Tidy up with Eth2GenesisConfig (ethereum#635)

* don't get genesis from constants

cache genesis_root request

* rename genesis_hash -> genesis_root

* Use Eth2GenesisConfig

* dummy

* fix lint

* fix plugin test

* PR feedback: type hint

* PR feedback: Fix test fixtures

Author: ChihChengLiang

eth2/beacon/chains/base.py

@@ -53,7 +53,9 @@
 from eth2.beacon.validation import (
     validate_slot,
 )
-from eth2.configs import Eth2Config
+from eth2.configs import (
+    Eth2GenesisConfig,
+)
 
 if TYPE_CHECKING:
     from eth2.beacon.state_machines.base import (  # noqa: F401
@@ -87,7 +89,7 @@ def from_genesis(cls,
                      base_db: BaseAtomicDB,
                      genesis_state: BeaconState,
                      genesis_block: BaseBeaconBlock,
-                     config: Eth2Config) -> 'BaseBeaconChain':
+                     genesis_config: Eth2GenesisConfig) -> 'BaseBeaconChain':
         pass
 
     #
@@ -111,6 +113,11 @@ def get_state_machine_class_for_block_slot(
             slot: Slot) -> Type['BaseBeaconStateMachine']:
         pass
 
+    @classmethod
+    @abstractmethod
+    def get_genesis_state_machine_class(self) -> Type['BaseBeaconStateMachine']:
+        pass
+
     #
     # Block API
     #
@@ -172,7 +179,7 @@ class BeaconChain(BaseBeaconChain):
 
     chaindb_class = BeaconChainDB  # type: Type[BaseBeaconChainDB]
 
-    def __init__(self, base_db: BaseAtomicDB, config: Eth2Config) -> None:
+    def __init__(self, base_db: BaseAtomicDB, genesis_config: Eth2GenesisConfig) -> None:
         if not self.sm_configuration:
             raise ValueError(
                 "The Chain class cannot be instantiated with an empty `sm_configuration`"
@@ -182,7 +189,7 @@ def __init__(self, base_db: BaseAtomicDB, config: Eth2Config) -> None:
             # validate_sm_configuration(self.sm_configuration)
             pass
 
-        self.chaindb = self.get_chaindb_class()(base_db, config)
+        self.chaindb = self.get_chaindb_class()(base_db, genesis_config)
 
     #
     # Helpers
@@ -201,7 +208,7 @@ def from_genesis(cls,
                      base_db: BaseAtomicDB,
                      genesis_state: BeaconState,
                      genesis_block: BaseBeaconBlock,
-                     config: Eth2Config) -> 'BaseBeaconChain':
+                     genesis_config: Eth2GenesisConfig) -> 'BaseBeaconChain':
         """
         Initialize the ``BeaconChain`` from a genesis state.
         """
@@ -214,21 +221,21 @@ def from_genesis(cls,
                 )
             )
 
-        chaindb = cls.get_chaindb_class()(db=base_db, config=config)
+        chaindb = cls.get_chaindb_class()(db=base_db, genesis_config=genesis_config)
         chaindb.persist_state(genesis_state)
-        return cls._from_genesis_block(base_db, genesis_block, config)
+        return cls._from_genesis_block(base_db, genesis_block, genesis_config)
 
     @classmethod
     def _from_genesis_block(cls,
                             base_db: BaseAtomicDB,
                             genesis_block: BaseBeaconBlock,
-                            config: Eth2Config) -> 'BaseBeaconChain':
+                            genesis_config: Eth2GenesisConfig) -> 'BaseBeaconChain':
         """
         Initialize the ``BeaconChain`` from the genesis block.
         """
-        chaindb = cls.get_chaindb_class()(db=base_db, config=config)
+        chaindb = cls.get_chaindb_class()(db=base_db, genesis_config=genesis_config)
         chaindb.persist_block(genesis_block, genesis_block.__class__)
-        return cls(base_db, config)
+        return cls(base_db, genesis_config)
 
     #
     # StateMachine API
@@ -268,6 +275,10 @@ def get_state_machine(self, at_block: BaseBeaconBlock=None) -> 'BaseBeaconStateM
             block=block,
         )
 
+    @classmethod
+    def get_genesis_state_machine_class(cls) -> Type['BaseBeaconStateMachine']:
+        return cls.sm_configuration[0][1]
+
     #
     # Block API
     #

eth2/beacon/db/chain.py

@@ -39,8 +39,6 @@
 from eth.validation import (
     validate_word,
 )
-
-from eth2.configs import Eth2Config
 from eth2.beacon.helpers import (
     slot_to_epoch,
 )
@@ -63,12 +61,16 @@
 )
 from eth2.beacon.db.schema import SchemaV1
 
+from eth2.configs import (
+    Eth2GenesisConfig,
+)
+
 
 class BaseBeaconChainDB(ABC):
     db = None  # type: BaseAtomicDB
 
     @abstractmethod
-    def __init__(self, db: BaseAtomicDB, config: Eth2Config) -> None:
+    def __init__(self, db: BaseAtomicDB, genesis_config: Eth2GenesisConfig) -> None:
         pass
 
     #
@@ -160,9 +162,9 @@ def get(self, key: bytes) -> bytes:
 
 
 class BeaconChainDB(BaseBeaconChainDB):
-    def __init__(self, db: BaseAtomicDB, config: Eth2Config) -> None:
+    def __init__(self, db: BaseAtomicDB, genesis_config: Eth2GenesisConfig) -> None:
         self.db = db
-        self.config = config
+        self.genesis_config = genesis_config
 
         self._finalized_root = self._get_finalized_root_if_present(db)
         self._highest_justified_epoch = self._get_highest_justified_epoch(db)
@@ -177,9 +179,9 @@ def _get_highest_justified_epoch(self, db: BaseDB) -> Epoch:
         try:
             justified_head_root = self._get_justified_head_root(db)
             slot = self.get_slot_by_root(justified_head_root)
-            return slot_to_epoch(slot, self.config.SLOTS_PER_EPOCH)
+            return slot_to_epoch(slot, self.genesis_config.SLOTS_PER_EPOCH)
         except JustifiedHeadNotFound:
-            return self.config.GENESIS_EPOCH
+            return self.genesis_config.GENESIS_EPOCH
 
     def persist_block(
             self,
@@ -708,7 +710,7 @@ def _handle_exceptional_justification_and_finality(self,
         """
         genesis_root = genesis_block.signing_root
         self._update_finalized_head(genesis_root)
-        self._update_justified_head(genesis_root, self.config.GENESIS_EPOCH)
+        self._update_justified_head(genesis_root, self.genesis_config.GENESIS_EPOCH)
 
     #
     # Raw Database API

eth2/beacon/state_machines/forks/xiao_long_bao/configs.py

@@ -4,13 +4,18 @@
 from eth2.beacon.state_machines.forks.serenity.configs import (
     SERENITY_CONFIG,
 )
+from eth2.beacon.typing import (
+    Slot,
+)
 
 
+GENESIS_SLOT = Slot(0)
 SLOTS_PER_EPOCH = 4
 
 XIAO_LONG_BAO_CONFIG = SERENITY_CONFIG._replace(
+    GENESIS_SLOT=GENESIS_SLOT,
     SLOTS_PER_EPOCH=SLOTS_PER_EPOCH,
-    GENESIS_EPOCH=slot_to_epoch(SERENITY_CONFIG.GENESIS_SLOT, SLOTS_PER_EPOCH),
+    GENESIS_EPOCH=slot_to_epoch(GENESIS_SLOT, SLOTS_PER_EPOCH),
     TARGET_COMMITTEE_SIZE=2,
     SHARD_COUNT=2,
     MIN_ATTESTATION_INCLUSION_DELAY=2,

eth2/configs.py

@@ -86,3 +86,18 @@ def __init__(self, config: Eth2Config):
         self.ACTIVATION_EXIT_DELAY = config.ACTIVATION_EXIT_DELAY
         self.LATEST_ACTIVE_INDEX_ROOTS_LENGTH = config.LATEST_ACTIVE_INDEX_ROOTS_LENGTH
         self.LATEST_RANDAO_MIXES_LENGTH = config.LATEST_RANDAO_MIXES_LENGTH
+
+
+class Eth2GenesisConfig:
+    """
+    Genesis parameters that might lives in
+    a state or a state machine config
+    but is assumed unlikely to change between forks.
+    Pass this to the chains, chain_db, or other objects that need them.
+    """
+
+    def __init__(self, config: Eth2Config) -> None:
+        self.GENESIS_SLOT = config.GENESIS_SLOT
+        self.GENESIS_EPOCH = config.GENESIS_EPOCH
+        self.SECONDS_PER_SLOT = config.SECONDS_PER_SLOT
+        self.SLOTS_PER_EPOCH = config.SLOTS_PER_EPOCH

tests/core/p2p-proto/bcc/helpers.py

@@ -39,6 +39,11 @@
     async_passthrough,
 )
 from eth2.beacon.state_machines.forks.serenity import SERENITY_CONFIG
+from eth2.configs import (
+    Eth2GenesisConfig,
+)
+
+SERENITY_GENESIS_CONFIG = Eth2GenesisConfig(SERENITY_CONFIG)
 
 
 class FakeAsyncBeaconChainDB(BaseAsyncBeaconChainDB, BeaconChainDB):
@@ -59,9 +64,9 @@ class FakeAsyncBeaconChainDB(BaseAsyncBeaconChainDB, BeaconChainDB):
     coro_get = async_passthrough('get')
 
 
-def create_test_block(parent=None, **kwargs):
+def create_test_block(parent=None, genesis_config=SERENITY_GENESIS_CONFIG, **kwargs):
     defaults = {
-        "slot": SERENITY_CONFIG.GENESIS_SLOT,
+        "slot": genesis_config.GENESIS_SLOT,
         "previous_block_root": ZERO_HASH32,
         "state_root": ZERO_HASH32,  # note: not the actual genesis state root
         "signature": EMPTY_SIGNATURE,
@@ -92,16 +97,16 @@ def create_branch(length, root=None, **start_kwargs):
         parent = child
 
 
-async def get_chain_db(blocks=(), config=SERENITY_CONFIG):
+async def get_chain_db(blocks=(), genesis_config=SERENITY_GENESIS_CONFIG):
     db = AtomicDB()
-    chain_db = FakeAsyncBeaconChainDB(db=db, config=config)
+    chain_db = FakeAsyncBeaconChainDB(db=db, genesis_config=genesis_config)
     await chain_db.coro_persist_block_chain(blocks, BeaconBlock)
     return chain_db
 
 
-async def get_genesis_chain_db(config=SERENITY_CONFIG):
-    genesis = create_test_block()
-    return await get_chain_db((genesis,), config=config)
+async def get_genesis_chain_db(genesis_config=SERENITY_GENESIS_CONFIG):
+    genesis = create_test_block(genesis_config=genesis_config)
+    return await get_chain_db((genesis,), genesis_config=genesis_config)
 
 
 async def _setup_alice_and_bob_factories(alice_chain_db, bob_chain_db):

tests/core/p2p-proto/bcc/test_handshake.py

@@ -72,7 +72,7 @@ async def test_unidirectional_handshake():
 
     assert msg["protocol_version"] == BCCProtocol.version
     assert msg["network_id"] == alice.context.network_id
-    assert msg["genesis_hash"] == alice_genesis_root
+    assert msg["genesis_root"] == alice_genesis_root
     assert msg["head_slot"] == alice_head_slot
 
     await bob.process_sub_proto_handshake(cmd, msg)

tests/eth2/core/beacon/conftest.py

@@ -10,6 +10,7 @@
 from eth2.configs import (
     Eth2Config,
     CommitteeConfig,
+    Eth2GenesisConfig,
 )
 from eth2.beacon.constants import (
     FAR_FUTURE_EPOCH,
@@ -50,6 +51,11 @@
     mock_validator,
 )
 
+from eth2.beacon.db.chain import (
+    BeaconChainDB,
+)
+
+
 DEFAULT_SHUFFLING_SEED = b'\00' * 32
 DEFAULT_RANDAO = b'\45' * 32
 DEFAULT_NUM_VALIDATORS = 40
@@ -791,9 +797,20 @@ def fixture_sm_class(config):
     )
 
 
+@pytest.fixture
+def genesis_config(config):
+    return Eth2GenesisConfig(config)
+
+
+@pytest.fixture
+def chaindb(base_db, genesis_config):
+    return BeaconChainDB(base_db, genesis_config)
+
 #
 # CommitteeConfig
 #
+
+
 @pytest.fixture
 def committee_config(config):
     return CommitteeConfig(config)

tests/eth2/core/beacon/db/test_beacon_chaindb.py

@@ -21,9 +21,6 @@
     validate_ssz_equal,
 )
 
-from eth2.beacon.db.chain import (
-    BeaconChainDB,
-)
 from eth2.beacon.db.exceptions import (
     FinalizedHeadNotFound,
     JustifiedHeadNotFound,
@@ -35,11 +32,6 @@
 from eth2.beacon.types.states import BeaconState
 
 
-@pytest.fixture
-def chaindb(base_db, config):
-    return BeaconChainDB(base_db, config)
-
-
 @pytest.fixture
 def chaindb_at_genesis(chaindb, genesis_state, genesis_block):
     chaindb.persist_state(genesis_state)

tests/eth2/core/beacon/state_machines/forks/test_serenity_operation_processing.py

@@ -10,7 +10,6 @@
 from eth2.beacon.committee_helpers import (
     get_beacon_proposer_index,
 )
-from eth2.beacon.db.chain import BeaconChainDB
 from eth2.beacon.helpers import (
     get_epoch_start_slot,
 )
@@ -41,7 +40,7 @@ def test_process_max_attestations(genesis_state,
                                   config,
                                   keymap,
                                   fixture_sm_class,
-                                  base_db):
+                                  chaindb):
     attestation_slot = config.GENESIS_SLOT
     current_slot = attestation_slot + config.MIN_ATTESTATION_INCLUSION_DELAY
     state = genesis_state.copy(
@@ -52,7 +51,7 @@ def test_process_max_attestations(genesis_state,
         state=state,
         config=config,
         state_machine=fixture_sm_class(
-            BeaconChainDB(base_db, config),
+            chaindb,
             genesis_block,
         ),
         attestation_slot=attestation_slot,
@@ -255,7 +254,7 @@ def test_process_attestations(genesis_state,
                               config,
                               keymap,
                               fixture_sm_class,
-                              base_db,
+                              chaindb,
                               success):
 
     attestation_slot = 0
@@ -268,7 +267,7 @@ def test_process_attestations(genesis_state,
         state=state,
         config=config,
         state_machine=fixture_sm_class(
-            BeaconChainDB(base_db, config),
+            chaindb,
             genesis_block,
         ),
         attestation_slot=attestation_slot,

tests/eth2/core/beacon/state_machines/test_state_transition.py

@@ -1,6 +1,5 @@
 import pytest
 
-from eth2.beacon.db.chain import BeaconChainDB
 from eth2.beacon.state_machines.forks.serenity.blocks import (
     SerenityBeaconBlock,
 )
@@ -46,14 +45,13 @@
         (16, 4, 1, 2, 2, 31, 8),
     ]
 )
-def test_per_slot_transition(base_db,
+def test_per_slot_transition(chaindb,
                              genesis_block,
                              genesis_state,
                              fixture_sm_class,
                              config,
                              state_slot,
                              keymap):
-    chaindb = BeaconChainDB(base_db, config)
     chaindb.persist_block(genesis_block, SerenityBeaconBlock)
     chaindb.persist_state(genesis_state)