Fix panic in lite

lite uses both ingester.Config and distributor.Config. Both of them has IngesterClientConfig, so calling RegisterFlags on them triggers panic.
This fix ignores second call to RegisterFlags on IngesterClientConfig and then populates it manually.

Was broken in 6191d41

Author: lelenanam

cmd/lite/main.go

@@ -57,6 +57,7 @@ func main() {
 		&ingesterConfig, &configStoreConfig, &rulerConfig, &storageConfig, &schemaConfig, &logLevel)
 	flag.BoolVar(&unauthenticated, "unauthenticated", false, "Set to true to disable multitenancy.")
 	flag.Parse()
+	ingesterConfig.SetClientConfig(distributorConfig.IngesterClientConfig)
 
 	// Setting the environment variable JAEGER_AGENT_HOST enables tracing
 	jaegerAgentHost := os.Getenv("JAEGER_AGENT_HOST")

pkg/ingester/client/client.go

@@ -1,14 +1,14 @@
 package client
 
 import (
+	"flag"
+
 	"github.com/grpc-ecosystem/grpc-opentracing/go/otgrpc"
 	"github.com/mwitkow/go-grpc-middleware"
 	"github.com/opentracing/opentracing-go"
+	"github.com/weaveworks/common/middleware"
 	"google.golang.org/grpc"
 	_ "google.golang.org/grpc/encoding/gzip" // get gzip compressor registered
-
-	"flag"
-	"github.com/weaveworks/common/middleware"
 )
 
 type closableIngesterClient struct {
@@ -56,6 +56,12 @@ type Config struct {
 
 // RegisterFlags registers configuration settings used by the ingester client config
 func (cfg *Config) RegisterFlags(f *flag.FlagSet) {
+	// lite uses both ingester.Config and distributor.Config.
+	// Both of them has IngesterClientConfig, so calling RegisterFlags on them triggers panic.
+	// This check ignores second call to RegisterFlags on IngesterClientConfig and then populates it manually with SetClientConfig
+	if flag.Lookup("ingester.client.max-recv-message-size") != nil {
+		return
+	}
 	// We have seen 20MB returns from queries - add a bit of headroom
 	f.IntVar(&cfg.MaxRecvMsgSize, "ingester.client.max-recv-message-size", 64*1024*1024, "Maximum message size, in bytes, this client will receive.")
 	flag.BoolVar(&cfg.CompressToIngester, "ingester.client.compress-to-ingester", false, "Compress data in calls to ingesters.")

pkg/ingester/ingester.go

@@ -94,6 +94,11 @@ type Config struct {
 	KVClient              ring.KVClient
 }
 
+// SetClientConfig sets clientConfig in config
+func (cfg *Config) SetClientConfig(clientConfig client.Config) {
+	cfg.clientConfig = clientConfig
+}
+
 // RegisterFlags adds the flags required to config this to the given FlagSet
 func (cfg *Config) RegisterFlags(f *flag.FlagSet) {
 	cfg.RingConfig.RegisterFlags(f)