Allow manager options to be set from environment

Signed-off-by: Vince Prignano <[email protected]>

examples/scratch-env/go.sum

@@ -1118,6 +1118,8 @@ github.com/ruudk/golang-pdf417 v0.0.0-20181029194003-1af4ab5afa58/go.mod h1:6lfF
 github.com/ruudk/golang-pdf417 v0.0.0-20201230142125-a7e3863a1245/go.mod h1:pQAZKsJ8yyVxGRWYNEm9oFB8ieLgKFnamEyDmSA0BRk=
 github.com/ryanuber/columnize v0.0.0-20160712163229-9b3edd62028f/go.mod h1:sm1tb6uqfes/u+d4ooFouqFdy9/2g9QGwK3SQygK0Ts=
 github.com/sean-/seed v0.0.0-20170313163322-e2103e2c3529/go.mod h1:DxrIzT+xaE7yg65j358z/aeFdxmN0P9QXhEzd20vsDc=
+github.com/sethvargo/go-envconfig v0.9.0 h1:Q6FQ6hVEeTECULvkJZakq3dZMeBQ3JUpcKMfPQbKMDE=
+github.com/sethvargo/go-envconfig v0.9.0/go.mod h1:Iz1Gy1Sf3T64TQlJSvee81qDhf7YIlt8GMUX6yyNFs0=
 github.com/shurcooL/sanitized_anchor_name v1.0.0/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=
 github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPxbbu5VWo=
 github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=

go.mod

@@ -14,6 +14,7 @@ require (
 	github.com/onsi/gomega v1.28.0
 	github.com/prometheus/client_golang v1.17.0
 	github.com/prometheus/client_model v0.5.0
+	github.com/sethvargo/go-envconfig v0.9.0
 	go.uber.org/goleak v1.2.1
 	go.uber.org/zap v1.26.0
 	golang.org/x/exp v0.0.0-20220722155223-a9213eeb770e

go.sum

@@ -254,6 +254,8 @@ github.com/rogpeppe/fastuuid v1.2.0/go.mod h1:jVj6XXZzXRy/MSR5jhDC/2q6DgLz+nrA6L
 github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
 github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjRBZyWFQ=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
+github.com/sethvargo/go-envconfig v0.9.0 h1:Q6FQ6hVEeTECULvkJZakq3dZMeBQ3JUpcKMfPQbKMDE=
+github.com/sethvargo/go-envconfig v0.9.0/go.mod h1:Iz1Gy1Sf3T64TQlJSvee81qDhf7YIlt8GMUX6yyNFs0=
 github.com/sirupsen/logrus v1.9.0 h1:trlNQbNUG3OdDrDil03MCb1H2o9nJ1x4/5LYw7byDE0=
 github.com/soheilhy/cmux v0.1.5 h1:jjzc5WVemNEDTLwv9tlmemhC73tI08BNOIGwBOo10Js=
 github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72/go.mod h1:JwIasOWyU6f++ZhiEuf87xNszmSA2myDM2Kzu9HwQUA=

pkg/manager/manager.go

@@ -26,6 +26,7 @@ import (
 	"time"
 
 	"github.com/go-logr/logr"
+	"github.com/sethvargo/go-envconfig"
 	coordinationv1 "k8s.io/api/coordination/v1"
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/meta"
@@ -318,6 +319,7 @@ func New(config *rest.Config, options Options) (Manager, error) {
 	}
 	// Set default values for options fields
 	options = setOptionsDefaults(options)
+	options = setOptionsFromEnv(options)
 
 	cluster, err := cluster.New(config, func(clusterOptions *cluster.Options) {
 		clusterOptions.Scheme = options.Scheme
@@ -667,3 +669,117 @@ func setOptionsDefaults(options Options) Options {
 
 	return options
 }
+
+type envOptions struct {
+	// Override determines whether or not to use environment variables to override
+	// controller global configuration options.
+	Override bool `env:"ENV_OVERRIDE"`
+
+	LeaderElection                *bool          `env:"LEADER_ELECTION_ENABLED,noinit"`
+	LeaderElectionResourceLock    *string        `env:"LEADER_ELECTION_RESOURCE_LOCK,noinit"`
+	LeaderElectionNamespace       *string        `env:"LEADER_ELECTION_NAMESPACE,noinit"`
+	LeaderElectionID              *string        `env:"LEADER_ELECTION_ID,noinit"`
+	LeaderElectionLeaseDuration   *time.Duration `env:"LEADER_ELECTION_LEASE_DURATION,noinit"`
+	LeaderElectionRenewDeadline   *time.Duration `env:"LEADER_ELECTION_RENEW_DEADLINE,noinit"`
+	LeaderElectionRetryPeriod     *time.Duration `env:"LEADER_ELECTION_RETRY_PERIOD,noinit"`
+	LeaderElectionReleaseOnCancel *bool          `env:"LEADER_ELECTION_RELEASE_ON_CANCEL,noinit`
+
+	MetricsSecureServing *bool   `env:"METRICS_SERVER_SECURE_SERVING,noinit"`
+	MetricsBindAddress   *string `env:"METRICS_SERVER_BIND_ADDRESS,noinit"`
+	MetricsCertDir       *string `env:"METRICS_SERVER_CERT_DIR,noinit"`
+
+	HealthProbeBindAddress *string `env:"HEALTH_PROBE_BIND_ADDRESS,noinit"`
+	PprofBindAddress       *string `env:"PPROF_BIND_ADDRESS,noinit"`
+
+	WebhookPort    *int    `env:"WEBHOOK_SERVER_PORT,noinit"`
+	WebhookHost    *string `env:"WEBHOOK_SERVER_HOST,noinit"`
+	WebhookCertDir *string `env:"WEBHOOK_SERVER_CERT_DIR,noinit"`
+
+	GracefulShutdownTimeout *metav1.Duration `env:"GRACEFUL_SHUTDOWN_TIMEOUT,noinit"`
+}
+
+func setOptionsFromEnv(options Options) Options {
+	env := &envOptions{}
+	look := envconfig.PrefixLookuper("CONTROLLER_RUNTIME_", envconfig.OsLookuper())
+	if err := envconfig.ProcessWith(context.Background(), env, look); err != nil {
+		// If there was an error processing the environment variables, log, and continue.
+		options.Logger.Error(err, "error processing environment variables")
+		return options
+	}
+
+	// If the override flag is not set, return the options as is.
+	if !env.Override {
+		return options
+	}
+
+	if env.LeaderElection != nil {
+		options.LeaderElection = *env.LeaderElection
+	}
+	if env.LeaderElectionResourceLock != nil {
+		options.LeaderElectionResourceLock = *env.LeaderElectionResourceLock
+	}
+	if env.LeaderElectionNamespace != nil {
+		options.LeaderElectionNamespace = *env.LeaderElectionNamespace
+	}
+	if env.LeaderElectionID != nil {
+		options.LeaderElectionID = *env.LeaderElectionID
+	}
+	if env.LeaderElectionLeaseDuration != nil {
+		options.LeaseDuration = env.LeaderElectionLeaseDuration
+	}
+	if env.LeaderElectionRenewDeadline != nil {
+		options.RenewDeadline = env.LeaderElectionRenewDeadline
+	}
+	if env.LeaderElectionRetryPeriod != nil {
+		options.RetryPeriod = env.LeaderElectionRetryPeriod
+	}
+	if env.LeaderElectionReleaseOnCancel != nil {
+		options.LeaderElectionReleaseOnCancel = *env.LeaderElectionReleaseOnCancel
+	}
+
+	if env.MetricsSecureServing != nil {
+		options.Metrics.SecureServing = *env.MetricsSecureServing
+	}
+	if env.MetricsBindAddress != nil {
+		options.Metrics.BindAddress = *env.MetricsBindAddress
+	}
+	if env.MetricsCertDir != nil {
+		options.Metrics.CertDir = *env.MetricsCertDir
+	}
+
+	if env.HealthProbeBindAddress != nil {
+		options.HealthProbeBindAddress = *env.HealthProbeBindAddress
+	}
+	if env.PprofBindAddress != nil {
+		options.PprofBindAddress = *env.PprofBindAddress
+	}
+
+	webhookServerOptions := webhook.Options{}
+	if env.WebhookPort != nil {
+		webhookServerOptions.Port = *env.WebhookPort
+	}
+	if env.WebhookHost != nil {
+		webhookServerOptions.Host = *env.WebhookHost
+	}
+	if env.WebhookCertDir != nil {
+		webhookServerOptions.CertDir = *env.WebhookCertDir
+	}
+
+	if options.WebhookServer == nil {
+		options.WebhookServer = webhook.NewServer(webhookServerOptions)
+	} else if dh, ok := options.WebhookServer.(*webhook.DefaultServer); ok {
+		current := &dh.Options
+		if webhookServerOptions.Port != 0 {
+			current.Port = webhookServerOptions.Port
+		}
+		if webhookServerOptions.Host != "" {
+			current.Host = webhookServerOptions.Host
+		}
+		if webhookServerOptions.CertDir != "" {
+			current.CertDir = webhookServerOptions.CertDir
+		}
+		dh.Options = *current
+	}
+
+	return options
+}