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balancer: fix connectivity state aggregation algorithm to follow the …
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,70 @@ | ||
| /* | ||
| * | ||
| * Copyright 2022 gRPC authors. | ||
| * | ||
| * Licensed under the Apache License, Version 2.0 (the "License"); | ||
| * you may not use this file except in compliance with the License. | ||
| * You may obtain a copy of the License at | ||
| * | ||
| * http://www.apache.org/licenses/LICENSE-2.0 | ||
| * | ||
| * Unless required by applicable law or agreed to in writing, software | ||
| * distributed under the License is distributed on an "AS IS" BASIS, | ||
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
| * See the License for the specific language governing permissions and | ||
| * limitations under the License. | ||
| * | ||
| */ | ||
|
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| package balancer | ||
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| import "google.golang.org/grpc/connectivity" | ||
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| // ConnectivityStateEvaluator takes the connectivity states of multiple SubConns | ||
| // and returns one aggregated connectivity state. | ||
| // | ||
| // It's not thread safe. | ||
| type ConnectivityStateEvaluator struct { | ||
| numReady uint64 // Number of addrConns in ready state. | ||
| numConnecting uint64 // Number of addrConns in connecting state. | ||
| numTransientFailure uint64 // Number of addrConns in transient failure state. | ||
| numIdle uint64 // Number of addrConns in idle state. | ||
| } | ||
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| // RecordTransition records state change happening in subConn and based on that | ||
| // it evaluates what aggregated state should be. | ||
| // | ||
| // - If at least one SubConn in Ready, the aggregated state is Ready; | ||
| // - Else if at least one SubConn in Connecting, the aggregated state is Connecting; | ||
| // - Else if at least one SubConn is Idle, the aggregated state is Idle; | ||
| // - Else if at least one SubConn is TransientFailure (or there are no SubConns), the aggregated state is Transient Failure. | ||
| // | ||
| // Shutdown is not considered. | ||
| func (cse *ConnectivityStateEvaluator) RecordTransition(oldState, newState connectivity.State) connectivity.State { | ||
| // Update counters. | ||
| for idx, state := range []connectivity.State{oldState, newState} { | ||
| updateVal := 2*uint64(idx) - 1 // -1 for oldState and +1 for new. | ||
| switch state { | ||
| case connectivity.Ready: | ||
| cse.numReady += updateVal | ||
| case connectivity.Connecting: | ||
| cse.numConnecting += updateVal | ||
| case connectivity.TransientFailure: | ||
| cse.numTransientFailure += updateVal | ||
| case connectivity.Idle: | ||
| cse.numIdle += updateVal | ||
| } | ||
| } | ||
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| // Evaluate. | ||
| if cse.numReady > 0 { | ||
| return connectivity.Ready | ||
| } | ||
| if cse.numConnecting > 0 { | ||
| return connectivity.Connecting | ||
| } | ||
| if cse.numIdle > 0 { | ||
| return connectivity.Idle | ||
| } | ||
| return connectivity.TransientFailure | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,245 @@ | ||
| /* | ||
| * | ||
| * Copyright 2022 gRPC authors. | ||
| * | ||
| * Licensed under the Apache License, Version 2.0 (the "License"); | ||
| * you may not use this file except in compliance with the License. | ||
| * You may obtain a copy of the License at | ||
| * | ||
| * http://www.apache.org/licenses/LICENSE-2.0 | ||
| * | ||
| * Unless required by applicable law or agreed to in writing, software | ||
| * distributed under the License is distributed on an "AS IS" BASIS, | ||
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
| * See the License for the specific language governing permissions and | ||
| * limitations under the License. | ||
| * | ||
| */ | ||
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| package balancer | ||
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| import ( | ||
| "testing" | ||
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| "google.golang.org/grpc/connectivity" | ||
| "google.golang.org/grpc/internal/grpctest" | ||
| ) | ||
|
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| type s struct { | ||
| grpctest.Tester | ||
| } | ||
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| func Test(t *testing.T) { | ||
| grpctest.RunSubTests(t, s{}) | ||
| } | ||
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| // TestRecordTransition_FirstStateChange tests the first call to | ||
| // RecordTransition where the `oldState` is usually set to `Shutdown` (a state | ||
| // that the ConnectivityStateEvaluator is set to ignore). | ||
| func (s) TestRecordTransition_FirstStateChange(t *testing.T) { | ||
| tests := []struct { | ||
| newState connectivity.State | ||
| wantState connectivity.State | ||
| }{ | ||
| { | ||
| newState: connectivity.Idle, | ||
| wantState: connectivity.Idle, | ||
| }, | ||
| { | ||
| newState: connectivity.Connecting, | ||
| wantState: connectivity.Connecting, | ||
| }, | ||
| { | ||
| newState: connectivity.Ready, | ||
| wantState: connectivity.Ready, | ||
| }, | ||
| { | ||
| newState: connectivity.TransientFailure, | ||
| wantState: connectivity.TransientFailure, | ||
| }, | ||
| { | ||
| newState: connectivity.Shutdown, | ||
| wantState: connectivity.TransientFailure, | ||
| }, | ||
| } | ||
| for _, test := range tests { | ||
| cse := &ConnectivityStateEvaluator{} | ||
| if gotState := cse.RecordTransition(connectivity.Shutdown, test.newState); gotState != test.wantState { | ||
| t.Fatalf("RecordTransition(%v, %v) = %v, want %v", connectivity.Shutdown, test.newState, gotState, test.wantState) | ||
| } | ||
| } | ||
| } | ||
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| // TestRecordTransition_SameState tests the scenario where state transitions to | ||
| // the same state are recorded multiple times. | ||
| func (s) TestRecordTransition_SameState(t *testing.T) { | ||
| tests := []struct { | ||
| newState connectivity.State | ||
| wantState connectivity.State | ||
| }{ | ||
| { | ||
| newState: connectivity.Idle, | ||
| wantState: connectivity.Idle, | ||
| }, | ||
| { | ||
| newState: connectivity.Connecting, | ||
| wantState: connectivity.Connecting, | ||
| }, | ||
| { | ||
| newState: connectivity.Ready, | ||
| wantState: connectivity.Ready, | ||
| }, | ||
| { | ||
| newState: connectivity.TransientFailure, | ||
| wantState: connectivity.TransientFailure, | ||
| }, | ||
| { | ||
| newState: connectivity.Shutdown, | ||
| wantState: connectivity.TransientFailure, | ||
| }, | ||
| } | ||
| const numStateChanges = 5 | ||
| for _, test := range tests { | ||
| cse := &ConnectivityStateEvaluator{} | ||
| var prevState, gotState connectivity.State | ||
| prevState = connectivity.Shutdown | ||
| for i := 0; i < numStateChanges; i++ { | ||
| gotState = cse.RecordTransition(prevState, test.newState) | ||
| prevState = test.newState | ||
| } | ||
| if gotState != test.wantState { | ||
| t.Fatalf("RecordTransition() = %v, want %v", gotState, test.wantState) | ||
| } | ||
| } | ||
| } | ||
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| // TestRecordTransition_SingleSubConn_DifferentStates tests some common | ||
| // connectivity state change scenarios, on a single subConn. | ||
| func (s) TestRecordTransition_SingleSubConn_DifferentStates(t *testing.T) { | ||
| tests := []struct { | ||
| name string | ||
| states []connectivity.State | ||
| wantState connectivity.State | ||
| }{ | ||
| { | ||
| name: "regular transition to ready", | ||
| states: []connectivity.State{connectivity.Idle, connectivity.Connecting, connectivity.Ready}, | ||
| wantState: connectivity.Ready, | ||
| }, | ||
| { | ||
| name: "regular transition to transient failure", | ||
| states: []connectivity.State{connectivity.Idle, connectivity.Connecting, connectivity.TransientFailure}, | ||
| wantState: connectivity.TransientFailure, | ||
| }, | ||
| { | ||
| name: "regular transition to ready", | ||
| states: []connectivity.State{connectivity.Idle, connectivity.Connecting, connectivity.Ready, connectivity.Idle}, | ||
| wantState: connectivity.Idle, | ||
| }, | ||
| { | ||
| name: "transition from ready to transient failure", | ||
| states: []connectivity.State{connectivity.Idle, connectivity.Connecting, connectivity.Ready, connectivity.TransientFailure}, | ||
| wantState: connectivity.TransientFailure, | ||
| }, | ||
| { | ||
| name: "transition from transient failure back to ready", | ||
| states: []connectivity.State{connectivity.Idle, connectivity.Connecting, connectivity.Ready, connectivity.TransientFailure, connectivity.Ready}, | ||
| wantState: connectivity.Ready, | ||
| }, | ||
| { | ||
| // This state transition is usually suppressed at the LB policy level, by | ||
| // not calling RecordTransition. | ||
| name: "transition from transient failure back to idle", | ||
| states: []connectivity.State{connectivity.Idle, connectivity.Connecting, connectivity.Ready, connectivity.TransientFailure, connectivity.Idle}, | ||
| wantState: connectivity.Idle, | ||
| }, | ||
| { | ||
| // This state transition is usually suppressed at the LB policy level, by | ||
| // not calling RecordTransition. | ||
| name: "transition from transient failure back to connecting", | ||
| states: []connectivity.State{connectivity.Idle, connectivity.Connecting, connectivity.Ready, connectivity.TransientFailure, connectivity.Connecting}, | ||
| wantState: connectivity.Connecting, | ||
| }, | ||
| } | ||
|
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| for _, test := range tests { | ||
| t.Run(test.name, func(t *testing.T) { | ||
| cse := &ConnectivityStateEvaluator{} | ||
| var prevState, gotState connectivity.State | ||
| prevState = connectivity.Shutdown | ||
| for _, newState := range test.states { | ||
| gotState = cse.RecordTransition(prevState, newState) | ||
| prevState = newState | ||
| } | ||
| if gotState != test.wantState { | ||
| t.Fatalf("RecordTransition() = %v, want %v", gotState, test.wantState) | ||
| } | ||
| }) | ||
| } | ||
| } | ||
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| // TestRecordTransition_MultipleSubConns_DifferentStates tests state transitions | ||
| // among multiple subConns, and verifies that the connectivity state aggregation | ||
| // algorithm produces the expected aggregate connectivity state. | ||
| func (s) TestRecordTransition_MultipleSubConns_DifferentStates(t *testing.T) { | ||
| tests := []struct { | ||
| name string | ||
| // Each entry in this slice corresponds to the state changes happening on an | ||
| // individual subConn. | ||
| subConnStates [][]connectivity.State | ||
| wantState connectivity.State | ||
| }{ | ||
| { | ||
| name: "atleast one ready", | ||
| subConnStates: [][]connectivity.State{ | ||
| {connectivity.Idle, connectivity.Connecting, connectivity.Ready}, | ||
| {connectivity.Idle}, | ||
| {connectivity.Idle, connectivity.Connecting}, | ||
| {connectivity.Idle, connectivity.Connecting, connectivity.TransientFailure}, | ||
| }, | ||
| wantState: connectivity.Ready, | ||
| }, | ||
| { | ||
| name: "atleast one connecting", | ||
| subConnStates: [][]connectivity.State{ | ||
| {connectivity.Idle, connectivity.Connecting, connectivity.Ready, connectivity.Connecting}, | ||
| {connectivity.Idle}, | ||
| {connectivity.Idle, connectivity.Connecting, connectivity.TransientFailure}, | ||
| }, | ||
| wantState: connectivity.Connecting, | ||
| }, | ||
| { | ||
| name: "atleast one idle", | ||
| subConnStates: [][]connectivity.State{ | ||
| {connectivity.Idle, connectivity.Connecting, connectivity.Ready, connectivity.Idle}, | ||
| {connectivity.Idle, connectivity.Connecting, connectivity.TransientFailure}, | ||
| }, | ||
| wantState: connectivity.Idle, | ||
| }, | ||
| { | ||
| name: "atleast one transient failure", | ||
| subConnStates: [][]connectivity.State{ | ||
| {connectivity.Idle, connectivity.Connecting, connectivity.Ready, connectivity.TransientFailure}, | ||
| {connectivity.TransientFailure}, | ||
| }, | ||
| wantState: connectivity.TransientFailure, | ||
| }, | ||
| } | ||
|
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| for _, test := range tests { | ||
| t.Run(test.name, func(t *testing.T) { | ||
| cse := &ConnectivityStateEvaluator{} | ||
| var prevState, gotState connectivity.State | ||
| for _, scStates := range test.subConnStates { | ||
| prevState = connectivity.Shutdown | ||
| for _, newState := range scStates { | ||
| gotState = cse.RecordTransition(prevState, newState) | ||
| prevState = newState | ||
| } | ||
| } | ||
| if gotState != test.wantState { | ||
| t.Fatalf("RecordTransition() = %v, want %v", gotState, test.wantState) | ||
| } | ||
| }) | ||
| } | ||
| } |