mirror of https://github.com/knative/caching.git
123 lines
3.3 KiB
Go
123 lines
3.3 KiB
Go
/*
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Copyright 2020 The Knative Authors
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package injection
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import (
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"errors"
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"flag"
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"log"
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"math"
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"os"
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"os/user"
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"path/filepath"
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"sync"
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"k8s.io/client-go/rest"
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"k8s.io/client-go/tools/clientcmd"
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"k8s.io/klog"
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)
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// Environment holds the config for flag based config.
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type Environment struct {
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// ServerURL - The address of the Kubernetes API server. Overrides any value in kubeconfig.
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ServerURL string
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// Kubeconfig - Path to a kubeconfig.
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Kubeconfig string // Note: named Kubeconfig because of legacy reasons vs KubeConfig.
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// Burst - Maximum burst for throttle.
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Burst int
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// QPS - Maximum QPS to the server from the client.
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QPS float64
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}
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var (
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env *Environment
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once sync.Once
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)
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func Flags() *Environment {
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once.Do(func() {
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env = new(Environment)
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flag.StringVar(&env.ServerURL, "server", "",
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"The address of the Kubernetes API server. Overrides any value in kubeconfig. Only required if out-of-cluster.")
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flag.StringVar(&env.Kubeconfig, "kubeconfig", os.Getenv("KUBECONFIG"),
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"Path to a kubeconfig. Only required if out-of-cluster.")
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flag.IntVar(&env.Burst, "kube-api-burst", 0, "Maximum burst for throttle.")
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flag.Float64Var(&env.QPS, "kube-api-qps", 0, "Maximum QPS to the server from the client.")
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})
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return env
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}
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// ParseAndGetRESTConfigOrDie parses the rest config flags and creates a client or
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// dies by calling log.Fatalf.
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func ParseAndGetRESTConfigOrDie() *rest.Config {
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env := Flags()
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klog.InitFlags(flag.CommandLine)
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flag.Parse()
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if env.Burst < 0 {
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log.Fatal("Invalid burst value", env.Burst)
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}
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if env.QPS < 0 || env.QPS > math.MaxFloat32 {
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log.Fatal("Invalid QPS value", env.QPS)
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}
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cfg, err := GetRESTConfig(env.ServerURL, env.Kubeconfig)
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if err != nil {
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log.Fatal("Error building kubeconfig: ", err)
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}
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cfg.Burst = env.Burst
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cfg.QPS = float32(env.QPS)
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return cfg
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}
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// GetRESTConfig returns a rest.Config to be used for kubernetes client creation.
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// It does so in the following order:
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// 1. Use the passed kubeconfig/serverURL.
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// 2. Fallback to the KUBECONFIG environment variable.
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// 3. Fallback to in-cluster config.
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// 4. Fallback to the ~/.kube/config.
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func GetRESTConfig(serverURL, kubeconfig string) (*rest.Config, error) {
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// If we have an explicit indication of where the kubernetes config lives, read that.
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if kubeconfig != "" {
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c, err := clientcmd.BuildConfigFromFlags(serverURL, kubeconfig)
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if err != nil {
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return nil, err
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}
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return c, nil
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}
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// If not, try the in-cluster config.
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if c, err := rest.InClusterConfig(); err == nil {
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return c, nil
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}
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// If no in-cluster config, try the default location in the user's home directory.
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if usr, err := user.Current(); err == nil {
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if c, err := clientcmd.BuildConfigFromFlags("", filepath.Join(usr.HomeDir, ".kube", "config")); err == nil {
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return c, nil
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}
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}
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return nil, errors.New("could not create a valid kubeconfig")
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}
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