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upstream.go
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upstream.go
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package proxy
import (
"fmt"
"io"
"io/ioutil"
"net/http"
"net/url"
"path"
"strconv"
"strings"
"time"
"github.com/mholt/caddy/caddyfile"
"github.com/mholt/caddy/caddyhttp/httpserver"
)
var (
supportedPolicies = make(map[string]func() Policy)
)
type staticUpstream struct {
from string
upstreamHeaders http.Header
downstreamHeaders http.Header
Hosts HostPool
Policy Policy
insecureSkipVerify bool
transparent bool
FailTimeout time.Duration
MaxFails int32
MaxConns int64
HealthCheck struct {
Client http.Client
Path string
Interval time.Duration
Timeout time.Duration
}
WithoutPathPrefix string
IgnoredSubPaths []string
}
// NewStaticUpstreams parses the configuration input and sets up
// static upstreams for the proxy middleware.
func NewStaticUpstreams(c caddyfile.Dispenser) ([]Upstream, error) {
var upstreams []Upstream
for c.Next() {
upstream := &staticUpstream{
from: "",
upstreamHeaders: make(http.Header),
downstreamHeaders: make(http.Header),
Hosts: nil,
Policy: &Random{},
FailTimeout: 10 * time.Second,
MaxFails: 1,
MaxConns: 0,
transparent: false,
}
if !c.Args(&upstream.from) {
return upstreams, c.ArgErr()
}
var to []string
for _, t := range c.RemainingArgs() {
parsed, err := parseUpstream(t)
if err != nil {
return upstreams, err
}
to = append(to, parsed...)
}
for c.NextBlock() {
switch c.Val() {
case "upstream":
if !c.NextArg() {
return upstreams, c.ArgErr()
}
parsed, err := parseUpstream(c.Val())
if err != nil {
return upstreams, err
}
to = append(to, parsed...)
default:
if err := parseBlock(&c, upstream); err != nil {
return upstreams, err
}
}
}
if len(to) == 0 {
return upstreams, c.ArgErr()
}
upstream.Hosts = make([]*UpstreamHost, len(to))
for i, host := range to {
uh, err := upstream.NewHost(host)
if err != nil {
return upstreams, err
}
upstream.Hosts[i] = uh
}
if upstream.HealthCheck.Path != "" {
upstream.HealthCheck.Client = http.Client{
Timeout: upstream.HealthCheck.Timeout,
}
go upstream.HealthCheckWorker(nil)
}
upstreams = append(upstreams, upstream)
}
return upstreams, nil
}
// RegisterPolicy adds a custom policy to the proxy.
func RegisterPolicy(name string, policy func() Policy) {
supportedPolicies[name] = policy
}
func (u *staticUpstream) From() string {
return u.from
}
func (u *staticUpstream) NewHost(host string) (*UpstreamHost, error) {
if !strings.HasPrefix(host, "http") &&
!strings.HasPrefix(host, "unix:") {
host = "http://" + host
}
uh := &UpstreamHost{
Name: host,
Conns: 0,
Fails: 0,
FailTimeout: u.FailTimeout,
Unhealthy: false,
UpstreamHeaders: u.upstreamHeaders,
DownstreamHeaders: u.downstreamHeaders,
CheckDown: func(u *staticUpstream) UpstreamHostDownFunc {
return func(uh *UpstreamHost) bool {
if uh.Unhealthy {
return true
}
if uh.Fails >= u.MaxFails &&
u.MaxFails != 0 {
return true
}
return false
}
}(u),
WithoutPathPrefix: u.WithoutPathPrefix,
MaxConns: u.MaxConns,
}
baseURL, err := url.Parse(uh.Name)
if err != nil {
return nil, err
}
uh.ReverseProxy = NewSingleHostReverseProxy(baseURL, uh.WithoutPathPrefix)
if u.insecureSkipVerify {
uh.ReverseProxy.Transport = InsecureTransport
}
return uh, nil
}
func parseUpstream(u string) ([]string, error) {
if !strings.HasPrefix(u, "unix:") {
colonIdx := strings.LastIndex(u, ":")
protoIdx := strings.Index(u, "://")
if colonIdx != -1 && colonIdx != protoIdx {
us := u[:colonIdx]
ports := u[len(us)+1:]
if separators := strings.Count(ports, "-"); separators > 1 {
return nil, fmt.Errorf("port range [%s] is invalid", ports)
} else if separators == 1 {
portsStr := strings.Split(ports, "-")
pIni, err := strconv.Atoi(portsStr[0])
if err != nil {
return nil, err
}
pEnd, err := strconv.Atoi(portsStr[1])
if err != nil {
return nil, err
}
if pEnd <= pIni {
return nil, fmt.Errorf("port range [%s] is invalid", ports)
}
hosts := []string{}
for p := pIni; p <= pEnd; p++ {
hosts = append(hosts, fmt.Sprintf("%s:%d", us, p))
}
return hosts, nil
}
}
}
return []string{u}, nil
}
func parseBlock(c *caddyfile.Dispenser, u *staticUpstream) error {
switch c.Val() {
case "policy":
if !c.NextArg() {
return c.ArgErr()
}
policyCreateFunc, ok := supportedPolicies[c.Val()]
if !ok {
return c.ArgErr()
}
u.Policy = policyCreateFunc()
case "fail_timeout":
if !c.NextArg() {
return c.ArgErr()
}
dur, err := time.ParseDuration(c.Val())
if err != nil {
return err
}
u.FailTimeout = dur
case "max_fails":
if !c.NextArg() {
return c.ArgErr()
}
n, err := strconv.Atoi(c.Val())
if err != nil {
return err
}
u.MaxFails = int32(n)
case "max_conns":
if !c.NextArg() {
return c.ArgErr()
}
n, err := strconv.ParseInt(c.Val(), 10, 64)
if err != nil {
return err
}
u.MaxConns = n
case "health_check":
if !c.NextArg() {
return c.ArgErr()
}
u.HealthCheck.Path = c.Val()
// Set defaults
if u.HealthCheck.Interval == 0 {
u.HealthCheck.Interval = 30 * time.Second
}
if u.HealthCheck.Timeout == 0 {
u.HealthCheck.Timeout = 60 * time.Second
}
case "health_check_interval":
var interval string
if !c.Args(&interval) {
return c.ArgErr()
}
dur, err := time.ParseDuration(interval)
if err != nil {
return err
}
u.HealthCheck.Interval = dur
case "health_check_timeout":
var interval string
if !c.Args(&interval) {
return c.ArgErr()
}
dur, err := time.ParseDuration(interval)
if err != nil {
return err
}
u.HealthCheck.Timeout = dur
case "proxy_header": // TODO: deprecate this shortly after 0.9
fallthrough
case "header_upstream":
var header, value string
if !c.Args(&header, &value) {
return c.ArgErr()
}
u.upstreamHeaders.Add(header, value)
case "header_downstream":
var header, value string
if !c.Args(&header, &value) {
return c.ArgErr()
}
u.downstreamHeaders.Add(header, value)
case "transparent":
u.transparent = true
u.upstreamHeaders.Add("X-Real-IP", "{remote}")
u.upstreamHeaders.Add("X-Forwarded-For", "{remote}")
u.upstreamHeaders.Add("X-Forwarded-Proto", "{scheme}")
case "websocket":
u.upstreamHeaders.Add("Connection", "{>Connection}")
u.upstreamHeaders.Add("Upgrade", "{>Upgrade}")
case "without":
if !c.NextArg() {
return c.ArgErr()
}
u.WithoutPathPrefix = c.Val()
case "except":
ignoredPaths := c.RemainingArgs()
if len(ignoredPaths) == 0 {
return c.ArgErr()
}
u.IgnoredSubPaths = ignoredPaths
case "insecure_skip_verify":
u.insecureSkipVerify = true
default:
return c.Errf("unknown property '%s'", c.Val())
}
return nil
}
func (u *staticUpstream) healthCheck() {
for _, host := range u.Hosts {
hostURL := host.Name + u.HealthCheck.Path
if r, err := u.HealthCheck.Client.Get(hostURL); err == nil {
io.Copy(ioutil.Discard, r.Body)
r.Body.Close()
host.Unhealthy = r.StatusCode < 200 || r.StatusCode >= 400
} else {
host.Unhealthy = true
}
}
}
func (u *staticUpstream) HealthCheckWorker(stop chan struct{}) {
ticker := time.NewTicker(u.HealthCheck.Interval)
u.healthCheck()
for {
select {
case <-ticker.C:
u.healthCheck()
case <-stop:
// TODO: the library should provide a stop channel and global
// waitgroup to allow goroutines started by plugins a chance
// to clean themselves up.
}
}
}
func (u *staticUpstream) Select() *UpstreamHost {
pool := u.Hosts
if len(pool) == 1 {
if !pool[0].Available() {
return nil
}
return pool[0]
}
allUnavailable := true
for _, host := range pool {
if host.Available() {
allUnavailable = false
break
}
}
if allUnavailable {
return nil
}
if u.Policy == nil {
return (&Random{}).Select(pool)
}
return u.Policy.Select(pool)
}
// Transparent returns true if upstream in transparent mode
func (u *staticUpstream) Transparent() bool {
return u.transparent
}
func (u *staticUpstream) AllowedPath(requestPath string) bool {
for _, ignoredSubPath := range u.IgnoredSubPaths {
if httpserver.Path(path.Clean(requestPath)).Matches(path.Join(u.From(), ignoredSubPath)) {
return false
}
}
return true
}