forked from ArthurHlt/go-eureka-client
/
requests.go
439 lines (371 loc) · 12.7 KB
/
requests.go
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package eureka
import (
"bytes"
"errors"
"fmt"
"io"
"io/ioutil"
"math/rand"
"net/http"
"net/url"
"strconv"
"sync"
"time"
)
// Errors introduced by handling requests
var (
ErrRequestCancelled = errors.New("sending request is cancelled")
)
type RawRequest struct {
method string
relativePath string
body []byte
cancel <-chan bool
}
type Applications struct {
VersionsDelta int `xml:"versions__delta"`
AppsHashcode string `xml:"apps__hashcode"`
Applications []Application `xml:"application,omitempty"`
}
type Application struct {
Name string `xml:"name"`
Instances []InstanceInfo `xml:"instance"`
}
type Instance struct {
Instance *InstanceInfo `xml:"instance" json:"instance"`
}
type Port struct {
Port int `xml:",chardata" json:"$"`
Enabled bool `xml:"enabled,attr" json:"@enabled"`
}
type InstanceInfo struct {
HostName string `xml:"hostName" json:"hostName"`
HomePageUrl string `xml:"homePageUrl,omitempty" json:"homePageUrl,omitempty"`
StatusPageUrl string `xml:"statusPageUrl" json:"statusPageUrl"`
HealthCheckUrl string `xml:"healthCheckUrl,omitempty" json:"healthCheckUrl,omitempty"`
App string `xml:"app" json:"app"`
IpAddr string `xml:"ipAddr" json:"ipAddr"`
VipAddress string `xml:"vipAddress" json:"vipAddress"`
SecureVipAddress string `xml:"secureVipAddress,omitempty" json:"secureVipAddress,omitempty"`
Status string `xml:"status" json:"status"`
Port *Port `xml:"port,omitempty" json:"port,omitempty"`
SecurePort *Port `xml:"securePort,omitempty" json:"securePort,omitempty"`
DataCenterInfo *DataCenterInfo `xml:"dataCenterInfo" json:"dataCenterInfo"`
LeaseInfo *LeaseInfo `xml:"leaseInfo,omitempty" json:"leaseInfo,omitempty"`
Metadata *MetaData `xml:"metadata,omitempty" json:"metadata,omitempty"`
IsCoordinatingDiscoveryServer bool `xml:"isCoordinatingDiscoveryServer,omitempty" json:"isCoordinatingDiscoveryServer,omitempty"`
LastUpdatedTimestamp int `xml:"lastUpdatedTimestamp,omitempty" json:"lastUpdatedTimestamp,omitempty"`
LastDirtyTimestamp int `xml:"lastDirtyTimestamp,omitempty" json:"lastDirtyTimestamp,omitempty"`
ActionType string `xml:"actionType,omitempty" json:"actionType,omitempty"`
Overriddenstatus string `xml:"overriddenstatus,omitempty" json:"overriddenstatus,omitempty"`
CountryId int `xml:"countryId,omitempty" json:"countryId,omitempty"`
InstanceID string `xml:"instanceId,omitempty" json:"instanceId,omitempty"`
}
type DataCenterInfo struct {
Name string `xml:"name" json:"name"`
Class string `xml:"class,attr" json:"@class"`
Metadata *DataCenterMetadata `xml:"metadata,omitempty" json:"metadata,omitempty"`
}
type DataCenterMetadata struct {
AmiLaunchIndex string `xml:"ami-launch-index,omitempty" json:"ami-launch-index,omitempty"`
LocalHostname string `xml:"local-hostname,omitempty" json:"local-hostname,omitempty"`
AvailabilityZone string `xml:"availability-zone,omitempty" json:"availability-zone,omitempty"`
InstanceId string `xml:"instance-id,omitempty" json:"instance-id,omitempty"`
PublicIpv4 string `xml:"public-ipv4,omitempty" json:"public-ipv4,omitempty"`
PublicHostname string `xml:"public-hostname,omitempty" json:"public-hostname,omitempty"`
AmiManifestPath string `xml:"ami-manifest-path,omitempty" json:"ami-manifest-path,omitempty"`
LocalIpv4 string `xml:"local-ipv4,omitempty" json:"local-ipv4,omitempty"`
Hostname string `xml:"hostname,omitempty" json:"hostname,omitempty"`
AmiId string `xml:"ami-id,omitempty" json:"ami-id,omitempty"`
InstanceType string `xml:"instance-type,omitempty" json:"instance-type,omitempty"`
}
type LeaseInfo struct {
EvictionDurationInSecs uint `xml:"evictionDurationInSecs,omitempty" json:"evictionDurationInSecs,omitempty"`
RenewalIntervalInSecs int `xml:"renewalIntervalInSecs,omitempty" json:"renewalIntervalInSecs,omitempty"`
DurationInSecs int `xml:"durationInSecs,omitempty" json:"durationInSecs,omitempty"`
RegistrationTimestamp int `xml:"registrationTimestamp,omitempty" json:"registrationTimestamp,omitempty"`
LastRenewalTimestamp int `xml:"lastRenewalTimestamp,omitempty" json:"lastRenewalTimestamp,omitempty"`
EvictionTimestamp int `xml:"evictionTimestamp,omitempty" json:"evictionTimestamp,omitempty"`
ServiceUpTimestamp int `xml:"serviceUpTimestamp,omitempty" json:"serviceUpTimestamp,omitempty"`
}
func NewRawRequest(method, relativePath string, body []byte, cancel <-chan bool) *RawRequest {
return &RawRequest{
method: method,
relativePath: relativePath,
body: body,
cancel: cancel,
}
}
func NewInstanceInfo(hostName, app, ip string, port int, ttl uint, isSsl bool) *InstanceInfo {
dataCenterInfo := &DataCenterInfo{
Name: "MyOwn",
Class: "com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo",
Metadata: nil,
}
leaseInfo := &LeaseInfo{
EvictionDurationInSecs: ttl,
}
instanceInfo := &InstanceInfo{
HostName: hostName,
App: app,
IpAddr: ip,
Status: UP,
DataCenterInfo: dataCenterInfo,
LeaseInfo: leaseInfo,
Metadata: nil,
}
stringPort := ""
if port != 80 && port != 443 {
stringPort = ":" + strconv.Itoa(port)
}
var protocol string = "http"
if isSsl {
protocol = "https"
instanceInfo.SecureVipAddress = protocol + "://" + hostName + stringPort
instanceInfo.SecurePort = &Port{
Port: port,
Enabled: true,
}
} else {
instanceInfo.VipAddress = protocol + "://" + hostName + stringPort
instanceInfo.Port = &Port{
Port: port,
Enabled: true,
}
}
instanceInfo.StatusPageUrl = protocol + "://" + hostName + stringPort + "/info"
return instanceInfo
}
// getCancelable issues a cancelable GET request
func (c *Client) getCancelable(endpoint string,
cancel <-chan bool) (*RawResponse, error) {
logger.Debug("get %s [%s]", endpoint, c.Cluster.Leader)
p := endpoint
req := NewRawRequest("GET", p, nil, cancel)
resp, err := c.SendRequest(req)
if err != nil {
return nil, err
}
return resp, nil
}
// get issues a GET request
func (c *Client) Get(endpoint string) (*RawResponse, error) {
return c.getCancelable(endpoint, nil)
}
// put issues a PUT request
func (c *Client) Put(endpoint string, body []byte) (*RawResponse, error) {
logger.Debug("put %s, %s, [%s]", endpoint, body, c.Cluster.Leader)
p := endpoint
req := NewRawRequest("PUT", p, body, nil)
resp, err := c.SendRequest(req)
if err != nil {
return nil, err
}
return resp, nil
}
// post issues a POST request
func (c *Client) Post(endpoint string, body []byte) (*RawResponse, error) {
logger.Debug("post %s, %s, [%s]", endpoint, body, c.Cluster.Leader)
p := endpoint
req := NewRawRequest("POST", p, body, nil)
resp, err := c.SendRequest(req)
if err != nil {
return nil, err
}
return resp, nil
}
// delete issues a DELETE request
func (c *Client) Delete(endpoint string) (*RawResponse, error) {
logger.Debug("delete %s [%s]", endpoint, c.Cluster.Leader)
p := endpoint
req := NewRawRequest("DELETE", p, nil, nil)
resp, err := c.SendRequest(req)
if err != nil {
return nil, err
}
return resp, nil
}
func (c *Client) SendRequest(rr *RawRequest) (*RawResponse, error) {
var req *http.Request
var resp *http.Response
var httpPath string
var err error
var respBody []byte
var numReqs = 1
checkRetry := c.CheckRetry
if checkRetry == nil {
checkRetry = DefaultCheckRetry
}
cancelled := make(chan bool, 1)
reqLock := new(sync.Mutex)
if rr.cancel != nil {
cancelRoutine := make(chan bool)
defer close(cancelRoutine)
go func() {
select {
case <-rr.cancel:
cancelled <- true
logger.Debug("send.request is cancelled")
case <-cancelRoutine:
return
}
// Repeat canceling request until this thread is stopped
// because we have no idea about whether it succeeds.
for {
reqLock.Lock()
c.httpClient.Transport.(*http.Transport).CancelRequest(req)
reqLock.Unlock()
select {
case <-time.After(100 * time.Millisecond):
case <-cancelRoutine:
return
}
}
}()
}
// If we connect to a follower and consistency is required, retry until
// we connect to a leader
sleep := 25 * time.Millisecond
maxSleep := time.Second
for attempt := 0; ; attempt++ {
if attempt > 0 {
select {
case <-cancelled:
return nil, ErrRequestCancelled
case <-time.After(sleep):
sleep = sleep * 2
if sleep > maxSleep {
sleep = maxSleep
}
}
}
logger.Debug("Connecting to eureka: attempt %d for %s", attempt+1, rr.relativePath)
httpPath = c.getHttpPath(false, rr.relativePath)
logger.Debug("send.request.to %s | method %s", httpPath, rr.method)
req, err := func() (*http.Request, error) {
reqLock.Lock()
defer reqLock.Unlock()
if req, err = http.NewRequest(rr.method, httpPath, bytes.NewReader(rr.body)); err != nil {
return nil, err
}
req.Header.Set("Content-Type",
"application/json")
return req, nil
}()
if err != nil {
return nil, err
}
resp, err = c.httpClient.Do(req)
defer func() {
if resp != nil {
resp.Body.Close()
}
}()
// If the request was cancelled, return ErrRequestCancelled directly
select {
case <-cancelled:
return nil, ErrRequestCancelled
default:
}
numReqs++
// network error, change a machine!
if err != nil {
logger.Error("network error: %v", err.Error())
lastResp := http.Response{}
if checkErr := checkRetry(c.Cluster, numReqs, lastResp, err); checkErr != nil {
return nil, checkErr
}
c.Cluster.switchLeader(attempt % len(c.Cluster.Machines))
continue
}
// if there is no error, it should receive response
logger.Debug("recv.response.from " + httpPath)
if validHttpStatusCode[resp.StatusCode] {
// try to read byte code and break the loop
respBody, err = ioutil.ReadAll(resp.Body)
if err == nil {
logger.Debug("recv.success " + httpPath)
break
}
// ReadAll error may be caused due to cancel request
select {
case <-cancelled:
return nil, ErrRequestCancelled
default:
}
if err == io.ErrUnexpectedEOF {
// underlying connection was closed prematurely, probably by timeout
// TODO: empty body or unexpectedEOF can cause http.Transport to get hosed;
// this allows the client to detect that and take evasive action. Need
// to revisit once code.google.com/p/go/issues/detail?id=8648 gets fixed.
respBody = []byte{}
break
}
}
// if resp is TemporaryRedirect, set the new leader and retry
if resp.StatusCode == http.StatusTemporaryRedirect {
u, err := resp.Location()
if err != nil {
logger.Warning("%v", err)
} else {
// Update cluster leader based on redirect location
// because it should point to the leader address
c.Cluster.updateLeaderFromURL(u)
logger.Debug("recv.response.relocate " + u.String())
}
resp.Body.Close()
continue
}
if checkErr := checkRetry(c.Cluster, numReqs, *resp,
errors.New("Unexpected HTTP status code")); checkErr != nil {
return nil, checkErr
}
resp.Body.Close()
}
r := &RawResponse{
StatusCode: resp.StatusCode,
Body: respBody,
Header: resp.Header,
}
return r, nil
}
// DefaultCheckRetry defines the retrying behaviour for bad HTTP requests
// If we have retried 2 * machine number, stop retrying.
// If status code is InternalServerError, sleep for 200ms.
func DefaultCheckRetry(cluster *Cluster, numReqs int, lastResp http.Response,
err error) error {
if numReqs >= 2*len(cluster.Machines) {
return newError(ErrCodeEurekaNotReachable,
"Tried to connect to each peer twice and failed", 0)
}
code := lastResp.StatusCode
if code == http.StatusInternalServerError {
time.Sleep(time.Millisecond * 200)
}
logger.Warning("bad response status code %d", code)
return nil
}
func (c *Client) getHttpPath(random bool, s ...string) string {
var machine string
if random {
machine = c.Cluster.Machines[rand.Intn(len(c.Cluster.Machines))]
} else {
machine = c.Cluster.Leader
}
fullPath := machine
for _, seg := range s {
fullPath += "/" + seg
}
return fullPath
}
// buildValues builds a url.Values map according to the given value and ttl
func buildValues(value string, ttl uint64) url.Values {
v := url.Values{}
if value != "" {
v.Set("value", value)
}
if ttl > 0 {
v.Set("ttl", fmt.Sprintf("%v", ttl))
}
return v
}