mirror of
https://github.com/kubernetes-sigs/node-feature-discovery.git
synced 2025-03-16 13:28:18 +00:00
a84b5c9d82
Implement a new feature source named 'local' whose only purpose is to run feature source hooks found under /etc/kubernetes/node-feature-discovery/source.d/ It tries to execute all files found under the directory, in alphabetical order. This feature source provides users a mechanism to implement custom feature sources in a pluggable way, without modifying nfd source code or Docker images. The hooks are supposed to print all discovered features in stdout, one feature per line. The output in stdout is used in the node label as is. Full node label name will have the following format: feature.node.kubernetes.io/<hook name>-<feature name> Stderr from the hooks is propagated to nfd log.
115 lines
2.6 KiB
Go
115 lines
2.6 KiB
Go
/*
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Copyright 2018 The Kubernetes 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 local
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import (
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"bytes"
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"fmt"
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"io/ioutil"
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"log"
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"os"
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"os/exec"
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"path/filepath"
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"github.com/kubernetes-incubator/node-feature-discovery/source"
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)
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// Config
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var (
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hookDir = "/etc/kubernetes/node-feature-discovery/source.d/"
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logger = log.New(os.Stderr, "", log.LstdFlags)
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)
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// Implement FeatureSource interface
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type Source struct{}
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func (s Source) Name() string { return "local" }
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func (s Source) Discover() (source.Features, error) {
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features := source.Features{}
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files, err := ioutil.ReadDir(hookDir)
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if err != nil {
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if os.IsNotExist(err) {
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log.Printf("ERROR: hook directory %v does not exist", hookDir)
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return features, nil
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}
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return features, fmt.Errorf("Unable to access %v: %v", hookDir, err)
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}
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for _, file := range files {
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hook := file.Name()
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hookFeatures, err := runHook(hook)
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if err != nil {
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log.Printf("ERROR: source hook '%v' failed: %v", hook, err)
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continue
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}
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for _, feature := range hookFeatures {
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features[hook+"-"+feature] = true
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}
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}
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return features, nil
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}
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// Run one hook
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func runHook(file string) ([]string, error) {
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var features []string
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path := filepath.Join(hookDir, file)
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filestat, err := os.Stat(path)
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if err != nil {
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log.Printf("ERROR: skipping %v, failed to get stat: %v", path, err)
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return features, err
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}
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if filestat.Mode().IsRegular() {
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cmd := exec.Command(path)
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var stdout bytes.Buffer
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var stderr bytes.Buffer
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cmd.Stdout = &stdout
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cmd.Stderr = &stderr
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// Run hook
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err = cmd.Run()
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// Forward stderr to our logger
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lines := bytes.Split(stderr.Bytes(), []byte("\n"))
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for i, line := range lines {
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if i == len(lines)-1 && len(line) == 0 {
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// Don't print the last empty string
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break
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}
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log.Printf("%v: %s", file, line)
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}
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// Do not return any features if an error occurred
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if err != nil {
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return features, err
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}
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// Return features printed to stdout
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lines = bytes.Split(stdout.Bytes(), []byte("\n"))
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for _, line := range lines {
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if len(line) > 0 {
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features = append(features, string(line))
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}
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}
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}
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return features, nil
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}
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