how to get the list of the empty namespaces in kubernetes through go?
I want to write a code in golng by which I can find empty namespaces in kubernetes
You can use a Kubernetes golang client to connect to your namespace and get all resources you want e.g. Pods and Deployments. So you can check if there is any resources or not.
For example, this code checks if there is a Deployment or not:
package main
import (
"context"
"fmt"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/client-go/kubernetes"
ctrl "sigs.k8s.io/controller-runtime"
)
func main() {
ctx := context.Background()
config := ctrl.GetConfigOrDie()
clientset := kubernetes.NewForConfigOrDie(config)
namespace := "namespace"
list, err := clientset.AppsV1().Deployments(namespace).List(ctx, metav1.ListOptions{})
if err != nil {
return
}
fmt.Printf("Namespace has %d Deployments", len(list.Items))
}
You can check the count of other resources as well.
Related
I am very new at Golang AWS SDK V2, I had similar code work without AWS results, but this one is getting me issues since the types are different. Also, I have search and none of the examples is with the code pipeline aws-sdk-v2 with the type of JSON I have to unmarshal.
I hope some of you can help me.
— This below is main.go I have the structs in another file called un-marshal.go that I created with the result of getting the same output I need from awscli tool and passing it by https://mholt.github.io/json-to-go/
package main
import (
"context"
"fmt"
"log"
"encoding/json"
"github.com/aws/aws-sdk-go-v2/config"
"github.com/aws/aws-sdk-go-v2/service/codepipeline"
)
func main() {
pipeline_name := "frontend"
// Load the Shared AWS Configuration (~/.aws/config)
cfg, err := config.LoadDefaultConfig(context.TODO(), config.WithRegion("eu-central-1"))
if err != nil {
log.Fatal(err)
}
if err != nil {
log.Fatalf("unable to load SDK config, %v", err)
}
client := codepipeline.NewFromConfig(cfg)
pipeJson, err := client.GetPipelineState(context.TODO(), &codepipeline.GetPipelineStateInput{
Name: &pipeline_name,
})
if err != nil {
log.Println("Error getting Pipeline")
}
var cookie PipeLineResult
json.Unmarshal(pipeJson, &cookie)
fmt.Println("The name of the pipeline is: %s",cookie.PipelineName)
}
The error I am getting is:
/main.go:39:17: cannot use pipeJson (variable of type *codepipeline.GetPipelineStateOutput) as type []byte in argument to json.Unmarshal
Here I am lost because it is a new type, and not sure if I should convert, how to convert or work with the native type etc.
Thanks in advance.
I have written the following function. Its does the following
Traverse through a given namespace and iterate through all pods.
Return a string slice containing pods that match a naming convention.
var slavePods []string
func getSlavePods(clientset *kubernetes.Clientset, ns string, release string) []string {
log.Printf("INFO :: Checking slave pods in %s namespace.\n", ns)
pods, err := clientset.CoreV1().Pods(ns).List(context.TODO(), metav1.ListOptions{})
if err != nil {
panic(err.Error())
}
for _, po := range pods.Items {
SlavePodRegex := "zjs-" + release + "-(tiny|small|medium|large)-(.*)"
log.Printf("INFO :: Regex is %s", SlavePodRegex)
matched, _ := regexp.MatchString(SlavePodRegex , po.Name)
if matched{
slavePods = append(slavePods, po.Name)
}
}
return slavePods
}
In the above case, the clientset is of type *"k8s.io/client-go/kubernetes".Clientset
The above functions works well and returns the required result.
Now I am writing a test for this function. The test is
import (
"context"
v1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/client-go/kubernetes/fake"
"log"
"testing"
)
func TestgetSlavePods(t *testing.T) {
// Create the fake client.
client := fake.NewSimpleClientset()
// Inject an event into the fake client.
p := &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "zjs-modelt-develop-small-n3d8t"}}
_, err := client.CoreV1().Pods("test-ns").Create(context.TODO(), p, metav1.CreateOptions{})
if err != nil {
t.Fatalf("error injecting pod add: %v", err)
}
// Actual test
podNames := getSlavePods(client, "test-ns", "modelt-develop")
if podNames != ["zjs-modelt-develop-small-n3d8t"] {
t.Error("Expected pod is not found")
}
}
I am leveraging the fake library to initialize a fake client, create a pod in a namespace and then test the function. But I am getting an error
Cannot use 'client' (type *"k8s.io/client-go/kubernetes/fake".Clientset) as type *"k8s.io/client-go/kubernetes".Clientset
So seems like there is an issue where I cannot invoke the function with the clientset because the types are different in the actual function v/s the test function. I am following this example and they seem to be doing the samething. Is there something I have missed ?
I'm trying to write a service in go with gRPC, and when i import the protobuff file , getting an error. i tried removing all the modules in my go path and reinitialising the go modules
build _/Users/tibinlukose/cart-service/pb: cannot find module for path _/Users/tibinlukose/cart-service/pb
Code
package main
import (
pbcart "../pb/"
"log"
"fmt"
"google.golang.org/grpc"
"net"
)
var (
port = 1000;
)
type CartServiceServer struct {
}
func main() {
log.SetFlags(log.LstdFlags | log.Lshortfile)
fmt.Println("Server Starting ..")
lis, err := net.Listen("tcp", fmt.Sprintf("localhost:%d", 10000))
if err != nil {
log.Fatal("unable to listen on the port")
}
serverOptions := []grpc.ServerOption{}
grpcServer := grpc.NewServer(serverOptions...)
srv := &CartServiceServer{}
pbcart.RegisterCartServiceServer(grpcServer, srv)
}
env
GOCACHE="/Users/tibinlukose/Library/Caches/go-build"
GOENV="/Users/tibinlukose/Library/Application Support/go/env"
GOPATH="/Users/tibinlukose/go"
GOROOT="/usr/local/Cellar/go/1.13.4/libexec"
GOTOOLDIR="/usr/local/Cellar/go/1.13.4/libexec/pkg/tool/darwin_amd64"
GOMOD="/Users/tibinlukose/cart-service/server/go.mod"
repo https://github.com/zycon/cart-service
Move your go.mod to the root and update import to github.com/zycon/cart-service/pb?
There is no relative import in Go. You can see this answer for an extended explanation: Relative imports in Go
There is a proposal: https://github.com/golang/go/issues/20883
The kubernetes go client has tons of methods and I can't find how I can get the current CPU & RAM usage of a specific (or all pods).
Can someone tell me what methods I need to call to get the current usage for pods & nodes?
My NodeList:
nodes, err := clientset.CoreV1().Nodes().List(metav1.ListOptions{})
Kubernetes Go Client: https://github.com/kubernetes/client-go
Metrics package: https://github.com/kubernetes/kubernetes/tree/master/staging/src/k8s.io/metrics
As far as I got the metrics server implements the Kubernetes metrics package in order to fetch the resource usage from pods and nodes, but I couldn't figure out where & how they do it: https://github.com/kubernetes-incubator/metrics-server
It is correct that go-client does not have support for metrics type, but in the metrics package there is a pregenerated client that can be used for fetching metrics objects and assign them right away to the appropriate structure. The only thing you need to do first is to generate a config and pass it to metrics client. So a simple client for metrics would look like this:
package main
import (
"k8s.io/client-go/tools/clientcmd"
metrics "k8s.io/metrics/pkg/client/clientset/versioned"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)
func main() {
var kubeconfig, master string //empty, assuming inClusterConfig
config, err := clientcmd.BuildConfigFromFlags(master, kubeconfig)
if err != nil{
panic(err)
}
mc, err := metrics.NewForConfig(config)
if err != nil {
panic(err)
}
mc.MetricsV1beta1().NodeMetricses().Get("your node name", metav1.GetOptions{})
mc.MetricsV1beta1().NodeMetricses().List(metav1.ListOptions{})
mc.MetricsV1beta1().PodMetricses(metav1.NamespaceAll).List(metav1.ListOptions{})
mc.MetricsV1beta1().PodMetricses(metav1.NamespaceAll).Get("your pod name", metav1.GetOptions{})
}
Each of the above methods from metric client returns an appropriate structure (you can check those here) and an error (if any) which you should process according to your requirements.
here is an example.
package main
import (
"fmt"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/client-go/tools/clientcmd"
metrics "k8s.io/metrics/pkg/client/clientset/versioned"
)
func main() {
var kubeconfig, master string //empty, assuming inClusterConfig
config, err := clientcmd.BuildConfigFromFlags(master, kubeconfig)
if err != nil {
panic(err)
}
mc, err := metrics.NewForConfig(config)
if err != nil {
panic(err)
}
podMetrics, err := mc.MetricsV1beta1().PodMetricses(metav1.NamespaceAll).List(metav1.ListOptions{})
if err != nil {
fmt.Println("Error:", err)
return
}
for _, podMetric := range podMetrics.Items {
podContainers := podMetric.Containers
for _, container := range podContainers {
cpuQuantity, ok := container.Usage.Cpu().AsInt64()
memQuantity, ok := container.Usage.Memory().AsInt64()
if !ok {
return
}
msg := fmt.Sprintf("Container Name: %s \n CPU usage: %d \n Memory usage: %d", container.Name, cpuQuantity, memQuantity)
fmt.Println(msg)
}
}
}
The API you're looking for in new versions of Kubernetes (tested on mine as of 1.10.7) is the metrics.k8s.io/v1beta1 API route.
You can see it locally if you run a kubectl proxy and check http://localhost:8001/apis/metrics.k8s.io/v1beta1/pods and /nodes on your localhost.
I see where your confusion is though. At the time of writing, it does not look like the metrics/v1beta1 has a generated typed package (https://godoc.org/k8s.io/client-go/kubernetes/typed), and doesn't appear in the kubernetes.ClientSet object.
You can hit all available endpoints directly though the rest.RestClient object, and just specify metrics/v1beta1 as the versionedAPIPath, which will be more work and less convenient than the nicely wrapped ClientSet, but I'm not sure how long it'll take before that API shows up in that interface.
I'm having some issues with implementing a slight MVC design with gorilla/mux.
The layout of the modules is as follows:
main.go
-- controllers
---- base.controller.go
---- example.controller.go
-- models
---- base.model.go
---- example.controller.go
All the files in controllers is in the controllers package, same with models and then the main.go is the main package.
Currently I'm just trying to get the Base Controller to be able to be shared with the main package which is working, although it's throwing some errors when trying to implement routes. The build is not throwing any errors, but the routes are not available. If I implement the Walk function in the Gorilla/Mux documentation to print out all the registered routes for the mux.Router then it gives me this error:
&{%!!(MISSING)s(*mux.Router=&{ [0xc4200901b0] map[] true
false false false}) %!!(MISSING)s(http.HandlerFunc=0xc8df0)
[%!!(MISSING)s(*mux.routeRegexp=&{/ false false true false
0xc420095360 / [] []})] %!!(MISSING)s(*mux.routeRegexpGroup=&{
0xc420016240 []}) %!!(MISSING)s(bool=true) %!!(MISSING)s(bool=false)
%!!(MISSING)s(bool=false) %!!(MISSING)s(bool=false)
%!!(MISSING)s(mux.BuildVarsFunc=)}
The reasoning for the global var V1Router *mux.Router is firstly to access it in the main package and also to create subrouters in the other controllers.
I am fairly new to Go, but I'm trying my best to learn the best practices! Any help would be greatly appreciated!
Example code below:
base.controllers.go
package controllers
import (
"fmt"
"bytes"
"net/http"
"github.com/gorilla/mux"
)
var V1Router *mux.Router
func init () {
V1Router = mux.NewRouter()
V1Router.StrictSlash(true)
V1Router.HandleFunc("/", BaseHandler)
}
// Base route to access the API Documentation.
func BaseHandler (w http.ResponseWriter, r *http.Request) {
fmt.Fprint(w, "Hello, Gophers!")
}
main.go
package main
import (
"net/http"
"log"
"github.com/projectrepo/project/models"
"github.com/projectrepo/project/controllers"
"github.com/gorilla/mux"
)
func main () {
http.Handle("/v1", controllers.V1Router)
if err := http.ListenAndServe(":8000", nil); err != nil {
log.Fatal("Serving error.")
}
}
In response to the comments, I tried this solution with the same result:
package main
import (
"net/http"
"log"
"github.com/projectrepo/project/models"
"github.com/projectrepo/project/controllers"
"github.com/gorilla/mux"
)
func main () {
r := mux.NewRouter()
r.Handle("/v1", controllers.V1Router)
if err := http.ListenAndServe(":8000", r); err != nil {
log.Fatal("Serving error.")
}
}
Gorilla mux.Router is supposed to be used to create mapping between a set of predefined rules (e.g. host, path, protocol, scheme, etc...) and it's handler (http.Handler or http.HandlerFunc). Gorilla mux can be used to replace standard server mux. If you combine gorilla/mux with built in http server mux as your original question, i.e.
func main () {
http.Handle("/v1", controllers.V1Router)
if err := http.ListenAndServe(":8000", nil); err != nil {
log.Fatal("Serving error.")
}
}
what actually happen when a client access /v1 is controllers.V1Router will be called with request path /v1 passed to V1Router1. In the controllers.V1Router, you defined that / will be handled by BaseHandler. However, since incoming request path is /v1, it won't match to your routing table. If you want to define sub routing, you can do as follows (this is what I mean in first comment):
func main () {
r := mux.NewRouter()
v1 := r.PathPrefix("/v1").Subrouter()
controllers.RegisterHandlers(v1)
if err := http.ListenAndServe(":8000", r); err != nil {
log.Fatal("Serving error.")
}
}
Then in the controllers (base.controllers.go) define
//Register handlers and it's sub router
func RegisterHandlers(r *mux.Router) {
//base handler, i.e. /v1
r.StrictSlash(true)
r.HandleFunc("/", BaseHandler)
//example sub-router, i.e. /v1/example
ex := r.PathPrefix("/example").Subrouter()
ex.HandleFunc("/", ExampleHandler)
//other handlers...
}