micro/util/kubernetes/client/client.go

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// Package client provides an implementation of a restricted subset of kubernetes API client
package client
import (
"bytes"
"crypto/tls"
"errors"
"io"
"io/ioutil"
"net/http"
"os"
"path"
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"strings"
"github.com/micro/go-micro/v2/logger"
"github.com/micro/go-micro/v2/util/kubernetes/api"
)
var (
// path to kubernetes service account token
serviceAccountPath = "/var/run/secrets/kubernetes.io/serviceaccount"
// ErrReadNamespace is returned when the names could not be read from service account
ErrReadNamespace = errors.New("Could not read namespace from service account secret")
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// DefaultImage is default micro image
DefaultImage = "micro/go-micro"
)
// Client ...
type client struct {
opts *api.Options
}
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// Kubernetes client
type Client interface {
// Create creates new API resource
Create(*Resource) error
// Get queries API resrouces
Get(*Resource, map[string]string) error
// Update patches existing API object
Update(*Resource) error
// Delete deletes API resource
Delete(*Resource) error
// List lists API resources
List(*Resource) error
// Log gets log for a pod
Log(*Resource, ...LogOption) (io.ReadCloser, error)
// Watch for events
Watch(*Resource, ...WatchOption) (Watcher, error)
}
func detectNamespace() (string, error) {
nsPath := path.Join(serviceAccountPath, "namespace")
// Make sure it's a file and we can read it
if s, e := os.Stat(nsPath); e != nil {
return "", e
} else if s.IsDir() {
return "", ErrReadNamespace
}
// Read the file, and cast to a string
if ns, e := ioutil.ReadFile(nsPath); e != nil {
return string(ns), e
} else {
return string(ns), nil
}
}
// Create creates new API object
func (c *client) Create(r *Resource) error {
b := new(bytes.Buffer)
if err := renderTemplate(r.Kind, b, r.Value); err != nil {
return err
}
return api.NewRequest(c.opts).
Post().
SetHeader("Content-Type", "application/yaml").
Resource(r.Kind).
Body(b).
Do().
Error()
}
// Get queries API objects and stores the result in r
func (c *client) Get(r *Resource, labels map[string]string) error {
return api.NewRequest(c.opts).
Get().
Resource(r.Kind).
Params(&api.Params{LabelSelector: labels}).
Do().
Into(r.Value)
}
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// Log returns logs for a pod
func (c *client) Log(r *Resource, opts ...LogOption) (io.ReadCloser, error) {
var options LogOptions
for _, o := range opts {
o(&options)
}
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req := api.NewRequest(c.opts).
Get().
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Resource(r.Kind).
SubResource("log").
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Name(r.Name)
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if options.Params != nil {
req.Params(&api.Params{Additional: options.Params})
}
resp, err := req.Raw()
if err != nil {
return nil, err
}
if resp.StatusCode < 200 || resp.StatusCode >= 300 {
resp.Body.Close()
return nil, errors.New(resp.Request.URL.String() + ": " + resp.Status)
}
return resp.Body, nil
}
// Update updates API object
func (c *client) Update(r *Resource) error {
req := api.NewRequest(c.opts).
Patch().
SetHeader("Content-Type", "application/strategic-merge-patch+json").
Resource(r.Kind).
Name(r.Name)
switch r.Kind {
case "service":
req.Body(r.Value.(*Service))
case "deployment":
req.Body(r.Value.(*Deployment))
case "pod":
req.Body(r.Value.(*Pod))
default:
return errors.New("unsupported resource")
}
return req.Do().Error()
}
// Delete removes API object
func (c *client) Delete(r *Resource) error {
return api.NewRequest(c.opts).
Delete().
Resource(r.Kind).
Name(r.Name).
Do().
Error()
}
// List lists API objects and stores the result in r
func (c *client) List(r *Resource) error {
labels := map[string]string{
"micro": "service",
}
return c.Get(r, labels)
}
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// Watch returns an event stream
func (c *client) Watch(r *Resource, opts ...WatchOption) (Watcher, error) {
var options WatchOptions
for _, o := range opts {
o(&options)
}
// set the watch param
params := &api.Params{Additional: map[string]string{
"watch": "true",
}}
// get options params
if options.Params != nil {
for k, v := range options.Params {
params.Additional[k] = v
}
}
req := api.NewRequest(c.opts).
Get().
Resource(r.Kind).
Name(r.Name).
Params(params)
return newWatcher(req)
}
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// NewService returns default micro kubernetes service definition
func NewService(name, version, typ string) *Service {
if logger.V(logger.TraceLevel, logger.DefaultLogger) {
logger.Tracef("kubernetes default service: name: %s, version: %s", name, version)
}
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Labels := map[string]string{
"name": name,
"version": version,
"micro": typ,
}
svcName := name
if len(version) > 0 {
// API service object name joins name and version over "-"
svcName = strings.Join([]string{name, version}, "-")
}
Metadata := &Metadata{
Name: svcName,
Namespace: "default",
Version: version,
Labels: Labels,
}
Spec := &ServiceSpec{
Type: "ClusterIP",
Selector: Labels,
Ports: []ServicePort{{
"service-port", 9090, "",
}},
}
return &Service{
Metadata: Metadata,
Spec: Spec,
}
}
// NewService returns default micro kubernetes deployment definition
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func NewDeployment(name, version, typ string) *Deployment {
if logger.V(logger.TraceLevel, logger.DefaultLogger) {
logger.Tracef("kubernetes default deployment: name: %s, version: %s", name, version)
}
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Labels := map[string]string{
"name": name,
"version": version,
"micro": typ,
}
depName := name
if len(version) > 0 {
// API deployment object name joins name and version over "-"
depName = strings.Join([]string{name, version}, "-")
}
Metadata := &Metadata{
Name: depName,
Namespace: "default",
Version: version,
Labels: Labels,
Annotations: map[string]string{},
}
// enable go modules by default
env := EnvVar{
Name: "GO111MODULE",
Value: "on",
}
Spec := &DeploymentSpec{
Replicas: 1,
Selector: &LabelSelector{
MatchLabels: Labels,
},
Template: &Template{
Metadata: Metadata,
PodSpec: &PodSpec{
Containers: []Container{{
Name: name,
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Image: DefaultImage,
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Env: []EnvVar{env},
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Command: []string{"go", "run", "main.go"},
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Ports: []ContainerPort{{
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Name: "service-port",
ContainerPort: 8080,
}},
}},
},
},
}
return &Deployment{
Metadata: Metadata,
Spec: Spec,
}
}
// NewLocalClient returns a client that can be used with `kubectl proxy`
func NewLocalClient(hosts ...string) *client {
if len(hosts) == 0 {
hosts[0] = "http://localhost:8001"
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}
return &client{
opts: &api.Options{
Client: http.DefaultClient,
Host: hosts[0],
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Namespace: "default",
},
}
}
// NewClusterClient creates a Kubernetes client for use from within a k8s pod.
func NewClusterClient() *client {
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host := "https://" + os.Getenv("KUBERNETES_SERVICE_HOST") + ":" + os.Getenv("KUBERNETES_SERVICE_PORT")
s, err := os.Stat(serviceAccountPath)
if err != nil {
logger.Fatal(err)
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}
if s == nil || !s.IsDir() {
logger.Fatal(errors.New("service account not found"))
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}
token, err := ioutil.ReadFile(path.Join(serviceAccountPath, "token"))
if err != nil {
logger.Fatal(err)
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}
t := string(token)
ns, err := detectNamespace()
if err != nil {
logger.Fatal(err)
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}
crt, err := CertPoolFromFile(path.Join(serviceAccountPath, "ca.crt"))
if err != nil {
logger.Fatal(err)
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}
c := &http.Client{
Transport: &http.Transport{
TLSClientConfig: &tls.Config{
RootCAs: crt,
},
DisableCompression: true,
},
}
return &client{
opts: &api.Options{
Client: c,
Host: host,
Namespace: ns,
BearerToken: &t,
},
}
}