fix(server): allow passing loglevels as env vars to Server (#12145)

Signed-off-by: Anton Gilgur <agilgur5@gmail.com>

cmd/argo/commands/root.go

@@ -1,9 +1,14 @@
 package commands
 
 import (
+	"fmt"
+	"strings"
+
 	"github.com/argoproj/pkg/cli"
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
+	"github.com/spf13/pflag"
+	"github.com/spf13/viper"
 
 	"github.com/argoproj/argo-workflows/v3"
 	"github.com/argoproj/argo-workflows/v3/cmd/argo/commands/archive"
@@ -133,5 +138,23 @@ If your server is behind an ingress with a path (you'll be running "argo server
 	command.PersistentFlags().IntVar(&glogLevel, "gloglevel", 0, "Set the glog logging level")
 	command.PersistentFlags().BoolVarP(&verbose, "verbose", "v", false, "Enabled verbose logging, i.e. --loglevel debug")
 
+	// set-up env vars for the CLI such that ARGO_* env vars can be used instead of flags
+	viper.AutomaticEnv()
+	viper.SetEnvPrefix("ARGO")
+	viper.SetEnvKeyReplacer(strings.NewReplacer("-", "_", ".", "_"))
+	// bind flags to env vars (https://github.com/spf13/viper/tree/v1.17.0#working-with-flags)
+	if err := viper.BindPFlags(command.PersistentFlags()); err != nil {
+		log.Fatal(err)
+	}
+	// workaround for handling required flags (https://github.com/spf13/viper/issues/397#issuecomment-544272457)
+	command.PersistentFlags().VisitAll(func(f *pflag.Flag) {
+		if !f.Changed && viper.IsSet(f.Name) {
+			val := viper.Get(f.Name)
+			if err := command.PersistentFlags().Set(f.Name, fmt.Sprintf("%v", val)); err != nil {
+				log.Fatal(err)
+			}
+		}
+	})
+
 	return command
 }

cmd/argo/commands/server.go

@@ -237,12 +237,15 @@ See %s`, help.ArgoServer),
 	command.Flags().Float32Var(&kubeAPIQPS, "kube-api-qps", 20.0, "QPS to use while talking with kube-apiserver.")
 	command.Flags().IntVar(&kubeAPIBurst, "kube-api-burst", 30, "Burst to use while talking with kube-apiserver.")
 
+	// set-up env vars for the CLI such that ARGO_* env vars can be used instead of flags
 	viper.AutomaticEnv()
 	viper.SetEnvPrefix("ARGO")
 	viper.SetEnvKeyReplacer(strings.NewReplacer("-", "_", ".", "_"))
+	// bind flags to env vars (https://github.com/spf13/viper/tree/v1.17.0#working-with-flags)
 	if err := viper.BindPFlags(command.Flags()); err != nil {
 		log.Fatal(err)
 	}
+	// workaround for handling required flags (https://github.com/spf13/viper/issues/397#issuecomment-544272457)
 	command.Flags().VisitAll(func(f *pflag.Flag) {
 		if !f.Changed && viper.IsSet(f.Name) {
 			val := viper.Get(f.Name)

cmd/workflow-controller/main.go

@@ -189,12 +189,15 @@ func NewRootCommand() *cobra.Command {
 	command.Flags().StringVar(&managedNamespace, "managed-namespace", "", "namespace that workflow-controller watches, default to the installation namespace")
 	command.Flags().BoolVar(&executorPlugins, "executor-plugins", false, "enable executor plugins")
 
+	// set-up env vars for the CLI such that ARGO_* env vars can be used instead of flags
 	viper.AutomaticEnv()
 	viper.SetEnvPrefix("ARGO")
 	viper.SetEnvKeyReplacer(strings.NewReplacer("-", "_", ".", "_"))
+	// bind flags to env vars (https://github.com/spf13/viper/tree/v1.17.0#working-with-flags)
 	if err := viper.BindPFlags(command.Flags()); err != nil {
 		log.Fatal(err)
 	}
+	// workaround for handling required flags (https://github.com/spf13/viper/issues/397#issuecomment-544272457)
 	command.Flags().VisitAll(func(f *pflag.Flag) {
 		if !f.Changed && viper.IsSet(f.Name) {
 			val := viper.Get(f.Name)