Refactor cmd/collector package (#337)

* Refactor collector cmd codebase

The cmd codebase was getting cluttered, and this aims to simplify and
restructure how collector startup occurred.

Testing Done: no functionality changed, tested manually.

* Add license to all new files

Author: Steven Karis

cmd/occollector/app/builder/builder.go

@@ -15,6 +15,7 @@
 package builder
 
 import (
+	"flag"
 	"fmt"
 	"strings"
 
@@ -26,8 +27,37 @@ const (
 	jaegerEntry     = "jaeger"
 	opencensusEntry = "opencensus"
 	zipkinEntry     = "zipkin"
+
+	// flags
+	configCfg         = "config"
+	jaegerReceiverFlg = "receive-jaeger"
+	ocReceiverFlg     = "receive-oc-trace"
+	zipkinReceiverFlg = "receive-zipkin"
+	debugProcessorFlg = "debug-processor"
 )
 
+// Flags adds flags related to basic building of the collector application to the given flagset.
+func Flags(flags *flag.FlagSet) {
+	flags.String(configCfg, "", "Path to the config file")
+	flags.Bool(jaegerReceiverFlg, false,
+		fmt.Sprintf("Flag to run the Jaeger receiver (i.e.: Jaeger Collector), default settings: %+v", *NewDefaultJaegerReceiverCfg()))
+	flags.Bool(ocReceiverFlg, true,
+		fmt.Sprintf("Flag to run the OpenCensus trace receiver, default settings: %+v", *NewDefaultOpenCensusReceiverCfg()))
+	flags.Bool(zipkinReceiverFlg, false,
+		fmt.Sprintf("Flag to run the Zipkin receiver, default settings: %+v", *NewDefaultZipkinReceiverCfg()))
+	flags.Bool(debugProcessorFlg, false, "Flag to add a debug processor (combine with log level DEBUG to log incoming spans)")
+}
+
+// GetConfigFile gets the config file from the config file flag.
+func GetConfigFile(v *viper.Viper) string {
+	return v.GetString(configCfg)
+}
+
+// DebugProcessorEnabled returns true if the debug processor is enabled, and false otherwise
+func DebugProcessorEnabled(v *viper.Viper) bool {
+	return v.GetBool(debugProcessorFlg)
+}
+
 // JaegerReceiverCfg holds configuration for Jaeger receivers.
 type JaegerReceiverCfg struct {
 	// ThriftTChannelPort is the port that the relay receives on for jaeger thrift tchannel requests
@@ -38,8 +68,8 @@ type JaegerReceiverCfg struct {
 
 // JaegerReceiverEnabled checks if the Jaeger receiver is enabled, via a command-line flag, environment
 // variable, or configuration file.
-func JaegerReceiverEnabled(v *viper.Viper, cmdFlag string) bool {
-	return featureEnabled(v, cmdFlag, receiversRoot, jaegerEntry)
+func JaegerReceiverEnabled(v *viper.Viper) bool {
+	return featureEnabled(v, jaegerReceiverFlg, receiversRoot, jaegerEntry)
 }
 
 // NewDefaultJaegerReceiverCfg returns an instance of JaegerReceiverCfg with default values
@@ -64,8 +94,8 @@ type OpenCensusReceiverCfg struct {
 
 // OpenCensusReceiverEnabled checks if the OpenCensus receiver is enabled, via a command-line flag, environment
 // variable, or configuration file.
-func OpenCensusReceiverEnabled(v *viper.Viper, cmdFlag string) bool {
-	return featureEnabled(v, cmdFlag, receiversRoot, opencensusEntry)
+func OpenCensusReceiverEnabled(v *viper.Viper) bool {
+	return featureEnabled(v, ocReceiverFlg, receiversRoot, opencensusEntry)
 }
 
 // NewDefaultOpenCensusReceiverCfg returns an instance of OpenCensusReceiverCfg with default values
@@ -89,8 +119,8 @@ type ZipkinReceiverCfg struct {
 
 // ZipkinReceiverEnabled checks if the Zipkin receiver is enabled, via a command-line flag, environment
 // variable, or configuration file.
-func ZipkinReceiverEnabled(v *viper.Viper, cmdFlag string) bool {
-	return featureEnabled(v, cmdFlag, receiversRoot, zipkinEntry)
+func ZipkinReceiverEnabled(v *viper.Viper) bool {
+	return featureEnabled(v, zipkinReceiverFlg, receiversRoot, zipkinEntry)
 }
 
 // NewDefaultZipkinReceiverCfg returns an instance of ZipkinReceiverCfg with default values

cmd/occollector/app/builder/builder_test.go

@@ -28,7 +28,7 @@ func TestReceiversEnabledByPresenceWithDefaultSettings(t *testing.T) {
 		t.Fatalf("Failed to load viper from test file: %v", err)
 	}
 
-	jaegerEnabled, opencensusEnabled, zipkinEnabled := JaegerReceiverEnabled(v, "j"), OpenCensusReceiverEnabled(v, "oc"), ZipkinReceiverEnabled(v, "z")
+	jaegerEnabled, opencensusEnabled, zipkinEnabled := JaegerReceiverEnabled(v), OpenCensusReceiverEnabled(v), ZipkinReceiverEnabled(v)
 	if !jaegerEnabled || !opencensusEnabled || !zipkinEnabled {
 		t.Fatalf("Some of the expected receivers were not enabled j:%v oc:%v z:%v", jaegerEnabled, opencensusEnabled, zipkinEnabled)
 	}
@@ -64,7 +64,7 @@ func TestReceiversDisabledByPresenceWithDefaultSettings(t *testing.T) {
 		t.Fatalf("Failed to load viper from test file: %v", err)
 	}
 
-	jaegerEnabled, opencensusEnabled, zipkinEnabled := JaegerReceiverEnabled(v, "j"), OpenCensusReceiverEnabled(v, "oc"), ZipkinReceiverEnabled(v, "z")
+	jaegerEnabled, opencensusEnabled, zipkinEnabled := JaegerReceiverEnabled(v), OpenCensusReceiverEnabled(v), ZipkinReceiverEnabled(v)
 	if jaegerEnabled || opencensusEnabled || zipkinEnabled {
 		t.Fatalf("Not all receivers were disabled j:%v oc:%v z:%v", jaegerEnabled, opencensusEnabled, zipkinEnabled)
 	}