traefik/integration/vendor/github.com/ArthurHlt/go-eureka-client/eureka/client.go
2017-03-09 13:13:03 +01:00

357 lines
8.2 KiB
Go

package eureka
import (
"crypto/tls"
"crypto/x509"
"encoding/json"
"errors"
"io"
"io/ioutil"
"net"
"net/http"
"net/url"
"os"
"path"
"time"
"strings"
)
const (
defaultBufferSize = 10
UP = "UP"
DOWN = "DOWN"
STARTING = "STARTING"
)
type Config struct {
CertFile string `json:"certFile"`
KeyFile string `json:"keyFile"`
CaCertFile []string `json:"caCertFiles"`
DialTimeout time.Duration `json:"timeout"`
Consistency string `json:"consistency"`
}
type Client struct {
Config Config `json:"config"`
Cluster *Cluster `json:"cluster"`
httpClient *http.Client
persistence io.Writer
cURLch chan string
// CheckRetry can be used to control the policy for failed requests
// and modify the cluster if needed.
// The client calls it before sending requests again, and
// stops retrying if CheckRetry returns some error. The cases that
// this function needs to handle include no response and unexpected
// http status code of response.
// If CheckRetry is nil, client will call the default one
// `DefaultCheckRetry`.
// Argument cluster is the eureka.Cluster object that these requests have been made on.
// Argument numReqs is the number of http.Requests that have been made so far.
// Argument lastResp is the http.Responses from the last request.
// Argument err is the reason of the failure.
CheckRetry func(cluster *Cluster, numReqs int,
lastResp http.Response, err error) error
}
// NewClient create a basic client that is configured to be used
// with the given machine list.
func NewClient(machines []string) *Client {
config := Config{
// default timeout is one second
DialTimeout: time.Second,
}
client := &Client{
Cluster: NewCluster(machines),
Config: config,
}
client.initHTTPClient()
return client
}
// NewTLSClient create a basic client with TLS configuration
func NewTLSClient(machines []string, cert string, key string, caCerts []string) (*Client, error) {
// overwrite the default machine to use https
if len(machines) == 0 {
machines = []string{"https://127.0.0.1:4001"}
}
config := Config{
// default timeout is one second
DialTimeout: time.Second,
CertFile: cert,
KeyFile: key,
CaCertFile: make([]string, 0),
}
client := &Client{
Cluster: NewCluster(machines),
Config: config,
}
err := client.initHTTPSClient(cert, key)
if err != nil {
return nil, err
}
for _, caCert := range caCerts {
if err := client.AddRootCA(caCert); err != nil {
return nil, err
}
}
return client, nil
}
// NewClientFromFile creates a client from a given file path.
// The given file is expected to use the JSON format.
func NewClientFromFile(fpath string) (*Client, error) {
fi, err := os.Open(fpath)
if err != nil {
return nil, err
}
defer func() {
if err := fi.Close(); err != nil {
panic(err)
}
}()
return NewClientFromReader(fi)
}
// NewClientFromReader creates a Client configured from a given reader.
// The configuration is expected to use the JSON format.
func NewClientFromReader(reader io.Reader) (*Client, error) {
c := new(Client)
b, err := ioutil.ReadAll(reader)
if err != nil {
return nil, err
}
err = json.Unmarshal(b, c)
if err != nil {
return nil, err
}
if c.Config.CertFile == "" {
c.initHTTPClient()
} else {
err = c.initHTTPSClient(c.Config.CertFile, c.Config.KeyFile)
}
if err != nil {
return nil, err
}
for _, caCert := range c.Config.CaCertFile {
if err := c.AddRootCA(caCert); err != nil {
return nil, err
}
}
return c, nil
}
// Override the Client's HTTP Transport object
func (c *Client) SetTransport(tr *http.Transport) {
c.httpClient.Transport = tr
}
// initHTTPClient initializes a HTTP client for eureka client
func (c *Client) initHTTPClient() {
tr := &http.Transport{
Dial: c.dial,
TLSClientConfig: &tls.Config{
InsecureSkipVerify: true,
},
}
c.httpClient = &http.Client{Transport: tr}
}
// initHTTPClient initializes a HTTPS client for eureka client
func (c *Client) initHTTPSClient(cert, key string) error {
if cert == "" || key == "" {
return errors.New("Require both cert and key path")
}
tlsCert, err := tls.LoadX509KeyPair(cert, key)
if err != nil {
return err
}
tlsConfig := &tls.Config{
Certificates: []tls.Certificate{tlsCert},
InsecureSkipVerify: true,
}
tr := &http.Transport{
TLSClientConfig: tlsConfig,
Dial: c.dial,
}
c.httpClient = &http.Client{Transport: tr}
return nil
}
// Sets the DialTimeout value
func (c *Client) SetDialTimeout(d time.Duration) {
c.Config.DialTimeout = d
}
// AddRootCA adds a root CA cert for the eureka client
func (c *Client) AddRootCA(caCert string) error {
if c.httpClient == nil {
return errors.New("Client has not been initialized yet!")
}
certBytes, err := ioutil.ReadFile(caCert)
if err != nil {
return err
}
tr, ok := c.httpClient.Transport.(*http.Transport)
if !ok {
panic("AddRootCA(): Transport type assert should not fail")
}
if tr.TLSClientConfig.RootCAs == nil {
caCertPool := x509.NewCertPool()
ok = caCertPool.AppendCertsFromPEM(certBytes)
if ok {
tr.TLSClientConfig.RootCAs = caCertPool
}
tr.TLSClientConfig.InsecureSkipVerify = false
} else {
ok = tr.TLSClientConfig.RootCAs.AppendCertsFromPEM(certBytes)
}
if !ok {
err = errors.New("Unable to load caCert")
}
c.Config.CaCertFile = append(c.Config.CaCertFile, caCert)
return err
}
// SetCluster updates cluster information using the given machine list.
func (c *Client) SetCluster(machines []string) bool {
success := c.internalSyncCluster(machines)
return success
}
func (c *Client) GetCluster() []string {
return c.Cluster.Machines
}
// SyncCluster updates the cluster information using the internal machine list.
func (c *Client) SyncCluster() bool {
return c.internalSyncCluster(c.Cluster.Machines)
}
// internalSyncCluster syncs cluster information using the given machine list.
func (c *Client) internalSyncCluster(machines []string) bool {
for _, machine := range machines {
httpPath := c.createHttpPath(machine, "machines")
resp, err := c.httpClient.Get(httpPath)
if err != nil {
// try another machine in the cluster
continue
} else {
b, err := ioutil.ReadAll(resp.Body)
resp.Body.Close()
if err != nil {
// try another machine in the cluster
continue
}
// update Machines List
c.Cluster.updateFromStr(string(b))
// update leader
// the first one in the machine list is the leader
c.Cluster.switchLeader(0)
logger.Debug("sync.machines " + strings.Join(c.Cluster.Machines, ", "))
return true
}
}
return false
}
// createHttpPath creates a complete HTTP URL.
// serverName should contain both the host name and a port number, if any.
func (c *Client) createHttpPath(serverName string, _path string) string {
u, err := url.Parse(serverName)
if err != nil {
panic(err)
}
u.Path = path.Join(u.Path, _path)
if u.Scheme == "" {
u.Scheme = "http"
}
return u.String()
}
// dial attempts to open a TCP connection to the provided address, explicitly
// enabling keep-alives with a one-second interval.
func (c *Client) dial(network, addr string) (net.Conn, error) {
conn, err := net.DialTimeout(network, addr, c.Config.DialTimeout)
if err != nil {
return nil, err
}
tcpConn, ok := conn.(*net.TCPConn)
if !ok {
return nil, errors.New("Failed type-assertion of net.Conn as *net.TCPConn")
}
// Keep TCP alive to check whether or not the remote machine is down
if err = tcpConn.SetKeepAlive(true); err != nil {
return nil, err
}
if err = tcpConn.SetKeepAlivePeriod(time.Second); err != nil {
return nil, err
}
return tcpConn, nil
}
// MarshalJSON implements the Marshaller interface
// as defined by the standard JSON package.
func (c *Client) MarshalJSON() ([]byte, error) {
b, err := json.Marshal(struct {
Config Config `json:"config"`
Cluster *Cluster `json:"cluster"`
}{
Config: c.Config,
Cluster: c.Cluster,
})
if err != nil {
return nil, err
}
return b, nil
}
// UnmarshalJSON implements the Unmarshaller interface
// as defined by the standard JSON package.
func (c *Client) UnmarshalJSON(b []byte) error {
temp := struct {
Config Config `json:"config"`
Cluster *Cluster `json:"cluster"`
}{}
err := json.Unmarshal(b, &temp)
if err != nil {
return err
}
c.Cluster = temp.Cluster
c.Config = temp.Config
return nil
}