Support Function-level idle timeout setting (#1538)

This PR allows users to specify the idle timeout setting at Function-level.
Fix #1050

pkg/apis/core/v1/types.go

@@ -343,6 +343,12 @@ type (
 		// a particular function execution should be complete.
 		// This is optional. If not specified default value will be taken as 60s
 		FunctionTimeout int `json:"functionTimeout,omitempty"`
+
+		// IdleTimeout specifies the length of time that a function is idle before the
+		// function pod(s) are eligible for deletion. If no traffic to the function
+		// is detected within the idle timeout, the executor will then recycle the
+		// function pod(s) to release resources.
+		IdleTimeout *int `json:"idletimeout,omitempty"`
 	}
 
 	// InvokeStrategy is a set of controls over how the function executes.

pkg/apis/core/v1/zz_generated.deepcopy.go

@@ -426,6 +426,11 @@ func (in *FunctionSpec) DeepCopyInto(out *FunctionSpec) {
 	}
 	in.Resources.DeepCopyInto(&out.Resources)
 	out.InvokeStrategy = in.InvokeStrategy
+	if in.IdleTimeout != nil {
+		in, out := &in.IdleTimeout, &out.IdleTimeout
+		*out = new(int)
+		**out = **in
+	}
 	return
 }