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prometheus-operator/pkg/operator/config_reloader.go
2025-09-25 14:11:04 +02:00

348 lines
9.8 KiB
Go

// Copyright 2020 The prometheus-operator Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package operator
import (
"fmt"
"net/url"
"path"
"strconv"
v1 "k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/util/intstr"
"k8s.io/utils/ptr"
)
const (
configReloaderPort = 8080
initConfigReloaderPort = 8081
// ShardEnvVar is the name of the environment variable injected into the
// config-reloader container that contains the shard number.
ShardEnvVar = "SHARD"
// PodNameEnvVar is the name of the environment variable injected in the
// config-reloader container that contains the pod name.
PodNameEnvVar = "POD_NAME"
// NodeNameEnvVar is the name of the environment variable injected in the
// config-reloader container that contains the node name.
NodeNameEnvVar = "NODE_NAME"
)
// ConfigReloader contains the options to configure
// a config-reloader container.
type ConfigReloader struct {
name string
config ContainerConfig
webConfigFile string
configFile string
configEnvsubstFile string
imagePullPolicy v1.PullPolicy
listenLocal bool
localHost string
logFormat string
logLevel string
reloadURL url.URL
runtimeInfoURL url.URL
initContainer bool
shard *int32
volumeMounts []v1.VolumeMount
watchedDirectories []string
useSignal bool
withNodeNameEnv bool
}
type ReloaderOption = func(*ConfigReloader)
func ReloaderUseSignal() ReloaderOption {
return func(c *ConfigReloader) {
c.useSignal = true
}
}
// InitContainer runs the config-reloader program as an init container meaning
// that it exits right after generating the configuration.
func InitContainer() ReloaderOption {
return func(c *ConfigReloader) {
c.initContainer = true
}
}
// WatchedDirectories sets the watchedDirectories option for the config-reloader container.
func WatchedDirectories(watchedDirectories []string) ReloaderOption {
return func(c *ConfigReloader) {
c.watchedDirectories = watchedDirectories
}
}
// WebConfigFile sets the webConfigFile option for the config-reloader container.
func WebConfigFile(config string) ReloaderOption {
return func(c *ConfigReloader) {
c.webConfigFile = config
}
}
// ConfigFile sets the configFile option for the config-reloader container.
func ConfigFile(configFile string) ReloaderOption {
return func(c *ConfigReloader) {
c.configFile = configFile
}
}
// ConfigEnvsubstFile sets the configEnvsubstFile option for the config-reloader container.
func ConfigEnvsubstFile(configEnvsubstFile string) ReloaderOption {
return func(c *ConfigReloader) {
c.configEnvsubstFile = configEnvsubstFile
}
}
// ReloaderConfig sets the config option for the config-reloader container.
func ReloaderConfig(rc ContainerConfig) ReloaderOption {
return func(c *ConfigReloader) {
c.config = rc
}
}
// ReloaderURL sets the reloaderURL option for the config-reloader container.
func ReloaderURL(u url.URL) ReloaderOption {
return func(c *ConfigReloader) {
c.reloadURL = u
}
}
// RuntimeInfoURL sets the runtimeInfoURL option for the config-reloader container.
func RuntimeInfoURL(u url.URL) ReloaderOption {
return func(c *ConfigReloader) {
c.runtimeInfoURL = u
}
}
// ListenLocal sets the listenLocal option for the config-reloader container.
func ListenLocal(listenLocal bool) ReloaderOption {
return func(c *ConfigReloader) {
c.listenLocal = listenLocal
}
}
// LocalHost sets the localHost option for the config-reloader container.
func LocalHost(localHost string) ReloaderOption {
return func(c *ConfigReloader) {
c.localHost = localHost
}
}
// LogFormat sets the logFormat option for the config-reloader container.
func LogFormat(logFormat string) ReloaderOption {
return func(c *ConfigReloader) {
c.logFormat = logFormat
}
}
// LogLevel sets the logLevel option for the config-reloader container.
func LogLevel(logLevel string) ReloaderOption {
return func(c *ConfigReloader) {
c.logLevel = logLevel
}
}
// VolumeMounts sets the volumeMounts option for the config-reloader container.
func VolumeMounts(mounts []v1.VolumeMount) ReloaderOption {
return func(c *ConfigReloader) {
c.volumeMounts = mounts
}
}
// Shard sets the shard option for the config-reloader container.
func Shard(shard int32) ReloaderOption {
return func(c *ConfigReloader) {
c.shard = &shard
}
}
// ImagePullPolicy sets the imagePullPolicy option for the config-reloader container.
func ImagePullPolicy(imagePullPolicy v1.PullPolicy) ReloaderOption {
return func(c *ConfigReloader) {
c.imagePullPolicy = imagePullPolicy
}
}
// WithDaemonSetMode sets the options that work for DaemonSet mode.
// Currently we set SHARD env equal to 0, eventhough DaemonSet doesn't use this env.
// TODO: Remove SHARD env for DaemonSet mode.
func WithDaemonSetMode() ReloaderOption {
return func(c *ConfigReloader) {
c.withNodeNameEnv = true
c.shard = ptr.To(int32(0))
}
}
// CreateConfigReloader returns the definition of the config-reloader
// container.
func CreateConfigReloader(name string, options ...ReloaderOption) v1.Container {
configReloader := ConfigReloader{name: name}
portName := "reloader-web"
for _, option := range options {
option(&configReloader)
}
var (
args = make([]string, 0)
envVars = []v1.EnvVar{
{
Name: PodNameEnvVar,
ValueFrom: &v1.EnvVarSource{
FieldRef: &v1.ObjectFieldSelector{FieldPath: "metadata.name"},
},
},
}
ports []v1.ContainerPort
)
if configReloader.withNodeNameEnv {
envVars = append(envVars, v1.EnvVar{
Name: NodeNameEnvVar,
ValueFrom: &v1.EnvVarSource{
FieldRef: &v1.ObjectFieldSelector{FieldPath: "spec.nodeName"},
},
})
}
if configReloader.initContainer {
portName = "reloader-init"
args = append(args, fmt.Sprintf("--watch-interval=%d", 0))
}
if configReloader.listenLocal {
args = append(args, fmt.Sprintf("--listen-address=%s:%d", configReloader.localHost, configReloaderPort))
} else {
port := configReloaderPort
// Use distinct ports for the init and "regular" containers to avoid
// warnings from the k8s client.
if configReloader.initContainer {
port = initConfigReloaderPort
}
args = append(args, fmt.Sprintf("--listen-address=:%d", port))
ports = append(
ports,
v1.ContainerPort{
Name: portName,
ContainerPort: int32(port),
Protocol: v1.ProtocolTCP,
},
)
}
if len(configReloader.webConfigFile) > 0 {
args = append(args, fmt.Sprintf("--web-config-file=%s", configReloader.webConfigFile))
}
if configReloader.useSignal {
args = append(args, "--reload-method=signal")
if len(configReloader.runtimeInfoURL.String()) > 0 {
args = append(args, fmt.Sprintf("--runtimeinfo-url=%s", configReloader.runtimeInfoURL.String()))
}
} else {
// Don't set the --reload-method argument in case the operator is
// configured with an older version of the config reloader.
if len(configReloader.reloadURL.String()) > 0 {
args = append(args, fmt.Sprintf("--reload-url=%s", configReloader.reloadURL.String()))
}
}
if len(configReloader.configFile) > 0 {
args = append(args, fmt.Sprintf("--config-file=%s", configReloader.configFile))
}
if len(configReloader.configEnvsubstFile) > 0 {
args = append(args, fmt.Sprintf("--config-envsubst-file=%s", configReloader.configEnvsubstFile))
}
if len(configReloader.watchedDirectories) > 0 {
for _, directory := range configReloader.watchedDirectories {
args = append(args, fmt.Sprintf("--watched-dir=%s", directory))
}
}
if configReloader.logLevel != "" && configReloader.logLevel != "info" {
args = append(args, fmt.Sprintf("--log-level=%s", configReloader.logLevel))
}
if configReloader.logFormat != "" && configReloader.logFormat != "logfmt" {
args = append(args, fmt.Sprintf("--log-format=%s", configReloader.logFormat))
}
if configReloader.shard != nil {
envVars = append(envVars, v1.EnvVar{
Name: ShardEnvVar,
Value: strconv.Itoa(int(*configReloader.shard)),
})
}
c := v1.Container{
Name: name,
Image: configReloader.config.Image,
ImagePullPolicy: configReloader.imagePullPolicy,
TerminationMessagePolicy: v1.TerminationMessageFallbackToLogsOnError,
Env: envVars,
Command: []string{"/bin/prometheus-config-reloader"},
Args: args,
Ports: ports,
VolumeMounts: configReloader.volumeMounts,
Resources: configReloader.config.ResourceRequirements(),
SecurityContext: &v1.SecurityContext{
AllowPrivilegeEscalation: ptr.To(false),
ReadOnlyRootFilesystem: ptr.To(true),
Capabilities: &v1.Capabilities{
Drop: []v1.Capability{"ALL"},
},
},
}
if !configReloader.initContainer && configReloader.config.EnableProbes {
c = configReloader.addProbes(c)
}
return c
}
func (cr *ConfigReloader) addProbes(c v1.Container) v1.Container {
probePath := path.Clean("/healthz")
handler := v1.ProbeHandler{}
if cr.listenLocal {
probeURL := url.URL{
Scheme: "http",
Host: fmt.Sprintf("localhost:%d", configReloaderPort),
Path: probePath,
}
handler.Exec = ExecAction(probeURL.String())
} else {
handler.HTTPGet = &v1.HTTPGetAction{
Path: probePath,
Port: intstr.FromInt(configReloaderPort),
}
}
c.LivenessProbe = &v1.Probe{ProbeHandler: handler}
c.ReadinessProbe = &v1.Probe{ProbeHandler: handler}
c.StartupProbe = &v1.Probe{ProbeHandler: handler}
return c
}