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Separate pending and effective validator updates.

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- Pending validator updates do not prevent elections from concluding.
- ValidatorElection overrides has_conclude to not conclude when there is a pending update for the matching height.
- Effective validator updates deem past elections inconclusive.
This commit is contained in:
Lev Berman 2018-09-18 16:37:03 +02:00
parent 126e90e732
commit 3414093578
4 changed files with 171 additions and 65 deletions
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83
bigchaindb/elections/election.py
View File

@ -1,7 +1,7 @@
# Copyright BigchainDB GmbH and BigchainDB contributors
# SPDX-License-Identifier: (Apache-2.0 AND CC-BY-4.0)
# Code is Apache-2.0 and docs are CC-BY-4.0
from collections import defaultdict
from collections import OrderedDict
import base58
from uuid import uuid4
@ -22,9 +22,13 @@ from bigchaindb.common.schema import (_validate_schema,
class Election(Transaction):
"""Represents election transactions.
To implement a custom election, create a class deriving from this one
with OPERATION set to the election operation, ALLOWED_OPERATIONS
set to (OPERATION,), CREATE set to OPERATION.
"""
# NOTE: this transaction class extends create so the operation inheritance is achieved
# by setting an ELECTION_TYPE and renaming CREATE = ELECTION_TYPE and ALLOWED_OPERATIONS = (ELECTION_TYPE,)
OPERATION = None
# Custom validation schema
TX_SCHEMA_CUSTOM = None
@ -34,7 +38,6 @@ class Election(Transaction):
INCONCLUSIVE = 'inconclusive'
# Vote ratio to approve an election
ELECTION_THRESHOLD = 2 / 3
CHANGES_VALIDATOR_SET = True
@classmethod
def get_validator_change(cls, bigchain):
@ -45,8 +48,10 @@ class Election(Transaction):
'validators': <validator_set>
}
"""
height = bigchain.get_latest_block()['height']
return bigchain.get_validator_change(height)
latest_block = bigchain.get_latest_block()
if latest_block is None:
return None
return bigchain.get_validator_change(latest_block['height'])
@classmethod
def get_validators(cls, bigchain, height=None):
@ -186,11 +191,11 @@ class Election(Transaction):
election_pk))
return self.count_votes(election_pk, txns, dict.get)
def has_concluded(self, bigchain, current_votes=[], height=None):
def has_concluded(self, bigchain, current_votes=[]):
"""Check if the election can be concluded or not.
* Elections can only be concluded if the current validator set
is exactly equal to the validator set encoded in the election outputs.
* Elections can only be concluded if the validator set has not changed
since the election was initiated.
* Elections can be concluded only if the current votes form a supermajority.
Custom elections may override this function and introduce additional checks.
@ -199,13 +204,16 @@ class Election(Transaction):
election_pk = self.to_public_key(self.id)
votes_committed = self.get_commited_votes(bigchain, election_pk)
votes_current = self.count_votes(election_pk, current_votes)
current_validators = self.get_validators(bigchain, height)
if self.is_same_topology(current_validators, self.outputs):
if self.has_validator_set_changed(bigchain):
return False
current_validators = self.get_validators(bigchain)
total_votes = sum(current_validators.values())
if (votes_committed < (2/3) * total_votes) and \
(votes_committed + votes_current >= (2/3)*total_votes):
return True
return False
def get_status(self, bigchain):
@ -213,14 +221,21 @@ class Election(Transaction):
if concluded:
return self.CONCLUDED
latest_change = self.get_validator_change(bigchain)
latest_change_height = latest_change['height']
election_height = bigchain.get_block_containing_tx(self.id)[0]
return self.INCONCLUSIVE if self.has_validator_set_changed(bigchain) else self.ONGOING
if latest_change_height >= election_height:
return self.INCONCLUSIVE
else:
return self.ONGOING
def has_validator_set_changed(self, bigchain):
latest_change = self.get_validator_change(bigchain)
if latest_change is None:
return False
latest_change_height = latest_change['height']
blocks = bigchain.get_block_containing_tx(self.id)
if not blocks:
return False
election_height = blocks[0]
return latest_change_height > election_height
def get_election(self, election_id, bigchain):
result = bigchain.get_election(election_id)
@ -244,44 +259,28 @@ class Election(Transaction):
@classmethod
def approved_elections(cls, bigchain, new_height, txns):
elections = defaultdict(list)
elections = OrderedDict()
for tx in txns:
if not isinstance(tx, Vote):
continue
election_id = tx.asset['id']
if election_id not in elections:
elections[election_id] = []
elections[election_id].append(tx)
validator_set_updated = False
validator_set_change = []
validator_update = None
for election_id, votes in elections.items():
election = bigchain.get_transaction(election_id)
if election is None:
continue
if not election.has_concluded(bigchain, votes, new_height):
if not election.has_concluded(bigchain, votes):
continue
if election.makes_validator_set_change():
if validator_set_updated:
continue
validator_set_change.append(election.get_validator_set_change(bigchain, new_height))
validator_set_updated = True
election.on_approval(bigchain, election, new_height)
validator_update = election.on_approval(bigchain, new_height)
election.store_election_results(bigchain, election, new_height)
return validator_set_change
return [validator_update] if validator_update else []
def makes_validator_set_change(self):
return self.CHANGES_VALIDATOR_SET
def get_validator_set_change(self, bigchain, new_height):
if self.makes_validator_set_change():
return self.change_validator_set(bigchain, new_height)
def change_validator_set(self, bigchain, new_height):
raise NotImplementedError
@classmethod
def on_approval(cls, bigchain, election, new_height):
def on_approval(self, bigchain, new_height):
raise NotImplementedError

4
bigchaindb/migrations/chain_migration_election.py
View File

@ -8,7 +8,6 @@ class ChainMigrationElection(Election):
CREATE = OPERATION
ALLOWED_OPERATIONS = (OPERATION,)
TX_SCHEMA_CUSTOM = TX_SCHEMA_CHAIN_MIGRATION_ELECTION
CHANGES_VALIDATOR_SET = False
def has_concluded(self, bigchaindb, *args, **kwargs):
chain = bigchaindb.get_latest_abci_chain()
@ -19,6 +18,5 @@ class ChainMigrationElection(Election):
return super().has_concluded(bigchaindb, *args, **kwargs)
@classmethod
def on_approval(cls, bigchain, election, new_height):
def on_approval(self, bigchain, *args, **kwargs):
bigchain.migrate_abci_chain()

26
bigchaindb/upsert_validator/validator_election.py
View File

@ -36,18 +36,28 @@ class ValidatorElection(Election):
super(ValidatorElection, cls).validate_schema(tx)
validate_asset_public_key(tx['asset']['data']['public_key'])
def change_validator_set(self, bigchain, new_height):
# The new validator set comes into effect from height = new_height+1
# (upcoming changes to Tendermint will change this to height = new_height+2)
def has_concluded(self, bigchain, *args, **kwargs):
latest_block = bigchain.get_latest_block()
if latest_block is not None:
latest_block_height = latest_block['height']
latest_validator_change = bigchain.get_validator_change()['height']
# TODO change to `latest_block_height + 2` when upgrading to Tendermint 0.24.0.
if latest_validator_change == latest_block_height + 1:
# do not conclude the election if there is a change assigned already
return False
return super().has_concluded(bigchain, *args, **kwargs)
def on_approval(self, bigchain, new_height):
validator_updates = [self.asset['data']]
curr_validator_set = bigchain.get_validators(new_height)
updated_validator_set = new_validator_set(curr_validator_set,
validator_updates)
updated_validator_set = [v for v in updated_validator_set if v['voting_power'] > 0]
updated_validator_set = [v for v in updated_validator_set
if v['voting_power'] > 0]
# TODO change to `new_height + 2` when upgrading to Tendermint 0.24.0.
bigchain.store_validator_set(new_height + 1, updated_validator_set)
return encode_validator(self.asset['data'])
@classmethod
def on_approval(cls, bigchain, election, new_height):
pass

113
tests/elections/test_election.py
View File

@ -17,18 +17,19 @@ def test_approved_elections_concludes_all_elections(b):
public_key = validators[0]['public_key']
private_key = validators[0]['private_key']
election, votes = generate_election(b,
ValidatorElection,
public_key, private_key,
new_validator['election'])
txs = [election]
total_votes = votes
election, votes = generate_election(b,
ChainMigrationElection,
public_key, private_key,
{})
txs = [election]
total_votes = votes
election, votes = generate_election(b,
ValidatorElection,
public_key, private_key,
new_validator['election'])
txs += [election]
total_votes += votes
@ -58,7 +59,7 @@ def test_approved_elections_concludes_all_elections(b):
@pytest.mark.bdb
def test_approved_elections_applies_only_one_validator_update(b):
def test_approved_elections_approves_only_one_validator_update(b):
validators = generate_validators([1] * 4)
b.store_validator_set(1, [v['storage'] for v in validators])
@ -98,6 +99,104 @@ def test_approved_elections_applies_only_one_validator_update(b):
assert not b.get_election(txs[1].id)
@pytest.mark.bdb
def test_approved_elections_approves_after_pending_validator_update(b):
validators = generate_validators([1] * 4)
b.store_validator_set(1, [v['storage'] for v in validators])
new_validator = generate_validators([1])[0]
public_key = validators[0]['public_key']
private_key = validators[0]['private_key']
election, votes = generate_election(b,
ValidatorElection,
public_key, private_key,
new_validator['election'])
txs = [election]
total_votes = votes
another_validator = generate_validators([1])[0]
election, votes = generate_election(b,
ValidatorElection,
public_key, private_key,
another_validator['election'])
txs += [election]
total_votes += votes
election, votes = generate_election(b,
ChainMigrationElection,
public_key, private_key,
{})
txs += [election]
total_votes += votes
b.store_abci_chain(1, 'chain-X')
b.store_block(Block(height=1,
transactions=[tx.id for tx in txs],
app_hash='')._asdict())
b.store_bulk_transactions(txs)
Election.approved_elections(b, 1, total_votes)
validators = b.get_validators()
assert len(validators) == 5
assert new_validator['storage'] in validators
assert another_validator['storage'] not in validators
assert b.get_election(txs[0].id)
assert not b.get_election(txs[1].id)
assert b.get_election(txs[2].id)
assert b.get_latest_abci_chain() == {'height': 2,
'chain_id': 'chain-X-migrated-at-height-1',
'is_synced': False}
@pytest.mark.bdb
def test_approved_elections_does_not_approve_after_validator_update(b):
validators = generate_validators([1] * 4)
b.store_validator_set(1, [v['storage'] for v in validators])
new_validator = generate_validators([1])[0]
public_key = validators[0]['public_key']
private_key = validators[0]['private_key']
election, votes = generate_election(b,
ValidatorElection,
public_key, private_key,
new_validator['election'])
txs = [election]
total_votes = votes
b.store_block(Block(height=1,
transactions=[tx.id for tx in txs],
app_hash='')._asdict())
b.store_bulk_transactions(txs)
Election.approved_elections(b, 1, total_votes)
b.store_block(Block(height=2,
transactions=[v.id for v in total_votes],
app_hash='')._asdict())
election, votes = generate_election(b,
ChainMigrationElection,
public_key, private_key,
{})
txs = [election]
total_votes = votes
b.store_abci_chain(1, 'chain-X')
Election.approved_elections(b, 2, total_votes)
assert not b.get_election(election.id)
assert b.get_latest_abci_chain() == {'height': 1,
'chain_id': 'chain-X',
'is_synced': True}
@pytest.mark.bdb
def test_approved_elections_applies_only_one_migration(b):
validators = generate_validators([1] * 4)