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proxy.go
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proxy.go
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package main
//qlb
import (
"context"
"fmt"
"net/http"
"net/http/httputil"
"net/url"
"strconv"
"sync"
"time"
"github.com/Vertamedia/chproxy/cache"
"github.com/Vertamedia/chproxy/config"
"github.com/Vertamedia/chproxy/log"
"github.com/prometheus/client_golang/prometheus"
)
type reverseProxy struct {
rp *httputil.ReverseProxy
// configLock serializes access to applyConfig.
// It protects reload* fields.
configLock sync.Mutex
reloadSignal chan struct{}
reloadWG sync.WaitGroup
// lock protects users, clusters and caches.
// RWMutex enables concurrent access to getScope.
lock sync.RWMutex
users map[string]*user
clusters map[string]*cluster
caches map[string]*cache.Cache
}
func newReverseProxy() *reverseProxy {
return &reverseProxy{
rp: &httputil.ReverseProxy{
Director: func(*http.Request) {},
// Suppress error logging in ReverseProxy, since all the errors
// are handled and logged in the code below.
ErrorLog: log.NilLogger,
},
reloadSignal: make(chan struct{}),
reloadWG: sync.WaitGroup{},
}
}
func (rp *reverseProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
startTime := time.Now()
s, status, err := rp.getScope(req)
if err != nil {
q := getQuerySnippet(req)
err = fmt.Errorf("%q: %s; query: %q", req.RemoteAddr, err, q)
respondWith(rw, err, status)
return
}
// WARNING: don't use s.labels before s.incQueued,
// since `replica` and `cluster_node` may change inside incQueued.
if err := s.incQueued(); err != nil {
limitExcess.With(s.labels).Inc()
q := getQuerySnippet(req)
err = fmt.Errorf("%s: %s; query: %q", s, err, q)
respondWith(rw, err, http.StatusTooManyRequests)
return
}
defer s.dec()
log.Debugf("%s: request start", s)
requestSum.With(s.labels).Inc()
if s.user.allowCORS {
origin := req.Header.Get("Origin")
if len(origin) == 0 {
origin = "*"
}
rw.Header().Set("Access-Control-Allow-Origin", origin)
}
req.Body = &statReadCloser{
ReadCloser: req.Body,
bytesRead: requestBodyBytes.With(s.labels),
}
srw := &statResponseWriter{
ResponseWriter: rw,
bytesWritten: responseBodyBytes.With(s.labels),
}
req, origParams := s.decorateRequest(req)
// wrap body into cachedReadCloser, so we could obtain the original
// request on error.
req.Body = &cachedReadCloser{
ReadCloser: req.Body,
}
if s.user.cache == nil {
rp.proxyRequest(s, srw, srw, req)
} else {
rp.serveFromCache(s, srw, req, origParams)
}
// It is safe calling getQuerySnippet here, since the request
// has been already read in proxyRequest or serveFromCache.
q := getQuerySnippet(req)
if srw.statusCode == http.StatusOK {
requestSuccess.With(s.labels).Inc()
log.Debugf("%s: request success; query: %q; URL: %q", s, q, req.URL.String())
} else {
log.Debugf("%s: request failure: non-200 status code %d; query: %q; URL: %q", s, srw.statusCode, q, req.URL.String())
}
statusCodes.With(
prometheus.Labels{
"user": s.user.name,
"cluster": s.cluster.name,
"cluster_user": s.clusterUser.name,
"replica": s.host.replica.name,
"cluster_node": s.host.addr.Host,
"code": strconv.Itoa(srw.statusCode),
},
).Inc()
since := float64(time.Since(startTime).Seconds())
requestDuration.With(s.labels).Observe(since)
}
// proxyRequest proxies the given request to clickhouse and sends response
// to rw.
//
// srw is required only for setting non-200 status codes on timeouts
// or on client connection disconnects.
func (rp *reverseProxy) proxyRequest(s *scope, rw http.ResponseWriter, srw *statResponseWriter, req *http.Request) {
// wrap body into cachedReadCloser, so we could obtain the original
// request on error.
if _, ok := req.Body.(*cachedReadCloser); !ok {
req.Body = &cachedReadCloser{
ReadCloser: req.Body,
}
}
timeout, timeoutErrMsg := s.getTimeoutWithErrMsg()
ctx := context.Background()
if timeout > 0 {
var cancel context.CancelFunc
ctx, cancel = context.WithTimeout(ctx, timeout)
defer cancel()
}
// Cancel the ctx if client closes the remote connection,
// so the proxied query may be killed instantly.
ctx, ctxCancel := context.WithCancel(ctx)
defer ctxCancel()
// rw must implement http.CloseNotifier.
ch := rw.(http.CloseNotifier).CloseNotify()
go func() {
select {
case <-ch:
ctxCancel()
case <-ctx.Done():
}
}()
req = req.WithContext(ctx)
startTime := time.Now()
rp.rp.ServeHTTP(rw, req)
err := ctx.Err()
switch err {
case nil:
// The request has been successfully proxied.
since := float64(time.Since(startTime).Seconds())
proxiedResponseDuration.With(s.labels).Observe(since)
// cache.ResponseWriter pushes status code to srw on Commit/Rollback actions
// but they didn't happen yet, so manually propagate the status code from crw to srw.
if crw, ok := rw.(*cache.ResponseWriter); ok {
srw.statusCode = crw.StatusCode()
}
// StatusBadGateway response is returned by http.ReverseProxy when
// it cannot establish connection to remote host.
if srw.statusCode == http.StatusBadGateway {
s.host.penalize()
q := getQuerySnippet(req)
err := fmt.Errorf("%s: cannot reach %s; query: %q", s, s.host.addr.Host, q)
respondWith(srw, err, srw.statusCode)
}
case context.Canceled:
canceledRequest.With(s.labels).Inc()
q := getQuerySnippet(req)
log.Debugf("%s: remote client closed the connection in %s; query: %q", s, time.Since(startTime), q)
if err := s.killQuery(); err != nil {
log.Errorf("%s: cannot kill query: %s; query: %q", s, err, q)
}
srw.statusCode = 499 // See https://httpstatuses.com/499 .
case context.DeadlineExceeded:
timeoutRequest.With(s.labels).Inc()
// Penalize host with the timed out query, because it may be overloaded.
s.host.penalize()
q := getQuerySnippet(req)
log.Debugf("%s: query timeout in %s; query: %q", s, time.Since(startTime), q)
if err := s.killQuery(); err != nil {
log.Errorf("%s: cannot kill query: %s; query: %q", s, err, q)
}
err = fmt.Errorf("%s: %s; query: %q", s, timeoutErrMsg, q)
respondWith(rw, err, http.StatusGatewayTimeout)
srw.statusCode = http.StatusGatewayTimeout
default:
panic(fmt.Sprintf("BUG: context.Context.Err() returned unexpected error: %s", err))
}
}
func (rp *reverseProxy) serveFromCache(s *scope, srw *statResponseWriter, req *http.Request, origParams url.Values) {
noCache := origParams.Get("no_cache")
if noCache == "1" || noCache == "true" {
// The response caching is disabled.
rp.proxyRequest(s, srw, srw, req)
return
}
q, err := getFullQuery(req)
if err != nil {
err = fmt.Errorf("%s: cannot read query: %s", s, err)
respondWith(srw, err, http.StatusBadRequest)
return
}
if !canCacheQuery(q) {
// The query cannot be cached, so just proxy it.
rp.proxyRequest(s, srw, srw, req)
return
}
// Do not store `replica` and `cluster_node` in labels, since they have
// no sense for cache metrics.
labels := prometheus.Labels{
"cache": s.user.cache.Name,
"user": s.labels["user"],
"cluster": s.labels["cluster"],
"cluster_user": s.labels["cluster_user"],
}
var paramsHash uint32
if s.user.params != nil {
paramsHash = s.user.params.key
}
key := &cache.Key{
Query: skipLeadingComments(q),
// sort `Accept-Encoding` header to get the same combination for different browsers
AcceptEncoding: sortHeader(req.Header.Get("Accept-Encoding")),
DefaultFormat: origParams.Get("default_format"),
Database: origParams.Get("database"),
Compress: origParams.Get("compress"),
EnableHTTPCompression: origParams.Get("enable_http_compression"),
Namespace: origParams.Get("cache_namespace"),
Extremes: origParams.Get("extremes"),
MaxResultRows: origParams.Get("max_result_rows"),
ResultOverflowMode: origParams.Get("result_overflow_mode"),
UserParamsHash: paramsHash,
}
startTime := time.Now()
err = s.user.cache.WriteTo(srw, key)
if err == nil {
// The response has been successfully served from cache.
cacheHit.With(labels).Inc()
since := float64(time.Since(startTime).Seconds())
cachedResponseDuration.With(labels).Observe(since)
log.Debugf("%s: cache hit", s)
return
}
if err != cache.ErrMissing {
// Unexpected error while serving the response.
err = fmt.Errorf("%s: %s; query: %q", s, err, q)
respondWith(srw, err, http.StatusInternalServerError)
return
}
// The response wasn't found in the cache.
// Request it from clickhouse.
cacheMiss.With(labels).Inc()
log.Debugf("%s: cache miss", s)
crw, err := s.user.cache.NewResponseWriter(srw, key)
if err != nil {
err = fmt.Errorf("%s: %s; query: %q", s, err, q)
respondWith(srw, err, http.StatusInternalServerError)
return
}
rp.proxyRequest(s, crw, srw, req)
if crw.StatusCode() != http.StatusOK || s.canceled {
// Do not cache non-200 or cancelled responses.
// Restore the original status code by proxyRequest if it was set.
if srw.statusCode != 0 {
crw.WriteHeader(srw.statusCode)
}
err = crw.Rollback()
} else {
err = crw.Commit()
}
if err != nil {
err = fmt.Errorf("%s: %s; query: %q", s, err, q)
respondWith(srw, err, http.StatusInternalServerError)
return
}
}
// applyConfig applies the given cfg to reverseProxy.
//
// New config is applied only if non-nil error returned.
// Otherwise old config version is kept.
func (rp *reverseProxy) applyConfig(cfg *config.Config) error {
// configLock protects from concurrent calls to applyConfig
// by serializing such calls.
// configLock shouldn't be used in other places.
rp.configLock.Lock()
defer rp.configLock.Unlock()
clusters, err := newClusters(cfg.Clusters)
if err != nil {
return err
}
caches := make(map[string]*cache.Cache, len(cfg.Caches))
defer func() {
// caches is swapped with old caches from rp.caches
// on successful config reload - see the end of reloadConfig.
for _, tmpCache := range caches {
// Speed up applyConfig by closing caches in background,
// since the process of cache closing may be lengthy
// due to cleaning.
go tmpCache.Close()
}
}()
for _, cc := range cfg.Caches {
if _, ok := caches[cc.Name]; ok {
return fmt.Errorf("duplicate config for cache %q", cc.Name)
}
tmpCache, err := cache.New(cc)
if err != nil {
return fmt.Errorf("cannot initialize cache %q: %s", cc.Name, err)
}
caches[cc.Name] = tmpCache
}
params := make(map[string]*paramsRegistry, len(cfg.ParamGroups))
for _, p := range cfg.ParamGroups {
if _, ok := params[p.Name]; ok {
return fmt.Errorf("duplicate config for ParamGroups %q", p.Name)
}
params[p.Name], err = newParamsRegistry(p.Params)
if err != nil {
return fmt.Errorf("cannot initialize params %q: %s", p.Name, err)
}
}
profile := &usersProfile{
cfg: cfg.Users,
clusters: clusters,
caches: caches,
params: params,
}
users, err := profile.newUsers()
if err != nil {
return err
}
// New configs have been successfully prepared.
// Restart service goroutines with new configs.
// Stop the previous service goroutines.
close(rp.reloadSignal)
rp.reloadWG.Wait()
rp.reloadSignal = make(chan struct{})
// Reset metrics from the previous configs, which may become irrelevant
// with new configs.
// Counters and Summary metrics are always relevant.
// Gauge metrics may become irrelevant if they may freeze at non-zero
// value after config reload.
hostHealth.Reset()
cacheSize.Reset()
cacheItems.Reset()
// Start service goroutines with new configs.
for _, c := range clusters {
for _, r := range c.replicas {
for _, h := range r.hosts {
rp.reloadWG.Add(1)
go func(h *host) {
h.runHeartbeat(rp.reloadSignal)
rp.reloadWG.Done()
}(h)
}
}
for _, cu := range c.users {
rp.reloadWG.Add(1)
go func(cu *clusterUser) {
cu.rateLimiter.run(rp.reloadSignal)
rp.reloadWG.Done()
}(cu)
}
}
for _, u := range users {
rp.reloadWG.Add(1)
go func(u *user) {
u.rateLimiter.run(rp.reloadSignal)
rp.reloadWG.Done()
}(u)
}
// Substitute old configs with the new configs in rp.
// All the currently running requests will continue with old configs,
// while all the new requests will use new configs.
rp.lock.Lock()
rp.clusters = clusters
rp.users = users
// Swap is needed for deferred closing of old caches.
// See the code above where new caches are created.
caches, rp.caches = rp.caches, caches
rp.lock.Unlock()
return nil
}
// refreshCacheMetrics refresehs cacheSize and cacheItems metrics.
func (rp *reverseProxy) refreshCacheMetrics() {
rp.lock.RLock()
defer rp.lock.RUnlock()
for _, c := range rp.caches {
stats := c.Stats()
labels := prometheus.Labels{
"cache": c.Name,
}
cacheSize.With(labels).Set(float64(stats.Size))
cacheItems.With(labels).Set(float64(stats.Items))
}
}
func (rp *reverseProxy) getScope(req *http.Request) (*scope, int, error) {
name, password := getAuth(req)
var (
u *user
c *cluster
cu *clusterUser
)
rp.lock.RLock()
u = rp.users[name]
if u != nil {
// c and cu for toCluster and toUser must exist if applyConfig
// is correct.
// Fix applyConfig if c or cu equal to nil.
c = rp.clusters[u.toCluster]
cu = c.users[u.toUser]
}
rp.lock.RUnlock()
if u == nil {
return nil, http.StatusUnauthorized, fmt.Errorf("invalid username or password for user %q", name)
}
if u.password != password {
return nil, http.StatusUnauthorized, fmt.Errorf("invalid username or password for user %q", name)
}
if u.denyHTTP && req.TLS == nil {
return nil, http.StatusForbidden, fmt.Errorf("user %q is not allowed to access via http", u.name)
}
if u.denyHTTPS && req.TLS != nil {
return nil, http.StatusForbidden, fmt.Errorf("user %q is not allowed to access via https", u.name)
}
if !u.allowedNetworks.Contains(req.RemoteAddr) {
return nil, http.StatusForbidden, fmt.Errorf("user %q is not allowed to access", u.name)
}
if !cu.allowedNetworks.Contains(req.RemoteAddr) {
return nil, http.StatusForbidden, fmt.Errorf("cluster user %q is not allowed to access", cu.name)
}
s := newScope(req, u, c, cu)
return s, 0, nil
}