syntax = "proto3";
package rpcpb;

import "github.com/gogo/protobuf/gogoproto/gogo.proto";

option (gogoproto.marshaler_all) = true;
option (gogoproto.sizer_all) = true;
option (gogoproto.unmarshaler_all) = true;
option (gogoproto.goproto_getters_all) = false;

message Request {
  Operation Operation = 1;
  // Member contains the same Member object from tester configuration.
  Member Member = 2;
  // Tester contains tester configuration.
  Tester Tester = 3;
}

// SnapshotInfo contains SAVE_SNAPSHOT request results.
message SnapshotInfo {
  string MemberName = 1;
  repeated string MemberClientURLs = 2;
  string SnapshotPath = 3;
  string SnapshotFileSize = 4;
  string SnapshotTotalSize = 5;
  int64 SnapshotTotalKey = 6;
  int64 SnapshotHash = 7;
  int64 SnapshotRevision = 8;
  string Took = 9;
}

message Response {
  bool Success = 1;
  string Status = 2;

  // Member contains the same Member object from tester request.
  Member Member = 3;

  // SnapshotInfo contains SAVE_SNAPSHOT request results.
  SnapshotInfo SnapshotInfo = 4;
}

service Transport {
  rpc Transport(stream Request) returns (stream Response) {}
}

message Member {
  // EtcdExec is the executable etcd binary path in agent server.
  string EtcdExec = 1 [(gogoproto.moretags) = "yaml:\"etcd-exec\""];

  // AgentAddr is the agent HTTP server address.
  string AgentAddr = 11 [(gogoproto.moretags) = "yaml:\"agent-addr\""];
  // FailpointHTTPAddr is the agent's failpoints HTTP server address.
  string FailpointHTTPAddr = 12 [(gogoproto.moretags) = "yaml:\"failpoint-http-addr\""];

  // BaseDir is the base directory where all logs and etcd data are stored.
  string BaseDir = 101 [(gogoproto.moretags) = "yaml:\"base-dir\""];

  // EtcdClientProxy is true when client traffic needs to be proxied.
  // If true, listen client URL port must be different than advertise client URL port.
  bool EtcdClientProxy = 201 [(gogoproto.moretags) = "yaml:\"etcd-client-proxy\""];
  // EtcdPeerProxy is true when peer traffic needs to be proxied.
  // If true, listen peer URL port must be different than advertise peer URL port.
  bool EtcdPeerProxy = 202 [(gogoproto.moretags) = "yaml:\"etcd-peer-proxy\""];

  // EtcdClientEndpoint is the etcd client endpoint.
  string EtcdClientEndpoint = 301 [(gogoproto.moretags) = "yaml:\"etcd-client-endpoint\""];
  // Etcd defines etcd binary configuration flags.
  Etcd Etcd = 302 [(gogoproto.moretags) = "yaml:\"etcd\""];
  // EtcdOnSnapshotRestore defines one-time use configuration during etcd
  // snapshot recovery process.
  Etcd EtcdOnSnapshotRestore = 303;

  // ClientCertData contains cert file contents from this member's etcd server.
  string ClientCertData = 401 [(gogoproto.moretags) = "yaml:\"client-cert-data\""];
  string ClientCertPath = 402 [(gogoproto.moretags) = "yaml:\"client-cert-path\""];
  // ClientKeyData contains key file contents from this member's etcd server.
  string ClientKeyData = 403 [(gogoproto.moretags) = "yaml:\"client-key-data\""];
  string ClientKeyPath = 404 [(gogoproto.moretags) = "yaml:\"client-key-path\""];
  // ClientTrustedCAData contains trusted CA file contents from this member's etcd server.
  string ClientTrustedCAData = 405 [(gogoproto.moretags) = "yaml:\"client-trusted-ca-data\""];
  string ClientTrustedCAPath = 406 [(gogoproto.moretags) = "yaml:\"client-trusted-ca-path\""];

  // PeerCertData contains cert file contents from this member's etcd server.
  string PeerCertData = 501 [(gogoproto.moretags) = "yaml:\"peer-cert-data\""];
  string PeerCertPath = 502 [(gogoproto.moretags) = "yaml:\"peer-cert-path\""];
  // PeerKeyData contains key file contents from this member's etcd server.
  string PeerKeyData = 503 [(gogoproto.moretags) = "yaml:\"peer-key-data\""];
  string PeerKeyPath = 504 [(gogoproto.moretags) = "yaml:\"peer-key-path\""];
  // PeerTrustedCAData contains trusted CA file contents from this member's etcd server.
  string PeerTrustedCAData = 505 [(gogoproto.moretags) = "yaml:\"peer-trusted-ca-data\""];
  string PeerTrustedCAPath = 506 [(gogoproto.moretags) = "yaml:\"peer-trusted-ca-path\""];

  // SnapshotPath is the snapshot file path to store or restore from.
  string SnapshotPath = 601 [(gogoproto.moretags) = "yaml:\"snapshot-path\""];
  // SnapshotInfo contains last SAVE_SNAPSHOT request results.
  SnapshotInfo SnapshotInfo = 602;
}

message Tester {
  string DataDir = 1 [(gogoproto.moretags) = "yaml:\"data-dir\""];
  string Network = 2 [(gogoproto.moretags) = "yaml:\"network\""];
  string Addr = 3 [(gogoproto.moretags) = "yaml:\"addr\""];

  // DelayLatencyMsRv is the delay latency in milliseconds,
  // to inject to simulated slow network.
  uint32 DelayLatencyMs = 11 [(gogoproto.moretags) = "yaml:\"delay-latency-ms\""];
  // DelayLatencyMsRv is the delay latency random variable in milliseconds.
  uint32 DelayLatencyMsRv = 12 [(gogoproto.moretags) = "yaml:\"delay-latency-ms-rv\""];
  // UpdatedDelayLatencyMs is the update delay latency in milliseconds,
  // to inject to simulated slow network. It's the final latency to apply,
  // in case the latency numbers are randomly generated from given delay latency field.
  uint32 UpdatedDelayLatencyMs = 13 [(gogoproto.moretags) = "yaml:\"updated-delay-latency-ms\""];

  // RoundLimit is the limit of rounds to run failure set (-1 to run without limits).
  int32 RoundLimit = 21 [(gogoproto.moretags) = "yaml:\"round-limit\""];
  // ExitOnCaseFail is true, then exit tester on first failure.
  bool ExitOnCaseFail = 22 [(gogoproto.moretags) = "yaml:\"exit-on-failure\""];
  // EnablePprof is true to enable profiler.
  bool EnablePprof = 23 [(gogoproto.moretags) = "yaml:\"enable-pprof\""];

  // CaseDelayMs is the delay duration after failure is injected.
  // Useful when triggering snapshot or no-op failure cases.
  uint32 CaseDelayMs = 31 [(gogoproto.moretags) = "yaml:\"case-delay-ms\""];
  // CaseShuffle is true to randomize failure injecting order.
  bool CaseShuffle = 32 [(gogoproto.moretags) = "yaml:\"case-shuffle\""];
  // Cases is the selected test cases to schedule.
  // If empty, run all failure cases.
  repeated string Cases = 33 [(gogoproto.moretags) = "yaml:\"cases\""];
  // FailpointCommands is the list of "gofail" commands
  // (e.g. panic("etcd-tester"),1*sleep(1000).
  repeated string FailpointCommands = 34 [(gogoproto.moretags) = "yaml:\"failpoint-commands\""];

  // RunnerExecPath is a path of etcd-runner binary.
  string RunnerExecPath = 41 [(gogoproto.moretags) = "yaml:\"runner-exec-path\""];
  // ExternalExecPath is a path of script for enabling/disabling an external fault injector.
  string ExternalExecPath = 42 [(gogoproto.moretags) = "yaml:\"external-exec-path\""];

  // Stressers is the list of stresser types:
  // KV, LEASE, ELECTION_RUNNER, WATCH_RUNNER, LOCK_RACER_RUNNER, LEASE_RUNNER.
  repeated Stresser Stressers = 101 [(gogoproto.moretags) = "yaml:\"stressers\""];
  // Checkers is the list of consistency checker types:
  // KV_HASH, LEASE_EXPIRE, NO_CHECK, RUNNER.
  // Leave empty to skip consistency checks.
  repeated string Checkers = 102 [(gogoproto.moretags) = "yaml:\"checkers\""];

  // StressKeySize is the size of each small key written into etcd.
  int32 StressKeySize = 201 [(gogoproto.moretags) = "yaml:\"stress-key-size\""];
  // StressKeySizeLarge is the size of each large key written into etcd.
  int32 StressKeySizeLarge = 202 [(gogoproto.moretags) = "yaml:\"stress-key-size-large\""];
  // StressKeySuffixRange is the count of key range written into etcd.
  // Stress keys are created with "fmt.Sprintf("foo%016x", rand.Intn(keySuffixRange)".
  int32 StressKeySuffixRange = 203 [(gogoproto.moretags) = "yaml:\"stress-key-suffix-range\""];
  // StressKeySuffixRangeTxn is the count of key range written into etcd txn (max 100).
  // Stress keys are created with "fmt.Sprintf("/k%03d", i)".
  int32 StressKeySuffixRangeTxn = 204 [(gogoproto.moretags) = "yaml:\"stress-key-suffix-range-txn\""];
  // StressKeyTxnOps is the number of operations per a transaction (max 64).
  int32 StressKeyTxnOps = 205 [(gogoproto.moretags) = "yaml:\"stress-key-txn-ops\""];

  // StressClients is the number of concurrent stressing clients
  // with "one" shared TCP connection.
  int32 StressClients = 301 [(gogoproto.moretags) = "yaml:\"stress-clients\""];
  // StressQPS is the maximum number of stresser requests per second.
  int32 StressQPS = 302 [(gogoproto.moretags) = "yaml:\"stress-qps\""];
}

enum StresserType {
  KV_WRITE_SMALL = 0;
  KV_WRITE_LARGE = 1;
  KV_READ_ONE_KEY = 2;
  KV_READ_RANGE = 3;
  KV_DELETE_ONE_KEY = 4;
  KV_DELETE_RANGE = 5;
  KV_TXN_WRITE_DELETE = 6;

  LEASE = 10;

  ELECTION_RUNNER = 20;
  WATCH_RUNNER = 31;
  LOCK_RACER_RUNNER = 41;
  LEASE_RUNNER = 51;
}

message Stresser {
  string Type = 1 [(gogoproto.moretags) = "yaml:\"type\""];
  double Weight = 2 [(gogoproto.moretags) = "yaml:\"weight\""];
}

enum Checker {
  KV_HASH = 0;
  LEASE_EXPIRE = 1;
  RUNNER = 2;
  NO_CHECK = 3;
}

message Etcd {
  string Name = 1 [(gogoproto.moretags) = "yaml:\"name\""];
  string DataDir = 2 [(gogoproto.moretags) = "yaml:\"data-dir\""];
  string WALDir = 3 [(gogoproto.moretags) = "yaml:\"wal-dir\""];

  // HeartbeatIntervalMs is the time (in milliseconds) of a heartbeat interval.
  // Default value is 100, which is 100ms.
  int64 HeartbeatIntervalMs = 11 [(gogoproto.moretags) = "yaml:\"heartbeat-interval\""];
  // ElectionTimeoutMs is the time (in milliseconds) for an election to timeout.
  // Default value is 1000, which is 1s.
  int64 ElectionTimeoutMs = 12 [(gogoproto.moretags) = "yaml:\"election-timeout\""];

  repeated string ListenClientURLs = 21 [(gogoproto.moretags) = "yaml:\"listen-client-urls\""];
  repeated string AdvertiseClientURLs = 22 [(gogoproto.moretags) = "yaml:\"advertise-client-urls\""];
  bool ClientAutoTLS = 23 [(gogoproto.moretags) = "yaml:\"auto-tls\""];
  bool ClientCertAuth = 24 [(gogoproto.moretags) = "yaml:\"client-cert-auth\""];
  string ClientCertFile = 25 [(gogoproto.moretags) = "yaml:\"cert-file\""];
  string ClientKeyFile = 26 [(gogoproto.moretags) = "yaml:\"key-file\""];
  string ClientTrustedCAFile = 27 [(gogoproto.moretags) = "yaml:\"trusted-ca-file\""];

  repeated string ListenPeerURLs = 31 [(gogoproto.moretags) = "yaml:\"listen-peer-urls\""];
  repeated string AdvertisePeerURLs = 32 [(gogoproto.moretags) = "yaml:\"initial-advertise-peer-urls\""];
  bool PeerAutoTLS = 33 [(gogoproto.moretags) = "yaml:\"peer-auto-tls\""];
  bool PeerClientCertAuth = 34 [(gogoproto.moretags) = "yaml:\"peer-client-cert-auth\""];
  string PeerCertFile = 35 [(gogoproto.moretags) = "yaml:\"peer-cert-file\""];
  string PeerKeyFile = 36 [(gogoproto.moretags) = "yaml:\"peer-key-file\""];
  string PeerTrustedCAFile = 37 [(gogoproto.moretags) = "yaml:\"peer-trusted-ca-file\""];

  string InitialCluster = 41 [(gogoproto.moretags) = "yaml:\"initial-cluster\""];
  string InitialClusterState = 42 [(gogoproto.moretags) = "yaml:\"initial-cluster-state\""];
  string InitialClusterToken = 43 [(gogoproto.moretags) = "yaml:\"initial-cluster-token\""];

  int64 SnapshotCount = 51 [(gogoproto.moretags) = "yaml:\"snapshot-count\""];
  int64 QuotaBackendBytes = 52 [(gogoproto.moretags) = "yaml:\"quota-backend-bytes\""];

  bool PreVote = 63 [(gogoproto.moretags) = "yaml:\"pre-vote\""];
  bool InitialCorruptCheck = 64 [(gogoproto.moretags) = "yaml:\"initial-corrupt-check\""];

  string Logger = 71 [(gogoproto.moretags) = "yaml:\"logger\""];
  // LogOutputs is the log file to store current etcd server logs.
  repeated string LogOutputs = 72 [(gogoproto.moretags) = "yaml:\"log-outputs\""];
  string LogLevel = 73 [(gogoproto.moretags) = "yaml:\"log-level\""];
}

enum Operation {
  // NOT_STARTED is the agent status before etcd first start.
  NOT_STARTED = 0;

  // INITIAL_START_ETCD is only called to start etcd, the very first time.
  INITIAL_START_ETCD = 10;
  // RESTART_ETCD is sent to restart killed etcd.
  RESTART_ETCD = 11;

  // SIGTERM_ETCD pauses etcd process while keeping data directories
  // and previous etcd configurations.
  SIGTERM_ETCD = 20;
  // SIGQUIT_ETCD_AND_REMOVE_DATA kills etcd process and removes all data
  // directories to simulate destroying the whole machine.
  SIGQUIT_ETCD_AND_REMOVE_DATA = 21;

  // SAVE_SNAPSHOT is sent to trigger local member to download its snapshot
  // onto its local disk with the specified path from tester.
  SAVE_SNAPSHOT = 30;
  // RESTORE_RESTART_FROM_SNAPSHOT is sent to trigger local member to
  // restore a cluster from existing snapshot from disk, and restart
  // an etcd instance from recovered data.
  RESTORE_RESTART_FROM_SNAPSHOT = 31;
  // RESTART_FROM_SNAPSHOT is sent to trigger local member to restart
  // and join an existing cluster that has been recovered from a snapshot.
  // Local member joins this cluster with fresh data.
  RESTART_FROM_SNAPSHOT = 32;

  // SIGQUIT_ETCD_AND_ARCHIVE_DATA is sent when consistency check failed,
  // thus need to archive etcd data directories.
  SIGQUIT_ETCD_AND_ARCHIVE_DATA = 40;
  // SIGQUIT_ETCD_AND_REMOVE_DATA_AND_STOP_AGENT destroys etcd process,
  // etcd data, and agent server.
  SIGQUIT_ETCD_AND_REMOVE_DATA_AND_STOP_AGENT = 41;

  // BLACKHOLE_PEER_PORT_TX_RX drops all outgoing/incoming packets from/to
  // the peer port on target member's peer port.
  BLACKHOLE_PEER_PORT_TX_RX = 100;
  // UNBLACKHOLE_PEER_PORT_TX_RX removes outgoing/incoming packet dropping.
  UNBLACKHOLE_PEER_PORT_TX_RX = 101;

  // DELAY_PEER_PORT_TX_RX delays all outgoing/incoming packets from/to
  // the peer port on target member's peer port.
  DELAY_PEER_PORT_TX_RX = 200;
  // UNDELAY_PEER_PORT_TX_RX removes all outgoing/incoming delays.
  UNDELAY_PEER_PORT_TX_RX = 201;
}

// Case defines various system faults or test case in distributed systems,
// in order to verify correct behavior of etcd servers and clients.
enum Case {
  // SIGTERM_ONE_FOLLOWER stops a randomly chosen follower (non-leader)
  // but does not delete its data directories on disk for next restart.
  // It waits "delay-ms" before recovering this failure.
  // The expected behavior is that the follower comes back online
  // and rejoins the cluster, and then each member continues to process
  // client requests ('Put' request that requires Raft consensus).
  SIGTERM_ONE_FOLLOWER = 0;

  // SIGTERM_ONE_FOLLOWER_UNTIL_TRIGGER_SNAPSHOT stops a randomly chosen
  // follower but does not delete its data directories on disk for next
  // restart. And waits until most up-to-date node (leader) applies the
  // snapshot count of entries since the stop operation.
  // The expected behavior is that the follower comes back online and
  // rejoins the cluster, and then active leader sends snapshot
  // to the follower to force it to follow the leader's log.
  // As always, after recovery, each member must be able to process
  // client requests.
  SIGTERM_ONE_FOLLOWER_UNTIL_TRIGGER_SNAPSHOT = 1;

  // SIGTERM_LEADER stops the active leader node but does not delete its
  // data directories on disk for next restart. Then it waits "delay-ms"
  // before recovering this failure, in order to trigger election timeouts.
  // The expected behavior is that a new leader gets elected, and the
  // old leader comes back online and rejoins the cluster as a follower.
  // As always, after recovery, each member must be able to process
  // client requests.
  SIGTERM_LEADER = 2;

  // SIGTERM_LEADER_UNTIL_TRIGGER_SNAPSHOT stops the active leader node
  // but does not delete its data directories on disk for next restart.
  // And waits until most up-to-date node ("new" leader) applies the
  // snapshot count of entries since the stop operation.
  // The expected behavior is that cluster elects a new leader, and the
  // old leader comes back online and rejoins the cluster as a follower.
  // And it receives the snapshot from the new leader to overwrite its
  // store. As always, after recovery, each member must be able to
  // process client requests.
  SIGTERM_LEADER_UNTIL_TRIGGER_SNAPSHOT = 3;

  // SIGTERM_QUORUM stops majority number of nodes to make the whole cluster
  // inoperable but does not delete data directories on stopped nodes
  // for next restart. And it waits "delay-ms" before recovering failure.
  // The expected behavior is that nodes come back online, thus cluster
  // comes back operative as well. As always, after recovery, each member
  // must be able to process client requests.
  SIGTERM_QUORUM = 4;

  // SIGTERM_ALL stops the whole cluster but does not delete data directories
  // on disk for next restart. And it waits "delay-ms" before  recovering
  // this failure.
  // The expected behavior is that nodes come back online, thus cluster
  // comes back operative as well. As always, after recovery, each member
  // must be able to process client requests.
  SIGTERM_ALL = 5;

  // SIGQUIT_AND_REMOVE_ONE_FOLLOWER stops a randomly chosen follower
  // (non-leader), deletes its data directories on disk, and removes
  // this member from cluster (membership reconfiguration). On recovery,
  // tester adds a new member, and this member joins the existing cluster
  // with fresh data. It waits "delay-ms" before recovering this
  // failure. This simulates destroying one follower machine, where operator
  // needs to add a new member from a fresh machine.
  // The expected behavior is that a new member joins the existing cluster,
  // and then each member continues to process client requests.
  SIGQUIT_AND_REMOVE_ONE_FOLLOWER = 10;

  // SIGQUIT_AND_REMOVE_ONE_FOLLOWER_UNTIL_TRIGGER_SNAPSHOT stops a randomly
  // chosen follower, deletes its data directories on disk, and removes
  // this member from cluster (membership reconfiguration). On recovery,
  // tester adds a new member, and this member joins the existing cluster
  // restart. On member remove, cluster waits until most up-to-date node
  // (leader) applies the snapshot count of entries since the stop operation.
  // This simulates destroying a leader machine, where operator needs to add
  // a new member from a fresh machine.
  // The expected behavior is that a new member joins the existing cluster,
  // and receives a snapshot from the active leader. As always, after
  // recovery, each member must be able to process client requests.
  SIGQUIT_AND_REMOVE_ONE_FOLLOWER_UNTIL_TRIGGER_SNAPSHOT = 11;

  // SIGQUIT_AND_REMOVE_LEADER stops the active leader node, deletes its
  // data directories on disk, and removes this member from cluster.
  // On recovery, tester adds a new member, and this member joins the
  // existing cluster with fresh data. It waits "delay-ms" before
  // recovering this failure. This simulates destroying a leader machine,
  // where operator needs to add a new member from a fresh machine.
  // The expected behavior is that a new member joins the existing cluster,
  // and then each member continues to process client requests.
  SIGQUIT_AND_REMOVE_LEADER = 12;

  // SIGQUIT_AND_REMOVE_LEADER_UNTIL_TRIGGER_SNAPSHOT stops the active leader,
  // deletes its data directories on disk, and removes this member from
  // cluster (membership reconfiguration). On recovery, tester adds a new
  // member, and this member joins the existing cluster restart. On member
  // remove, cluster waits until most up-to-date node (new leader) applies
  // the snapshot count of entries since the stop operation. This simulates
  // destroying a leader machine, where operator needs to add a new member
  // from a fresh machine.
  // The expected behavior is that on member remove, cluster elects a new
  // leader, and a new member joins the existing cluster and receives a
  // snapshot from the newly elected leader. As always, after recovery, each
  // member must be able to process client requests.
  SIGQUIT_AND_REMOVE_LEADER_UNTIL_TRIGGER_SNAPSHOT = 13;

  // SIGQUIT_AND_REMOVE_QUORUM_AND_RESTORE_LEADER_SNAPSHOT_FROM_SCRATCH first
  // stops majority number of nodes, deletes data directories on those quorum
  // nodes, to make the whole cluster inoperable. Now that quorum and their
  // data are totally destroyed, cluster cannot even remove unavailable nodes
  // (e.g. 2 out of 3 are lost, so no leader can be elected).
  // Let's assume 3-node cluster of node A, B, and C. One day, node A and B
  // are destroyed and all their data are gone. The only viable solution is
  // to recover from C's latest snapshot.
  //
  // To simulate:
  //  1. Assume node C is the current leader with most up-to-date data.
  //  2. Download snapshot from node C, before destroying node A and B.
  //  3. Destroy node A and B, and make the whole cluster inoperable.
  //  4. Now node C cannot operate either.
  //  5. SIGTERM node C and remove its data directories.
  //  6. Restore a new seed member from node C's latest snapshot file.
  //  7. Add another member to establish 2-node cluster.
  //  8. Add another member to establish 3-node cluster.
  //  9. Add more if any.
  //
  // The expected behavior is that etcd successfully recovers from such
  // disastrous situation as only 1-node survives out of 3-node cluster,
  // new members joins the existing cluster, and previous data from snapshot
  // are still preserved after recovery process. As always, after recovery,
  // each member must be able to process client requests.
  SIGQUIT_AND_REMOVE_QUORUM_AND_RESTORE_LEADER_SNAPSHOT_FROM_SCRATCH = 14;

  // BLACKHOLE_PEER_PORT_TX_RX_ONE_FOLLOWER drops all outgoing/incoming
  // packets from/to the peer port on a randomly chosen follower
  // (non-leader), and waits for "delay-ms" until recovery.
  // The expected behavior is that once dropping operation is undone,
  // each member must be able to process client requests.
  BLACKHOLE_PEER_PORT_TX_RX_ONE_FOLLOWER = 100;

  // BLACKHOLE_PEER_PORT_TX_RX_ONE_FOLLOWER_UNTIL_TRIGGER_SNAPSHOT drops
  // all outgoing/incoming packets from/to the peer port on a randomly
  // chosen follower (non-leader), and waits for most up-to-date node
  // (leader) applies the snapshot count of entries since the blackhole
  // operation.
  // The expected behavior is that once packet drop operation is undone,
  // the slow follower tries to catch up, possibly receiving the snapshot
  // from the active leader. As always, after recovery, each member must
  // be able to process client requests.
  BLACKHOLE_PEER_PORT_TX_RX_ONE_FOLLOWER_UNTIL_TRIGGER_SNAPSHOT = 101;

  // BLACKHOLE_PEER_PORT_TX_RX_LEADER drops all outgoing/incoming packets
  // from/to the peer port on the active leader (isolated), and waits for
  // "delay-ms" until recovery, in order to trigger election timeout.
  // The expected behavior is that after election timeout, a new leader gets
  // elected, and once dropping operation is undone, the old leader comes
  // back and rejoins the cluster as a follower. As always, after recovery,
  // each member must be able to process client requests.
  BLACKHOLE_PEER_PORT_TX_RX_LEADER = 102;

  // BLACKHOLE_PEER_PORT_TX_RX_LEADER_UNTIL_TRIGGER_SNAPSHOT drops all
  // outgoing/incoming packets from/to the peer port on the active leader,
  // and waits for most up-to-date node (leader) applies the snapshot
  // count of entries since the blackhole operation.
  // The expected behavior is that cluster elects a new leader, and once
  // dropping operation is undone, the old leader comes back and rejoins
  // the cluster as a follower. The slow follower tries to catch up, likely
  // receiving the snapshot from the new active leader. As always, after
  // recovery, each member must be able to process client requests.
  BLACKHOLE_PEER_PORT_TX_RX_LEADER_UNTIL_TRIGGER_SNAPSHOT = 103;

  // BLACKHOLE_PEER_PORT_TX_RX_QUORUM drops all outgoing/incoming packets
  // from/to the peer ports on majority nodes of cluster, thus losing its
  // leader and cluster being inoperable. And it waits for "delay-ms"
  // until recovery.
  // The expected behavior is that once packet drop operation is undone,
  // nodes come back online, thus cluster comes back operative. As always,
  // after recovery, each member must be able to process client requests.
  BLACKHOLE_PEER_PORT_TX_RX_QUORUM = 104;

  // BLACKHOLE_PEER_PORT_TX_RX_ALL drops all outgoing/incoming packets
  // from/to the peer ports on all nodes, thus making cluster totally
  // inoperable. It waits for "delay-ms" until recovery.
  // The expected behavior is that once packet drop operation is undone,
  // nodes come back online, thus cluster comes back operative. As always,
  // after recovery, each member must be able to process client requests.
  BLACKHOLE_PEER_PORT_TX_RX_ALL = 105;

  // DELAY_PEER_PORT_TX_RX_ONE_FOLLOWER delays outgoing/incoming packets
  // from/to the peer port on a randomly chosen follower (non-leader).
  // It waits for "delay-ms" until recovery.
  // The expected behavior is that once packet delay operation is undone,
  // the follower comes back and tries to catch up with latest changes from
  // cluster. And as always, after recovery, each member must be able to
  // process client requests.
  DELAY_PEER_PORT_TX_RX_ONE_FOLLOWER = 200;

  // RANDOM_DELAY_PEER_PORT_TX_RX_ONE_FOLLOWER delays outgoing/incoming
  // packets from/to the peer port on a randomly chosen follower
  // (non-leader) with a randomized time duration (thus isolated). It
  // waits for "delay-ms" until recovery.
  // The expected behavior is that once packet delay operation is undone,
  // each member must be able to process client requests.
  RANDOM_DELAY_PEER_PORT_TX_RX_ONE_FOLLOWER = 201;

  // DELAY_PEER_PORT_TX_RX_ONE_FOLLOWER_UNTIL_TRIGGER_SNAPSHOT delays
  // outgoing/incoming packets from/to the peer port on a randomly chosen
  // follower (non-leader), and waits for most up-to-date node (leader)
  // applies the snapshot count of entries since the delay operation.
  // The expected behavior is that the delayed follower gets isolated
  // and behind the current active leader, and once delay operation is undone,
  // the slow follower comes back and catches up possibly receiving snapshot
  // from the active leader. As always, after recovery, each member must be
  // able to process client requests.
  DELAY_PEER_PORT_TX_RX_ONE_FOLLOWER_UNTIL_TRIGGER_SNAPSHOT = 202;

  // RANDOM_DELAY_PEER_PORT_TX_RX_ONE_FOLLOWER_UNTIL_TRIGGER_SNAPSHOT delays
  // outgoing/incoming packets from/to the peer port on a randomly chosen
  // follower (non-leader) with a randomized time duration, and waits for
  // most up-to-date node (leader) applies the snapshot count of entries
  // since the delay operation.
  // The expected behavior is that the delayed follower gets isolated
  // and behind the current active leader, and once delay operation is undone,
  // the slow follower comes back and catches up, possibly receiving a
  // snapshot from the active leader. As always, after recovery, each member
  // must be able to process client requests.
  RANDOM_DELAY_PEER_PORT_TX_RX_ONE_FOLLOWER_UNTIL_TRIGGER_SNAPSHOT = 203;

  // DELAY_PEER_PORT_TX_RX_LEADER delays outgoing/incoming packets from/to
  // the peer port on the active leader. And waits for "delay-ms" until
  // recovery.
  // The expected behavior is that cluster may elect a new leader, and
  // once packet delay operation is undone, the (old) leader comes back
  // and tries to catch up with latest changes from cluster. As always,
  // after recovery, each member must be able to process client requests.
  DELAY_PEER_PORT_TX_RX_LEADER = 204;

  // RANDOM_DELAY_PEER_PORT_TX_RX_LEADER delays outgoing/incoming packets
  // from/to the peer port on the active leader with a randomized time
  // duration. And waits for "delay-ms" until recovery.
  // The expected behavior is that cluster may elect a new leader, and
  // once packet delay operation is undone, the (old) leader comes back
  // and tries to catch up with latest changes from cluster. As always,
  // after recovery, each member must be able to process client requests.
  RANDOM_DELAY_PEER_PORT_TX_RX_LEADER = 205;

  // DELAY_PEER_PORT_TX_RX_LEADER_UNTIL_TRIGGER_SNAPSHOT delays
  // outgoing/incoming packets from/to the peer port on the active leader,
  // and waits for most up-to-date node (current or new leader) applies the
  // snapshot count of entries since the delay operation.
  // The expected behavior is that cluster may elect a new leader, and
  // the old leader gets isolated and behind the current active leader,
  // and once delay operation is undone, the slow follower comes back
  // and catches up, likely receiving a snapshot from the active leader.
  // As always, after recovery, each member must be able to process client
  // requests.
  DELAY_PEER_PORT_TX_RX_LEADER_UNTIL_TRIGGER_SNAPSHOT = 206;

  // RANDOM_DELAY_PEER_PORT_TX_RX_LEADER_UNTIL_TRIGGER_SNAPSHOT delays
  // outgoing/incoming packets from/to the peer port on the active leader,
  // with a randomized time duration. And it waits for most up-to-date node
  // (current or new leader) applies the snapshot count of entries since the
  // delay operation.
  // The expected behavior is that cluster may elect a new leader, and
  // the old leader gets isolated and behind the current active leader,
  // and once delay operation is undone, the slow follower comes back
  // and catches up, likely receiving a snapshot from the active leader.
  // As always, after recovery, each member must be able to process client
  // requests.
  RANDOM_DELAY_PEER_PORT_TX_RX_LEADER_UNTIL_TRIGGER_SNAPSHOT = 207;

  // DELAY_PEER_PORT_TX_RX_QUORUM delays outgoing/incoming packets from/to
  // the peer ports on majority nodes of cluster. And it waits for
  // "delay-ms" until recovery, likely to trigger election timeouts.
  // The expected behavior is that cluster may elect a new leader, while
  // quorum of nodes struggle with slow networks, and once delay operation
  // is undone, nodes come back and cluster comes back operative. As always,
  // after recovery, each member must be able to process client requests.
  DELAY_PEER_PORT_TX_RX_QUORUM = 208;

  // RANDOM_DELAY_PEER_PORT_TX_RX_QUORUM delays outgoing/incoming packets
  // from/to the peer ports on majority nodes of cluster, with randomized
  // time durations. And it waits for "delay-ms" until recovery, likely
  // to trigger election timeouts.
  // The expected behavior is that cluster may elect a new leader, while
  // quorum of nodes struggle with slow networks, and once delay operation
  // is undone, nodes come back and cluster comes back operative. As always,
  // after recovery, each member must be able to process client requests.
  RANDOM_DELAY_PEER_PORT_TX_RX_QUORUM = 209;

  // DELAY_PEER_PORT_TX_RX_ALL delays outgoing/incoming packets from/to the
  // peer ports on all nodes. And it waits for "delay-ms" until recovery,
  // likely to trigger election timeouts.
  // The expected behavior is that cluster may become totally inoperable,
  // struggling with slow networks across the whole cluster. Once delay
  // operation is undone, nodes come back and cluster comes back operative.
  // As always, after recovery, each member must be able to process client
  // requests.
  DELAY_PEER_PORT_TX_RX_ALL = 210;

  // RANDOM_DELAY_PEER_PORT_TX_RX_ALL delays outgoing/incoming packets
  // from/to the peer ports on all nodes, with randomized time durations.
  // And it waits for "delay-ms" until recovery, likely to trigger
  // election timeouts.
  // The expected behavior is that cluster may become totally inoperable,
  // struggling with slow networks across the whole cluster. Once delay
  // operation is undone, nodes come back and cluster comes back operative.
  // As always, after recovery, each member must be able to process client
  // requests.
  RANDOM_DELAY_PEER_PORT_TX_RX_ALL = 211;

  // NO_FAIL_WITH_STRESS stops injecting failures while testing the
  // consistency and correctness under pressure loads, for the duration of
  // "delay-ms". Goal is to ensure cluster be still making progress
  // on recovery, and verify system does not deadlock following a sequence
  // of failure injections.
  // The expected behavior is that cluster remains fully operative in healthy
  // condition. As always, after recovery, each member must be able to process
  // client requests.
  NO_FAIL_WITH_STRESS = 300;

  // NO_FAIL_WITH_NO_STRESS_FOR_LIVENESS neither injects failures nor
  // sends stressig client requests to the cluster, for the duration of
  // "delay-ms". Goal is to ensure cluster be still making progress
  // on recovery, and verify system does not deadlock following a sequence
  // of failure injections.
  // The expected behavior is that cluster remains fully operative in healthy
  // condition, and clients requests during liveness period succeed without
  // errors.
  // Note: this is how Google Chubby does failure injection testing
  // https://static.googleusercontent.com/media/research.google.com/en//archive/paxos_made_live.pdf.
  NO_FAIL_WITH_NO_STRESS_FOR_LIVENESS = 301;

  // FAILPOINTS injects failpoints to etcd server runtime, triggering panics
  // in critical code paths.
  FAILPOINTS = 400;

  // EXTERNAL runs external failure injection scripts.
  EXTERNAL = 500;
}