401 lines
15 KiB
Go
401 lines
15 KiB
Go
package raft
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import (
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"reflect"
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"sync"
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"testing"
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"time"
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)
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//------------------------------------------------------------------------------
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//
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// Tests
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//
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//------------------------------------------------------------------------------
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//--------------------------------------
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// Request Vote
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//--------------------------------------
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// Ensure that we can request a vote from a server that has not voted.
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func TestServerRequestVote(t *testing.T) {
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server := newTestServer("1", &testTransporter{})
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server.Start()
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defer server.Stop()
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resp, err := server.RequestVote(NewRequestVoteRequest(1, "foo", 0, 0))
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if !(resp.Term == 1 && resp.VoteGranted && err == nil) {
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t.Fatalf("Invalid request vote response: %v/%v (%v)", resp.Term, resp.VoteGranted, err)
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}
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}
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// Ensure that a vote request is denied if it comes from an old term.
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func TestServerRequestVoteDeniedForStaleTerm(t *testing.T) {
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server := newTestServer("1", &testTransporter{})
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server.state = Leader
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server.currentTerm = 2
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server.Start()
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defer server.Stop()
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resp, err := server.RequestVote(NewRequestVoteRequest(1, "foo", 0, 0))
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if !(resp.Term == 2 && !resp.VoteGranted && err != nil && err.Error() == "raft.Server: Stale term: 1 < 2") {
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t.Fatalf("Invalid request vote response: %v/%v (%v)", resp.Term, resp.VoteGranted, err)
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}
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if server.currentTerm != 2 && server.state != Follower {
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t.Fatalf("Server did not update term and demote: %v / %v", server.currentTerm, server.state)
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}
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}
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// Ensure that a vote request is denied if we've already voted for a different candidate.
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func TestServerRequestVoteDeniedIfAlreadyVoted(t *testing.T) {
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server := newTestServer("1", &testTransporter{})
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server.currentTerm = 2
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server.Start()
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defer server.Stop()
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resp, err := server.RequestVote(NewRequestVoteRequest(2, "foo", 0, 0))
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if !(resp.Term == 2 && resp.VoteGranted && err == nil) {
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t.Fatalf("First vote should not have been denied (%v)", err)
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}
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resp, err = server.RequestVote(NewRequestVoteRequest(2, "bar", 0, 0))
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if !(resp.Term == 2 && !resp.VoteGranted && err != nil && err.Error() == "raft.Server: Already voted for foo") {
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t.Fatalf("Second vote should have been denied (%v)", err)
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}
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}
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// Ensure that a vote request is approved if vote occurs in a new term.
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func TestServerRequestVoteApprovedIfAlreadyVotedInOlderTerm(t *testing.T) {
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server := newTestServer("1", &testTransporter{})
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server.currentTerm = 2
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server.Start()
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defer server.Stop()
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resp, err := server.RequestVote(NewRequestVoteRequest(2, "foo", 0, 0))
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if !(resp.Term == 2 && resp.VoteGranted && server.VotedFor() == "foo" && err == nil) {
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t.Fatalf("First vote should not have been denied (%v)", err)
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}
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resp, err = server.RequestVote(NewRequestVoteRequest(3, "bar", 0, 0))
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if !(resp.Term == 3 && resp.VoteGranted && server.VotedFor() == "bar" && err == nil) {
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t.Fatalf("Second vote should have been approved (%v)", err)
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}
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}
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// Ensure that a vote request is denied if the log is out of date.
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func TestServerRequestVoteDenyIfCandidateLogIsBehind(t *testing.T) {
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server := newTestServerWithLog("1", &testTransporter{},
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`cf4aab23 0000000000000001 0000000000000001 cmd_1 {"val":"foo","i":20}`+"\n"+
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`4c08d91f 0000000000000002 0000000000000001 cmd_2 {"x":100}`+"\n"+
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`6ac5807c 0000000000000003 0000000000000002 cmd_1 {"val":"bar","i":0}`+"\n")
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if err := server.Start(); err != nil {
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t.Fatalf("Unable to start server: %v", err)
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}
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defer server.Stop()
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resp, err := server.RequestVote(NewRequestVoteRequest(2, "foo", 2, 2))
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if !(resp.Term == 2 && !resp.VoteGranted && err != nil && err.Error() == "raft.Server: Out-of-date log: [3/2] > [2/2]") {
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t.Fatalf("Stale index vote should have been denied [%v/%v] (%v)", resp.Term, resp.VoteGranted, err)
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}
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resp, err = server.RequestVote(NewRequestVoteRequest(2, "foo", 3, 1))
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if !(resp.Term == 2 && !resp.VoteGranted && err != nil && err.Error() == "raft.Server: Out-of-date log: [3/2] > [3/1]") {
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t.Fatalf("Stale term vote should have been denied [%v/%v] (%v)", resp.Term, resp.VoteGranted, err)
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}
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resp, err = server.RequestVote(NewRequestVoteRequest(2, "foo", 3, 2))
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if !(resp.Term == 2 && resp.VoteGranted && err == nil) {
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t.Fatalf("Matching log vote should have been granted (%v)", err)
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}
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resp, err = server.RequestVote(NewRequestVoteRequest(2, "foo", 4, 3))
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if !(resp.Term == 2 && resp.VoteGranted && err == nil) {
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t.Fatalf("Ahead-of-log vote should have been granted (%v)", err)
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}
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}
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//--------------------------------------
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// Promotion
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//--------------------------------------
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// Ensure that we can self-promote a server to candidate, obtain votes and become a fearless leader.
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func TestServerPromoteSelf(t *testing.T) {
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server := newTestServer("1", &testTransporter{})
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server.Start()
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defer server.Stop()
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if success, err := server.promote(); !(success && err == nil && server.state == Leader) {
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t.Fatalf("Server self-promotion failed: %v (%v)", server.state, err)
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}
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}
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// Ensure that we can promote a server within a cluster to a leader.
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func TestServerPromote(t *testing.T) {
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lookup := map[string]*Server{}
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transporter := &testTransporter{}
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transporter.sendVoteRequestFunc = func(server *Server, peer *Peer, req *RequestVoteRequest) (*RequestVoteResponse, error) {
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return lookup[peer.Name()].RequestVote(req)
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}
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transporter.sendAppendEntriesRequestFunc = func(server *Server, peer *Peer, req *AppendEntriesRequest) (*AppendEntriesResponse, error) {
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return lookup[peer.Name()].AppendEntries(req)
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}
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servers := newTestCluster([]string{"1", "2", "3"}, transporter, lookup)
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for _, server := range servers {
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defer server.Stop()
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}
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leader := servers[0]
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if success, err := leader.promote(); !(success && err == nil && leader.state == Leader) {
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t.Fatalf("Server promotion in cluster failed: %v (%v)", leader.state, err)
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}
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}
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// Ensure that a server will restart election if not enough votes are obtained before timeout.
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func TestServerPromoteDoubleElection(t *testing.T) {
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lookup := map[string]*Server{}
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transporter := &testTransporter{}
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transporter.sendVoteRequestFunc = func(server *Server, peer *Peer, req *RequestVoteRequest) (*RequestVoteResponse, error) {
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resp, err := lookup[peer.Name()].RequestVote(req)
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return resp, err
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}
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transporter.sendAppendEntriesRequestFunc = func(server *Server, peer *Peer, req *AppendEntriesRequest) (*AppendEntriesResponse, error) {
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resp, err := lookup[peer.Name()].AppendEntries(req)
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return resp, err
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}
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servers := newTestCluster([]string{"1", "2", "3"}, transporter, lookup)
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lookup["2"].currentTerm, lookup["2"].votedFor = 1, "2"
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lookup["3"].currentTerm, lookup["3"].votedFor = 1, "3"
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lookup["2"].electionTimer.Stop()
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lookup["3"].electionTimer.Stop()
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for _, server := range servers {
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defer server.Stop()
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}
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leader := servers[0]
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if success, err := leader.promote(); !(success && err == nil && leader.state == Leader && leader.currentTerm == 2) {
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t.Fatalf("Server promotion in cluster failed: %v (%v)", leader.state, err)
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}
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time.Sleep(50 * time.Millisecond)
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if lookup["2"].votedFor != "1" {
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t.Fatalf("Unexpected vote for server 2: %v", lookup["2"].votedFor)
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}
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if lookup["3"].votedFor != "1" {
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t.Fatalf("Unexpected vote for server 3: %v", lookup["3"].votedFor)
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}
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}
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//--------------------------------------
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// Append Entries
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//--------------------------------------
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// Ensure we can append entries to a server.
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func TestServerAppendEntries(t *testing.T) {
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server := newTestServer("1", &testTransporter{})
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server.Start()
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defer server.Stop()
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// Append single entry.
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entries := []*LogEntry{NewLogEntry(nil, 1, 1, &TestCommand1{"foo", 10})}
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resp, err := server.AppendEntries(NewAppendEntriesRequest(1, "ldr", 0, 0, entries, 0))
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if !(resp.Term == 1 && resp.Success && err == nil) {
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t.Fatalf("AppendEntries failed: %v/%v : %v", resp.Term, resp.Success, err)
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}
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if index, term := server.log.CommitInfo(); !(index == 0 && term == 0) {
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t.Fatalf("Invalid commit info [IDX=%v, TERM=%v]", index, term)
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}
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// Append multiple entries + commit the last one.
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entries = []*LogEntry{NewLogEntry(nil, 2, 1, &TestCommand1{"bar", 20}), NewLogEntry(nil, 3, 1, &TestCommand1{"baz", 30})}
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resp, err = server.AppendEntries(NewAppendEntriesRequest(1, "ldr", 1, 1, entries, 1))
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if !(resp.Term == 1 && resp.Success && err == nil) {
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t.Fatalf("AppendEntries failed: %v/%v : %v", resp.Term, resp.Success, err)
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}
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if index, term := server.log.CommitInfo(); !(index == 1 && term == 1) {
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t.Fatalf("Invalid commit info [IDX=%v, TERM=%v]", index, term)
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}
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// Send zero entries and commit everything.
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resp, err = server.AppendEntries(NewAppendEntriesRequest(2, "ldr", 3, 1, []*LogEntry{}, 3))
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if !(resp.Term == 2 && resp.Success && err == nil) {
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t.Fatalf("AppendEntries failed: %v/%v : %v", resp.Term, resp.Success, err)
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}
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if index, term := server.log.CommitInfo(); !(index == 3 && term == 1) {
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t.Fatalf("Invalid commit info [IDX=%v, TERM=%v]", index, term)
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}
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}
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// Ensure that entries with stale terms are rejected.
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func TestServerAppendEntriesWithStaleTermsAreRejected(t *testing.T) {
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server := newTestServer("1", &testTransporter{})
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server.Start()
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defer server.Stop()
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server.currentTerm = 2
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// Append single entry.
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entries := []*LogEntry{NewLogEntry(nil, 1, 1, &TestCommand1{"foo", 10})}
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resp, err := server.AppendEntries(NewAppendEntriesRequest(1, "ldr", 0, 0, entries, 0))
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if !(resp.Term == 2 && !resp.Success && err != nil && err.Error() == "raft.Server: Stale request term") {
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t.Fatalf("AppendEntries should have failed: %v/%v : %v", resp.Term, resp.Success, err)
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}
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if index, term := server.log.CommitInfo(); !(index == 0 && term == 0) {
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t.Fatalf("Invalid commit info [IDX=%v, TERM=%v]", index, term)
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}
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}
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// Ensure that we reject entries if the commit log is different.
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func TestServerAppendEntriesRejectedIfAlreadyCommitted(t *testing.T) {
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server := newTestServer("1", &testTransporter{})
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server.Start()
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defer server.Stop()
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// Append single entry + commit.
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entries := []*LogEntry{
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NewLogEntry(nil, 1, 1, &TestCommand1{"foo", 10}),
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NewLogEntry(nil, 2, 1, &TestCommand1{"foo", 15}),
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}
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resp, err := server.AppendEntries(NewAppendEntriesRequest(1, "ldr", 0, 0, entries, 2))
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if !(resp.Term == 1 && resp.Success && err == nil) {
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t.Fatalf("AppendEntries failed: %v/%v : %v", resp.Term, resp.Success, err)
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}
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// Append entry again (post-commit).
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entries = []*LogEntry{NewLogEntry(nil, 2, 1, &TestCommand1{"bar", 20})}
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resp, err = server.AppendEntries(NewAppendEntriesRequest(1, "ldr", 2, 1, entries, 1))
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if !(resp.Term == 1 && !resp.Success && err != nil && err.Error() == "raft.Log: Cannot append entry with earlier index in the same term (1:2 <= 1:2)") {
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t.Fatalf("AppendEntries should have failed: %v/%v : %v", resp.Term, resp.Success, err)
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}
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}
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// Ensure that we uncommitted entries are rolled back if new entries overwrite them.
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func TestServerAppendEntriesOverwritesUncommittedEntries(t *testing.T) {
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server := newTestServer("1", &testTransporter{})
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server.Start()
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defer server.Stop()
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entry1 := NewLogEntry(nil, 1, 1, &TestCommand1{"foo", 10})
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entry2 := NewLogEntry(nil, 2, 1, &TestCommand1{"foo", 15})
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entry3 := NewLogEntry(nil, 2, 2, &TestCommand1{"bar", 20})
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// Append single entry + commit.
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entries := []*LogEntry{entry1, entry2}
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resp, err := server.AppendEntries(NewAppendEntriesRequest(1, "ldr", 0, 0, entries, 1))
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if !(resp.Term == 1 && resp.Success && err == nil && server.log.CommitIndex() == 1 && reflect.DeepEqual(server.log.entries, []*LogEntry{entry1, entry2})) {
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t.Fatalf("AppendEntries failed: %v/%v : %v", resp.Term, resp.Success, err)
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}
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// Append entry that overwrites the second (uncommitted) entry.
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entries = []*LogEntry{entry3}
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resp, err = server.AppendEntries(NewAppendEntriesRequest(2, "ldr", 1, 1, entries, 2))
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if !(resp.Term == 2 && resp.Success && err == nil && server.log.CommitIndex() == 2 && reflect.DeepEqual(server.log.entries, []*LogEntry{entry1, entry3})) {
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t.Fatalf("AppendEntries should have succeeded: %v/%v : %v", resp.Term, resp.Success, err)
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}
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}
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//--------------------------------------
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// Command Execution
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//--------------------------------------
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// Ensure that a follower cannot execute a command.
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func TestServerDenyCommandExecutionWhenFollower(t *testing.T) {
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server := newTestServer("1", &testTransporter{})
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server.Start()
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defer server.Stop()
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if err := server.Do(&TestCommand1{"foo", 10}); err != NotLeaderError {
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t.Fatalf("Expected error: %v, got: %v", NotLeaderError, err)
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}
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}
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//--------------------------------------
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// Membership
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//--------------------------------------
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// Ensure that we can start a single server and append to its log.
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func TestServerSingleNode(t *testing.T) {
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server := newTestServer("1", &testTransporter{})
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if server.state != Stopped {
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t.Fatalf("Unexpected server state: %v", server.state)
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}
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// Get the server running.
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if err := server.Start(); err != nil {
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t.Fatalf("Unable to start server: %v", err)
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}
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defer server.Stop()
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if server.state != Follower {
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t.Fatalf("Unexpected server state: %v", server.state)
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}
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// Join the server to itself.
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server.Initialize()
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if err := server.Do(&joinCommand{Name:"1"}); err != nil {
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t.Fatalf("Unable to join: %v", err)
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}
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if server.state != Leader {
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t.Fatalf("Unexpected server state: %v", server.state)
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}
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// Stop the server.
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server.Stop()
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if server.state != Stopped {
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t.Fatalf("Unexpected server state: %v", server.state)
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}
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}
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// Ensure that we can start multiple servers and determine a leader.
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func TestServerMultiNode(t *testing.T) {
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// Initialize the servers.
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var mutex sync.Mutex
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names := []string{"1", "2", "3"}
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servers := map[string]*Server{}
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for _, server := range servers {
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defer server.Stop()
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}
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transporter := &testTransporter{}
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transporter.sendVoteRequestFunc = func(server *Server, peer *Peer, req *RequestVoteRequest) (*RequestVoteResponse, error) {
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mutex.Lock()
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s := servers[peer.name]
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mutex.Unlock()
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resp, err := s.RequestVote(req)
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return resp, err
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}
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transporter.sendAppendEntriesRequestFunc = func(server *Server, peer *Peer, req *AppendEntriesRequest) (*AppendEntriesResponse, error) {
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mutex.Lock()
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s := servers[peer.name]
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mutex.Unlock()
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resp, err := s.AppendEntries(req)
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return resp, err
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}
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var leader *Server
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for _, name := range names {
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server := newTestServer(name, transporter)
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server.SetElectionTimeout(testElectionTimeout)
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server.SetHeartbeatTimeout(testHeartbeatTimeout)
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if err := server.Start(); err != nil {
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t.Fatalf("Unable to start server[%s]: %v", name, err)
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}
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if name == "1" {
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leader = server
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if err := server.Initialize(); err != nil {
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t.Fatalf("Unable to initialize server[%s]: %v", name, err)
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}
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}
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if err := leader.Do(&joinCommand{Name:name}); err != nil {
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t.Fatalf("Unable to join server[%s]: %v", name, err)
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}
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mutex.Lock()
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servers[name] = server
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mutex.Unlock()
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}
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time.Sleep(100 * time.Millisecond)
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// Check that two peers exist on leader.
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mutex.Lock()
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if leader.MemberCount() != 3 {
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t.Fatalf("Expected member count to be 3, got %v", leader.MemberCount())
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}
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mutex.Unlock()
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// Stop the first server and wait for a re-election.
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time.Sleep(100 * time.Millisecond)
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leader.Stop()
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time.Sleep(100 * time.Millisecond)
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// Check that either server 2 or 3 is the leader now.
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mutex.Lock()
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if servers["2"].State() != Leader && servers["3"].State() != Leader {
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t.Fatalf("Expected leader re-election: 2=%v, 3=%v\n", servers["2"].state, servers["3"].state)
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}
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mutex.Unlock()
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}
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