Fix poolmanager terminates running function pod periodically (#1435)

The pool manager keeps terminating function pod periodically even there are
traffic to the function. The root cause is that executor, poolmgr, newdeploy
manage their own functionServiceCache separately. And when router taps a
function, executor updates the access time of the function service entry in its
own cache without notifying executor types to do the update as well. Hence,
the access time of function service entry in poolmanager cache never gets updated.
Due to the access time never gets updated, the idle pod reaper in poolmanager
then thinks the function pod is in idle state and recycle it.

This PR removes the cache in executor itself, and when router tries to tap a function,
executor will call executor type to tap the function and update access time.

pkg/fission-cli/cmd/function/function_test.go

@@ -48,7 +48,7 @@ func TestGetInvokeStrategy(t *testing.T) {
 		},
 		{
 			// case: executor type set to poolmgr
-			testArgs:               map[string]interface{}{flagkey.FnExecutorType: fv1.ExecutorTypePoolmgr},
+			testArgs:               map[string]interface{}{flagkey.FnExecutorType: string(fv1.ExecutorTypePoolmgr)},
 			existingInvokeStrategy: nil,
 			expectedResult: &fv1.InvokeStrategy{
 				StrategyType: fv1.StrategyTypeExecution,
@@ -60,7 +60,7 @@ func TestGetInvokeStrategy(t *testing.T) {
 		},
 		{
 			// case: executor type set to newdeploy
-			testArgs:               map[string]interface{}{flagkey.FnExecutorType: fv1.ExecutorTypeNewdeploy},
+			testArgs:               map[string]interface{}{flagkey.FnExecutorType: string(fv1.ExecutorTypeNewdeploy)},
 			existingInvokeStrategy: nil,
 			expectedResult: &fv1.InvokeStrategy{
 				StrategyType: fv1.StrategyTypeExecution,
@@ -76,7 +76,7 @@ func TestGetInvokeStrategy(t *testing.T) {
 		},
 		{
 			// case: executor type change from poolmgr to newdeploy
-			testArgs: map[string]interface{}{flagkey.FnExecutorType: fv1.ExecutorTypeNewdeploy},
+			testArgs: map[string]interface{}{flagkey.FnExecutorType: string(fv1.ExecutorTypeNewdeploy)},
 			existingInvokeStrategy: &fv1.InvokeStrategy{
 				StrategyType: fv1.StrategyTypeExecution,
 				ExecutionStrategy: fv1.ExecutionStrategy{
@@ -97,7 +97,7 @@ func TestGetInvokeStrategy(t *testing.T) {
 		},
 		{
 			// case: executor type change from newdeploy to poolmgr
-			testArgs: map[string]interface{}{flagkey.FnExecutorType: fv1.ExecutorTypePoolmgr},
+			testArgs: map[string]interface{}{flagkey.FnExecutorType: string(fv1.ExecutorTypePoolmgr)},
 			existingInvokeStrategy: &fv1.InvokeStrategy{
 				StrategyType: fv1.StrategyTypeExecution,
 				ExecutionStrategy: fv1.ExecutionStrategy{
@@ -119,7 +119,7 @@ func TestGetInvokeStrategy(t *testing.T) {
 		{
 			// case: minscale < maxscale
 			testArgs: map[string]interface{}{
-				flagkey.FnExecutorType:   fv1.ExecutorTypeNewdeploy,
+				flagkey.FnExecutorType:   string(fv1.ExecutorTypeNewdeploy),
 				flagkey.ReplicasMinscale: 2,
 				flagkey.ReplicasMaxscale: 3,
 			},
@@ -139,7 +139,7 @@ func TestGetInvokeStrategy(t *testing.T) {
 		{
 			// case: minscale > maxscale
 			testArgs: map[string]interface{}{
-				flagkey.FnExecutorType:   fv1.ExecutorTypeNewdeploy,
+				flagkey.FnExecutorType:   string(fv1.ExecutorTypeNewdeploy),
 				flagkey.ReplicasMinscale: 5,
 				flagkey.ReplicasMaxscale: 3,
 			},
@@ -150,7 +150,7 @@ func TestGetInvokeStrategy(t *testing.T) {
 		{
 			// case: maxscale not specified
 			testArgs: map[string]interface{}{
-				flagkey.FnExecutorType:   fv1.ExecutorTypeNewdeploy,
+				flagkey.FnExecutorType:   string(fv1.ExecutorTypeNewdeploy),
 				flagkey.ReplicasMinscale: 5,
 			},
 			existingInvokeStrategy: nil,
@@ -160,7 +160,7 @@ func TestGetInvokeStrategy(t *testing.T) {
 		{
 			// case: minscale not specified
 			testArgs: map[string]interface{}{
-				flagkey.FnExecutorType:   fv1.ExecutorTypeNewdeploy,
+				flagkey.FnExecutorType:   string(fv1.ExecutorTypeNewdeploy),
 				flagkey.ReplicasMaxscale: 3,
 			},
 			existingInvokeStrategy: nil,
@@ -179,7 +179,7 @@ func TestGetInvokeStrategy(t *testing.T) {
 		{
 			// case: maxscale set to 0
 			testArgs: map[string]interface{}{
-				flagkey.FnExecutorType:   fv1.ExecutorTypeNewdeploy,
+				flagkey.FnExecutorType:   string(fv1.ExecutorTypeNewdeploy),
 				flagkey.ReplicasMaxscale: 0,
 			},
 			existingInvokeStrategy: nil,
@@ -189,7 +189,7 @@ func TestGetInvokeStrategy(t *testing.T) {
 		{
 			// case: maxscale set to 9 when existing is 5
 			testArgs: map[string]interface{}{
-				flagkey.FnExecutorType:   fv1.ExecutorTypeNewdeploy,
+				flagkey.FnExecutorType:   string(fv1.ExecutorTypeNewdeploy),
 				flagkey.ReplicasMaxscale: 9,
 			},
 			existingInvokeStrategy: &fv1.InvokeStrategy{
@@ -217,7 +217,7 @@ func TestGetInvokeStrategy(t *testing.T) {
 		{
 			// case: change nothing for existing strategy
 			testArgs: map[string]interface{}{
-				flagkey.FnExecutorType: fv1.ExecutorTypeNewdeploy,
+				flagkey.FnExecutorType: string(fv1.ExecutorTypeNewdeploy),
 			},
 			existingInvokeStrategy: &fv1.InvokeStrategy{
 				StrategyType: fv1.StrategyTypeExecution,
@@ -244,7 +244,7 @@ func TestGetInvokeStrategy(t *testing.T) {
 		{
 			// case: set target cpu percentage
 			testArgs: map[string]interface{}{
-				flagkey.FnExecutorType:   fv1.ExecutorTypeNewdeploy,
+				flagkey.FnExecutorType:   string(fv1.ExecutorTypeNewdeploy),
 				flagkey.RuntimeTargetcpu: 50,
 			},
 			existingInvokeStrategy: nil,
@@ -263,7 +263,7 @@ func TestGetInvokeStrategy(t *testing.T) {
 		{
 			// case: change target cpu percentage
 			testArgs: map[string]interface{}{
-				flagkey.FnExecutorType:   fv1.ExecutorTypeNewdeploy,
+				flagkey.FnExecutorType:   string(fv1.ExecutorTypeNewdeploy),
 				flagkey.RuntimeTargetcpu: 20,
 			},
 			existingInvokeStrategy: &fv1.InvokeStrategy{
@@ -291,7 +291,7 @@ func TestGetInvokeStrategy(t *testing.T) {
 		{
 			// case: change specializationtimeout
 			testArgs: map[string]interface{}{
-				flagkey.FnExecutorType:          fv1.ExecutorTypeNewdeploy,
+				flagkey.FnExecutorType:          string(fv1.ExecutorTypeNewdeploy),
 				flagkey.FnSpecializationTimeout: 200,
 			},
 			existingInvokeStrategy: &fv1.InvokeStrategy{
@@ -318,7 +318,7 @@ func TestGetInvokeStrategy(t *testing.T) {
 		{
 			// case: specializationtimeout should not work for poolmgr
 			testArgs: map[string]interface{}{
-				flagkey.FnExecutorType:          fv1.ExecutorTypePoolmgr,
+				flagkey.FnExecutorType:          string(fv1.ExecutorTypePoolmgr),
 				flagkey.FnSpecializationTimeout: 10,
 			},
 			existingInvokeStrategy: nil,
@@ -328,7 +328,7 @@ func TestGetInvokeStrategy(t *testing.T) {
 		{
 			// case: specializationtimeout should not be less than 120
 			testArgs: map[string]interface{}{
-				flagkey.FnExecutorType:          fv1.ExecutorTypeNewdeploy,
+				flagkey.FnExecutorType:          string(fv1.ExecutorTypeNewdeploy),
 				flagkey.FnSpecializationTimeout: 90,
 			},
 			existingInvokeStrategy: nil,