())
+			flags.TryLoadConfigFile(v, logger)
 
-			cOpts := new(collector.CollectorOptions).InitFromViper(v)
+			runtime.GOMAXPROCS(runtime.NumCPU())
 			sFlags := new(flags.SharedFlags).InitFromViper(v)
+			cOpts := new(collector.CollectorOptions).InitFromViper(v)
 			qOpts := new(query.QueryOptions).InitFromViper(v)
 
 			metricsFactory := xkit.Wrap("jaeger-standalone", expvar.NewFactory(10))
@@ -80,6 +81,7 @@ func main() {
 	config.AddFlags(
 		v,
 		command,
+		flags.AddConfigFileFlag,
 		flags.AddFlags,
 		collector.AddFlags,
 		query.AddFlags,