From 609e999c28f35dc4b2e7bef93ca8f3526c218200 Mon Sep 17 00:00:00 2001
From: Venkat <venkat@uber.com>
Date: Tue, 24 Mar 2020 16:22:49 -0700
Subject: [PATCH] ringpop: add method to selfEvict from ring (#3132)

---
 common/membership/interfaces.go      |  4 ++++
 common/membership/interfaces_mock.go | 14 ++++++++++++++
 common/membership/rpMonitor.go       |  4 ++++
 host/simpleMonitor.go                |  4 ++++
 4 files changed, 26 insertions(+)

diff --git a/common/membership/interfaces.go b/common/membership/interfaces.go
index b4e2d6205ff..604f415bc34 100644
--- a/common/membership/interfaces.go
+++ b/common/membership/interfaces.go
@@ -53,6 +53,10 @@ type (
 		common.Daemon
 
 		WhoAmI() (*HostInfo, error)
+		// EvictSelf evicts this member from the membership ring. After this method is
+		// called, other members will discover that this node is no longer part of the
+		// ring. This primitive is useful to carry out graceful host shutdown during deployments.
+		EvictSelf() error
 		Lookup(service string, key string) (*HostInfo, error)
 		GetResolver(service string) (ServiceResolver, error)
 		// AddListener adds a listener for this service.
diff --git a/common/membership/interfaces_mock.go b/common/membership/interfaces_mock.go
index 44f99888c73..93e1874cf49 100644
--- a/common/membership/interfaces_mock.go
+++ b/common/membership/interfaces_mock.go
@@ -95,6 +95,20 @@ func (mr *MockMonitorMockRecorder) WhoAmI() *gomock.Call {
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "WhoAmI", reflect.TypeOf((*MockMonitor)(nil).WhoAmI))
 }
 
+// EvictSelf mocks base method
+func (m *MockMonitor) EvictSelf() error {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "EvictSelf")
+	ret0, _ := ret[0].(error)
+	return ret0
+}
+
+// EvictSelf indicates an expected call of EvictSelf
+func (mr *MockMonitorMockRecorder) EvictSelf() *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "EvictSelf", reflect.TypeOf((*MockMonitor)(nil).EvictSelf))
+}
+
 // Lookup mocks base method
 func (m *MockMonitor) Lookup(service, key string) (*HostInfo, error) {
 	m.ctrl.T.Helper()
diff --git a/common/membership/rpMonitor.go b/common/membership/rpMonitor.go
index ef30d50f4bb..72879138ed4 100644
--- a/common/membership/rpMonitor.go
+++ b/common/membership/rpMonitor.go
@@ -115,6 +115,10 @@ func (rpo *ringpopMonitor) WhoAmI() (*HostInfo, error) {
 	return NewHostInfo(address, labels.AsMap()), nil
 }
 
+func (rpo *ringpopMonitor) EvictSelf() error {
+	return rpo.rp.SelfEvict()
+}
+
 func (rpo *ringpopMonitor) GetResolver(service string) (ServiceResolver, error) {
 	ring, found := rpo.rings[service]
 	if !found {
diff --git a/host/simpleMonitor.go b/host/simpleMonitor.go
index 540617ff146..857105ed9ab 100644
--- a/host/simpleMonitor.go
+++ b/host/simpleMonitor.go
@@ -47,6 +47,10 @@ func (s *simpleMonitor) Start() {
 func (s *simpleMonitor) Stop() {
 }
 
+func (s *simpleMonitor) EvictSelf() error {
+	return nil
+}
+
 func (s *simpleMonitor) WhoAmI() (*membership.HostInfo, error) {
 	return s.hostInfo, nil
 }