test: add stress tests for initialization

2 files changed, 183 insertions, 0 deletions

diff --git a/test/functional/feature_init.py b/test/functional/feature_init.py
new file mode 100755
index 0000000000..cffbd40271
--- /dev/null
+++ b/test/functional/feature_init.py
@@ -0,0 +1,182 @@
+#!/usr/bin/env python3
+# Copyright (c) 2021 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+"""Stress tests related to node initialization."""
+import random
+import time
+import os
+from pathlib import Path
+
+from test_framework.test_framework import BitcoinTestFramework, SkipTest
+from test_framework.test_node import ErrorMatch
+from test_framework.util import assert_equal
+
+
+class InitStressTest(BitcoinTestFramework):
+    """
+    Ensure that initialization can be interrupted at a number of points and not impair
+    subsequent starts.
+    """
+
+    def set_test_params(self):
+        self.setup_clean_chain = False
+        self.num_nodes = 1
+
+    def run_test(self):
+        """
+        - test terminating initialization after seeing a certain log line.
+        - test terminating init after seeing a random number of log lines.
+        - test removing certain essential files to test startup error paths.
+        """
+        # TODO: skip Windows for now since it isn't clear how to SIGTERM.
+        #
+        # Windows doesn't support `process.terminate()`.
+        # and other approaches (like below) don't work:
+        #
+        #   os.kill(node.process.pid, signal.CTRL_C_EVENT)
+        if os.name == 'nt':
+            raise SkipTest("can't SIGTERM on Windows")
+
+        self.stop_node(0)
+        node = self.nodes[0]
+
+        def sigterm_node():
+            node.process.terminate()
+            node.process.wait()
+            node.debug_log_path.unlink()
+            node.debug_log_path.touch()
+
+        def check_clean_start():
+            """Ensure that node restarts successfully after various interrupts."""
+            # TODO: add -txindex=1 to fully test index initiatlization.
+            # See https://github.com/bitcoin/bitcoin/pull/23289#discussion_r735159180 for
+            # a discussion of the related bug.
+            node.start()
+            node.wait_for_rpc_connection()
+            assert_equal(200, node.getblockcount())
+
+        lines_to_terminate_after = [
+            'scheduler thread start',
+            'Loading P2P addresses',
+            'Loading banlist',
+            'Loading block index',
+            'Switching active chainstate',
+            'Loaded best chain:',
+            'init message: Verifying blocks',
+            'loadblk thread start',
+            # TODO: reenable - see above TODO
+            # 'txindex thread start',
+            'net thread start',
+            'addcon thread start',
+            'msghand thread start',
+        ]
+        if self.is_wallet_compiled():
+            lines_to_terminate_after.append('Verifying wallet')
+
+        for terminate_line in lines_to_terminate_after:
+            self.log.info(f"Starting node and will exit after line '{terminate_line}'")
+            node.start(
+                # TODO: add -txindex=1 to fully test index initiatlization.
+                # extra_args=['-txindex=1'],
+            )
+            logfile = open(node.debug_log_path, 'r', encoding='utf8')
+
+            MAX_SECS_TO_WAIT = 30
+            start = time.time()
+            num_lines = 0
+
+            while True:
+                line = logfile.readline()
+                if line:
+                    num_lines += 1
+
+                if line and terminate_line.lower() in line.lower():
+                    self.log.debug(f"Terminating node after {num_lines} log lines seen")
+                    sigterm_node()
+                    break
+
+                if (time.time() - start) > MAX_SECS_TO_WAIT:
+                    raise AssertionError(
+                        f"missed line {terminate_line}; terminating now after {num_lines} lines")
+
+                if node.process.poll() is not None:
+                    raise AssertionError(f"node failed to start (line: '{terminate_line}')")
+
+        check_clean_start()
+        num_total_logs = len(node.debug_log_path.read_text().splitlines())
+        self.stop_node(0)
+
+        self.log.info(
+            f"Terminate at some random point in the init process (max logs: {num_total_logs})")
+
+        for _ in range(40):
+            terminate_after = random.randint(1, num_total_logs)
+            self.log.debug(f"Starting node and will exit after {terminate_after} lines")
+            node.start(
+                # TODO: add -txindex=1 to fully test index initiatlization.
+                # extra_args=['-txindex=1'],
+            )
+            logfile = open(node.debug_log_path, 'r', encoding='utf8')
+
+            MAX_SECS_TO_WAIT = 10
+            start = time.time()
+            num_lines = 0
+
+            while True:
+                line = logfile.readline()
+                if line:
+                    num_lines += 1
+
+                if num_lines >= terminate_after or (time.time() - start) > MAX_SECS_TO_WAIT:
+                    self.log.debug(f"Terminating node after {num_lines} log lines seen")
+                    sigterm_node()
+                    break
+
+                if node.process.poll() is not None:
+                    raise AssertionError("node failed to start")
+
+        check_clean_start()
+        self.stop_node(0)
+
+        self.log.info("Test startup errors after removing certain essential files")
+
+        files_to_disturb = {
+            'blocks/index/*.ldb': 'Error opening block database.',
+            'chainstate/*.ldb': 'Error opening block database.',
+            'blocks/blk*.dat': 'Error loading block database.',
+        }
+
+        for file_patt, err_fragment in files_to_disturb.items():
+            target_file = list(node.chain_path.glob(file_patt))[0]
+
+            self.log.info(f"Tweaking file to ensure failure {target_file}")
+            bak_path = str(target_file) + ".bak"
+            target_file.rename(bak_path)
+
+            # TODO: at some point, we should test perturbing the files instead of removing
+            # them, e.g.
+            #
+            # contents = target_file.read_bytes()
+            # tweaked_contents = bytearray(contents)
+            # tweaked_contents[50:250] = b'1' * 200
+            # target_file.write_bytes(bytes(tweaked_contents))
+            #
+            # At the moment I can't get this to work (bitcoind loads successfully?) so
+            # investigate doing this later.
+
+            node.assert_start_raises_init_error(
+                # TODO: add -txindex=1 to fully test index initiatlization.
+                # extra_args=['-txindex=1'],
+                expected_msg=err_fragment,
+                match=ErrorMatch.PARTIAL_REGEX,
+            )
+
+            self.log.info(f"Restoring file from {bak_path} and restarting")
+            Path(bak_path).rename(target_file)
+            check_clean_start()
+            self.stop_node(0)
+
+
+if __name__ == '__main__':
+    InitStressTest().main()
diff --git a/test/functional/test_runner.py b/test/functional/test_runner.py
index c5f08b27f2..8c828eab56 100755
--- a/test/functional/test_runner.py
+++ b/test/functional/test_runner.py
@@ -275,6 +275,7 @@ BASE_SCRIPTS = [
     'wallet_taproot.py',
     'p2p_fingerprint.py',
     'feature_uacomment.py',
+    'feature_init.py',
     'wallet_coinbase_category.py --legacy-wallet',
     'wallet_coinbase_category.py --descriptors',
     'feature_filelock.py',