delete k8s registry (#1522)
This commit is contained in:
Asim Aslam
GitHub
parent
6a666c9c7d
commit
9a685b2df5
@ -42,7 +42,6 @@ import (
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// registries
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"github.com/micro/go-micro/v2/registry/etcd"
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kreg "github.com/micro/go-micro/v2/registry/kubernetes"
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"github.com/micro/go-micro/v2/registry/mdns"
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rmem "github.com/micro/go-micro/v2/registry/memory"
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regSrv "github.com/micro/go-micro/v2/registry/service"
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@ -332,7 +331,6 @@ var (
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"etcd": etcd.NewRegistry,
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"mdns": mdns.NewRegistry,
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"memory": rmem.NewRegistry,
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"kubernetes": kreg.NewRegistry,
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}
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DefaultSelectors = map[string]func(...selector.Option) selector.Selector{
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@ -1,66 +0,0 @@
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# Kubernetes Registry Plugin for micro
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This is a plugin for go-micro that allows you to use Kubernetes as a registry.
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## Overview
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This registry plugin makes use of Annotations and Labels on a Kubernetes pod
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to build a service discovery mechanism.
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## RBAC
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If your Kubernetes cluster has RBAC enabled, a role and role binding
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will need to be created to allow this plugin to `list` and `patch` pods.
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A cluster role can be used to specify the `list` and `patch`
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requirements, while a role binding per namespace can be used to apply
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the cluster role. The example RBAC configs below assume your Micro-based
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services are running in the `test` namespace, and the pods that contain
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the services are using the `micro-services` service account.
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```
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apiVersion: rbac.authorization.k8s.io/v1
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kind: ClusterRole
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metadata:
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name: micro-registry
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rules:
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- apiGroups:
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- ""
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resources:
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- pods
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verbs:
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- list
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- patch
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- watch
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```
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```
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apiVersion: rbac.authorization.k8s.io/v1
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kind: RoleBinding
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metadata:
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name: micro-registry
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roleRef:
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apiGroup: rbac.authorization.k8s.io
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kind: ClusterRole
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name: micro-registry
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subjects:
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- kind: ServiceAccount
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name: micro-services
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namespace: test
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```
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## Gotchas
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* Registering/Deregistering relies on the HOSTNAME Environment Variable, which inside a pod
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is the place where it can be retrieved from. (This needs improving)
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## Connecting to the Kubernetes API
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### Within a pod
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If the `--registry_address` flag is omitted, the plugin will securely connect to
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the Kubernetes API using the pods "Service Account". No extra configuration is necessary.
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Find out more about service accounts here. http://kubernetes.io/docs/user-guide/accessing-the-cluster/
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### Outside of Kubernetes
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Some functions of the plugin should work, but its not been heavily tested.
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Currently no TLS support.
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@ -1,289 +0,0 @@
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// Package kubernetes provides a kubernetes registry
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package kubernetes
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import (
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"encoding/json"
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"errors"
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"fmt"
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"os"
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"regexp"
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"strings"
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"time"
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"github.com/micro/go-micro/v2/registry"
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"github.com/micro/go-micro/v2/util/kubernetes/client"
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)
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type kregistry struct {
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client client.Client
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timeout time.Duration
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options registry.Options
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}
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var (
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// used on pods as labels & services to select
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// eg: svcSelectorPrefix+"svc.name"
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servicePrefix = "go.micro/"
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serviceValue = "service"
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labelTypeKey = "micro"
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labelTypeValue = "service"
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// used on k8s services to scope a serialised
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// micro service by pod name
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annotationPrefix = "go.micro/"
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// Pod status
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podRunning = "Running"
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// label name regex
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labelRe = regexp.MustCompilePOSIX("[-A-Za-z0-9_.]")
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)
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// podSelector
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var podSelector = map[string]string{
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labelTypeKey: labelTypeValue,
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}
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func configure(k *kregistry, opts ...registry.Option) error {
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for _, o := range opts {
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o(&k.options)
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}
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// get first host
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var host string
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if len(k.options.Addrs) > 0 && len(k.options.Addrs[0]) > 0 {
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host = k.options.Addrs[0]
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}
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if k.options.Timeout == 0 {
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k.options.Timeout = time.Second * 1
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}
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// if no hosts setup, assume InCluster
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var c client.Client
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if len(host) > 0 {
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c = client.NewLocalClient(host)
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} else {
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c = client.NewClusterClient()
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}
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k.client = c
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k.timeout = k.options.Timeout
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return nil
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}
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// serviceName generates a valid service name for k8s labels
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func serviceName(name string) string {
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aname := make([]byte, len(name))
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for i, r := range []byte(name) {
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if !labelRe.Match([]byte{r}) {
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aname[i] = '_'
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continue
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}
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aname[i] = r
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}
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return string(aname)
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}
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// Init allows reconfig of options
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func (c *kregistry) Init(opts ...registry.Option) error {
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return configure(c, opts...)
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}
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// Options returns the registry Options
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func (c *kregistry) Options() registry.Options {
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return c.options
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}
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// Register sets a service selector label and an annotation with a
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// serialised version of the service passed in.
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func (c *kregistry) Register(s *registry.Service, opts ...registry.RegisterOption) error {
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if len(s.Nodes) == 0 {
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return errors.New("no nodes")
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}
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// TODO: grab podname from somewhere better than this.
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podName := os.Getenv("HOSTNAME")
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svcName := s.Name
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// encode micro service
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b, err := json.Marshal(s)
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if err != nil {
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return err
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}
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/// marshalled service
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svc := string(b)
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pod := &client.Pod{
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Metadata: &client.Metadata{
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Labels: map[string]string{
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// micro: service
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labelTypeKey: labelTypeValue,
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// micro/service/name: service
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servicePrefix + serviceName(svcName): serviceValue,
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},
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Annotations: map[string]string{
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// micro/service/name: definition
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annotationPrefix + serviceName(svcName): svc,
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},
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},
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}
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return c.client.Update(&client.Resource{
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Name: podName,
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Kind: "pod",
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Value: pod,
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})
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}
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// Deregister nils out any things set in Register
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func (c *kregistry) Deregister(s *registry.Service) error {
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if len(s.Nodes) == 0 {
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return errors.New("you must deregister at least one node")
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}
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// TODO: grab podname from somewhere better than this.
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podName := os.Getenv("HOSTNAME")
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svcName := s.Name
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pod := &client.Pod{
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Metadata: &client.Metadata{
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Labels: map[string]string{
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servicePrefix + serviceName(svcName): "",
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},
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Annotations: map[string]string{
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annotationPrefix + serviceName(svcName): "",
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},
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},
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}
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return c.client.Update(&client.Resource{
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Name: podName,
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Kind: "pod",
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Value: pod,
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})
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}
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// GetService will get all the pods with the given service selector,
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// and build services from the annotations.
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func (c *kregistry) GetService(name string) ([]*registry.Service, error) {
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var pods client.PodList
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if err := c.client.Get(&client.Resource{
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Kind: "pod",
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Value: &pods,
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}, map[string]string{
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servicePrefix + serviceName(name): serviceValue,
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}); err != nil {
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return nil, err
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}
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if len(pods.Items) == 0 {
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return nil, registry.ErrNotFound
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}
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// svcs mapped by version
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svcs := make(map[string]*registry.Service)
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// loop through items
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for _, pod := range pods.Items {
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if pod.Status.Phase != podRunning {
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continue
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}
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// get serialised service from annotation
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svcStr, ok := pod.Metadata.Annotations[annotationPrefix+serviceName(name)]
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if !ok {
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continue
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}
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// unmarshal service string
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var svc registry.Service
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if err := json.Unmarshal([]byte(svcStr), &svc); err != nil {
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return nil, fmt.Errorf("could not unmarshal service '%s' from pod annotation", name)
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}
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// merge up pod service & ip with versioned service.
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vs, ok := svcs[svc.Version]
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if !ok {
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svcs[svc.Version] = &svc
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continue
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}
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vs.Nodes = append(vs.Nodes, svc.Nodes...)
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}
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list := make([]*registry.Service, 0, len(svcs))
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for _, val := range svcs {
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list = append(list, val)
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}
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return list, nil
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}
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// ListServices will list all the service names
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func (c *kregistry) ListServices() ([]*registry.Service, error) {
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var pods client.PodList
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if err := c.client.Get(&client.Resource{
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Kind: "pod",
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Value: &pods,
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}, podSelector); err != nil {
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return nil, err
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}
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// svcs mapped by name
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svcs := make(map[string]bool)
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for _, pod := range pods.Items {
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if pod.Status.Phase != podRunning {
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continue
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}
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for k, v := range pod.Metadata.Annotations {
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if !strings.HasPrefix(k, annotationPrefix) {
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continue
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}
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// we have to unmarshal the annotation itself since the
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// key is encoded to match the regex restriction.
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var svc registry.Service
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if err := json.Unmarshal([]byte(v), &svc); err != nil {
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continue
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}
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svcs[svc.Name] = true
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}
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}
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var list []*registry.Service
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for val := range svcs {
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list = append(list, ®istry.Service{Name: val})
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}
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return list, nil
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}
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// Watch returns a kubernetes watcher
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func (c *kregistry) Watch(opts ...registry.WatchOption) (registry.Watcher, error) {
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return newWatcher(c, opts...)
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}
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func (c *kregistry) String() string {
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return "kubernetes"
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}
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// NewRegistry creates a kubernetes registry
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func NewRegistry(opts ...registry.Option) registry.Registry {
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k := &kregistry{
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options: registry.Options{},
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}
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configure(k, opts...)
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return k
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}
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@ -1,263 +0,0 @@
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package kubernetes
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import (
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"encoding/json"
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"errors"
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"strings"
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"sync"
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"github.com/micro/go-micro/v2/logger"
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"github.com/micro/go-micro/v2/registry"
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"github.com/micro/go-micro/v2/util/kubernetes/client"
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)
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type k8sWatcher struct {
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registry *kregistry
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watcher client.Watcher
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next chan *registry.Result
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stop chan bool
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sync.RWMutex
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pods map[string]*client.Pod
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}
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// build a cache of pods when the watcher starts.
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func (k *k8sWatcher) updateCache() ([]*registry.Result, error) {
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var pods client.PodList
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if err := k.registry.client.Get(&client.Resource{
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Kind: "pod",
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Value: &pods,
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}, podSelector); err != nil {
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return nil, err
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}
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var results []*registry.Result
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for _, pod := range pods.Items {
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rslts := k.buildPodResults(&pod, nil)
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for _, r := range rslts {
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results = append(results, r)
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}
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k.Lock()
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k.pods[pod.Metadata.Name] = &pod
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k.Unlock()
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}
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return results, nil
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}
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// look through pod annotations, compare against cache if present
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// and return a list of results to send down the wire.
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func (k *k8sWatcher) buildPodResults(pod *client.Pod, cache *client.Pod) []*registry.Result {
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var results []*registry.Result
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ignore := make(map[string]bool)
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if pod.Metadata != nil {
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for ak, av := range pod.Metadata.Annotations {
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// check this annotation kv is a service notation
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if !strings.HasPrefix(ak, annotationPrefix) {
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continue
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}
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if len(av) == 0 {
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continue
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}
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// ignore when we check the cached annotations
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// as we take care of it here
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ignore[ak] = true
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// compare aginst cache.
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var cacheExists bool
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var cav string
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if cache != nil && cache.Metadata != nil {
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cav, cacheExists = cache.Metadata.Annotations[ak]
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if cacheExists && len(cav) > 0 && cav == av {
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// service notation exists and is identical -
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// no change result required.
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continue
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}
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}
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rslt := ®istry.Result{}
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if cacheExists {
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rslt.Action = "update"
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} else {
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rslt.Action = "create"
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}
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// unmarshal service notation from annotation value
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err := json.Unmarshal([]byte(av), &rslt.Service)
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if err != nil {
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continue
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}
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results = append(results, rslt)
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}
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}
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// loop through cache annotations to find services
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// not accounted for above, and "delete" them.
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if cache != nil && cache.Metadata != nil {
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for ak, av := range cache.Metadata.Annotations {
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if ignore[ak] {
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continue
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}
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// check this annotation kv is a service notation
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if !strings.HasPrefix(ak, annotationPrefix) {
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continue
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}
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rslt := ®istry.Result{Action: "delete"}
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// unmarshal service notation from annotation value
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err := json.Unmarshal([]byte(av), &rslt.Service)
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if err != nil {
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continue
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}
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results = append(results, rslt)
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}
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}
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return results
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}
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// handleEvent will taken an event from the k8s pods API and do the correct
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// things with the result, based on the local cache.
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func (k *k8sWatcher) handleEvent(event client.Event) {
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var pod client.Pod
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if err := json.Unmarshal([]byte(event.Object), &pod); err != nil {
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if logger.V(logger.InfoLevel, logger.DefaultLogger) {
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logger.Info("K8s Watcher: Couldnt unmarshal event object from pod")
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}
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return
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}
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switch event.Type {
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case client.Modified:
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// Pod was modified
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k.RLock()
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cache := k.pods[pod.Metadata.Name]
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k.RUnlock()
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// service could have been added, edited or removed.
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var results []*registry.Result
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if pod.Status.Phase == podRunning {
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results = k.buildPodResults(&pod, cache)
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} else {
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// passing in cache might not return all results
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results = k.buildPodResults(&pod, nil)
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}
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for _, result := range results {
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// pod isnt running
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if pod.Status.Phase != podRunning {
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result.Action = "delete"
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}
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select {
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case k.next <- result:
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case <-k.stop:
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return
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}
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}
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k.Lock()
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k.pods[pod.Metadata.Name] = &pod
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k.Unlock()
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return
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case client.Deleted:
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// Pod was deleted
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// passing in cache might not return all results
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results := k.buildPodResults(&pod, nil)
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for _, result := range results {
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result.Action = "delete"
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select {
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case k.next <- result:
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case <-k.stop:
|
||||
return
|
||||
}
|
||||
}
|
||||
|
||||
k.Lock()
|
||||
delete(k.pods, pod.Metadata.Name)
|
||||
k.Unlock()
|
||||
return
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
// Next will block until a new result comes in
|
||||
func (k *k8sWatcher) Next() (*registry.Result, error) {
|
||||
select {
|
||||
case r := <-k.next:
|
||||
return r, nil
|
||||
case <-k.stop:
|
||||
return nil, errors.New("watcher stopped")
|
||||
}
|
||||
}
|
||||
|
||||
// Stop will cancel any requests, and close channels
|
||||
func (k *k8sWatcher) Stop() {
|
||||
select {
|
||||
case <-k.stop:
|
||||
return
|
||||
default:
|
||||
k.watcher.Stop()
|
||||
close(k.stop)
|
||||
}
|
||||
}
|
||||
|
||||
func newWatcher(kr *kregistry, opts ...registry.WatchOption) (registry.Watcher, error) {
|
||||
var wo registry.WatchOptions
|
||||
for _, o := range opts {
|
||||
o(&wo)
|
||||
}
|
||||
|
||||
selector := podSelector
|
||||
if len(wo.Service) > 0 {
|
||||
selector = map[string]string{
|
||||
servicePrefix + serviceName(wo.Service): serviceValue,
|
||||
}
|
||||
}
|
||||
|
||||
// Create watch request
|
||||
watcher, err := kr.client.Watch(&client.Resource{
|
||||
Kind: "pod",
|
||||
}, client.WatchParams(selector))
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
k := &k8sWatcher{
|
||||
registry: kr,
|
||||
watcher: watcher,
|
||||
next: make(chan *registry.Result),
|
||||
stop: make(chan bool),
|
||||
pods: make(map[string]*client.Pod),
|
||||
}
|
||||
|
||||
// update cache, but dont emit changes
|
||||
if _, err := k.updateCache(); err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
// range over watch request changes, and invoke
|
||||
// the update event
|
||||
go func() {
|
||||
for event := range watcher.Chan() {
|
||||
k.handleEvent(event)
|
||||
}
|
||||
}()
|
||||
|
||||
return k, nil
|
||||
}
|
||||
Loading…
x
Reference in New Issue
Block a user