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Reload CustomResourceState Config File on Change
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This change adds hot reloading support for the customresourcestate
config file.

It also resolves a bug in which the customresourcestate config file was
included in the ksm config file, in which it did not get detected.

It also resolves a bug in which customresourcestatemetrics were not
added when set resources were non-default resources.

Code for this file change detection was reused from https://github.com/spf13/viper
licensed under MIT license.

Fixes: #1892
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@mrueg
mrueg committed Dec 8, 2022
1 parent 448becb commit b4500fa
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Showing 2 changed files with 111 additions and 40 deletions.
94 changes: 68 additions & 26 deletions internal/wrapper.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19,40 +19,28 @@ package internal
import (
"context"
"errors"
"os"
"path/filepath"
"strings"
"sync"
"time"

"github.com/fsnotify/fsnotify"
"github.com/spf13/viper"
"gopkg.in/yaml.v3"
"k8s.io/klog/v2"

"k8s.io/kube-state-metrics/v2/pkg/app"
"k8s.io/kube-state-metrics/v2/pkg/customresource"
"k8s.io/kube-state-metrics/v2/pkg/customresourcestate"
"k8s.io/kube-state-metrics/v2/pkg/options"
)

// RunKubeStateMetricsWrapper is a wrapper around KSM, delegated to the root command.
func RunKubeStateMetricsWrapper(opts *options.Options) {
var factories []customresource.RegistryFactory
if config, set := resolveCustomResourceConfig(opts); set {
crf, err := customresourcestate.FromConfig(config)
if err != nil {
klog.ErrorS(err, "Parsing from Custom Resource State Metrics file failed")
klog.FlushAndExit(klog.ExitFlushTimeout, 1)
}
factories = append(factories, crf...)
}

KSMRunOrDie := func(ctx context.Context) {
if err := app.RunKubeStateMetricsWrapper(ctx, opts, factories...); err != nil {
if err := app.RunKubeStateMetricsWrapper(ctx, opts); err != nil {
klog.ErrorS(err, "Failed to run kube-state-metrics")
klog.FlushAndExit(klog.ExitFlushTimeout, 1)
}
}

ctx, cancel := context.WithCancel(context.Background())
if file := options.GetConfigFile(*opts); file != "" {
viper.SetConfigType("yaml")
Expand All @@ -75,22 +63,76 @@ func RunKubeStateMetricsWrapper(opts *options.Options) {
})
viper.WatchConfig()
}

if opts.CustomResourceConfigFile != "" {
WatchConfig(opts.CustomResourceConfigFile, func(e fsnotify.Event) {
klog.Infof("Changes detected: %s\n", e.Name)
cancel()
// Wait for the ports to be released.
<-time.After(3 * time.Second)
ctx, cancel = context.WithCancel(context.Background())
go KSMRunOrDie(ctx)
})
}
klog.Infoln("Starting kube-state-metrics")
KSMRunOrDie(ctx)
select {}
}

func resolveCustomResourceConfig(opts *options.Options) (customresourcestate.ConfigDecoder, bool) {
if s := opts.CustomResourceConfig; s != "" {
return yaml.NewDecoder(strings.NewReader(s)), true
}
if file := opts.CustomResourceConfigFile; file != "" {
f, err := os.Open(filepath.Clean(file))
// WatchConfig is taken and adapted from https://github.com/spf13/viper/blob/b89e554a96abde447ad13a26dcc59fd00375e555/viper.go#L429 MIT-Licensed
func WatchConfig(filename string, onConfigChange func(fsnotify.Event)) {
initWG := sync.WaitGroup{}
initWG.Add(1)
go func() {
watcher, err := fsnotify.NewWatcher()
if err != nil {
klog.ErrorS(err, "Custom Resource State Metrics file could not be opened")
klog.FlushAndExit(klog.ExitFlushTimeout, 1)
klog.ErrorS(err, "Failed to create new watcher")
}
return yaml.NewDecoder(f), true
}
return nil, false
defer watcher.Close()

// we have to watch the entire directory to pick up renames/atomic saves in a cross-platform way
configFile := filepath.Clean(filename)
configDir, _ := filepath.Split(configFile)
realConfigFile, _ := filepath.EvalSymlinks(filename)

eventsWG := sync.WaitGroup{}
eventsWG.Add(1)
go func() {
for {
select {
case event, ok := <-watcher.Events:
if !ok { // 'Events' channel is closed
eventsWG.Done()
return
}
currentConfigFile, _ := filepath.EvalSymlinks(filename)
// we only care about the config file with the following cases:
// 1 - if the config file was modified or created
// 2 - if the real path to the config file changed (eg: k8s ConfigMap replacement)
if (filepath.Clean(event.Name) == configFile &&
(event.Has(fsnotify.Write) || event.Has(fsnotify.Create))) ||
(currentConfigFile != "" && currentConfigFile != realConfigFile) {
realConfigFile = currentConfigFile
if onConfigChange != nil {
onConfigChange(event)
}
} else if filepath.Clean(event.Name) == configFile && event.Has(fsnotify.Remove) {
eventsWG.Done()
return
}

case err, ok := <-watcher.Errors:
if ok { // 'Errors' channel is not closed
klog.ErrorS(err, "Watcher received an error")
}
eventsWG.Done()
return
}
}
}()
watcher.Add(configDir)
initWG.Done() // done initializing the watch in this go routine, so the parent routine can move on...
eventsWG.Wait() // now, wait for event loop to end in this go-routine...
}()
initWG.Wait() // make sure that the go routine above fully ended before returning
}
57 changes: 43 additions & 14 deletions pkg/app/server.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@ import (
"os"
"path/filepath"
"strconv"
"strings"
"time"

"gopkg.in/yaml.v3"
Expand All @@ -47,6 +48,7 @@ import (
"k8s.io/kube-state-metrics/v2/internal/store"
"k8s.io/kube-state-metrics/v2/pkg/allowdenylist"
"k8s.io/kube-state-metrics/v2/pkg/customresource"
"k8s.io/kube-state-metrics/v2/pkg/customresourcestate"
generator "k8s.io/kube-state-metrics/v2/pkg/metric_generator"
"k8s.io/kube-state-metrics/v2/pkg/metricshandler"
"k8s.io/kube-state-metrics/v2/pkg/optin"
Expand All @@ -73,8 +75,8 @@ func (pl promLogger) Log(v ...interface{}) error {
}

// RunKubeStateMetricsWrapper runs KSM with context cancellation.
func RunKubeStateMetricsWrapper(ctx context.Context, opts *options.Options, factories ...customresource.RegistryFactory) error {
err := RunKubeStateMetrics(ctx, opts, factories...)
func RunKubeStateMetricsWrapper(ctx context.Context, opts *options.Options) error {
err := RunKubeStateMetrics(ctx, opts)
if ctx.Err() == context.Canceled {
klog.Infoln("Restarting: kube-state-metrics, metrics will be reset")
return nil
Expand All @@ -85,11 +87,11 @@ func RunKubeStateMetricsWrapper(ctx context.Context, opts *options.Options, fact
// RunKubeStateMetrics will build and run the kube-state-metrics.
// Any out-of-tree custom resource metrics could be registered by newing a registry factory
// which implements customresource.RegistryFactory and pass all factories into this function.
func RunKubeStateMetrics(ctx context.Context, opts *options.Options, factories ...customresource.RegistryFactory) error {
func RunKubeStateMetrics(ctx context.Context, opts *options.Options) error {
var factories []customresource.RegistryFactory
promLogger := promLogger{}

storeBuilder := store.NewBuilder()
storeBuilder.WithCustomResourceStoreFactories(factories...)

ksmMetricsRegistry := prometheus.NewRegistry()
ksmMetricsRegistry.MustRegister(version.NewCollector("kube_state_metrics"))
Expand Down Expand Up @@ -144,6 +146,21 @@ func RunKubeStateMetrics(ctx context.Context, opts *options.Options, factories .
}
}

// Loading custom resource state configuration from cli argument or config file
config, err := resolveCustomResourceConfig(opts)
if err != nil {
return err
}

if config != nil {
crf, err := customresourcestate.FromConfig(config)
if err != nil {
return fmt.Errorf("Parsing from Custom Resource State Metrics file failed: %v", err)
}
factories = append(factories, crf...)
}
storeBuilder.WithCustomResourceStoreFactories(factories...)

if opts.CustomResourceConfigFile != "" {
crcFile, err := os.ReadFile(filepath.Clean(opts.CustomResourceConfigFile))
if err != nil {
Expand All @@ -157,23 +174,21 @@ func RunKubeStateMetrics(ctx context.Context, opts *options.Options, factories .
}

var resources []string

for _, factory := range factories {
resources = append(resources, factory.Name())
}

switch {
case len(opts.Resources) == 0 && !opts.CustomResourcesOnly:
resources = append(resources, options.DefaultResources.AsSlice()...)
klog.InfoS("Used default resources")
resources = options.DefaultResources.AsSlice()
// enable custom resource
for _, factory := range factories {
resources = append(resources, factory.Name())
}
case opts.CustomResourcesOnly:
// enable custom resource only
for _, factory := range factories {
resources = append(resources, factory.Name())
}
klog.InfoS("Used CRD resources only", "resources", resources)
default:
klog.InfoS("Used resources", "resources", opts.Resources.String())
resources = opts.Resources.AsSlice()
resources = append(resources, opts.Resources.AsSlice()...)
klog.InfoS("Used resources", "resources", resources)
}

if err := storeBuilder.WithEnabledResources(resources); err != nil {
Expand Down Expand Up @@ -419,3 +434,17 @@ func md5HashAsMetricValue(data []byte) float64 {
copy(bytes, smallSum)
return float64(binary.LittleEndian.Uint64(bytes))
}

func resolveCustomResourceConfig(opts *options.Options) (customresourcestate.ConfigDecoder, error) {
if s := opts.CustomResourceConfig; s != "" {
return yaml.NewDecoder(strings.NewReader(s)), nil
}
if file := opts.CustomResourceConfigFile; file != "" {
f, err := os.Open(filepath.Clean(file))
if err != nil {
return nil, fmt.Errorf("Custom Resource State Metrics file could not be opened: %v", err)
}
return yaml.NewDecoder(f), nil
}
return nil, nil
}

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