Serve only one request and garbage collect (#1978)

Adding once only execution pattern to pool manager based functions. This is for use cases where you don't want to share the samne pod for another execution instance!

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

@@ -36,6 +36,7 @@ func Commands() *cobra.Command {
 			flag.FnExecutorType, flag.FnCfgMap, flag.FnSecret,
 			flag.FnSpecializationTimeout, flag.FnExecutionTimeout,
 			flag.FnIdleTimeout, flag.FnConcurrency, flag.FnRequestsPerPod,
+			flag.FnOnceOnly,
 
 			// TODO retired pkg & trigger related flags from function cmd
 			flag.PkgCode, flag.PkgSrcArchive, flag.PkgDeployArchive,
@@ -87,6 +88,7 @@ func Commands() *cobra.Command {
 			flag.FnExecutorType, flag.FnSecret, flag.FnCfgMap,
 			flag.FnSpecializationTimeout, flag.FnExecutionTimeout,
 			flag.FnIdleTimeout, flag.FnConcurrency, flag.FnRequestsPerPod,
+			flag.FnOnceOnly,
 
 			flag.PkgCode, flag.PkgSrcArchive, flag.PkgDeployArchive,
 			flag.PkgSrcChecksum, flag.PkgDeployChecksum, flag.PkgInsecure,

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

@@ -104,6 +104,8 @@ func (opts *CreateSubCommand) complete(input cli.Input) error {
 
 	requestsPerPod := input.Int(flagkey.FnRequestsPerPod)
 
+	fnOnceOnly := input.Bool(flagkey.FnOnceOnly)
+
 	pkgName := input.String(flagkey.FnPackageName)
 
 	secretNames := input.StringSlice(flagkey.FnSecret)
@@ -304,6 +306,7 @@ func (opts *CreateSubCommand) complete(input cli.Input) error {
 			IdleTimeout:     &fnIdleTimeout,
 			Concurrency:     fnConcurrency,
 			RequestsPerPod:  requestsPerPod,
+			OnceOnly:        fnOnceOnly,
 		},
 	}
 

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

@@ -163,6 +163,9 @@ func (opts *UpdateSubCommand) complete(input cli.Input) error {
 		function.Spec.RequestsPerPod = input.Int(flagkey.FnRequestsPerPod)
 	}
 
+	if input.IsSet(flagkey.FnOnceOnly) {
+		function.Spec.OnceOnly = input.Bool(flagkey.FnOnceOnly)
+	}
 	if len(pkgName) == 0 {
 		pkgName = function.Spec.Package.PackageRef.Name
 	}