Handle exception when getting block timestamp (#792)

* Handle exception when getting block timestamp

* Return 0 on error

* Test error handling

* Prettier naming

* Fix order

* Fix test

df_py/util/blocktime.py

@@ -116,7 +116,11 @@ def __init__(self, target_timestamp):
             self.target_timestamp = target_timestamp
 
         def timeSinceTimestamp(self, block_i):
-            block_timestamp = web3.eth.get_block(int(block_i)).timestamp
+            try:
+                block_timestamp = web3.eth.get_block(int(block_i)).timestamp
+            except Exception as e:
+                print(f"An exception occurred while getting block {block_i}, {e}")
+                return 0
             return block_timestamp - self.target_timestamp
 
     f = C(timestamp).timeSinceTimestamp

df_py/util/test/test_blocktime_eth_mainnet.py

@@ -1,3 +1,4 @@
+import random
 from datetime import datetime
 
 from enforce_typing import enforce_types
@@ -28,6 +29,31 @@ def test_eth_timestamp_to_block(monkeypatch):
     assert guess == approx(block, 10)
 
 
+@enforce_types
+def test_eth_timestamp_to_block_error_handling(monkeypatch):
+    monkeypatch.setenv("WEB3_INFURA_PROJECT_ID", "9aa3d95b3bc440fa88ea12eaa4456161")
+    monkeypatch.setenv("MAINNET_RPC_URL", "https://mainnet.infura.io/v3/")
+    monkeypatch.setenv("INFURA_NETWORKS", "mainnet")
+    web3 = get_web3(get_rpc_url("mainnet"))
+    _get_block = web3.eth.get_block
+
+    def random_error_get_block(number):
+        if random.randint(1, 6) == 1 and number != "latest":
+            raise Exception("Random error occurred!")
+        return _get_block(number)
+
+    current_block = web3.eth.get_block("latest").number
+    blocks_ago = web3.eth.get_block(current_block - 5000)
+
+    ts = blocks_ago.timestamp
+    block = blocks_ago.number
+
+    web3.eth.get_block = random_error_get_block
+    guess = eth_timestamp_to_block(web3, ts)
+
+    assert guess == approx(block, 10)
+
+
 def test_timestr_to_block_eth_1(monkeypatch):
     monkeypatch.setenv("WEB3_INFURA_PROJECT_ID", "9aa3d95b3bc440fa88ea12eaa4456161")
     monkeypatch.setenv("MAINNET_RPC_URL", "https://mainnet.infura.io/v3/")