Merge "FAB-13665 consensus migration: kafka2raft green path #2"

Author: C0rWin

orderer/consensus/migration/migration.go

@@ -0,0 +1,327 @@
+// Copyright IBM Corp. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package migration
+
+import (
+	"fmt"
+	"sync"
+
+	"github.com/hyperledger/fabric/common/flogging"
+	"github.com/hyperledger/fabric/protos/orderer"
+)
+
+// Status provides access to the consensus-type migration status of the underlying chain.
+// The implementation of this interface knows whether the chain is a system or standard channel.
+type Status interface {
+	fmt.Stringer
+
+	// StateContext returns the consensus-type migration state and context of the underlying chain.
+	StateContext() (state orderer.ConsensusType_MigrationState, context uint64)
+
+	// SetStateContext sets the consensus-type migration state and context of the underlying chain.
+	SetStateContext(state orderer.ConsensusType_MigrationState, context uint64)
+
+	// IsPending returns true if consensus-type migration is pending on the underlying chain.
+	// The definition of "pending" differs between the system and standard channels.
+	// Returns true when: START on system channel, START or CONTEXT on standard channel.
+	IsPending() bool
+
+	// IsCommitted returns true if consensus-type migration is committed on the underlying chain.
+	// The definition of "committed" differs between the system and standard channels.
+	// Returns true when: COMMIT on system channel; always false on standard channel.
+	IsCommitted() bool
+}
+
+// Stepper allows the underlying chain to execute the migration state machine.
+type Stepper interface {
+	// Step evaluates the migration state machine of a particular chain. It returns whether the block should be
+	// committed to the ledger or dropped (commitBlock), and whether the bootstrap file (a.k.a. genesis block)
+	// should be replaced (commitMigration).
+	Step(
+		chainID string,
+		nextConsensusType string,
+		nextMigState orderer.ConsensusType_MigrationState,
+		nextMigContext uint64,
+		lastCutBlockNumber uint64,
+		migrationController Controller,
+	) (commitBlock bool, commitMigration bool)
+}
+
+// StatusStepper is a composition of the Status and Stepper interfaces.
+type StatusStepper interface {
+	Status
+	Stepper
+}
+
+//go:generate counterfeiter -o mocks/consensus_migration_controller.go . Controller
+
+// Controller defines methods for controlling and coordinating the process of consensus-type migration.
+// It is implemented by the Registrar and is used by the system and standard chains.
+type Controller interface {
+	// ConsensusMigrationPending checks whether consensus-type migration had started,
+	// by inspecting the status of the system channel.
+	ConsensusMigrationPending() bool
+
+	// ConsensusMigrationStart marks every standard channel as "START" with the given context.
+	// It should first check that consensus-type migration is not pending on any of the standard channels.
+	// This call is always triggered by a MigrationState="START" config update on the system channel.
+	// The context is the height of the system channel config block that carries said config update.
+	ConsensusMigrationStart(context uint64) (err error)
+
+	// ConsensusMigrationCommit verifies that the conditions for committing the consensus-type migration
+	// are met, and if so, marks the system channel as committed.
+	// The conditions are:
+	// 1. system channel mast be at START with context >0;
+	// 2. all standard channels must be at START with the same context as the system channel.
+	ConsensusMigrationCommit() (err error)
+
+	// ConsensusMigrationAbort verifies that the conditions for aborting the consensus-type migration
+	// are met, and if so, marks the system channel as aborted.
+	// The conditions are:
+	// 1. system channel mast be at START
+	// 2. all standard channels must be at START or CONTEXT
+	ConsensusMigrationAbort() (err error)
+}
+
+// StatusImpl is an implementation of the StatusStepper interface,
+// which provides access to the consensus-type migration status of the underlying chain.
+// The methods that accept objects of this type are thread-safe.
+type StatusImpl struct {
+	// mutex protects state and context.
+	mutex sync.Mutex
+	// state must be accessed with mutex locked.
+	state orderer.ConsensusType_MigrationState
+	// context must be accessed with mutex locked.
+	context uint64
+
+	// systemChannel does not need to be protected by mutex since it is immutable after creation.
+	systemChannel bool
+
+	logger *flogging.FabricLogger
+}
+
+// NewStatusStepper generates a new StatusStepper implementation.
+func NewStatusStepper(sysChan bool, chainID string) StatusStepper {
+	return &StatusImpl{
+		systemChannel: sysChan,
+		logger:        flogging.MustGetLogger("orderer.consensus.migration").With("channel", chainID),
+	}
+}
+
+// StateContext returns the consensus-type migration state and context.
+func (ms *StatusImpl) StateContext() (state orderer.ConsensusType_MigrationState, context uint64) {
+	ms.mutex.Lock()
+	defer ms.mutex.Unlock()
+	return ms.state, ms.context
+}
+
+// SetStateContext sets the consensus-type migration state and context.
+func (ms *StatusImpl) SetStateContext(state orderer.ConsensusType_MigrationState, context uint64) {
+	ms.mutex.Lock()
+	defer ms.mutex.Unlock()
+	ms.state = state
+	ms.context = context
+}
+
+// IsPending returns true if migration is pending.
+func (ms *StatusImpl) IsPending() bool {
+	ms.mutex.Lock()
+	defer ms.mutex.Unlock()
+
+	if ms.systemChannel {
+		return ms.state == orderer.ConsensusType_MIG_STATE_START
+	}
+
+	return ms.state == orderer.ConsensusType_MIG_STATE_START || ms.state == orderer.ConsensusType_MIG_STATE_CONTEXT
+}
+
+// IsCommitted returns true if migration is committed.
+func (ms *StatusImpl) IsCommitted() bool {
+	ms.mutex.Lock()
+	defer ms.mutex.Unlock()
+
+	if ms.systemChannel {
+		return ms.state == orderer.ConsensusType_MIG_STATE_COMMIT
+	}
+
+	return false
+}
+
+// String returns a text representation.
+func (ms *StatusImpl) String() string {
+	ms.mutex.Lock()
+	defer ms.mutex.Unlock()
+
+	return fmt.Sprintf("State=%s, Context=%d, Sys=%t", ms.state, ms.context, ms.systemChannel)
+}
+
+// Step evaluates the migration state machine of a particular chain. It returns whether
+// the block should be committed to the ledger or dropped (commitBlock), and whether the bootstrap file
+// (a.k.a. genesis block) should be replaced (commitMigration).
+//
+// When we get a message, we check whether it is a permitted transition of the state machine, and whether the
+// parameters are correct. If it is a valid transition, we return commitBlock=true, which will cause the caller to
+// commit the block to the ledger.
+//
+// When we get a message that is a COMMIT, which is the final step of migration (this can only happen on the system
+// channel), we also return commitMigration=true, which will cause the caller to replace the bootstrap file
+// (genesis block), as well as commit the block to the ledger.
+//
+// Note: the method may call the multichannel.Registrar (migrationController). The Registrar takes a mutex, and then
+// calls individual migration.Status objects (.i.e. the lock of the migration.Status mutex is nested within the lock of
+// Registrar mutex). In order to avoid deadlocks, here we only call the Registrar (migrationController) when the
+// internal mutex in NOT taken.
+func (ms *StatusImpl) Step(
+	chainID string,
+	nextConsensusType string,
+	nextMigState orderer.ConsensusType_MigrationState,
+	nextMigContext uint64,
+	lastCutBlockNumber uint64,
+	migrationController Controller,
+) (commitBlock bool, commitMigration bool) {
+
+	ms.logger.Debugf("Consensus-type migration: Config tx; Current status: %s; Input TX: Type=%s, State=%s, Ctx=%d; lastBlock=%d",
+		ms, nextConsensusType, nextMigState, nextMigContext, lastCutBlockNumber)
+
+	if ms.systemChannel {
+		commitBlock, commitMigration = ms.stepSystem(
+			nextConsensusType, nextMigState, nextMigContext, lastCutBlockNumber, migrationController)
+	} else {
+		commitBlock = ms.stepStandard(
+			nextConsensusType, nextMigState, nextMigContext, migrationController)
+	}
+
+	return commitBlock, commitMigration
+}
+
+func (ms *StatusImpl) stepSystem(
+	nextConsensusType string,
+	nextMigState orderer.ConsensusType_MigrationState,
+	nextMigContext uint64,
+	lastCutBlockNumber uint64,
+	migrationController Controller,
+) (commitBlock bool, commitMigration bool) {
+
+	unexpectedTransitionResponse := func(from, to orderer.ConsensusType_MigrationState) {
+		ms.logger.Debugf("Consensus-type migration: Dropping config tx because: unexpected consensus-type migration state transition: %s to %s", from, to)
+		commitBlock = false
+		commitMigration = false
+	}
+
+	currState, currContext := ms.StateContext()
+
+	switch currState {
+	case orderer.ConsensusType_MIG_STATE_START:
+		//=== Migration is pending, expect COMMIT or ABORT ===
+		switch nextMigState {
+		case orderer.ConsensusType_MIG_STATE_COMMIT:
+			if currContext == nextMigContext {
+				err := migrationController.ConsensusMigrationCommit()
+				if err != nil {
+					ms.logger.Warningf("Consensus-type migration: Reject Config tx on system channel, migrationCommit failed; error=%s", err)
+				} else {
+					commitBlock = true
+					commitMigration = true
+				}
+			} else {
+				ms.logger.Warningf("Consensus-type migration: Reject Config tx on system channel; %s to %s, because of bad context:(tx=%d/exp=%d)",
+					currState, nextMigState, nextMigContext, currContext)
+			}
+		case orderer.ConsensusType_MIG_STATE_ABORT:
+			ms.logger.Panicf("Consensus-type migration: Not implemented yet, transition %s to %s", currState, nextMigState)
+			//TODO implement abort path
+		default:
+			unexpectedTransitionResponse(currState, nextMigState)
+		}
+
+	case orderer.ConsensusType_MIG_STATE_COMMIT:
+		//=== Migration committed, nothing left to do ===
+		ms.logger.Debug("Consensus-type migration: Config tx on system channel, migration already committed, nothing left to do, dropping;")
+
+	case orderer.ConsensusType_MIG_STATE_ABORT, orderer.ConsensusType_MIG_STATE_NONE:
+		//=== Migration is NOT pending, expect NONE or START ===
+		switch nextMigState {
+		case orderer.ConsensusType_MIG_STATE_START:
+			err := migrationController.ConsensusMigrationStart(lastCutBlockNumber + 1)
+			if err != nil {
+				ms.logger.Warningf("Consensus-type migration: Reject Config tx on system channel, migrationStart failed; error=%s", err)
+			} else {
+				ms.logger.Infof("Consensus-type migration: started; Status: %s", ms)
+				commitBlock = true
+			}
+		case orderer.ConsensusType_MIG_STATE_NONE:
+			commitBlock = true
+		default:
+			unexpectedTransitionResponse(currState, nextMigState)
+		}
+
+	default:
+		ms.logger.Panicf("Consensus-type migration: Unexpected status, probably a bug; Current: %s; Input TX: State=%s, Context=%d, nextConsensusType=%s",
+			ms, nextMigState, nextMigContext, nextConsensusType)
+	}
+
+	return commitBlock, commitMigration
+}
+
+func (ms *StatusImpl) stepStandard(
+	nextConsensusType string,
+	nextMigState orderer.ConsensusType_MigrationState,
+	nextMigContext uint64,
+	migrationController Controller,
+) (commitBlock bool) {
+
+	unexpectedTransitionResponse := func(from, to orderer.ConsensusType_MigrationState) {
+		ms.logger.Debugf("Consensus-type migration: Dropping config tx because: unexpected consensus-type migration state transition: %s to %s", from, to)
+		commitBlock = false
+	}
+
+	currState, currContext := ms.StateContext()
+
+	switch currState {
+	case orderer.ConsensusType_MIG_STATE_START:
+		//=== Migration is pending (START is set by system channel, via migrationController, not message), expect CONTEXT or ABORT ===
+		switch nextMigState {
+		case orderer.ConsensusType_MIG_STATE_CONTEXT:
+			if migrationController.ConsensusMigrationPending() && //On the system channel
+				(nextMigContext == currContext) {
+				ms.SetStateContext(nextMigState, nextMigContext)
+				ms.logger.Infof("Consensus-type migration: context accepted; Status: %s", ms)
+				commitBlock = true
+			} else {
+				ms.logger.Warningf("Consensus-type migration: context rejected; migrationPending=%v, context:(tx=%d/exp=%d)",
+					migrationController.ConsensusMigrationPending(), nextMigContext, currContext)
+			}
+		case orderer.ConsensusType_MIG_STATE_ABORT:
+			ms.logger.Panicf("Consensus-type migration: Not implemented yet, transition %s to %s", currState, nextMigState)
+			//TODO implement abort path
+		default:
+			unexpectedTransitionResponse(currState, nextMigState)
+		}
+
+	case orderer.ConsensusType_MIG_STATE_NONE, orderer.ConsensusType_MIG_STATE_ABORT:
+		//=== Migration not started or aborted, expect NONE (START is set by system channel, not message)
+		switch nextMigState {
+		case orderer.ConsensusType_MIG_STATE_NONE:
+			commitBlock = true
+		default:
+			unexpectedTransitionResponse(currState, nextMigState)
+		}
+
+	case orderer.ConsensusType_MIG_STATE_CONTEXT:
+		//=== Migration pending, expect ABORT, or nothing else to do (restart to Raft)
+		switch nextMigState {
+		case orderer.ConsensusType_MIG_STATE_ABORT:
+			ms.logger.Panicf("Consensus-type migration: Not implemented yet, transition %s to %s", currState, nextMigState)
+			//TODO implement abort path
+		default:
+			unexpectedTransitionResponse(currState, nextMigState)
+		}
+
+	default:
+		ms.logger.Panicf("Consensus-type migration: Unexpected status, probably a bug; Current: %s; Input TX: State=%s, Context=%d, nextConsensusType=%s",
+			ms, nextMigState, nextMigContext, nextConsensusType)
+	}
+
+	return commitBlock
+}