class IncomingBatchQueue:
"""This queue keeps track of the batch ids so that components on the edge
can filter out duplicates early. However, there is still an opportunity for
duplicates to make it into this queue, which is intentional to avoid
blocking threads trying to put/get from the queue. Any duplicates
introduced by this must be filtered out later.
"""
def __init__(self):
self._queue = queue.Queue()
self._ids = ConcurrentSet()
def put(self, batch):
if batch.header_signature not in self._ids:
self._ids.add(batch.header_signature)
self._queue.put(batch)
def get(self, timeout=None, and_then=None):
"""Get a batch from the queue, blocking until a batch is available or
timeout has occurred. If 'and_then' is passed, it is called with the
batch before the batch is fully removed from the queue. This avoids
concurrent client from observing that a batch is not present while it
is transferred from one component to another.
"""
batch = self._queue.get(timeout=timeout)
if and_then is not None:
and_then(batch)
try:
self._ids.remove(batch.header_signature)
except KeyError:
pass
return batch
def __contains__(self, batch_id):
return batch_id in self._ids
class IncomingBatchQueue:
"""This queue keeps track of the batch ids so that components on the edge
can filter out duplicates early. However, there is still an opportunity for
duplicates to make it into this queue, which is intentional to avoid
blocking threads trying to put/get from the queue. Any duplicates
introduced by this must be filtered out later.
"""
def __init__(self):
self._queue = queue.Queue()
self._ids = ConcurrentSet()
def put(self, batch):
if batch.header_signature not in self._ids:
self._queue.put(batch)
def get(self, timeout=None):
batch = self._queue.get(timeout=timeout)
try:
self._ids.remove(batch.header_signature)
except KeyError:
pass
return batch
def __contains__(self, batch_id):
return batch_id in self._ids
class BlockValidator(object):
"""
Responsible for validating a block, handles both chain extensions and fork
will determine if the new block should be the head of the chain and return
the information necessary to do the switch if necessary.
"""
def __init__(self,
block_cache,
state_view_factory,
transaction_executor,
identity_signer,
data_dir,
config_dir,
permission_verifier,
thread_pool=None):
"""Initialize the BlockValidator
Args:
block_cache: The cache of all recent blocks and the processing
state associated with them.
state_view_factory: A factory that can be used to create read-
only views of state for a particular merkle root, in
particular the state as it existed when a particular block
was the chain head.
transaction_executor: The transaction executor used to
process transactions.
identity_signer: A cryptographic signer for signing blocks.
data_dir: Path to location where persistent data for the
consensus module can be stored.
config_dir: Path to location where config data for the
consensus module can be found.
permission_verifier: The delegate for handling permission
validation on blocks.
thread_pool: (Optional) Executor pool used to submit block
validation jobs. If not specified, a default will be created.
Returns:
None
"""
self._block_cache = block_cache
self._state_view_factory = state_view_factory
self._transaction_executor = transaction_executor
self._identity_signer = identity_signer
self._data_dir = data_dir
self._config_dir = config_dir
self._permission_verifier = permission_verifier
self._settings_view_factory = SettingsViewFactory(state_view_factory)
self._thread_pool = InstrumentedThreadPoolExecutor(1) \
if thread_pool is None else thread_pool
self._moved_to_fork_count = COLLECTOR.counter(
'chain_head_moved_to_fork_count', instance=self)
# Blocks that are currently being processed
self._blocks_processing = ConcurrentSet()
# Descendant blocks that are waiting for an in process block
# to complete
self._blocks_pending = ConcurrentMultiMap()
def stop(self):
self._thread_pool.shutdown(wait=True)
def _get_previous_block_state_root(self, blkw):
if blkw.previous_block_id == NULL_BLOCK_IDENTIFIER:
return INIT_ROOT_KEY
return self._block_cache[blkw.previous_block_id].state_root_hash
def _validate_batches_in_block(self, blkw, prev_state_root):
"""
Validate all batches in the block. This includes:
- Validating all transaction dependencies are met
- Validating there are no duplicate batches or transactions
- Validating execution of all batches in the block produces the
correct state root hash
Args:
blkw: the block of batches to validate
prev_state_root: the state root to execute transactions on top of
Raises:
BlockValidationFailure:
If validation fails, raises this error with the reason.
MissingDependency:
Validation failed because of a missing dependency.
DuplicateTransaction:
Validation failed because of a duplicate transaction.
DuplicateBatch:
Validation failed because of a duplicate batch.
"""
if not blkw.block.batches:
return
try:
chain_commit_state = ChainCommitState(
blkw.previous_block_id,
self._block_cache,
self._block_cache.block_store)
scheduler = self._transaction_executor.create_scheduler(
prev_state_root)
chain_commit_state.check_for_duplicate_batches(
blkw.block.batches)
transactions = []
for batch in blkw.block.batches:
transactions.extend(batch.transactions)
chain_commit_state.check_for_duplicate_transactions(
transactions)
chain_commit_state.check_for_transaction_dependencies(
transactions)
for batch, has_more in look_ahead(blkw.block.batches):
if has_more:
scheduler.add_batch(batch)
else:
scheduler.add_batch(batch, blkw.state_root_hash)
except (DuplicateBatch,
DuplicateTransaction,
MissingDependency) as err:
scheduler.cancel()
raise BlockValidationFailure(
"Block {} failed validation: {}".format(blkw, err))
except Exception:
scheduler.cancel()
raise
scheduler.finalize()
scheduler.complete(block=True)
state_hash = None
for batch in blkw.batches:
batch_result = scheduler.get_batch_execution_result(
batch.header_signature)
if batch_result is not None and batch_result.is_valid:
txn_results = \
scheduler.get_transaction_execution_results(
batch.header_signature)
blkw.execution_results.extend(txn_results)
state_hash = batch_result.state_hash
blkw.num_transactions += len(batch.transactions)
else:
raise BlockValidationFailure(
"Block {} failed validation: Invalid batch "
"{}".format(blkw, batch))
if blkw.state_root_hash != state_hash:
raise BlockValidationFailure(
"Block {} failed state root hash validation. Expected {}"
" but got {}".format(
blkw, blkw.state_root_hash, state_hash))
def _validate_permissions(self, blkw, prev_state_root):
"""
Validate that all of the batch signers and transaction signer for the
batches in the block are permitted by the transactor permissioning
roles stored in state as of the previous block. If a transactor is
found to not be permitted, the block is invalid.
"""
if blkw.block_num != 0:
for batch in blkw.batches:
if not self._permission_verifier.is_batch_signer_authorized(
batch, prev_state_root, from_state=True):
return False
return True
def _validate_on_chain_rules(self, blkw, prev_state_root):
"""
Validate that the block conforms to all validation rules stored in
state. If the block breaks any of the stored rules, the block is
invalid.
"""
if blkw.block_num != 0:
return enforce_validation_rules(
self._settings_view_factory.create_settings_view(
prev_state_root),
blkw.header.signer_public_key,
blkw.batches)
return True
def validate_block(self, blkw, chain_head=None):
if blkw.status == BlockStatus.Valid:
return
elif blkw.status == BlockStatus.Invalid:
raise BlockValidationFailure(
'Block {} is already invalid'.format(blkw))
# pylint: disable=broad-except
try:
if chain_head is None:
# Try to get the chain head from the block store; note that the
# block store may also return None for the chain head if a
# genesis block hasn't been committed yet.
chain_head = self._block_cache.block_store.chain_head
try:
prev_state_root = self._get_previous_block_state_root(blkw)
except KeyError:
raise BlockValidationError(
'Block {} rejected due to missing predecessor'.format(
blkw))
if not self._validate_permissions(blkw, prev_state_root):
raise BlockValidationFailure(
'Block {} failed permission validation'.format(blkw))
try:
prev_block = self._block_cache[blkw.previous_block_id]
except KeyError:
prev_block = None
consensus = self._load_consensus(prev_block)
public_key = \
self._identity_signer.get_public_key().as_hex()
consensus_block_verifier = consensus.BlockVerifier(
block_cache=self._block_cache,
state_view_factory=self._state_view_factory,
data_dir=self._data_dir,
config_dir=self._config_dir,
validator_id=public_key)
if not consensus_block_verifier.verify_block(blkw):
raise BlockValidationFailure(
'Block {} failed {} consensus validation'.format(
blkw, consensus))
if not self._validate_on_chain_rules(blkw, prev_state_root):
raise BlockValidationFailure(
'Block {} failed on-chain validation rules'.format(
blkw))
self._validate_batches_in_block(blkw, prev_state_root)
# since changes to the chain-head can change the state of the
# blocks in BlockStore we have to revalidate this block.
block_store = self._block_cache.block_store
# The chain_head is None when this is the genesis block or if the
# block store has no chain_head.
if chain_head is not None:
if chain_head.identifier != block_store.chain_head.identifier:
raise ChainHeadUpdated()
blkw.status = BlockStatus.Valid
except BlockValidationFailure as err:
blkw.status = BlockStatus.Invalid
raise err
except BlockValidationError as err:
blkw.status = BlockStatus.Unknown
raise err
except ChainHeadUpdated as e:
raise e
except Exception as e:
LOGGER.exception(
"Unhandled exception BlockValidator.validate_block()")
raise e
@staticmethod
def _compare_chain_height(head_a, head_b):
"""Returns True if head_a is taller, False if head_b is taller, and
True if the heights are the same."""
return head_a.block_num - head_b.block_num >= 0
def _build_fork_diff_to_common_height(self, head_long, head_short):
"""Returns a list of blocks on the longer chain since the greatest
common height between the two chains. Note that the chains may not
have the same block id at the greatest common height.
Args:
head_long (BlockWrapper)
head_short (BlockWrapper)
Returns:
(list of BlockWrapper) All blocks in the longer chain since the
last block in the shorter chain. Ordered newest to oldest.
Raises:
BlockValidationError
The block is missing a predecessor. Note that normally this
shouldn't happen because of the completer."""
fork_diff = []
last = head_short.block_num
blk = head_long
while blk.block_num > last:
if blk.previous_block_id == NULL_BLOCK_IDENTIFIER:
break
fork_diff.append(blk)
try:
blk = self._block_cache[blk.previous_block_id]
except KeyError:
raise BlockValidationError(
'Failed to build fork diff: block {} missing predecessor'
.format(blk))
return blk, fork_diff
def _extend_fork_diff_to_common_ancestor(
self, new_blkw, cur_blkw, new_chain, cur_chain
):
""" Finds a common ancestor of the two chains. new_blkw and cur_blkw
must be at the same height, or this will always fail.
"""
while cur_blkw.identifier != new_blkw.identifier:
if (cur_blkw.previous_block_id == NULL_BLOCK_IDENTIFIER
or new_blkw.previous_block_id == NULL_BLOCK_IDENTIFIER):
# We are at a genesis block and the blocks are not the same
for b in new_chain:
b.status = BlockStatus.Invalid
raise BlockValidationFailure(
'Block {} rejected due to wrong genesis {}'.format(
cur_blkw, new_blkw))
new_chain.append(new_blkw)
try:
new_blkw = self._block_cache[new_blkw.previous_block_id]
except KeyError:
raise BlockValidationError(
'Block {} rejected due to missing predecessor {}'.format(
new_blkw, new_blkw.previous_block_id))
cur_chain.append(cur_blkw)
cur_blkw = self._block_cache[cur_blkw.previous_block_id]
def _compare_forks_consensus(self, chain_head, new_block):
"""Ask the consensus module which fork to choose.
"""
public_key = self._identity_signer.get_public_key().as_hex()
consensus = self._load_consensus(chain_head)
fork_resolver = consensus.ForkResolver(
block_cache=self._block_cache,
state_view_factory=self._state_view_factory,
data_dir=self._data_dir,
config_dir=self._config_dir,
validator_id=public_key)
return fork_resolver.compare_forks(chain_head, new_block)
def _load_consensus(self, block):
"""Load the consensus module using the state as of the given block."""
if block is not None:
return ConsensusFactory.get_configured_consensus_module(
block.header_signature,
BlockWrapper.state_view_for_block(
block,
self._state_view_factory))
return ConsensusFactory.get_consensus_module('genesis')
@staticmethod
def _get_batch_commit_changes(new_chain, cur_chain):
"""
Get all the batches that should be committed from the new chain and
all the batches that should be uncommitted from the current chain.
"""
committed_batches = []
for blkw in new_chain:
for batch in blkw.batches:
committed_batches.append(batch)
uncommitted_batches = []
for blkw in cur_chain:
for batch in blkw.batches:
uncommitted_batches.append(batch)
return (committed_batches, uncommitted_batches)
def submit_blocks_for_verification(self, blocks, callback):
for block in blocks:
if self.in_process(block.header_signature):
LOGGER.debug("Block already in process: %s", block)
continue
if self.in_process(block.previous_block_id):
LOGGER.debug(
"Previous block '%s' in process,"
" adding '%s' pending",
block.previous_block_id, block)
self._add_block_to_pending(block)
continue
if self.in_pending(block.previous_block_id):
LOGGER.debug(
"Previous block '%s' is pending,"
" adding '%s' pending",
block.previous_block_id, block)
self._add_block_to_pending(block)
continue
LOGGER.debug(
"Adding block %s for processing", block.identifier)
# Add the block to the set of blocks being processed
self._blocks_processing.add(block.identifier)
# Schedule the block for processing
self._thread_pool.submit(
self.process_block_verification, block,
self._wrap_callback(block, callback))
def _wrap_callback(self, block, callback):
# Internal cleanup after verification
def wrapper(commit_new_block, result, chain_head_updated=False):
block = result.block
LOGGER.debug("Removing block from processing %s", block.identifier)
try:
self._blocks_processing.remove(block.identifier)
except KeyError:
LOGGER.warning(
"Tried to remove block from in process but it"
" wasn't in processes: %s",
block.identifier)
# If the block was valid, submit all pending blocks for validation
if block.status == BlockStatus.Valid:
blocks_now_ready = self._blocks_pending.pop(
block.identifier, [])
self.submit_blocks_for_verification(blocks_now_ready, callback)
elif block.status == BlockStatus.Invalid:
# If the block was invalid, mark all pending blocks as invalid
blocks_now_invalid = self._blocks_pending.pop(
block.identifier, [])
while blocks_now_invalid:
invalid_block = blocks_now_invalid.pop()
invalid_block.status = BlockStatus.Invalid
LOGGER.debug(
'Marking descendant block invalid: %s',
invalid_block)
# Get descendants of the descendant
blocks_now_invalid.extend(
self._blocks_pending.pop(invalid_block.identifier, []))
elif not chain_head_updated:
# If an error occured during validation, something is wrong
# internally and we need to abort validation of this block
# and all its children without marking them as invalid.
blocks_to_remove = self._blocks_pending.pop(
block.identifier, [])
while blocks_to_remove:
block = blocks_to_remove.pop()
LOGGER.error(
'Removing block from cache and pending due to error '
'during validation: %s; status: %s',
block, block.status)
del self._block_cache[block.identifier]
# Get descendants of the descendant
blocks_to_remove.extend(
self._blocks_pending.pop(block.identifier, []))
callback(commit_new_block, result)
return wrapper
def in_process(self, block_id):
return block_id in self._blocks_processing
def in_pending(self, block_id):
return block_id in self._blocks_pending
def _add_block_to_pending(self, block):
previous = block.previous_block_id
self._blocks_pending.append(previous, block)
def process_block_verification(self, block, callback):
"""
Main entry for Block Validation, Take a given candidate block
and decide if it is valid then if it is valid determine if it should
be the new head block. Returns the results to the ChainController
so that the change over can be made if necessary.
"""
try:
result = BlockValidationResult(block)
LOGGER.info("Starting block validation of : %s", block)
# Get the current chain_head and store it in the result
chain_head = self._block_cache.block_store.chain_head
result.chain_head = chain_head
# Create new local variables for current and new block, since
# these variables get modified later
current_block = chain_head
new_block = block
try:
# Get all the blocks since the greatest common height from the
# longer chain.
if self._compare_chain_height(current_block, new_block):
current_block, result.current_chain =\
self._build_fork_diff_to_common_height(
current_block, new_block)
else:
new_block, result.new_chain =\
self._build_fork_diff_to_common_height(
new_block, current_block)
# Add blocks to the two chains until a common ancestor is found
# or raise an exception if no common ancestor is found
self._extend_fork_diff_to_common_ancestor(
new_block, current_block,
result.new_chain, result.current_chain)
except BlockValidationFailure as err:
LOGGER.warning(
'Block %s failed validation: %s',
block, err)
block.status = BlockStatus.Invalid
except BlockValidationError as err:
LOGGER.error(
'Encountered an error while validating %s: %s',
block, err)
callback(False, result)
return
valid = True
for blk in reversed(result.new_chain):
if valid:
try:
self.validate_block(
blk, chain_head)
except BlockValidationFailure as err:
LOGGER.warning(
'Block %s failed validation: %s',
blk, err)
valid = False
except BlockValidationError as err:
LOGGER.error(
'Encountered an error while validating %s: %s',
blk, err)
callback(False, result)
result.transaction_count += block.num_transactions
else:
LOGGER.info(
"Block marked invalid (invalid predecessor): %s", blk)
blk.status = BlockStatus.Invalid
if not valid:
callback(False, result)
return
# Ask consensus if the new chain should be committed
LOGGER.info(
"Comparing current chain head '%s' against new block '%s'",
chain_head, new_block)
for i in range(max(
len(result.new_chain), len(result.current_chain)
)):
cur = new = num = "-"
if i < len(result.current_chain):
cur = result.current_chain[i].header_signature[:8]
num = result.current_chain[i].block_num
if i < len(result.new_chain):
new = result.new_chain[i].header_signature[:8]
num = result.new_chain[i].block_num
LOGGER.info(
"Fork comparison at height %s is between %s and %s",
num, cur, new)
commit_new_chain = self._compare_forks_consensus(chain_head, block)
# If committing the new chain, get the list of committed batches
# from the current chain that need to be uncommitted and the list
# of uncommitted batches from the new chain that need to be
# committed.
if commit_new_chain:
commit, uncommit =\
self._get_batch_commit_changes(
result.new_chain, result.current_chain)
result.committed_batches = commit
result.uncommitted_batches = uncommit
if result.new_chain[0].previous_block_id \
!= chain_head.identifier:
self._moved_to_fork_count.inc()
# Pass the results to the callback function
callback(commit_new_chain, result)
LOGGER.info("Finished block validation of: %s", block)
except ChainHeadUpdated:
LOGGER.debug(
"Block validation failed due to chain head update: %s", block)
callback(False, result, chain_head_updated=True)
return
except Exception: # pylint: disable=broad-except
LOGGER.exception(
"Block validation failed with unexpected error: %s", block)
# callback to clean up the block out of the processing list.
callback(False, result)
class BlockValidator(object):
"""
Responsible for validating a block, handles both chain extensions and fork
will determine if the new block should be the head of the chain and return
the information necessary to do the switch if necessary.
"""
def __init__(self,
block_cache,
state_view_factory,
transaction_executor,
squash_handler,
identity_signer,
data_dir,
config_dir,
permission_verifier,
metrics_registry=None,
thread_pool=None):
"""Initialize the BlockValidator
Args:
block_cache: The cache of all recent blocks and the processing
state associated with them.
state_view_factory: A factory that can be used to create read-
only views of state for a particular merkle root, in
particular the state as it existed when a particular block
was the chain head.
transaction_executor: The transaction executor used to
process transactions.
squash_handler: A parameter passed when creating transaction
schedulers.
identity_signer: A cryptographic signer for signing blocks.
data_dir: Path to location where persistent data for the
consensus module can be stored.
config_dir: Path to location where config data for the
consensus module can be found.
permission_verifier: The delegate for handling permission
validation on blocks.
metrics_registry: (Optional) Pyformance metrics registry handle for
creating new metrics.
thread_pool: (Optional) Executor pool used to submit block
validation jobs. If not specified, a default will be created.
Returns:
None
"""
self._block_cache = block_cache
self._state_view_factory = state_view_factory
self._transaction_executor = transaction_executor
self._squash_handler = squash_handler
self._identity_signer = identity_signer
self._data_dir = data_dir
self._config_dir = config_dir
self._permission_verifier = permission_verifier
self._validation_rule_enforcer = ValidationRuleEnforcer(
SettingsViewFactory(state_view_factory))
self._thread_pool = InstrumentedThreadPoolExecutor(1) \
if thread_pool is None else thread_pool
if metrics_registry:
self._moved_to_fork_count = CounterWrapper(
metrics_registry.counter('chain_head_moved_to_fork_count'))
else:
self._moved_to_fork_count = CounterWrapper()
# Blocks that are currently being processed
self._blocks_processing = ConcurrentSet()
# Descendant blocks that are waiting for an in process block
# to complete
self._blocks_pending = ConcurrentMultiMap()
def stop(self):
self._thread_pool.shutdown(wait=True)
def _get_previous_block_state_root(self, blkw):
if blkw.previous_block_id == NULL_BLOCK_IDENTIFIER:
return INIT_ROOT_KEY
return self._block_cache[blkw.previous_block_id].state_root_hash
def _validate_batches_in_block(self, blkw, prev_state_root):
"""
Validate all batches in the block. This includes:
- Validating all transaction dependencies are met
- Validating there are no duplicate batches or transactions
- Validating execution of all batches in the block produces the
correct state root hash
Args:
blkw: the block of batches to validate
prev_state_root: the state root to execute transactions on top of
Raises:
BlockValidationError:
If validation fails, raises this error with the reason.
MissingDependency:
Validation failed because of a missing dependency.
DuplicateTransaction:
Validation failed because of a duplicate transaction.
DuplicateBatch:
Validation failed because of a duplicate batch.
"""
if not blkw.block.batches:
return
try:
chain_commit_state = ChainCommitState(
blkw.previous_block_id, self._block_cache,
self._block_cache.block_store)
scheduler = self._transaction_executor.create_scheduler(
self._squash_handler, prev_state_root)
self._transaction_executor.execute(scheduler)
chain_commit_state.check_for_duplicate_batches(blkw.block.batches)
transactions = []
for batch in blkw.block.batches:
transactions.extend(batch.transactions)
chain_commit_state.check_for_duplicate_transactions(transactions)
chain_commit_state.check_for_transaction_dependencies(transactions)
for batch, has_more in look_ahead(blkw.block.batches):
if has_more:
scheduler.add_batch(batch)
else:
scheduler.add_batch(batch, blkw.state_root_hash)
except (DuplicateBatch, DuplicateTransaction,
MissingDependency) as err:
scheduler.cancel()
raise BlockValidationError("Block {} failed validation: {}".format(
blkw, err))
except Exception:
scheduler.cancel()
raise
scheduler.finalize()
scheduler.complete(block=True)
state_hash = None
for batch in blkw.batches:
batch_result = scheduler.get_batch_execution_result(
batch.header_signature)
if batch_result is not None and batch_result.is_valid:
txn_results = \
scheduler.get_transaction_execution_results(
batch.header_signature)
blkw.execution_results.extend(txn_results)
state_hash = batch_result.state_hash
blkw.num_transactions += len(batch.transactions)
else:
raise BlockValidationError(
"Block {} failed validation: Invalid batch "
"{}".format(blkw, batch))
if blkw.state_root_hash != state_hash:
raise BlockValidationError(
"Block {} failed state root hash validation. Expected {}"
" but got {}".format(blkw, blkw.state_root_hash, state_hash))
def _validate_permissions(self, blkw, prev_state_root):
"""
Validate that all of the batch signers and transaction signer for the
batches in the block are permitted by the transactor permissioning
roles stored in state as of the previous block. If a transactor is
found to not be permitted, the block is invalid.
"""
if blkw.block_num != 0:
for batch in blkw.batches:
if not self._permission_verifier.is_batch_signer_authorized(
batch, prev_state_root, from_state=True):
return False
return True
def _validate_on_chain_rules(self, blkw, prev_state_root):
"""
Validate that the block conforms to all validation rules stored in
state. If the block breaks any of the stored rules, the block is
invalid.
"""
if blkw.block_num != 0:
return self._validation_rule_enforcer.validate(
blkw, prev_state_root)
return True
def validate_block(self, blkw, chain_head=None):
if blkw.status == BlockStatus.Valid:
return
elif blkw.status == BlockStatus.Invalid:
raise BlockValidationError(
'Block {} is already invalid'.format(blkw))
# pylint: disable=broad-except
try:
if chain_head is None:
# Try to get the chain head from the block store; note that the
# block store may also return None for the chain head if a
# genesis block hasn't been committed yet.
chain_head = self._block_cache.block_store.chain_head
try:
prev_state_root = self._get_previous_block_state_root(blkw)
except KeyError:
raise BlockValidationError(
'Block {} rejected due to missing predecessor'.format(
blkw))
if not self._validate_permissions(blkw, prev_state_root):
raise BlockValidationError(
'Block {} failed permission validation'.format(blkw))
try:
prev_block = self._block_cache[blkw.previous_block_id]
except KeyError:
prev_block = None
consensus = self._load_consensus(prev_block)
public_key = \
self._identity_signer.get_public_key().as_hex()
consensus_block_verifier = consensus.BlockVerifier(
block_cache=self._block_cache,
state_view_factory=self._state_view_factory,
data_dir=self._data_dir,
config_dir=self._config_dir,
validator_id=public_key)
if not consensus_block_verifier.verify_block(blkw):
raise BlockValidationError(
'Block {} failed {} consensus validation'.format(
blkw, consensus))
if not self._validate_on_chain_rules(blkw, prev_state_root):
raise BlockValidationError(
'Block {} failed on-chain validation rules'.format(blkw))
self._validate_batches_in_block(blkw, prev_state_root)
# since changes to the chain-head can change the state of the
# blocks in BlockStore we have to revalidate this block.
block_store = self._block_cache.block_store
# The chain_head is None when this is the genesis block or if the
# block store has no chain_head.
if chain_head is not None:
if chain_head.identifier != block_store.chain_head.identifier:
raise ChainHeadUpdated()
blkw.status = BlockStatus.Valid
except BlockValidationError as err:
blkw.status = BlockStatus.Invalid
raise err
except ChainHeadUpdated as e:
raise e
except Exception as e:
LOGGER.exception(
"Unhandled exception BlockValidator.validate_block()")
raise e
@staticmethod
def _compare_chain_height(head_a, head_b):
"""Returns True if head_a is taller, False if head_b is taller, and
True if the heights are the same."""
return head_a.block_num - head_b.block_num >= 0
def _build_fork_diff_to_common_height(self, head_long, head_short):
"""Returns a list of blocks on the longer chain since the greatest
common height between the two chains. Note that the chains may not
have the same block id at the greatest common height.
Args:
head_long (BlockWrapper)
head_short (BlockWrapper)
Returns:
(list of BlockWrapper) All blocks in the longer chain since the
last block in the shorter chain. Ordered newest to oldest.
Raises:
BlockValidationError
The block is missing a predecessor. Note that normally this
shouldn't happen because of the completer."""
fork_diff = []
last = head_short.block_num
blk = head_long
while blk.block_num > last:
if blk.previous_block_id == NULL_BLOCK_IDENTIFIER:
break
fork_diff.append(blk)
try:
blk = self._block_cache[blk.previous_block_id]
except KeyError:
LOGGER.debug(
"Failed to build fork diff due to missing predecessor: %s",
blk)
# Mark all blocks in the longer chain since the invalid block
# as invalid.
for blk in fork_diff:
blk.status = BlockStatus.Invalid
raise BlockValidationError(
'Failed to build fork diff: block {} missing predecessor'.
format(blk))
return blk, fork_diff
def _extend_fork_diff_to_common_ancestor(self, new_blkw, cur_blkw,
new_chain, cur_chain):
""" Finds a common ancestor of the two chains. new_blkw and cur_blkw
must be at the same height, or this will always fail.
"""
while cur_blkw.identifier != new_blkw.identifier:
if (cur_blkw.previous_block_id == NULL_BLOCK_IDENTIFIER
or new_blkw.previous_block_id == NULL_BLOCK_IDENTIFIER):
# We are at a genesis block and the blocks are not the same
for b in new_chain:
b.status = BlockStatus.Invalid
raise BlockValidationError(
'Block {} rejected due to wrong genesis {}'.format(
cur_blkw, new_blkw))
new_chain.append(new_blkw)
try:
new_blkw = self._block_cache[new_blkw.previous_block_id]
except KeyError:
for b in new_chain:
b.status = BlockStatus.Invalid
raise BlockValidationError(
'Block {} rejected due to missing predecessor {}'.format(
new_blkw, new_blkw.previous_block_id))
cur_chain.append(cur_blkw)
cur_blkw = self._block_cache[cur_blkw.previous_block_id]
def _compare_forks_consensus(self, chain_head, new_block):
"""Ask the consensus module which fork to choose.
"""
public_key = self._identity_signer.get_public_key().as_hex()
consensus = self._load_consensus(chain_head)
fork_resolver = consensus.ForkResolver(
block_cache=self._block_cache,
state_view_factory=self._state_view_factory,
data_dir=self._data_dir,
config_dir=self._config_dir,
validator_id=public_key)
return fork_resolver.compare_forks(chain_head, new_block)
def _load_consensus(self, block):
"""Load the consensus module using the state as of the given block."""
if block is not None:
return ConsensusFactory.get_configured_consensus_module(
block.header_signature,
BlockWrapper.state_view_for_block(block,
self._state_view_factory))
return ConsensusFactory.get_consensus_module('genesis')
@staticmethod
def _get_batch_commit_changes(new_chain, cur_chain):
"""
Get all the batches that should be committed from the new chain and
all the batches that should be uncommitted from the current chain.
"""
committed_batches = []
for blkw in new_chain:
for batch in blkw.batches:
committed_batches.append(batch)
uncommitted_batches = []
for blkw in cur_chain:
for batch in blkw.batches:
uncommitted_batches.append(batch)
return (committed_batches, uncommitted_batches)
def submit_blocks_for_verification(self, blocks, callback):
for block in blocks:
if self.in_process(block.header_signature):
LOGGER.debug("Block already in process: %s", block)
continue
if self.in_process(block.previous_block_id):
LOGGER.debug(
"Previous block '%s' in process,"
" adding '%s' pending", block.previous_block_id, block)
self._add_block_to_pending(block)
continue
if self.in_pending(block.previous_block_id):
LOGGER.debug(
"Previous block '%s' is pending,"
" adding '%s' pending", block.previous_block_id, block)
self._add_block_to_pending(block)
continue
LOGGER.debug("Adding block %s for processing", block.identifier)
# Add the block to the set of blocks being processed
self._blocks_processing.add(block.identifier)
# Schedule the block for processing
self._thread_pool.submit(self.process_block_verification, block,
self._wrap_callback(block, callback))
def _wrap_callback(self, block, callback):
# Internal cleanup after verification
def wrapper(commit_new_block, result):
LOGGER.debug("Removing block from processing %s",
block.identifier[:6])
try:
self._blocks_processing.remove(block.identifier)
except KeyError:
LOGGER.warning(
"Tried to remove block from in process but it"
" wasn't in processes: %s", block.identifier)
# If the block is invalid, mark all descendant blocks as invalid
# and remove from pending.
if block.status == BlockStatus.Valid:
blocks_now_ready = self._blocks_pending.pop(
block.identifier, [])
self.submit_blocks_for_verification(blocks_now_ready, callback)
else:
# Get all the pending blocks that can now be processed
blocks_now_invalid = self._blocks_pending.pop(
block.identifier, [])
while blocks_now_invalid:
invalid_block = blocks_now_invalid.pop()
invalid_block.status = BlockStatus.Invalid
LOGGER.debug('Marking descendant block invalid: %s',
invalid_block)
# Get descendants of the descendant
blocks_now_invalid.extend(
self._blocks_pending.pop(invalid_block.identifier, []))
callback(commit_new_block, result)
return wrapper
def in_process(self, block_id):
return block_id in self._blocks_processing
def in_pending(self, block_id):
return block_id in self._blocks_pending
def _add_block_to_pending(self, block):
previous = block.previous_block_id
self._blocks_pending.append(previous, block)
def process_block_verification(self, block, callback):
"""
Main entry for Block Validation, Take a given candidate block
and decide if it is valid then if it is valid determine if it should
be the new head block. Returns the results to the ChainController
so that the change over can be made if necessary.
"""
try:
result = BlockValidationResult(block)
LOGGER.info("Starting block validation of : %s", block)
# Get the current chain_head and store it in the result
chain_head = self._block_cache.block_store.chain_head
result.chain_head = chain_head
# Create new local variables for current and new block, since
# these variables get modified later
current_block = chain_head
new_block = block
try:
# Get all the blocks since the greatest common height from the
# longer chain.
if self._compare_chain_height(current_block, new_block):
current_block, result.current_chain =\
self._build_fork_diff_to_common_height(
current_block, new_block)
else:
new_block, result.new_chain =\
self._build_fork_diff_to_common_height(
new_block, current_block)
# Add blocks to the two chains until a common ancestor is found
# or raise an exception if no common ancestor is found
self._extend_fork_diff_to_common_ancestor(
new_block, current_block, result.new_chain,
result.current_chain)
except BlockValidationError as err:
LOGGER.warning('%s', err)
callback(False, result)
return
valid = True
for blk in reversed(result.new_chain):
if valid:
try:
self.validate_block(blk, chain_head)
except BlockValidationError as err:
LOGGER.warning('Block %s failed validation: %s', blk,
err)
valid = False
result.transaction_count += block.num_transactions
else:
LOGGER.info(
"Block marked invalid(invalid predecessor): %s", blk)
blk.status = BlockStatus.Invalid
if not valid:
callback(False, result)
return
# Ask consensus if the new chain should be committed
LOGGER.info(
"Comparing current chain head '%s' against new block '%s'",
chain_head, new_block)
for i in range(
max(len(result.new_chain), len(result.current_chain))):
cur = new = num = "-"
if i < len(result.current_chain):
cur = result.current_chain[i].header_signature[:8]
num = result.current_chain[i].block_num
if i < len(result.new_chain):
new = result.new_chain[i].header_signature[:8]
num = result.new_chain[i].block_num
LOGGER.info(
"Fork comparison at height %s is between %s and %s", num,
cur, new)
commit_new_chain = self._compare_forks_consensus(chain_head, block)
# If committing the new chain, get the list of committed batches
# from the current chain that need to be uncommitted and the list
# of uncommitted batches from the new chain that need to be
# committed.
if commit_new_chain:
commit, uncommit =\
self._get_batch_commit_changes(
result.new_chain, result.current_chain)
result.committed_batches = commit
result.uncommitted_batches = uncommit
if result.new_chain[0].previous_block_id \
!= chain_head.identifier:
self._moved_to_fork_count.inc()
# Pass the results to the callback function
callback(commit_new_chain, result)
LOGGER.info("Finished block validation of: %s", block)
except ChainHeadUpdated:
callback(False, result)
return
except Exception: # pylint: disable=broad-except
LOGGER.exception(
"Block validation failed with unexpected error: %s", block)
# callback to clean up the block out of the processing list.
callback(False, result)