add ingester interface (#3352)

* use interface for ingester

Signed-off-by: Mauro Stettler <[email protected]>

* add comment

Author: replay

pkg/api/api.go

@@ -30,7 +30,6 @@ import (
 	"github.com/cortexproject/cortex/pkg/chunk/purger"
 	"github.com/cortexproject/cortex/pkg/compactor"
 	"github.com/cortexproject/cortex/pkg/distributor"
-	"github.com/cortexproject/cortex/pkg/ingester"
 	"github.com/cortexproject/cortex/pkg/ingester/client"
 	"github.com/cortexproject/cortex/pkg/querier"
 	"github.com/cortexproject/cortex/pkg/querier/frontend"
@@ -201,8 +200,17 @@ func (a *API) RegisterDistributor(d *distributor.Distributor, pushConfig distrib
 	a.RegisterRoute("/ha-tracker", d.HATracker, false, "GET")
 }
 
+// ingester is defined as an interface to allow for alternative implementations
+// of ingesters to be passed into the API.RegisterIngester() method.
+type ingester interface {
+	client.IngesterServer
+	FlushHandler(http.ResponseWriter, *http.Request)
+	ShutdownHandler(http.ResponseWriter, *http.Request)
+	Push(context.Context, *client.WriteRequest) (*client.WriteResponse, error)
+}
+
 // RegisterIngester registers the ingesters HTTP and GRPC service
-func (a *API) RegisterIngester(i *ingester.Ingester, pushConfig distributor.Config) {
+func (a *API) RegisterIngester(i ingester, pushConfig distributor.Config) {
 	client.RegisterIngesterServer(a.server.GRPC, i)
 
 	a.indexPage.AddLink(SectionDangerous, "/ingester/flush", "Trigger a Flush of data from Ingester to storage")