Refactor logging to remove logger, use fluentd with kubernetes filter (#380)

Remove the `logger` container from the logging daemonset. 

Remove the outgoing call from the poolmgr to the logger.  Use Fluentd's Kubernetes filter to add function name and UID to influx metadata.  

This means fluentd now figures out when to start collecting function logs on its own, without being informed by poolmgr.  This is great for other execution strategies, and for autoscaling, where fission isn't in direct control of function pod creation.

Also adds an integration test to make sure logging keeps working.

poolmgr/gp.go

@@ -43,7 +43,6 @@ import (
 	"github.com/fission/fission/crd"
 	"github.com/fission/fission/environments/fetcher"
 	fetcherClient "github.com/fission/fission/environments/fetcher/client"
-	"github.com/fission/fission/logger"
 )
 
 const POOLMGR_INSTANCEID_LABEL string = "poolmgrInstanceId"
@@ -348,9 +347,6 @@ func (gp *GenericPool) specializePod(pod *apiv1.Pod, metadata *metav1.ObjectMeta
 		return err
 	}
 
-	// Tell logging helper about this function invocation
-	gp.setupLogging(pod, metadata)
-
 	// get function run container to specialize
 	log.Printf("[%v] specializing pod", metadata.Name)
 
@@ -682,32 +678,3 @@ func (gp *GenericPool) destroy() error {
 
 	return nil
 }
-
-// Calls the logging daemonset pod on the node where the given pod is
-// running.
-func (gp *GenericPool) setupLogging(pod *apiv1.Pod, metadata *metav1.ObjectMeta) {
-	logReq := logger.LogRequest{
-		Namespace: pod.Namespace,
-		Pod:       pod.Name,
-		Container: gp.env.Metadata.Name,
-		FuncName:  metadata.Name,
-		FuncUid:   string(metadata.UID),
-	}
-	reqbody, err := json.Marshal(logReq)
-	if err != nil {
-		log.Printf("Error creating log request")
-		return
-	}
-	go func() {
-		loggerUrl := fmt.Sprintf("http://%s:1234/v1/log", pod.Status.HostIP)
-		resp, err := http.Post(loggerUrl, "application/json", bytes.NewReader(reqbody))
-		if err != nil {
-			log.Printf("Error connecting to %s log daemonset pod: %v", pod.Spec.NodeName, err)
-		} else {
-			if resp.StatusCode != 200 {
-				log.Printf("Error from %s log daemonset pod: %s", pod.Spec.NodeName, resp.Status)
-			}
-			resp.Body.Close()
-		}
-	}()
-}