/
context.go
327 lines (279 loc) · 8.45 KB
/
context.go
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package proxy
import (
"bytes"
"errors"
"io"
"io/ioutil"
"net/http"
"net/url"
"time"
"github.com/opentracing/opentracing-go"
"github.com/zalando/skipper/filters"
"github.com/zalando/skipper/metrics"
"github.com/zalando/skipper/routing"
)
const unknownHost = "_unknownhost_"
type flushedResponseWriter interface {
http.ResponseWriter
http.Flusher
}
type context struct {
responseWriter flushedResponseWriter
request *http.Request
response *http.Response
route *routing.Route
deprecatedServed bool
servedWithResponse bool // to support the deprecated way independently
pathParams map[string]string
stateBag map[string]interface{}
originalRequest *http.Request
originalResponse *http.Response
outgoingHost string
debugFilterPanics []interface{}
outgoingDebugRequest *http.Request
executionCounter int
startServe time.Time
metrics *filterMetrics
tracer opentracing.Tracer
proxySpan opentracing.Span
parentSpan opentracing.Span
proxy *Proxy
routeLookup *routing.RouteLookup
}
type filterMetrics struct {
prefix string
impl metrics.Metrics
}
type noopFlushedResponseWriter struct {
ignoredHeader http.Header
}
func defaultBody() io.ReadCloser {
return ioutil.NopCloser(&bytes.Buffer{})
}
func defaultResponse(r *http.Request) *http.Response {
return &http.Response{
StatusCode: http.StatusNotFound,
Header: make(http.Header),
Body: defaultBody(),
Request: r,
}
}
func cloneURL(u *url.URL) *url.URL {
uc := *u
return &uc
}
func cloneRequestMetadata(r *http.Request) *http.Request {
return &http.Request{
Method: r.Method,
URL: cloneURL(r.URL),
Proto: r.Proto,
ProtoMajor: r.ProtoMajor,
ProtoMinor: r.ProtoMinor,
Header: cloneHeader(r.Header),
Trailer: cloneHeader(r.Trailer),
Body: defaultBody(),
ContentLength: r.ContentLength,
TransferEncoding: r.TransferEncoding,
Close: r.Close,
Host: r.Host,
RemoteAddr: r.RemoteAddr,
RequestURI: r.RequestURI,
TLS: r.TLS,
}
}
func cloneResponseMetadata(r *http.Response) *http.Response {
return &http.Response{
Status: r.Status,
StatusCode: r.StatusCode,
Proto: r.Proto,
ProtoMajor: r.ProtoMajor,
ProtoMinor: r.ProtoMinor,
Header: cloneHeader(r.Header),
Trailer: cloneHeader(r.Trailer),
Body: defaultBody(),
ContentLength: r.ContentLength,
TransferEncoding: r.TransferEncoding,
Close: r.Close,
Request: r.Request,
TLS: r.TLS,
}
}
// this is required during looping to preserve the original set of
// params in the outer routes
func appendParams(to, from map[string]string) map[string]string {
if to == nil {
to = make(map[string]string)
}
for k, v := range from {
to[k] = v
}
return to
}
func newContext(
w flushedResponseWriter,
r *http.Request,
p *Proxy,
) *context {
c := &context{
responseWriter: w,
request: r,
stateBag: make(map[string]interface{}),
outgoingHost: r.Host,
metrics: &filterMetrics{impl: p.metrics},
proxy: p,
routeLookup: p.routing.Get(),
}
if p.flags.PreserveOriginal() {
c.originalRequest = cloneRequestMetadata(r)
}
return c
}
func (c *context) applyRoute(route *routing.Route, params map[string]string, preserveHost bool) {
c.route = route
if preserveHost {
c.outgoingHost = c.request.Host
} else {
c.outgoingHost = route.Host
}
c.pathParams = appendParams(c.pathParams, params)
}
func (c *context) ensureDefaultResponse() {
if c.response == nil {
c.response = defaultResponse(c.request)
return
}
if c.response.Header == nil {
c.response.Header = make(http.Header)
}
if c.response.Body == nil {
c.response.Body = defaultBody()
}
}
func (c *context) deprecatedShunted() bool {
return c.deprecatedServed
}
func (c *context) shunted() bool {
return c.servedWithResponse
}
func (c *context) setResponse(r *http.Response, preserveOriginal bool) {
c.response = r
if preserveOriginal {
c.originalResponse = cloneResponseMetadata(r)
}
}
func (c *context) ResponseWriter() http.ResponseWriter { return c.responseWriter }
func (c *context) Request() *http.Request { return c.request }
func (c *context) Response() *http.Response { return c.response }
func (c *context) MarkServed() { c.deprecatedServed = true }
func (c *context) Served() bool { return c.deprecatedServed || c.servedWithResponse }
func (c *context) PathParam(key string) string { return c.pathParams[key] }
func (c *context) StateBag() map[string]interface{} { return c.stateBag }
func (c *context) BackendUrl() string { return c.route.Backend }
func (c *context) OriginalRequest() *http.Request { return c.originalRequest }
func (c *context) OriginalResponse() *http.Response { return c.originalResponse }
func (c *context) OutgoingHost() string { return c.outgoingHost }
func (c *context) SetOutgoingHost(h string) { c.outgoingHost = h }
func (c *context) Metrics() filters.Metrics { return c.metrics }
func (c *context) Tracer() opentracing.Tracer { return c.tracer }
func (c *context) ParentSpan() opentracing.Span { return c.parentSpan }
func (c *context) Serve(r *http.Response) {
r.Request = c.Request()
if r.Header == nil {
r.Header = make(http.Header)
}
if r.Body == nil {
r.Body = defaultBody()
}
c.servedWithResponse = true
c.response = r
}
func (c *context) metricsHost() string {
if c.route == nil || len(c.route.HostRegexps) == 0 {
return unknownHost
}
return c.request.Host
}
func (c *context) clone() *context {
cc := *c
// preserve the original path params by cloning the set:
cc.pathParams = appendParams(nil, c.pathParams)
return &cc
}
func (c *context) wasExecuted() bool {
return c.executionCounter != 0
}
func (c *context) setMetricsPrefix(prefix string) {
c.metrics.prefix = prefix + ".custom."
}
func (c *context) Split() (filters.FilterContext, error) {
originalRequest := c.Request()
if c.proxy.experimentalUpgrade && isUpgradeRequest(originalRequest) {
return nil, errors.New("context: cannot split the context that contains an upgrade request")
}
cc := c.clone()
cc.stateBag = map[string]interface{}{}
cc.responseWriter = noopFlushedResponseWriter{}
cc.metrics = &filterMetrics{
prefix: cc.metrics.prefix,
impl: cc.proxy.metrics,
}
u := new(url.URL)
*u = *originalRequest.URL
u.Host = originalRequest.Host
cr, body, err := cloneRequest(u, originalRequest)
if err != nil {
c.proxy.log.Errorf("context: failed to clone request: %v", err)
return nil, err
}
serverSpan := opentracing.SpanFromContext(originalRequest.Context())
cr = cr.WithContext(opentracing.ContextWithSpan(cr.Context(), serverSpan))
originalRequest.Body = body
cc.request = cr
return cc, nil
}
func (c *context) Loopback() {
err := c.proxy.do(c)
if c.response != nil && c.response.Body != nil {
if _, err := io.Copy(ioutil.Discard, c.response.Body); err != nil {
c.proxy.log.Errorf("context: error while discarding remainder response body: %v.", err)
}
err := c.response.Body.Close()
if err != nil {
c.proxy.log.Errorf("context: error during closing the response body: %v", err)
}
}
if c.proxySpan != nil {
c.proxy.tracing.setTag(c.proxySpan, "shadow", "true")
c.proxySpan.Finish()
}
perr, ok := err.(*proxyError)
if ok && perr.handled {
return
}
if err != nil {
c.proxy.log.Errorf("context: failed to execute loopback request: %v", err)
}
}
func (m *filterMetrics) IncCounter(key string) {
m.impl.IncCounter(m.prefix + key)
}
func (m *filterMetrics) IncCounterBy(key string, value int64) {
m.impl.IncCounterBy(m.prefix+key, value)
}
func (m *filterMetrics) MeasureSince(key string, start time.Time) {
m.impl.MeasureSince(m.prefix+key, start)
}
func (m *filterMetrics) IncFloatCounterBy(key string, value float64) {
m.impl.IncFloatCounterBy(m.prefix+key, value)
}
func (w noopFlushedResponseWriter) Header() http.Header {
if w.ignoredHeader == nil {
w.ignoredHeader = make(http.Header)
}
return w.ignoredHeader
}
func (w noopFlushedResponseWriter) Write([]byte) (int, error) {
return 0, nil
}
func (w noopFlushedResponseWriter) WriteHeader(_ int) {}
func (w noopFlushedResponseWriter) Flush() {}