/
frontend_processor.go
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/
frontend_processor.go
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package worker
import (
"context"
"fmt"
"net/http"
"net/textproto"
"time"
"github.com/go-kit/log"
"github.com/go-kit/log/level"
"github.com/weaveworks/common/httpgrpc"
"github.com/weaveworks/common/user"
"google.golang.org/grpc"
"github.com/cortexproject/cortex/pkg/frontend/v1/frontendv1pb"
"github.com/cortexproject/cortex/pkg/querier/stats"
querier_stats "github.com/cortexproject/cortex/pkg/querier/stats"
"github.com/cortexproject/cortex/pkg/util/backoff"
util_log "github.com/cortexproject/cortex/pkg/util/log"
)
var (
processorBackoffConfig = backoff.Config{
MinBackoff: 50 * time.Millisecond,
MaxBackoff: 1 * time.Second,
}
)
func newFrontendProcessor(cfg Config, handler RequestHandler, log log.Logger) processor {
return &frontendProcessor{
log: log,
handler: handler,
maxMessageSize: cfg.GRPCClientConfig.MaxSendMsgSize,
querierID: cfg.QuerierID,
targetHeaders: cfg.TargetHeaders,
}
}
// Handles incoming queries from frontend.
type frontendProcessor struct {
handler RequestHandler
maxMessageSize int
querierID string
log log.Logger
targetHeaders []string
}
// notifyShutdown implements processor.
func (fp *frontendProcessor) notifyShutdown(ctx context.Context, conn *grpc.ClientConn, address string) {
client := frontendv1pb.NewFrontendClient(conn)
req := &frontendv1pb.NotifyClientShutdownRequest{ClientID: fp.querierID}
if _, err := client.NotifyClientShutdown(ctx, req); err != nil {
// Since we're shutting down there's nothing we can do except logging it.
level.Warn(fp.log).Log("msg", "failed to notify querier shutdown to query-frontend", "address", address, "err", err)
}
}
// runOne loops, trying to establish a stream to the frontend to begin request processing.
func (fp *frontendProcessor) processQueriesOnSingleStream(ctx context.Context, conn *grpc.ClientConn, address string) {
client := frontendv1pb.NewFrontendClient(conn)
backoff := backoff.New(ctx, processorBackoffConfig)
for backoff.Ongoing() {
c, err := client.Process(ctx)
if err != nil {
level.Error(fp.log).Log("msg", "error contacting frontend", "address", address, "err", err)
backoff.Wait()
continue
}
if err := fp.process(c); err != nil {
level.Error(fp.log).Log("msg", "error processing requests", "address", address, "err", err)
backoff.Wait()
continue
}
backoff.Reset()
}
}
// process loops processing requests on an established stream.
func (fp *frontendProcessor) process(c frontendv1pb.Frontend_ProcessClient) error {
// Build a child context so we can cancel a query when the stream is closed.
ctx, cancel := context.WithCancel(c.Context())
defer cancel()
for {
request, err := c.Recv()
if err != nil {
return err
}
switch request.Type {
case frontendv1pb.HTTP_REQUEST:
// Handle the request on a "background" goroutine, so we go back to
// blocking on c.Recv(). This allows us to detect the stream closing
// and cancel the query. We don't actually handle queries in parallel
// here, as we're running in lock step with the server - each Recv is
// paired with a Send.
go fp.runRequest(ctx, request.HttpRequest, request.StatsEnabled, func(response *httpgrpc.HTTPResponse, stats *stats.QueryStats) error {
return c.Send(&frontendv1pb.ClientToFrontend{
HttpResponse: response,
Stats: stats,
})
})
case frontendv1pb.GET_ID:
err := c.Send(&frontendv1pb.ClientToFrontend{ClientID: fp.querierID})
if err != nil {
return err
}
default:
return fmt.Errorf("unknown request type: %v", request.Type)
}
}
}
func (fp *frontendProcessor) runRequest(ctx context.Context, request *httpgrpc.HTTPRequest, statsEnabled bool, sendHTTPResponse func(response *httpgrpc.HTTPResponse, stats *stats.QueryStats) error) {
var stats *querier_stats.QueryStats
if statsEnabled {
stats, ctx = querier_stats.ContextWithEmptyStats(ctx)
}
headers := make(map[string]string, 0)
for _, h := range request.Headers {
headers[h.Key] = h.Values[0]
}
headerMap := make(map[string]string, 0)
// Remove non-existent header.
for _, header := range fp.targetHeaders {
if v, ok := headers[textproto.CanonicalMIMEHeaderKey(header)]; ok {
headerMap[header] = v
}
}
orgID, ok := headers[textproto.CanonicalMIMEHeaderKey(user.OrgIDHeaderName)]
if ok {
ctx = user.InjectOrgID(ctx, orgID)
}
ctx = util_log.ContextWithHeaderMap(ctx, headerMap)
logger := util_log.WithContext(ctx, fp.log)
response, err := fp.handler.Handle(ctx, request)
if err != nil {
var ok bool
response, ok = httpgrpc.HTTPResponseFromError(err)
if !ok {
response = &httpgrpc.HTTPResponse{
Code: http.StatusInternalServerError,
Body: []byte(err.Error()),
}
}
}
if statsEnabled {
level.Info(logger).Log("msg", "finished request", "status_code", response.Code, "response_size", len(response.GetBody()))
}
// Ensure responses that are too big are not retried.
if len(response.Body) >= fp.maxMessageSize {
errMsg := fmt.Sprintf("response larger than the max (%d vs %d)", len(response.Body), fp.maxMessageSize)
response = &httpgrpc.HTTPResponse{
Code: http.StatusRequestEntityTooLarge,
Body: []byte(errMsg),
}
level.Error(fp.log).Log("msg", "error processing query", "err", errMsg)
}
if err := sendHTTPResponse(response, stats); err != nil {
level.Error(fp.log).Log("msg", "error processing requests", "err", err)
}
}