config.go

package main

import (
	"flag"
	"os"
	"strconv"
	"time"
)

const (
	defaultAuthenticationTokenRenewalInterval = 6 * time.Hour
	defaultAWSCredentialsSecretPrefix         = "eatr-aws-credentials"
	defaultHostNamespace                      = "ci-cd"
	defaultInformersResyncInterval            = 5 * time.Minute
	defaultLoggingVerbosityLevel              = 0
	defaultPort                               = 5000
	defaultShutdownGracePeriod                = 3 * time.Second
)

type config struct {
	AuthenticationTokenRenewalInterval time.Duration
	AWSCredentialsSecretPrefix         string
	HostNamespace                      string
	InformersResyncInterval            time.Duration
	KubeConfigFilePath                 string
	LoggingVerbosityLevel              int
	Port                               int
	ShutdownGracePeriod                time.Duration
}

func getConfig(args []string) (config, error) {
	config := getDefaultConfig()

	// Using an explicit flagset so we do not mix the glog flags via the client-go package
	fs := flag.NewFlagSet(args[0], flag.ExitOnError)
	fs.DurationVar(&config.AuthenticationTokenRenewalInterval, "auth-token-renewal-interval", config.AuthenticationTokenRenewalInterval, "Authentication token renewal interval - ECR tokens expire after 12 hours so should be less")
	fs.StringVar(&config.AWSCredentialsSecretPrefix, "aws-credentials-secret-prefix", config.AWSCredentialsSecretPrefix, "AWS credentials secret prefix - Prefix for host namespace AWS credentials secret names, these secrets will be used to store the AWS credentials used to connect to create ECR auth tokens needed for image pulling, will take the form [Prefix]-[ECRDNS]")
	fs.StringVar(&config.HostNamespace, "host-namespace", config.HostNamespace, "Host namespace")
	fs.DurationVar(&config.InformersResyncInterval, "informers-resync-interval", config.InformersResyncInterval, "Shared informers resync interval")
	fs.StringVar(&config.KubeConfigFilePath, "config-file-path", config.KubeConfigFilePath, "Kube config file path, optional, only used for testing outside the cluster, can also set the KUBECONFIG env var")
	fs.IntVar(&config.LoggingVerbosityLevel, "logging-verbosity-level", config.LoggingVerbosityLevel, "Logging verbosity level, can set to 6 or higher to get debug level logs, will also see client-go logs")
	fs.IntVar(&config.Port, "port", config.Port, "Port to surface diagnostics on")
	fs.DurationVar(&config.ShutdownGracePeriod, "shutdown-grace-period", config.ShutdownGracePeriod, "Shutdown grace period")
	if err := fs.Parse(args[1:]); err != nil {
		return config, err
	}

	// Limited glog config
	// See https://stackoverflow.com/questions/28207226/how-do-i-set-the-log-directory-of-glog-from-cod://stackoverflow.com/questions/28207226/how-do-i-set-the-log-directory-of-glog-from-code
	// Simulate global flags so we can configure some of the glog flags
	// Need to add global flags as the default is to exit on error - i.e. Unknown flags which is how our flags above will be seen
	fs.VisitAll(func(f *flag.Flag) { _ = flag.String((*f).Name, "", "") })
	flag.Lookup("logtostderr").Value.Set("true")
	flag.Lookup("v").Value.Set(strconv.Itoa(config.LoggingVerbosityLevel))
	flag.Parse()

	return config, nil
}

func getDefaultConfig() config {
	return config{
		AuthenticationTokenRenewalInterval: defaultAuthenticationTokenRenewalInterval,
		AWSCredentialsSecretPrefix:         defaultAWSCredentialsSecretPrefix,
		HostNamespace:                      defaultHostNamespace,
		InformersResyncInterval:            defaultInformersResyncInterval,
		KubeConfigFilePath:                 os.Getenv("KUBECONFIG"),
		LoggingVerbosityLevel:              defaultLoggingVerbosityLevel,
		Port:                defaultPort,
		ShutdownGracePeriod: defaultShutdownGracePeriod,
	}
}