text: #!/usr/bin/env python3
  # Copyright (c) 2017-2018 The Bitcoin Core developers
  # Distributed under the MIT software license, see the accompanying
  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  """Class for scancoinsd node under test"""
  
  import contextlib
  import decimal
  import errno
  from enum import Enum
  import http.client
  import json
  import logging
  import os
  import re
  import subprocess
  import tempfile
  import time
  import urllib.parse
  import collections
  import shlex
  import sys
  
  from .authproxy import JSONRPCException
  from .util import (
      append_config,
      delete_cookie_file,
      get_rpc_proxy,
      rpc_url,
      wait_until,
      p2p_port,
  )
  
  # For Python 3.4 compatibility
  JSONDecodeError = getattr(json, "JSONDecodeError", ValueError)
  
  BITCOIND_PROC_WAIT_TIMEOUT = 60
  
  
  class FailedToStartError(Exception):
      """Raised when a node fails to start correctly."""
  
  
  class ErrorMatch(Enum):
      FULL_TEXT = 1
      FULL_REGEX = 2
      PARTIAL_REGEX = 3
  
  
  class TestNode():
      """A class for representing a scancoinsd node under test.
  
      This class contains:
  
      - state about the node (whether it's running, etc)
      - a Python subprocess.Popen object representing the running process
      - an RPC connection to the node
      - one or more P2P connections to the node
  
  
      To make things easier for the test writer, any unrecognised messages will
      be dispatched to the RPC connection."""
  
      def __init__(self, i, datadir, *, rpchost, timewait, bitcoind, bitcoin_cli, coverage_dir, cwd, extra_conf=None, extra_args=None, use_cli=False, start_perf=False):
          """
          Kwargs:
              start_perf (bool): If True, begin profiling the node with `perf` as soon as
                  the node starts.
          """
  
          self.index = i
          self.datadir = datadir
          self.stdout_dir = os.path.join(self.datadir, "stdout")
          self.stderr_dir = os.path.join(self.datadir, "stderr")
          self.rpchost = rpchost
          self.rpc_timeout = timewait
          self.binary = bitcoind
          self.coverage_dir = coverage_dir
          self.cwd = cwd
          if extra_conf is not None:
              append_config(datadir, extra_conf)
          # Most callers will just need to add extra args to the standard list below.
          # For those callers that need more flexibility, they can just set the args property directly.
          # Note that common args are set in the config file (see initialize_datadir)
          self.extra_args = extra_args
          self.args = [
              self.binary,
              "-datadir=" + self.datadir,
              "-logtimemicros",
              "-debug",
              "-debugexclude=libevent",
              "-debugexclude=leveldb",
              "-uacomment=testnode%d" % i,
          ]
  
          self.cli = TestNodeCLI(bitcoin_cli, self.datadir)
          self.use_cli = use_cli
          self.start_perf = start_perf
  
          self.running = False
          self.process = None
          self.rpc_connected = False
          self.rpc = None
          self.url = None
          self.log = logging.getLogger('TestFramework.node%d' % i)
          self.cleanup_on_exit = True # Whether to kill the node when this object goes away
          # Cache perf subprocesses here by their data output filename.
          self.perf_subprocesses = {}
  
          self.p2ps = []
  
      def get_deterministic_priv_key(self):
          """Return a deterministic priv key in base58, that only depends on the node's index"""
          AddressKeyPair = collections.namedtuple('AddressKeyPair', ['address', 'key'])
          PRIV_KEYS = [
              # address , privkey
              AddressKeyPair('mjTkW3DjgyZck4KbiRusZsqTgaYTxdSz6z', 'cVpF924EspNh8KjYsfhgY96mmxvT6DgdWiTYMtMjuM74hJaU5psW'),
              AddressKeyPair('msX6jQXvxiNhx3Q62PKeLPrhrqZQdSimTg', 'cUxsWyKyZ9MAQTaAhUQWJmBbSvHMwSmuv59KgxQV7oZQU3PXN3KE'),
              AddressKeyPair('mnonCMyH9TmAsSj3M59DsbH8H63U3RKoFP', 'cTrh7dkEAeJd6b3MRX9bZK8eRmNqVCMH3LSUkE3dSFDyzjU38QxK'),
              AddressKeyPair('mqJupas8Dt2uestQDvV2NH3RU8uZh2dqQR', 'cVuKKa7gbehEQvVq717hYcbE9Dqmq7KEBKqWgWrYBa2CKKrhtRim'),
              AddressKeyPair('msYac7Rvd5ywm6pEmkjyxhbCDKqWsVeYws', 'cQDCBuKcjanpXDpCqacNSjYfxeQj8G6CAtH1Dsk3cXyqLNC4RPuh'),
              AddressKeyPair('n2rnuUnwLgXqf9kk2kjvVm8R5BZK1yxQBi', 'cQakmfPSLSqKHyMFGwAqKHgWUiofJCagVGhiB4KCainaeCSxeyYq'),
              AddressKeyPair('myzuPxRwsf3vvGzEuzPfK9Nf2RfwauwYe6', 'cQMpDLJwA8DBe9NcQbdoSb1BhmFxVjWD5gRyrLZCtpuF9Zi3a9RK'),
              AddressKeyPair('mumwTaMtbxEPUswmLBBN3vM9oGRtGBrys8', 'cSXmRKXVcoouhNNVpcNKFfxsTsToY5pvB9DVsFksF1ENunTzRKsy'),
              AddressKeyPair('mpV7aGShMkJCZgbW7F6iZgrvuPHjZjH9qg', 'cSoXt6tm3pqy43UMabY6eUTmR3eSUYFtB2iNQDGgb3VUnRsQys2k'),
          ]
          return PRIV_KEYS[self.index]
  
      def get_mem_rss_kilobytes(self):
          """Get the memory usage (RSS) per `ps`.
  
          Returns None if `ps` is unavailable.
          """
          assert self.running
  
          try:
              return int(subprocess.check_output(
                  ["ps", "h", "-o", "rss", "{}".format(self.process.pid)],
                  stderr=subprocess.DEVNULL).split()[-1])
  
          # Avoid failing on platforms where ps isn't installed.
          #
          # We could later use something like `psutils` to work across platforms.
          except (FileNotFoundError, subprocess.SubprocessError):
              self.log.exception("Unable to get memory usage")
              return None
  
      def _node_msg(self, msg: str) -> str:
          """Return a modified msg that identifies this node by its index as a debugging aid."""
          return "[node %d] %s" % (self.index, msg)
  
      def _raise_assertion_error(self, msg: str):
          """Raise an AssertionError with msg modified to identify this node."""
          raise AssertionError(self._node_msg(msg))
  
      def __del__(self):
          # Ensure that we don't leave any bitcoind processes lying around after
          # the test ends
          if self.process and self.cleanup_on_exit:
              # Should only happen on test failure
              # Avoid using logger, as that may have already been shutdown when
              # this destructor is called.
              print(self._node_msg("Cleaning up leftover process"))
              self.process.kill()
  
      def __getattr__(self, name):
          """Dispatches any unrecognised messages to the RPC connection or a CLI instance."""
          if self.use_cli:
              return getattr(self.cli, name)
          else:
              assert self.rpc_connected and self.rpc is not None, self._node_msg("Error: no RPC connection")
              return getattr(self.rpc, name)
  
      def start(self, extra_args=None, *, cwd=None, stdout=None, stderr=None, **kwargs):
          """Start the node."""
          if extra_args is None:
              extra_args = self.extra_args
  
          # Add a new stdout and stderr file each time bitcoind is started
          if stderr is None:
              stderr = tempfile.NamedTemporaryFile(dir=self.stderr_dir, delete=False)
          if stdout is None:
              stdout = tempfile.NamedTemporaryFile(dir=self.stdout_dir, delete=False)
          self.stderr = stderr
          self.stdout = stdout
  
          if cwd is None:
              cwd = self.cwd
  
          # Delete any existing cookie file -- if such a file exists (eg due to
          # unclean shutdown), it will get overwritten anyway by bitcoind, and
          # potentially interfere with our attempt to authenticate
          delete_cookie_file(self.datadir)
  
          # add environment variable LIBC_FATAL_STDERR_=1 so that libc errors are written to stderr and not the terminal
          subp_env = dict(os.environ, LIBC_FATAL_STDERR_="1")
  
          self.process = subprocess.Popen(self.args + extra_args, env=subp_env, stdout=stdout, stderr=stderr, cwd=cwd, **kwargs)
  
          self.running = True
          self.log.debug("scancoinsd started, waiting for RPC to come up")
  
          if self.start_perf:
              self._start_perf()
  
      def wait_for_rpc_connection(self):
          """Sets up an RPC connection to the scancoinsd process. Returns False if unable to connect."""
          # Poll at a rate of four times per second
          poll_per_s = 4
          for _ in range(poll_per_s * self.rpc_timeout):
              if self.process.poll() is not None:
                  raise FailedToStartError(self._node_msg(
                      'scancoinsd exited with status {} during initialization'.format(self.process.returncode)))
              try:
                  rpc = get_rpc_proxy(rpc_url(self.datadir, self.index, self.rpchost), self.index, timeout=self.rpc_timeout, coveragedir=self.coverage_dir)
                  rpc.getblockcount()
                  # If the call to getblockcount() succeeds then the RPC connection is up
                  self.log.debug("RPC successfully started")
                  if self.use_cli:
                      return
                  self.rpc = rpc
                  self.rpc_connected = True
                  self.url = self.rpc.url
                  return
              except IOError as e:
                  if e.errno != errno.ECONNREFUSED:  # Port not yet open?
                      raise  # unknown IO error
              except JSONRPCException as e:  # Initialization phase
                  # -28 RPC in warmup
                  # -342 Service unavailable, RPC server started but is shutting down due to error
                  if e.error['code'] != -28 and e.error['code'] != -342:
                      raise  # unknown JSON RPC exception
              except ValueError as e:  # cookie file not found and no rpcuser or rpcassword. bitcoind still starting
                  if "No RPC credentials" not in str(e):
                      raise
              time.sleep(1.0 / poll_per_s)
          self._raise_assertion_error("Unable to connect to scancoinsd")
  
      def generate(self, nblocks, maxtries=1000000):
          self.log.debug("TestNode.generate() dispatches `generate` call to `generatetoaddress`")
          return self.generatetoaddress(nblocks=nblocks, address=self.get_deterministic_priv_key().address, maxtries=maxtries)
  
      def get_wallet_rpc(self, wallet_name):
          if self.use_cli:
              return self.cli("-rpcwallet={}".format(wallet_name))
          else:
              assert self.rpc_connected and self.rpc, self._node_msg("RPC not connected")
              wallet_path = "wallet/{}".format(urllib.parse.quote(wallet_name))
              return self.rpc / wallet_path
  
      def stop_node(self, expected_stderr='', wait=0):
          """Stop the node."""
          if not self.running:
              return
          self.log.debug("Stopping node")
          try:
              self.stop(wait=wait)
          except http.client.CannotSendRequest:
              self.log.exception("Unable to stop node.")
  
          # If there are any running perf processes, stop them.
          for profile_name in tuple(self.perf_subprocesses.keys()):
              self._stop_perf(profile_name)
  
          # Check that stderr is as expected
          self.stderr.seek(0)
          stderr = self.stderr.read().decode('utf-8').strip()
          if stderr != expected_stderr:
              raise AssertionError("Unexpected stderr {} != {}".format(stderr, expected_stderr))
  
          self.stdout.close()
          self.stderr.close()
  
          del self.p2ps[:]
  
      def is_node_stopped(self):
          """Checks whether the node has stopped.
  
          Returns True if the node has stopped. False otherwise.
          This method is responsible for freeing resources (self.process)."""
          if not self.running:
              return True
          return_code = self.process.poll()
          if return_code is None:
              return False
  
          # process has stopped. Assert that it didn't return an error code.
          assert return_code == 0, self._node_msg(
              "Node returned non-zero exit code (%d) when stopping" % return_code)
          self.running = False
          self.process = None
          self.rpc_connected = False
          self.rpc = None
          self.log.debug("Node stopped")
          return True
  
      def wait_until_stopped(self, timeout=BITCOIND_PROC_WAIT_TIMEOUT):
          wait_until(self.is_node_stopped, timeout=timeout)
  
      @contextlib.contextmanager
      def assert_debug_log(self, expected_msgs):
          debug_log = os.path.join(self.datadir, 'regtest', 'debug.log')
          with open(debug_log, encoding='utf-8') as dl:
              dl.seek(0, 2)
              prev_size = dl.tell()
          try:
              yield
          finally:
              with open(debug_log, encoding='utf-8') as dl:
                  dl.seek(prev_size)
                  log = dl.read()
              print_log = " - " + "\n - ".join(log.splitlines())
              for expected_msg in expected_msgs:
                  if re.search(re.escape(expected_msg), log, flags=re.MULTILINE) is None:
                      self._raise_assertion_error('Expected message "{}" does not partially match log:\n\n{}\n\n'.format(expected_msg, print_log))
  
      @contextlib.contextmanager
      def assert_memory_usage_stable(self, *, increase_allowed=0.03):
          """Context manager that allows the user to assert that a node's memory usage (RSS)
          hasn't increased beyond some threshold percentage.
  
          Args:
              increase_allowed (float): the fractional increase in memory allowed until failure;
                  e.g. `0.12` for up to 12% increase allowed.
          """
          before_memory_usage = self.get_mem_rss_kilobytes()
  
          yield
  
          after_memory_usage = self.get_mem_rss_kilobytes()
  
          if not (before_memory_usage and after_memory_usage):
              self.log.warning("Unable to detect memory usage (RSS) - skipping memory check.")
              return
  
          perc_increase_memory_usage = (after_memory_usage / before_memory_usage) - 1
  
          if perc_increase_memory_usage > increase_allowed:
              self._raise_assertion_error(
                  "Memory usage increased over threshold of {:.3f}% from {} to {} ({:.3f}%)".format(
                      increase_allowed * 100, before_memory_usage, after_memory_usage,
                      perc_increase_memory_usage * 100))
  
      @contextlib.contextmanager
      def profile_with_perf(self, profile_name):
          """
          Context manager that allows easy profiling of node activity using `perf`.
  
          See `test/functional/README.md` for details on perf usage.
  
          Args:
              profile_name (str): This string will be appended to the
                  profile data filename generated by perf.
          """
          subp = self._start_perf(profile_name)
  
          yield
  
          if subp:
              self._stop_perf(profile_name)
  
      def _start_perf(self, profile_name=None):
          """Start a perf process to profile this node.
  
          Returns the subprocess running perf."""
          subp = None
  
          def test_success(cmd):
              return subprocess.call(
                  # shell=True required for pipe use below
                  cmd, shell=True,
                  stderr=subprocess.DEVNULL, stdout=subprocess.DEVNULL) == 0
  
          if not sys.platform.startswith('linux'):
              self.log.warning("Can't profile with perf; only availabe on Linux platforms")
              return None
  
          if not test_success('which perf'):
              self.log.warning("Can't profile with perf; must install perf-tools")
              return None
  
          if not test_success('readelf -S {} | grep .debug_str'.format(shlex.quote(self.binary))):
              self.log.warning(
                  "perf output won't be very useful without debug symbols compiled into scancoinsd")
  
          output_path = tempfile.NamedTemporaryFile(
              dir=self.datadir,
              prefix="{}.perf.data.".format(profile_name or 'test'),
              delete=False,
          ).name
  
          cmd = [
              'perf', 'record',
              '-g',                     # Record the callgraph.
              '--call-graph', 'dwarf',  # Compatibility for gcc's --fomit-frame-pointer.
              '-F', '101',              # Sampling frequency in Hz.
              '-p', str(self.process.pid),
              '-o', output_path,
          ]
          subp = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
          self.perf_subprocesses[profile_name] = subp
  
          return subp
  
      def _stop_perf(self, profile_name):
          """Stop (and pop) a perf subprocess."""
          subp = self.perf_subprocesses.pop(profile_name)
          output_path = subp.args[subp.args.index('-o') + 1]
  
          subp.terminate()
          subp.wait(timeout=10)
  
          stderr = subp.stderr.read().decode()
          if 'Consider tweaking /proc/sys/kernel/perf_event_paranoid' in stderr:
              self.log.warning(
                  "perf couldn't collect data! Try "
                  "'sudo sysctl -w kernel.perf_event_paranoid=-1'")
          else:
              report_cmd = "perf report -i {}".format(output_path)
              self.log.info("See perf output by running '{}'".format(report_cmd))
  
      def assert_start_raises_init_error(self, extra_args=None, expected_msg=None, match=ErrorMatch.FULL_TEXT, *args, **kwargs):
          """Attempt to start the node and expect it to raise an error.
  
          extra_args: extra arguments to pass through to scancoinsd
          expected_msg: regex that stderr should match when scancoinsd fails
  
          Will throw if scancoinsd starts without an error.
          Will throw if an expected_msg is provided and it does not match scancoinsd's stdout."""
          with tempfile.NamedTemporaryFile(dir=self.stderr_dir, delete=False) as log_stderr, \
               tempfile.NamedTemporaryFile(dir=self.stdout_dir, delete=False) as log_stdout:
              try:
                  self.start(extra_args, stdout=log_stdout, stderr=log_stderr, *args, **kwargs)
                  self.wait_for_rpc_connection()
                  self.stop_node()
                  self.wait_until_stopped()
              except FailedToStartError as e:
                  self.log.debug('scancoinsd failed to start: %s', e)
                  self.running = False
                  self.process = None
                  # Check stderr for expected message
                  if expected_msg is not None:
                      log_stderr.seek(0)
                      stderr = log_stderr.read().decode('utf-8').strip()
                      if match == ErrorMatch.PARTIAL_REGEX:
                          if re.search(expected_msg, stderr, flags=re.MULTILINE) is None:
                              self._raise_assertion_error(
                                  'Expected message "{}" does not partially match stderr:\n"{}"'.format(expected_msg, stderr))
                      elif match == ErrorMatch.FULL_REGEX:
                          if re.fullmatch(expected_msg, stderr) is None:
                              self._raise_assertion_error(
                                  'Expected message "{}" does not fully match stderr:\n"{}"'.format(expected_msg, stderr))
                      elif match == ErrorMatch.FULL_TEXT:
                          if expected_msg != stderr:
                              self._raise_assertion_error(
                                  'Expected message "{}" does not fully match stderr:\n"{}"'.format(expected_msg, stderr))
              else:
                  if expected_msg is None:
                      assert_msg = "scancoinsd should have exited with an error"
                  else:
                      assert_msg = "scancoinsd should have exited with expected error " + expected_msg
                  self._raise_assertion_error(assert_msg)
  
      def add_p2p_connection(self, p2p_conn, *, wait_for_verack=True, **kwargs):
          """Add a p2p connection to the node.
  
          This method adds the p2p connection to the self.p2ps list and also
          returns the connection to the caller."""
          if 'dstport' not in kwargs:
              kwargs['dstport'] = p2p_port(self.index)
          if 'dstaddr' not in kwargs:
              kwargs['dstaddr'] = '127.0.0.1'
  
          p2p_conn.peer_connect(**kwargs)()
          self.p2ps.append(p2p_conn)
          if wait_for_verack:
              p2p_conn.wait_for_verack()
  
          return p2p_conn
  
      @property
      def p2p(self):
          """Return the first p2p connection
  
          Convenience property - most tests only use a single p2p connection to each
          node, so this saves having to write node.p2ps[0] many times."""
          assert self.p2ps, self._node_msg("No p2p connection")
          return self.p2ps[0]
  
      def disconnect_p2ps(self):
          """Close all p2p connections to the node."""
          for p in self.p2ps:
              p.peer_disconnect()
          del self.p2ps[:]
  
  class TestNodeCLIAttr:
      def __init__(self, cli, command):
          self.cli = cli
          self.command = command
  
      def __call__(self, *args, **kwargs):
          return self.cli.send_cli(self.command, *args, **kwargs)
  
      def get_request(self, *args, **kwargs):
          return lambda: self(*args, **kwargs)
  
  def arg_to_cli(arg):
      if isinstance(arg, bool):
          return str(arg).lower()
      elif isinstance(arg, dict) or isinstance(arg, list):
          return json.dumps(arg)
      else:
          return str(arg)
  
  class TestNodeCLI():
      """Interface to scancoins-cli for an individual node"""
  
      def __init__(self, binary, datadir):
          self.options = []
          self.binary = binary
          self.datadir = datadir
          self.input = None
          self.log = logging.getLogger('TestFramework.bitcoincli')
  
      def __call__(self, *options, input=None):
          # TestNodeCLI is callable with bitcoin-cli command-line options
          cli = TestNodeCLI(self.binary, self.datadir)
          cli.options = [str(o) for o in options]
          cli.input = input
          return cli
  
      def __getattr__(self, command):
          return TestNodeCLIAttr(self, command)
  
      def batch(self, requests):
          results = []
          for request in requests:
              try:
                  results.append(dict(result=request()))
              except JSONRPCException as e:
                  results.append(dict(error=e))
          return results
  
      def send_cli(self, command=None, *args, **kwargs):
          """Run scancoins-cli command. Deserializes returned string as python object."""
          pos_args = [arg_to_cli(arg) for arg in args]
          named_args = [str(key) + "=" + arg_to_cli(value) for (key, value) in kwargs.items()]
          assert not (pos_args and named_args), "Cannot use positional arguments and named arguments in the same scancoins-cli call"
          p_args = [self.binary, "-datadir=" + self.datadir] + self.options
          if named_args:
              p_args += ["-named"]
          if command is not None:
              p_args += [command]
          p_args += pos_args + named_args
          self.log.debug("Running scancoins-cli command: %s" % command)
          process = subprocess.Popen(p_args, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True)
          cli_stdout, cli_stderr = process.communicate(input=self.input)
          returncode = process.poll()
          if returncode:
              match = re.match(r'error code: ([-0-9]+)\nerror message:\n(.*)', cli_stderr)
              if match:
                  code, message = match.groups()
                  raise JSONRPCException(dict(code=int(code), message=message))
              # Ignore cli_stdout, raise with cli_stderr
              raise subprocess.CalledProcessError(returncode, self.binary, output=cli_stderr)
          try:
              return json.loads(cli_stdout, parse_float=decimal.Decimal)
          except JSONDecodeError:
              return cli_stdout.rstrip("\n")
  