feat: Use viper for config handling and flags

2026-08-20 04:26:28 +00:00 · 2025-12-28 11:31:27 +01:00
parent 9a5fbf190d
commit 2f9633c3f1
4 changed files with 358 additions and 212 deletions
@@ -39,6 +39,7 @@ require (
 	github.com/go-openapi/swag/stringutils v0.25.4 // indirect
 	github.com/go-openapi/swag/typeutils v0.25.4 // indirect
 	github.com/go-openapi/swag/yamlutils v0.25.4 // indirect
+	github.com/go-viper/mapstructure/v2 v2.4.0 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/google/btree v1.1.3 // indirect
 	github.com/google/gnostic-models v0.7.1 // indirect
@@ -52,9 +53,16 @@ require (
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.3-0.20250322232337-35a7c28c31ee // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
+	github.com/pelletier/go-toml/v2 v2.2.4 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/common v0.67.4 // indirect
 	github.com/prometheus/procfs v0.19.2 // indirect
+	github.com/sagikazarmark/locafero v0.11.0 // indirect
+	github.com/sourcegraph/conc v0.3.1-0.20240121214520-5f936abd7ae8 // indirect
+	github.com/spf13/afero v1.15.0 // indirect
+	github.com/spf13/cast v1.10.0 // indirect
+	github.com/spf13/viper v1.21.0 // indirect
+	github.com/subosito/gotenv v1.6.0 // indirect
 	github.com/x448/float16 v0.8.4 // indirect
 	go.yaml.in/yaml/v2 v2.4.3 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
@@ -65,6 +65,8 @@ github.com/go-openapi/testify/v2 v2.0.2 h1:X999g3jeLcoY8qctY/c/Z8iBHTbwLz7R2WXd6
 github.com/go-openapi/testify/v2 v2.0.2/go.mod h1:HCPmvFFnheKK2BuwSA0TbbdxJ3I16pjwMkYkP4Ywn54=
 github.com/go-task/slim-sprig/v3 v3.0.0 h1:sUs3vkvUymDpBKi3qH1YSqBQk9+9D/8M2mN1vB6EwHI=
 github.com/go-task/slim-sprig/v3 v3.0.0/go.mod h1:W848ghGpv3Qj3dhTPRyJypKRiqCdHZiAzKg9hl15HA8=
+github.com/go-viper/mapstructure/v2 v2.4.0 h1:EBsztssimR/CONLSZZ04E8qAkxNYq4Qp9LvH92wZUgs=
+github.com/go-viper/mapstructure/v2 v2.4.0/go.mod h1:oJDH3BJKyqBA2TXFhDsKDGDTlndYOZ6rGS0BRZIxGhM=
 github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/gogo/protobuf v1.3.2 h1:Ov1cvc58UF3b5XjBnZv7+opcTcQFZebYjWzi34vdm4Q=
 github.com/gogo/protobuf v1.3.2/go.mod h1:P1XiOD3dCwIKUDQYPy72D8LYyHL2YPYrpS2s69NZV8Q=
@@ -114,6 +116,8 @@ github.com/onsi/ginkgo/v2 v2.27.2 h1:LzwLj0b89qtIy6SSASkzlNvX6WktqurSHwkk2ipF/Ns
 github.com/onsi/ginkgo/v2 v2.27.2/go.mod h1:ArE1D/XhNXBXCBkKOLkbsb2c81dQHCRcF5zwn/ykDRo=
 github.com/onsi/gomega v1.38.2 h1:eZCjf2xjZAqe+LeWvKb5weQ+NcPwX84kqJ0cZNxok2A=
 github.com/onsi/gomega v1.38.2/go.mod h1:W2MJcYxRGV63b418Ai34Ud0hEdTVXq9NW9+Sx6uXf3k=
+github.com/pelletier/go-toml/v2 v2.2.4 h1:mye9XuhQ6gvn5h28+VilKrrPoQVanw5PMw/TB0t5Ec4=
+github.com/pelletier/go-toml/v2 v2.2.4/go.mod h1:2gIqNv+qfxSVS7cM2xJQKtLSTLUE9V8t9Stt+h56mCY=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
@@ -132,17 +136,29 @@ github.com/rs/xid v1.6.0/go.mod h1:7XoLgs4eV+QndskICGsho+ADou8ySMSjJKDIan90Nz0=
 github.com/rs/zerolog v1.34.0 h1:k43nTLIwcTVQAncfCw4KZ2VY6ukYoZaBPNOE8txlOeY=
 github.com/rs/zerolog v1.34.0/go.mod h1:bJsvje4Z08ROH4Nhs5iH600c3IkWhwp44iRc54W6wYQ=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
+github.com/sagikazarmark/locafero v0.11.0 h1:1iurJgmM9G3PA/I+wWYIOw/5SyBtxapeHDcg+AAIFXc=
+github.com/sagikazarmark/locafero v0.11.0/go.mod h1:nVIGvgyzw595SUSUE6tvCp3YYTeHs15MvlmU87WwIik=
+github.com/sourcegraph/conc v0.3.1-0.20240121214520-5f936abd7ae8 h1:+jumHNA0Wrelhe64i8F6HNlS8pkoyMv5sreGx2Ry5Rw=
+github.com/sourcegraph/conc v0.3.1-0.20240121214520-5f936abd7ae8/go.mod h1:3n1Cwaq1E1/1lhQhtRK2ts/ZwZEhjcQeJQ1RuC6Q/8U=
+github.com/spf13/afero v1.15.0 h1:b/YBCLWAJdFWJTN9cLhiXXcD7mzKn9Dm86dNnfyQw1I=
+github.com/spf13/afero v1.15.0/go.mod h1:NC2ByUVxtQs4b3sIUphxK0NioZnmxgyCrfzeuq8lxMg=
+github.com/spf13/cast v1.10.0 h1:h2x0u2shc1QuLHfxi+cTJvs30+ZAHOGRic8uyGTDWxY=
+github.com/spf13/cast v1.10.0/go.mod h1:jNfB8QC9IA6ZuY2ZjDp0KtFO2LZZlg4S/7bzP6qqeHo=
 github.com/spf13/cobra v1.10.2 h1:DMTTonx5m65Ic0GOoRY2c16WCbHxOOw6xxezuLaBpcU=
 github.com/spf13/cobra v1.10.2/go.mod h1:7C1pvHqHw5A4vrJfjNwvOdzYu0Gml16OCs2GRiTUUS4=
 github.com/spf13/pflag v1.0.9/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
 github.com/spf13/pflag v1.0.10 h1:4EBh2KAYBwaONj6b2Ye1GiHfwjqyROoF4RwYO+vPwFk=
 github.com/spf13/pflag v1.0.10/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
+github.com/spf13/viper v1.21.0 h1:x5S+0EU27Lbphp4UKm1C+1oQO+rKx36vfCoaVebLFSU=
+github.com/spf13/viper v1.21.0/go.mod h1:P0lhsswPGWD/1lZJ9ny3fYnVqxiegrlNrEmgLjbTCAY=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.5.2 h1:xuMeJ0Sdp5ZMRXx/aWO6RZxdr3beISkG5/G/aIRr3pY=
 github.com/stretchr/objx v0.5.2/go.mod h1:FRsXN1f5AsAjCGJKqEizvkpNtU+EGNCLh3NxZ/8L+MA=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
 github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
+github.com/subosito/gotenv v1.6.0 h1:9NlTDc1FTs4qu0DDq7AEtTPNw6SVm7uBMsUCUjABIf8=
+github.com/subosito/gotenv v1.6.0/go.mod h1:Dk4QP5c2W3ibzajGcXpNraDfq2IrhjMIvMSWPKKo0FU=
 github.com/x448/float16 v0.8.4 h1:qLwI1I70+NjRFUR3zs1JPUCgaCXSh3SW62uAKT1mSBM=
 github.com/x448/float16 v0.8.4/go.mod h1:14CWIYCyZA/cWjXOioeEpHeN/83MdbZDRQHoFcYsOfg=
 github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
@@ -2,215 +2,211 @@ package config

 import (
 	"strings"
+	"time"

 	"github.com/spf13/pflag"
+	"github.com/spf13/viper"
 )

-// flagValues holds intermediate string values from CLI flags
-// that need further parsing into the Config struct.
-type flagValues struct {
-	namespaceSelectors string
-	resourceSelectors  string
-	ignoredResources   string
-	ignoredWorkloads   string
-	ignoredNamespaces  string
-	isArgoRollouts     string
-	reloadOnCreate     string
-	reloadOnDelete     string
-}
+// v is the viper instance for configuration.
+var v *viper.Viper

-var fv flagValues
+func init() {
+	v = viper.New()
+	// Convert flag names like "alert-webhook-url" to env vars like "ALERT_WEBHOOK_URL"
+	v.SetEnvKeyReplacer(strings.NewReplacer("-", "_"))
+	v.AutomaticEnv()
+}

 // BindFlags binds configuration flags to the provided flag set.
 // Call this before parsing flags, then call ApplyFlags after parsing.
 func BindFlags(fs *pflag.FlagSet, cfg *Config) {
 	// Auto reload
-	fs.BoolVar(
-		&cfg.AutoReloadAll, "auto-reload-all", cfg.AutoReloadAll,
-		"Automatically reload all resources when their configmaps/secrets are updated, without requiring annotations",
-	)
+	fs.Bool("auto-reload-all", cfg.AutoReloadAll,
+		"Automatically reload all resources when their configmaps/secrets are updated, without requiring annotations")

 	// Reload strategy
-	fs.StringVar(
-		(*string)(&cfg.ReloadStrategy), "reload-strategy", string(cfg.ReloadStrategy),
-		"Strategy for triggering workload restart: 'env-vars' (default, GitOps friendly) or 'annotations'",
-	)
+	fs.String("reload-strategy", string(cfg.ReloadStrategy),
+		"Strategy for triggering workload restart: 'env-vars' (default, GitOps friendly) or 'annotations'")

 	// Argo Rollouts
-	fs.StringVar(
-		&fv.isArgoRollouts, "is-Argo-Rollouts", "false",
-		"Enable Argo Rollouts support (true/false)",
-	)
+	fs.String("is-Argo-Rollouts", "false",
+		"Enable Argo Rollouts support (true/false)")

 	// Event watching
-	fs.StringVar(
-		&fv.reloadOnCreate, "reload-on-create", "false",
-		"Reload when configmaps/secrets are created (true/false)",
-	)
-	fs.StringVar(
-		&fv.reloadOnDelete, "reload-on-delete", "false",
-		"Reload when configmaps/secrets are deleted (true/false)",
-	)
+	fs.String("reload-on-create", "false",
+		"Reload when configmaps/secrets are created (true/false)")
+	fs.String("reload-on-delete", "false",
+		"Reload when configmaps/secrets are deleted (true/false)")

 	// Sync after restart
-	fs.BoolVar(
-		&cfg.SyncAfterRestart, "sync-after-restart", cfg.SyncAfterRestart,
-		"Trigger sync operation after restart",
-	)
+	fs.Bool("sync-after-restart", cfg.SyncAfterRestart,
+		"Trigger sync operation after restart")

 	// High availability / Leader election
-	fs.BoolVar(
-		&cfg.EnableHA, "enable-ha", cfg.EnableHA,
-		"Enable high-availability mode with leader election",
-	)
-	fs.StringVar(
-		&cfg.LeaderElection.LockName, "leader-election-id", cfg.LeaderElection.LockName,
-		"Name of the lease resource for leader election",
-	)
-	fs.StringVar(
-		&cfg.LeaderElection.Namespace, "leader-election-namespace", cfg.LeaderElection.Namespace,
-		"Namespace for the leader election lease (defaults to pod namespace)",
-	)
-	fs.DurationVar(
-		&cfg.LeaderElection.LeaseDuration, "leader-election-lease-duration", cfg.LeaderElection.LeaseDuration,
-		"Duration that non-leader candidates will wait before attempting to acquire leadership",
-	)
-	fs.DurationVar(
-		&cfg.LeaderElection.RenewDeadline, "leader-election-renew-deadline", cfg.LeaderElection.RenewDeadline,
-		"Duration that the acting leader will retry refreshing leadership before giving up",
-	)
-	fs.DurationVar(
-		&cfg.LeaderElection.RetryPeriod, "leader-election-retry-period", cfg.LeaderElection.RetryPeriod,
-		"Duration between leader election retries",
-	)
-	fs.BoolVar(
-		&cfg.LeaderElection.ReleaseOnCancel, "leader-election-release-on-cancel", cfg.LeaderElection.ReleaseOnCancel,
-		"Release the leader lock when the manager is stopped",
-	)
+	fs.Bool("enable-ha", cfg.EnableHA,
+		"Enable high-availability mode with leader election")
+	fs.String("leader-election-id", cfg.LeaderElection.LockName,
+		"Name of the lease resource for leader election")
+	fs.String("leader-election-namespace", cfg.LeaderElection.Namespace,
+		"Namespace for the leader election lease (defaults to pod namespace)")
+	fs.Duration("leader-election-lease-duration", cfg.LeaderElection.LeaseDuration,
+		"Duration that non-leader candidates will wait before attempting to acquire leadership")
+	fs.Duration("leader-election-renew-deadline", cfg.LeaderElection.RenewDeadline,
+		"Duration that the acting leader will retry refreshing leadership before giving up")
+	fs.Duration("leader-election-retry-period", cfg.LeaderElection.RetryPeriod,
+		"Duration between leader election retries")
+	fs.Bool("leader-election-release-on-cancel", cfg.LeaderElection.ReleaseOnCancel,
+		"Release the leader lock when the manager is stopped")

 	// Webhook
-	fs.StringVar(
-		&cfg.WebhookURL, "webhook-url", cfg.WebhookURL,
-		"URL to send notification instead of triggering reload",
-	)
+	fs.String("webhook-url", cfg.WebhookURL,
+		"URL to send notification instead of triggering reload")

-	// Filtering - resources (use StringVar not StringSliceVar for simpler parsing)
-	fs.StringVar(
-		&fv.ignoredResources, "resources-to-ignore", "",
-		"Comma-separated list of resources to ignore (valid options: 'configMaps' or 'secrets')",
-	)
-	fs.StringVar(
-		&fv.ignoredWorkloads, "ignored-workload-types", "",
-		"Comma-separated list of workload types to ignore (valid options: 'jobs', 'cronjobs', or both)",
-	)
-	fs.StringVar(
-		&fv.ignoredNamespaces, "namespaces-to-ignore", "",
-		"Comma-separated list of namespaces to ignore",
-	)
+	// Filtering - resources
+	fs.String("resources-to-ignore", "",
+		"Comma-separated list of resources to ignore (valid options: 'configMaps' or 'secrets')")
+	fs.String("ignored-workload-types", "",
+		"Comma-separated list of workload types to ignore (valid options: 'jobs', 'cronjobs', or both)")
+	fs.String("namespaces-to-ignore", "",
+		"Comma-separated list of namespaces to ignore")

 	// Filtering - selectors
-	fs.StringVar(
-		&fv.namespaceSelectors, "namespace-selector", "",
-		"Comma-separated list of namespace label selectors",
-	)
-	fs.StringVar(
-		&fv.resourceSelectors, "resource-label-selector", "",
-		"Comma-separated list of resource label selectors",
-	)
+	fs.String("namespace-selector", "",
+		"Comma-separated list of namespace label selectors")
+	fs.String("resource-label-selector", "",
+		"Comma-separated list of resource label selectors")

 	// Logging
-	fs.StringVar(
-		&cfg.LogFormat, "log-format", cfg.LogFormat,
-		"Log format: 'json' or empty for default",
-	)
-	fs.StringVar(
-		&cfg.LogLevel, "log-level", cfg.LogLevel,
-		"Log level: trace, debug, info, warning, error, fatal, panic",
-	)
+	fs.String("log-format", cfg.LogFormat,
+		"Log format: 'json' or empty for default")
+	fs.String("log-level", cfg.LogLevel,
+		"Log level: trace, debug, info, warning, error, fatal, panic")

 	// Metrics
-	fs.StringVar(
-		&cfg.MetricsAddr, "metrics-addr", cfg.MetricsAddr,
-		"Address to serve metrics on",
-	)
+	fs.String("metrics-addr", cfg.MetricsAddr,
+		"Address to serve metrics on")

 	// Health probes
-	fs.StringVar(
-		&cfg.HealthAddr, "health-addr", cfg.HealthAddr,
-		"Address to serve health probes on",
-	)
+	fs.String("health-addr", cfg.HealthAddr,
+		"Address to serve health probes on")

 	// Profiling
-	fs.BoolVar(
-		&cfg.EnablePProf, "enable-pprof", cfg.EnablePProf,
-		"Enable pprof profiling server",
-	)
-	fs.StringVar(
-		&cfg.PProfAddr, "pprof-addr", cfg.PProfAddr,
-		"Address for pprof server",
-	)
+	fs.Bool("enable-pprof", cfg.EnablePProf,
+		"Enable pprof profiling server")
+	fs.String("pprof-addr", cfg.PProfAddr,
+		"Address for pprof server")

 	// Annotation customization (flag names match v1 for backward compatibility)
-	fs.StringVar(
-		&cfg.Annotations.Auto, "auto-annotation", cfg.Annotations.Auto,
-		"Annotation to detect changes in secrets/configmaps",
-	)
-	fs.StringVar(
-		&cfg.Annotations.ConfigmapAuto, "configmap-auto-annotation", cfg.Annotations.ConfigmapAuto,
-		"Annotation to detect changes in configmaps",
-	)
-	fs.StringVar(
-		&cfg.Annotations.SecretAuto, "secret-auto-annotation", cfg.Annotations.SecretAuto,
-		"Annotation to detect changes in secrets",
-	)
-	fs.StringVar(
-		&cfg.Annotations.ConfigmapReload, "configmap-annotation", cfg.Annotations.ConfigmapReload,
-		"Annotation to detect changes in configmaps, specified by name",
-	)
-	fs.StringVar(
-		&cfg.Annotations.SecretReload, "secret-annotation", cfg.Annotations.SecretReload,
-		"Annotation to detect changes in secrets, specified by name",
-	)
-	fs.StringVar(
-		&cfg.Annotations.Search, "auto-search-annotation", cfg.Annotations.Search,
-		"Annotation to detect changes in configmaps or secrets tagged with special match annotation",
-	)
-	fs.StringVar(
-		&cfg.Annotations.Match, "search-match-annotation", cfg.Annotations.Match,
-		"Annotation to mark secrets or configmaps to match the search",
-	)
-	fs.StringVar(
-		&cfg.Annotations.PausePeriod, "pause-deployment-annotation", cfg.Annotations.PausePeriod,
-		"Annotation to define the time period to pause a deployment after a configmap/secret change",
-	)
-	fs.StringVar(
-		&cfg.Annotations.PausedAt, "pause-deployment-time-annotation", cfg.Annotations.PausedAt,
-		"Annotation to indicate when a deployment was paused by Reloader",
-	)
+	fs.String("auto-annotation", cfg.Annotations.Auto,
+		"Annotation to detect changes in secrets/configmaps")
+	fs.String("configmap-auto-annotation", cfg.Annotations.ConfigmapAuto,
+		"Annotation to detect changes in configmaps")
+	fs.String("secret-auto-annotation", cfg.Annotations.SecretAuto,
+		"Annotation to detect changes in secrets")
+	fs.String("configmap-annotation", cfg.Annotations.ConfigmapReload,
+		"Annotation to detect changes in configmaps, specified by name")
+	fs.String("secret-annotation", cfg.Annotations.SecretReload,
+		"Annotation to detect changes in secrets, specified by name")
+	fs.String("auto-search-annotation", cfg.Annotations.Search,
+		"Annotation to detect changes in configmaps or secrets tagged with special match annotation")
+	fs.String("search-match-annotation", cfg.Annotations.Match,
+		"Annotation to mark secrets or configmaps to match the search")
+	fs.String("pause-deployment-annotation", cfg.Annotations.PausePeriod,
+		"Annotation to define the time period to pause a deployment after a configmap/secret change")
+	fs.String("pause-deployment-time-annotation", cfg.Annotations.PausedAt,
+		"Annotation to indicate when a deployment was paused by Reloader")

 	// Watched namespace (for single-namespace mode)
-	fs.StringVar(
-		&cfg.WatchedNamespace, "watch-namespace", cfg.WatchedNamespace,
-		"Namespace to watch (empty for all namespaces)",
-	)
+	fs.String("watch-namespace", cfg.WatchedNamespace,
+		"Namespace to watch (empty for all namespaces)")
+
+	// Alerting
+	fs.Bool("alert-on-reload", cfg.Alerting.Enabled,
+		"Enable sending alerts when resources are reloaded")
+	fs.String("alert-webhook-url", cfg.Alerting.WebhookURL,
+		"Webhook URL to send alerts to")
+	fs.String("alert-sink", cfg.Alerting.Sink,
+		"Alert sink type: 'slack', 'teams', 'gchat', or 'raw' (default)")
+	fs.String("alert-proxy", cfg.Alerting.Proxy,
+		"Proxy URL for alert webhook requests")
+	fs.String("alert-additional-info", cfg.Alerting.Additional,
+		"Additional info to include in alerts (e.g., cluster name)")
+	fs.Bool("alert-structured", cfg.Alerting.Structured,
+		"For raw sink: send structured JSON instead of plain text")
+
+	// Bind pflags to viper
+	_ = v.BindPFlags(fs)
+
+	// Bind legacy env var names that don't match the automatic conversion
+	// (flag "alert-proxy" -> env "ALERT_PROXY", but legacy is "ALERT_WEBHOOK_PROXY")
+	_ = v.BindEnv("alert-proxy", "ALERT_PROXY", "ALERT_WEBHOOK_PROXY")
 }

-// ApplyFlags applies flag values that need post-processing.
+// ApplyFlags applies flag values from viper to the config struct.
 // Call this after parsing flags.
 func ApplyFlags(cfg *Config) error {
-	// Parse boolean string flags
-	cfg.ArgoRolloutsEnabled = parseBoolString(fv.isArgoRollouts)
-	cfg.ReloadOnCreate = parseBoolString(fv.reloadOnCreate)
-	cfg.ReloadOnDelete = parseBoolString(fv.reloadOnDelete)
+	// Boolean flags
+	cfg.AutoReloadAll = v.GetBool("auto-reload-all")
+	cfg.SyncAfterRestart = v.GetBool("sync-after-restart")
+	cfg.EnableHA = v.GetBool("enable-ha")
+	cfg.EnablePProf = v.GetBool("enable-pprof")
+
+	// Boolean string flags (legacy format: "true"/"false" strings)
+	cfg.ArgoRolloutsEnabled = parseBoolString(v.GetString("is-Argo-Rollouts"))
+	cfg.ReloadOnCreate = parseBoolString(v.GetString("reload-on-create"))
+	cfg.ReloadOnDelete = parseBoolString(v.GetString("reload-on-delete"))
+
+	// String flags
+	cfg.ReloadStrategy = ReloadStrategy(v.GetString("reload-strategy"))
+	cfg.WebhookURL = v.GetString("webhook-url")
+	cfg.LogFormat = v.GetString("log-format")
+	cfg.LogLevel = v.GetString("log-level")
+	cfg.MetricsAddr = v.GetString("metrics-addr")
+	cfg.HealthAddr = v.GetString("health-addr")
+	cfg.PProfAddr = v.GetString("pprof-addr")
+	cfg.WatchedNamespace = v.GetString("watch-namespace")
+
+	// Leader election
+	cfg.LeaderElection.LockName = v.GetString("leader-election-id")
+	cfg.LeaderElection.Namespace = v.GetString("leader-election-namespace")
+	cfg.LeaderElection.LeaseDuration = v.GetDuration("leader-election-lease-duration")
+	cfg.LeaderElection.RenewDeadline = v.GetDuration("leader-election-renew-deadline")
+	cfg.LeaderElection.RetryPeriod = v.GetDuration("leader-election-retry-period")
+	cfg.LeaderElection.ReleaseOnCancel = v.GetBool("leader-election-release-on-cancel")
+
+	// Annotations
+	cfg.Annotations.Auto = v.GetString("auto-annotation")
+	cfg.Annotations.ConfigmapAuto = v.GetString("configmap-auto-annotation")
+	cfg.Annotations.SecretAuto = v.GetString("secret-auto-annotation")
+	cfg.Annotations.ConfigmapReload = v.GetString("configmap-annotation")
+	cfg.Annotations.SecretReload = v.GetString("secret-annotation")
+	cfg.Annotations.Search = v.GetString("auto-search-annotation")
+	cfg.Annotations.Match = v.GetString("search-match-annotation")
+	cfg.Annotations.PausePeriod = v.GetString("pause-deployment-annotation")
+	cfg.Annotations.PausedAt = v.GetString("pause-deployment-time-annotation")
+
+	// Alerting
+	cfg.Alerting.Enabled = v.GetBool("alert-on-reload")
+	cfg.Alerting.WebhookURL = v.GetString("alert-webhook-url")
+	cfg.Alerting.Sink = strings.ToLower(v.GetString("alert-sink"))
+	cfg.Alerting.Proxy = v.GetString("alert-proxy")
+	cfg.Alerting.Additional = v.GetString("alert-additional-info")
+	cfg.Alerting.Structured = v.GetBool("alert-structured")
+
+	// Special case: if webhook URL is set, auto-enable alerting
+	if cfg.Alerting.WebhookURL != "" {
+		cfg.Alerting.Enabled = true
+	}

 	// Parse comma-separated lists
-	cfg.IgnoredResources = splitAndTrim(fv.ignoredResources)
-	cfg.IgnoredWorkloads = splitAndTrim(fv.ignoredWorkloads)
-	cfg.IgnoredNamespaces = splitAndTrim(fv.ignoredNamespaces)
+	cfg.IgnoredResources = splitAndTrim(v.GetString("resources-to-ignore"))
+	cfg.IgnoredWorkloads = splitAndTrim(v.GetString("ignored-workload-types"))
+	cfg.IgnoredNamespaces = splitAndTrim(v.GetString("namespaces-to-ignore"))

 	// Store raw selector strings
-	cfg.NamespaceSelectorStrings = splitAndTrim(fv.namespaceSelectors)
-	cfg.ResourceSelectorStrings = splitAndTrim(fv.resourceSelectors)
+	cfg.NamespaceSelectorStrings = splitAndTrim(v.GetString("namespace-selector"))
+	cfg.ResourceSelectorStrings = splitAndTrim(v.GetString("resource-label-selector"))

 	// Parse selectors into labels.Selector
 	var err error
@@ -223,9 +219,25 @@ func ApplyFlags(cfg *Config) error {
 		return err
 	}

+	// Ensure duration defaults are preserved if not set
+	if cfg.LeaderElection.LeaseDuration == 0 {
+		cfg.LeaderElection.LeaseDuration = 15 * time.Second
+	}
+	if cfg.LeaderElection.RenewDeadline == 0 {
+		cfg.LeaderElection.RenewDeadline = 10 * time.Second
+	}
+	if cfg.LeaderElection.RetryPeriod == 0 {
+		cfg.LeaderElection.RetryPeriod = 2 * time.Second
+	}
+
 	return nil
 }

+// GetViper returns the viper instance for testing or advanced configuration.
+func GetViper() *viper.Viper {
+	return v
+}
+
 // parseBoolString parses a string as a boolean, defaulting to false.
 func parseBoolString(s string) bool {
 	s = strings.ToLower(strings.TrimSpace(s))
@@ -1,12 +1,23 @@
 package config

 import (
+	"os"
+	"strings"
 	"testing"

 	"github.com/spf13/pflag"
+	"github.com/spf13/viper"
 )

+// resetViper resets the viper instance for testing.
+func resetViper() {
+	v = viper.New()
+	v.SetEnvKeyReplacer(strings.NewReplacer("-", "_"))
+	v.AutomaticEnv()
+}
+
 func TestBindFlags(t *testing.T) {
+	resetViper()
 	cfg := NewDefault()
 	fs := pflag.NewFlagSet("test", pflag.ContinueOnError)

@@ -48,6 +59,12 @@ func TestBindFlags(t *testing.T) {
 		"pause-deployment-annotation",
 		"pause-deployment-time-annotation",
 		"watch-namespace",
+		"alert-on-reload",
+		"alert-webhook-url",
+		"alert-sink",
+		"alert-proxy",
+		"alert-additional-info",
+		"alert-structured",
 	}

 	for _, flagName := range expectedFlags {
@@ -58,6 +75,7 @@ func TestBindFlags(t *testing.T) {
 }

 func TestBindFlags_DefaultValues(t *testing.T) {
+	resetViper()
 	cfg := NewDefault()
 	fs := pflag.NewFlagSet("test", pflag.ContinueOnError)

@@ -67,6 +85,10 @@ func TestBindFlags_DefaultValues(t *testing.T) {
 		t.Fatalf("Parse() error = %v", err)
 	}

+	if err := ApplyFlags(cfg); err != nil {
+		t.Fatalf("ApplyFlags() error = %v", err)
+	}
+
 	if cfg.ReloadStrategy != ReloadStrategyEnvVars {
 		t.Errorf("ReloadStrategy = %v, want %v", cfg.ReloadStrategy, ReloadStrategyEnvVars)
 	}
@@ -77,6 +99,7 @@ func TestBindFlags_DefaultValues(t *testing.T) {
 }

 func TestBindFlags_CustomValues(t *testing.T) {
+	resetViper()
 	cfg := NewDefault()
 	fs := pflag.NewFlagSet("test", pflag.ContinueOnError)

@@ -96,6 +119,10 @@ func TestBindFlags_CustomValues(t *testing.T) {
 		t.Fatalf("Parse() error = %v", err)
 	}

+	if err := ApplyFlags(cfg); err != nil {
+		t.Fatalf("ApplyFlags() error = %v", err)
+	}
+
 	if !cfg.AutoReloadAll {
 		t.Error("AutoReloadAll should be true")
 	}
@@ -143,35 +170,31 @@ func TestApplyFlags_BooleanStrings(t *testing.T) {
 	}

 	for _, tt := range tests {
-		t.Run(
-			tt.name, func(t *testing.T) {
-				fv = flagValues{}
+		t.Run(tt.name, func(t *testing.T) {
+			resetViper()
+			cfg := NewDefault()
+			fs := pflag.NewFlagSet("test", pflag.ContinueOnError)
+			BindFlags(fs, cfg)

-				cfg := NewDefault()
-				fs := pflag.NewFlagSet("test", pflag.ContinueOnError)
-				BindFlags(fs, cfg)
+			if err := fs.Parse(tt.args); err != nil {
+				t.Fatalf("Parse() error = %v", err)
+			}

-				if err := fs.Parse(tt.args); err != nil {
-					t.Fatalf("Parse() error = %v", err)
-				}
+			err := ApplyFlags(cfg)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("ApplyFlags() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}

-				err := ApplyFlags(cfg)
-				if (err != nil) != tt.wantErr {
-					t.Errorf("ApplyFlags() error = %v, wantErr %v", err, tt.wantErr)
-					return
-				}
-
-				if cfg.ArgoRolloutsEnabled != tt.want {
-					t.Errorf("ArgoRolloutsEnabled = %v, want %v", cfg.ArgoRolloutsEnabled, tt.want)
-				}
-			},
-		)
+			if cfg.ArgoRolloutsEnabled != tt.want {
+				t.Errorf("ArgoRolloutsEnabled = %v, want %v", cfg.ArgoRolloutsEnabled, tt.want)
+			}
+		})
 	}
 }

 func TestApplyFlags_CommaSeparatedLists(t *testing.T) {
-	fv = flagValues{}
-
+	resetViper()
 	cfg := NewDefault()
 	fs := pflag.NewFlagSet("test", pflag.ContinueOnError)
 	BindFlags(fs, cfg)
@@ -201,15 +224,13 @@ func TestApplyFlags_CommaSeparatedLists(t *testing.T) {
 		t.Errorf("IgnoredWorkloads length = %d, want 2", len(cfg.IgnoredWorkloads))
 	}

-	// Check ignored namespaces
 	if len(cfg.IgnoredNamespaces) != 2 {
 		t.Errorf("IgnoredNamespaces length = %d, want 2", len(cfg.IgnoredNamespaces))
 	}
 }

 func TestApplyFlags_Selectors(t *testing.T) {
-	fv = flagValues{}
-
+	resetViper()
 	cfg := NewDefault()
 	fs := pflag.NewFlagSet("test", pflag.ContinueOnError)
 	BindFlags(fs, cfg)
@@ -241,8 +262,7 @@ func TestApplyFlags_Selectors(t *testing.T) {
 }

 func TestApplyFlags_InvalidSelector(t *testing.T) {
-	fv = flagValues{}
-
+	resetViper()
 	cfg := NewDefault()
 	fs := pflag.NewFlagSet("test", pflag.ContinueOnError)
 	BindFlags(fs, cfg)
@@ -261,6 +281,100 @@ func TestApplyFlags_InvalidSelector(t *testing.T) {
 	}
 }

+func TestApplyFlags_AlertingEnvVars(t *testing.T) {
+	tests := []struct {
+		name       string
+		envVars    map[string]string
+		wantURL    string
+		wantSink   string
+		wantEnable bool
+	}{
+		{
+			name: "ALERT_WEBHOOK_URL enables alerting",
+			envVars: map[string]string{
+				"ALERT_WEBHOOK_URL": "https://hooks.example.com",
+			},
+			wantURL:    "https://hooks.example.com",
+			wantEnable: true,
+		},
+		{
+			name: "all alert env vars",
+			envVars: map[string]string{
+				"ALERT_WEBHOOK_URL":   "https://hooks.example.com",
+				"ALERT_SINK":          "slack",
+				"ALERT_WEBHOOK_PROXY": "http://proxy:8080",
+			},
+			wantURL:    "https://hooks.example.com",
+			wantSink:   "slack",
+			wantEnable: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Clear env and reset viper
+			for k := range tt.envVars {
+				os.Unsetenv(k)
+			}
+			resetViper()
+
+			// Set env vars
+			for k, val := range tt.envVars {
+				os.Setenv(k, val)
+				defer os.Unsetenv(k)
+			}
+
+			cfg := NewDefault()
+			fs := pflag.NewFlagSet("test", pflag.ContinueOnError)
+			BindFlags(fs, cfg)
+
+			if err := fs.Parse([]string{}); err != nil {
+				t.Fatalf("Parse() error = %v", err)
+			}
+
+			if err := ApplyFlags(cfg); err != nil {
+				t.Fatalf("ApplyFlags() error = %v", err)
+			}
+
+			if cfg.Alerting.WebhookURL != tt.wantURL {
+				t.Errorf("Alerting.WebhookURL = %q, want %q", cfg.Alerting.WebhookURL, tt.wantURL)
+			}
+
+			if tt.wantSink != "" && cfg.Alerting.Sink != tt.wantSink {
+				t.Errorf("Alerting.Sink = %q, want %q", cfg.Alerting.Sink, tt.wantSink)
+			}
+
+			if cfg.Alerting.Enabled != tt.wantEnable {
+				t.Errorf("Alerting.Enabled = %v, want %v", cfg.Alerting.Enabled, tt.wantEnable)
+			}
+		})
+	}
+}
+
+func TestApplyFlags_LegacyProxyEnvVar(t *testing.T) {
+	resetViper()
+
+	// Set legacy env var
+	os.Setenv("ALERT_WEBHOOK_PROXY", "http://legacy-proxy:8080")
+	defer os.Unsetenv("ALERT_WEBHOOK_PROXY")
+
+	cfg := NewDefault()
+	fs := pflag.NewFlagSet("test", pflag.ContinueOnError)
+	BindFlags(fs, cfg)
+
+	if err := fs.Parse([]string{}); err != nil {
+		t.Fatalf("Parse() error = %v", err)
+	}
+
+	if err := ApplyFlags(cfg); err != nil {
+		t.Fatalf("ApplyFlags() error = %v", err)
+	}
+
+	if cfg.Alerting.Proxy != "http://legacy-proxy:8080" {
+		t.Errorf("Alerting.Proxy = %q, want %q", cfg.Alerting.Proxy, "http://legacy-proxy:8080")
+	}
+}
+
 func TestParseBoolString(t *testing.T) {
 	tests := []struct {
 		input string
@@ -282,14 +396,12 @@ func TestParseBoolString(t *testing.T) {
 	}

 	for _, tt := range tests {
-		t.Run(
-			tt.input, func(t *testing.T) {
-				got := parseBoolString(tt.input)
-				if got != tt.want {
-					t.Errorf("parseBoolString(%q) = %v, want %v", tt.input, got, tt.want)
-				}
-			},
-		)
+		t.Run(tt.input, func(t *testing.T) {
+			got := parseBoolString(tt.input)
+			if got != tt.want {
+				t.Errorf("parseBoolString(%q) = %v, want %v", tt.input, got, tt.want)
+			}
+		})
 	}
 }

@@ -308,19 +420,17 @@ func TestSplitAndTrim(t *testing.T) {
 	}

 	for _, tt := range tests {
-		t.Run(
-			tt.name, func(t *testing.T) {
-				got := splitAndTrim(tt.input)
-				if len(got) != len(tt.want) {
-					t.Errorf("splitAndTrim(%q) length = %d, want %d", tt.input, len(got), len(tt.want))
-					return
+		t.Run(tt.name, func(t *testing.T) {
+			got := splitAndTrim(tt.input)
+			if len(got) != len(tt.want) {
+				t.Errorf("splitAndTrim(%q) length = %d, want %d", tt.input, len(got), len(tt.want))
+				return
+			}
+			for i := range got {
+				if got[i] != tt.want[i] {
+					t.Errorf("splitAndTrim(%q)[%d] = %q, want %q", tt.input, i, got[i], tt.want[i])
 				}
-				for i := range got {
-					if got[i] != tt.want[i] {
-						t.Errorf("splitAndTrim(%q)[%d] = %q, want %q", tt.input, i, got[i], tt.want[i])
-					}
-				}
-			},
-		)
+			}
+		})
 	}
 }