# SNIPPET: target_table
target_table = "public:ccf.gov.nodes.info"
# SNIPPET_START: iterate_over_ledger
for chunk in ledger:
for transaction in chunk:
# Retrieve all public tables changed in transaction
public_tables = transaction.get_public_domain().get_tables()
if target_table in public_tables:
# Ledger verification is happening implicitly in ccf.ledger.Ledger()
for key, value in public_tables[target_table].items():
# Note: `key` and `value` are raw bytes here.
# This code needs to have knowledge of the serialisation format for each table.
# In this case, the target table 'public:ccf.gov.nodes.info' is raw bytes to JSON.
LOG.info(f"{key.decode()} : {json.loads(value)}")
# SNIPPET_END: iterate_over_ledger
# Read state of ledger
latest_state, latest_seqno = ledger.get_latest_public_state()
seqnos = [1, 2, 3, latest_seqno // 2, latest_seqno]
random.shuffle(seqnos)
for seqno in seqnos:
transaction = ledger.get_transaction(seqno)
# Confirm latest state can still be accessed, and is unchanged
latest_state1, latest_seqno1 = ledger.get_latest_public_state()
assert latest_seqno == latest_seqno1
assert latest_state == latest_state1
def get_ledger_public_tables_at(self, seqno):
ledger = ccf.ledger.Ledger(self.remote.ledger_paths())
assert ledger.last_committed_chunk_range[1] >= seqno
tx = ledger.get_transaction(seqno)
return tx.get_public_domain().get_tables()