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
 	}

pkg/fission-cli/flag/flag.go

@@ -112,6 +112,7 @@ var (
 	FnIdleTimeout           = Flag{Type: Int, Name: flagkey.FnIdleTimeout, Usage: "The length of time (in seconds) that a function is idle before pod(s) are eligible for recycling", DefaultValue: 120}
 	FnConcurrency           = Flag{Type: Int, Name: flagkey.FnConcurrency, Aliases: []string{"con"}, Usage: "Maximum number of pods specialized concurrently to serve requests", DefaultValue: 500}
 	FnRequestsPerPod        = Flag{Type: Int, Name: flagkey.FnRequestsPerPod, Aliases: []string{"rpp"}, Usage: "Maximum number of concurrent requests that can be served by a specialized pod", DefaultValue: 1}
+	FnOnceOnly              = Flag{Type: Bool, Name: flagkey.FnOnceOnly, Aliases: []string{"yolo"}, Usage: "Specifies if specialized pod will serve exactly one request in its lifetime"}
 
 	HtName              = Flag{Type: String, Name: flagkey.HtName, Usage: "HTTP trigger name"}
 	HtMethod            = Flag{Type: String, Name: flagkey.HtMethod, Usage: "HTTP Method: GET|POST|PUT|DELETE|HEAD", DefaultValue: http.MethodGet}

pkg/fission-cli/flag/key/key.go

@@ -65,6 +65,7 @@ const (
 	FnIdleTimeout           = "idletimeout"
 	FnConcurrency           = "concurrency"
 	FnRequestsPerPod        = "requestsperpod"
+	FnOnceOnly              = "onceonly"
 
 	HtName              = resourceName
 	HtMethod            = "method"