commands.py

"""Command implementations."""

import abc
import asyncio
import asyncio.subprocess
import logging
import re
import typing
from pathlib import Path

import attr

from . import worker

command_handlers = {}

# Timeout of subprocess.stdout.readline() call.
SUBPROC_READLINE_TIMEOUT = 3600  # seconds

MERGE_EXR_PYTHON = """\
import bpy
scene = bpy.context.scene
nodes = scene.node_tree.nodes
image1 = bpy.data.images.load("%(input1)s")
image2 = bpy.data.images.load("%(input2)s")

nodes["image1"].image = image1
nodes["image2"].image = image2
nodes["weight1"].outputs[0].default_value = %(weight1)i
nodes["weight2"].outputs[0].default_value = %(weight2)i

nodes["output"].base_path = "%(tmpdir)s"
scene.render.resolution_x, scene.render.resolution_y = image1.size
scene.render.tile_x, scene.render.tile_y = image1.size
scene.render.filepath = "%(tmpdir)s/preview.jpg"

bpy.ops.render.render(write_still=True)
"""


def command_executor(cmdname):
    """Class decorator, registers a command executor."""

    def decorator(cls):
        assert cmdname not in command_handlers

        command_handlers[cmdname] = cls
        cls.command_name = cmdname
        return cls

    return decorator


class CommandExecutionError(Exception):
    """Raised when there was an error executing a command."""
    pass


@attr.s
class AbstractCommand(metaclass=abc.ABCMeta):
    """Command executor.

    This class (or any of its subclasses) should not directly set the task status.
    This should be left to the Worker.
    """
    worker = attr.ib(validator=attr.validators.instance_of(worker.FlamencoWorker),
                     repr=False)
    task_id = attr.ib(validator=attr.validators.instance_of(str))
    command_idx = attr.ib(validator=attr.validators.instance_of(int))

    # Set by @command_executor
    command_name = ''

    # Set by __attr_post_init__()
    identifier = attr.ib(default=None, init=False,
                         validator=attr.validators.optional(attr.validators.instance_of(str)))
    _log = attr.ib(default=None, init=False,
                   validator=attr.validators.optional(attr.validators.instance_of(logging.Logger)))

    def __attrs_post_init__(self):
        self.identifier = '%s.(task_id=%s, command_idx=%s)' % (
            self.command_name,
            self.task_id,
            self.command_idx)
        self._log = logging.getLogger('%s.%s' % (__name__, self.identifier))

    async def run(self, settings: dict) -> bool:
        """Runs the command, parsing output and sending it back to the worker.

        Returns True when the command was succesful, and False otherwise.
        """

        verr = self.validate(settings)
        if verr is not None:
            self._log.warning('%s: Error in settings: %s', self.identifier, verr)
            await self.worker.register_log('%s: Error in settings: %s', self.identifier, verr)
            await self.worker.register_task_update(
                task_status='failed',
                activity='%s: Invalid settings: %s' % (self.identifier, verr),
            )
            return False

        await self.worker.register_log('%s: Starting' % self.command_name)
        await self.worker.register_task_update(
            activity='starting %s' % self.command_name,
            current_command_idx=self.command_idx,
            command_progress_percentage=0
        )

        try:
            await self.execute(settings)
        except CommandExecutionError as ex:
            # This is something we threw ourselves, and there is no need to log the traceback.
            self._log.warning('Error executing: %s', ex)
            await self._register_exception(ex)
            return False
        except asyncio.CancelledError as ex:
            self._log.warning('Command execution was canceled')
            raise
        except Exception as ex:
            # This is something unexpected, so do log the traceback.
            self._log.exception('Error executing.')
            await self._register_exception(ex)
            return False

        await self.worker.register_log('%s: Finished' % self.command_name)
        await self.worker.register_task_update(
            activity='finished %s' % self.command_name,
            current_command_idx=self.command_idx,
            command_progress_percentage=100
        )

        return True

    async def abort(self):
        """Aborts the command. This may or may not be actually possible.

        A subprocess that's started by this command will be killed.
        However, any asyncio coroutines that are not managed by this command
        (such as the 'run' function) should be cancelled by the caller.
        """

    async def _register_exception(self, ex: Exception):
        """Registers an exception with the worker, and set the task status to 'failed'."""

        await self.worker.register_log('%s: Error executing: %s' % (self.identifier, ex))
        await self.worker.register_task_update(
            activity='%s: Error executing: %s' % (self.identifier, ex),
        )

    @abc.abstractmethod
    async def execute(self, settings: dict):
        """Executes the command.

        An error should be indicated by an exception.
        """

    def validate(self, settings: dict):
        """Validates the settings for this command.

        If there is an error, a description of the error is returned.
        If the settings are valid, None is returned.

        By default all settings are considered valid.
        """

        return None

    def _setting(self, settings: dict, key: str, is_required: bool, valtype: typing.Type = str) -> (
            typing.Any, typing.Optional[str]):
        """Parses a setting, returns either (value, None) or (None, errormsg)"""

        try:
            value = settings[key]
        except KeyError:
            if is_required:
                return None, 'Missing "%s"' % key
            return None, None

        if value is None and not is_required:
            return None, None

        if not isinstance(value, valtype):
            return None, '"%s" must be a %s, not a %s' % (key, valtype, type(value))

        return value, None


@command_executor('echo')
class EchoCommand(AbstractCommand):
    def validate(self, settings: dict):
        try:
            msg = settings['message']
        except KeyError:
            return 'Missing "message"'

        if not isinstance(msg, str):
            return 'Message must be a string'

    async def execute(self, settings: dict):
        await self.worker.register_log(settings['message'])


@command_executor('sleep')
class SleepCommand(AbstractCommand):
    def validate(self, settings: dict):
        try:
            sleeptime = settings['time_in_seconds']
        except KeyError:
            return 'Missing "time_in_seconds"'

        if not isinstance(sleeptime, (int, float)):
            return 'time_in_seconds must be an int or float'

    async def execute(self, settings: dict):
        time_in_seconds = settings['time_in_seconds']
        await self.worker.register_log('Sleeping for %s seconds' % time_in_seconds)
        await asyncio.sleep(time_in_seconds)
        await self.worker.register_log('Done sleeping for %s seconds' % time_in_seconds)


def _timestamped_path(path: Path) -> Path:
    """Returns the path with its modification time appended to the name."""

    from datetime import datetime

    mtime = path.stat().st_mtime

    # Round away the milliseconds, as those aren't all that interesting.
    # Uniqueness is ensured by calling _unique_path().
    mdatetime = datetime.fromtimestamp(round(mtime))

    # Make the ISO-8601 timestamp a bit more eye- and filename-friendly.
    iso = mdatetime.isoformat().replace('T', '_').replace(':', '')
    dst = path.with_name('%s-%s' % (path.name, iso))

    return dst


def _unique_path(path: Path) -> Path:
    """Returns the path, or if it exists, the path with a unique suffix."""

    import re

    suf_re = re.compile(r'~([0-9]+)$')

    # See which suffixes are in use
    max_nr = 0
    for altpath in path.parent.glob(path.name + '~*'):
        m = suf_re.search(altpath.name)
        if not m:
            continue

        suffix = m.group(1)
        try:
            suffix = int(suffix)
        except ValueError:
            continue
        max_nr = max(max_nr, suffix)
    return path.with_name(path.name + '~%i' % (max_nr + 1))


@command_executor('move_out_of_way')
class MoveOutOfWayCommand(AbstractCommand):
    def validate(self, settings: dict):
        try:
            src = settings['src']
        except KeyError:
            return 'Missing "src"'

        if not isinstance(src, str):
            return 'src must be a string'

    async def execute(self, settings: dict):
        src = Path(settings['src'])
        if not src.exists():
            self._log.info('Render output path %s does not exist, not moving out of way', src)
            await self.worker.register_log('%s: Render output path %s does not exist, '
                                           'not moving out of way', self.command_name, src)
            return

        dst = _timestamped_path(src)
        if dst.exists():
            self._log.debug('Destination %s exists, finding one that does not', dst)
            dst = _unique_path(dst)
            self._log.debug('New destination is %s', dst)

        self._log.info('Moving %s to %s', src, dst)
        await self.worker.register_log('%s: Moving %s to %s', self.command_name, src, dst)
        src.rename(dst)


@command_executor('move_to_final')
class MoveToFinalCommand(AbstractCommand):
    def validate(self, settings: dict):
        _, err1 = self._setting(settings, 'src', True)
        _, err2 = self._setting(settings, 'dest', True)
        return err1 or err2

    async def execute(self, settings: dict):
        src = Path(settings['src'])
        if not src.exists():
            msg = 'Path %s does not exist, not moving' % src
            self._log.info(msg)
            await self.worker.register_log('%s: %s', self.command_name, msg)
            return

        dest = Path(settings['dest'])
        if dest.exists():
            backup = _timestamped_path(dest)
            self._log.debug('Destination %s exists, moving out of the way to %s', dest, backup)

            if backup.exists():
                self._log.debug('Destination %s exists, finding one that does not', backup)
                backup = _unique_path(backup)
                self._log.debug('New destination is %s', backup)

            self._log.info('Moving %s to %s', dest, backup)
            await self.worker.register_log('%s: Moving %s to %s', self.command_name, dest, backup)
            dest.rename(backup)

        self._log.info('Moving %s to %s', src, dest)
        await self.worker.register_log('%s: Moving %s to %s', self.command_name, src, dest)
        src.rename(dest)


@attr.s
class AbstractSubprocessCommand(AbstractCommand):
    readline_timeout = attr.ib(default=SUBPROC_READLINE_TIMEOUT)
    proc = attr.ib(validator=attr.validators.instance_of(asyncio.subprocess.Process),
                   init=False)

    async def subprocess(self, args: list):
        import subprocess
        import shlex

        cmd_to_log = ' '.join(shlex.quote(s) for s in args)
        self._log.info('Executing %s', cmd_to_log)
        await self.worker.register_log('Executing %s', cmd_to_log)

        self.proc = await asyncio.create_subprocess_exec(
            *args,
            stdin=subprocess.DEVNULL,
            stdout=subprocess.PIPE,
            stderr=subprocess.STDOUT,
        )

        try:
            while not self.proc.stdout.at_eof():
                try:
                    line = await asyncio.wait_for(self.proc.stdout.readline(),
                                                  self.readline_timeout)
                except asyncio.TimeoutError:
                    raise CommandExecutionError('Command timed out after %i seconds' %
                                                self.readline_timeout)

                if len(line) == 0:
                    # EOF received, so let's bail.
                    break

                try:
                    line = line.decode('utf8')
                except UnicodeDecodeError as ex:
                    await self.abort()
                    raise CommandExecutionError('Command produced non-UTF8 output, '
                                                'aborting: %s' % ex)

                line = line.rstrip()
                self._log.debug('Read line: %s', line)
                line = await self.process_line(line)
                if line is not None:
                    await self.worker.register_log(line)

            retcode = await self.proc.wait()
            self._log.info('Command %r stopped with status code %s', args, retcode)

            if retcode:
                raise CommandExecutionError('Command failed with status %s' % retcode)
        except asyncio.CancelledError:
            self._log.info('asyncio task got canceled, killing subprocess.')
            await self.abort()
            raise

    async def process_line(self, line: str) -> typing.Optional[str]:
        """Processes the line, returning None to ignore it."""

        return '> %s' % line

    async def abort(self):
        """Aborts the command by killing the subprocess."""

        if self.proc is None or self.proc == attr.NOTHING:
            self._log.debug("No process to kill. That's ok.")
            return

        self._log.info('Aborting subprocess')
        try:
            self.proc.kill()
        except ProcessLookupError:
            # The process is already stopped, so killing is impossible. That's ok.
            self._log.debug("The process was already stopped, aborting is impossible. That's ok.")
            return
        except AttributeError:
            # This can happen in some race conditions, it's fine.
            self._log.debug("The process was not yet started, aborting is impossible. That's ok.")
            return

        retval = await self.proc.wait()
        self._log.info('The process aborted with status code %s', retval)


@command_executor('exec')
class ExecCommand(AbstractSubprocessCommand):
    def validate(self, settings: dict):
        try:
            cmd = settings['cmd']
        except KeyError:
            return 'Missing "cmd"'

        if not isinstance(cmd, str):
            return '"cmd" must be a string'
        if not cmd:
            return '"cmd" may not be empty'

    async def execute(self, settings: dict):
        import shlex
        await self.subprocess(shlex.split(settings['cmd']))


@command_executor('blender_render')
class BlenderRenderCommand(AbstractSubprocessCommand):
    re_global_progress = attr.ib(init=False)
    re_time = attr.ib(init=False)
    re_remaining = attr.ib(init=False)
    re_status = attr.ib(init=False)
    re_path_not_found = attr.ib(init=False)

    def __attrs_post_init__(self):
        super().__attrs_post_init__()

        # Delay regexp compilation until a BlenderRenderCommand is actually constructed.
        self.re_global_progress = re.compile(
            r"^Fra:(?P<fra>\d+) Mem:(?P<mem>[^ ]+) \(.*?, Peak (?P<peakmem>[^ ]+)\)")
        self.re_time = re.compile(
            r'\| Time:((?P<hours>\d+):)?(?P<minutes>\d+):(?P<seconds>\d+)\.(?P<hunds>\d+) ')
        self.re_remaining = re.compile(
            r'\| Remaining:((?P<hours>\d+):)?(?P<minutes>\d+):(?P<seconds>\d+)\.(?P<hunds>\d+) ')
        self.re_status = re.compile(r'\| (?P<status>[^\|]+)\s*$')
        self.re_path_not_found = re.compile(r"Warning: Path '.*' not found")

    def validate(self, settings: dict):
        import shlex

        blender_cmd, err = self._setting(settings, 'blender_cmd', True)
        if err:
            return err
        cmd = shlex.split(blender_cmd)
        if not Path(cmd[0]).exists():
            return 'blender_cmd %r does not exist' % cmd[0]
        settings['blender_cmd'] = cmd

        filepath, err = self._setting(settings, 'filepath', True)
        if err:
            return err
        if not Path(filepath).exists():
            return 'filepath %r does not exist' % filepath

        render_output, err = self._setting(settings, 'render_output', False)
        if err:
            return err
        if render_output:
            outpath = Path(render_output).parent
            try:
                outpath.mkdir(parents=True, exist_ok=True)
            except Exception as ex:
                return '"render_output": dir %s cannot be created: %s' % (outpath, ex)

        _, err = self._setting(settings, 'frames', False)
        if err:
            return err
        _, err = self._setting(settings, 'render_format', False)
        if err:
            return err

        return None

    async def execute(self, settings: dict):
        cmd = self._build_blender_cmd(settings)

        await self.worker.register_task_update(activity='Starting Blender')
        await self.subprocess(cmd)

    def _build_blender_cmd(self, settings):
        cmd = settings['blender_cmd'][:]
        cmd += [
            '--factory-startup',
            '--enable-autoexec',
            '-noaudio',
            '--background',
            settings['filepath'],
        ]
        if settings.get('render_output'):
            cmd.extend(['--render-output', settings['render_output']])
        if settings.get('format'):
            cmd.extend(['--render-format', settings['format']])
        if settings.get('frames'):
            cmd.extend(['--render-frame', settings['frames']])
        return cmd

    def parse_render_line(self, line: str) -> typing.Optional[dict]:
        """Parses a single line of render progress.

        Returns None if this line does not contain render progress.
        """

        m = self.re_global_progress.search(line)
        if not m:
            return None
        info = m.groupdict()
        info['fra'] = int(info['fra'])

        m = self.re_time.search(line)
        if m:
            info['time_sec'] = (3600 * int(m.group('hours') or 0) +
                                60 * int(m.group('minutes')) +
                                int(m.group('seconds')) +
                                int(m.group('hunds')) / 100)

        m = self.re_remaining.search(line)
        if m:
            info['remaining_sec'] = (3600 * int(m.group('hours') or 0) +
                                     60 * int(m.group('minutes')) +
                                     int(m.group('seconds')) +
                                     int(m.group('hunds')) / 100)

        m = self.re_status.search(line)
        if m:
            info['status'] = m.group('status')

        return info

    async def process_line(self, line: str) -> typing.Optional[str]:
        """Processes the line, returning None to ignore it."""

        # See if there are any warnings about missing files. If so, we update the activity for it.
        if 'Warning: Unable to open' in line or self.re_path_not_found.search(line):
            await self.worker.register_task_update(activity=line)

        render_info = self.parse_render_line(line)
        if render_info:
            # Render progress. Not interesting to log all of them, but we do use
            # them to update the render progress.
            # TODO: For now we return this as a string, but at some point we may want
            # to consider this as a subdocument.
            if 'remaining_sec' in render_info:
                fmt = 'Fra:{fra} Mem:{mem} | Time:{time_sec} | Remaining:{remaining_sec} | {status}'
                activity = fmt.format(**render_info)
            else:
                self._log.debug('Unable to find remaining time in line: %s', line)
                activity = line
            await self.worker.register_task_update(activity=activity)

        # Not a render progress line; just log it for now.
        return '> %s' % line


@command_executor('blender_render_progressive')
class BlenderRenderProgressiveCommand(BlenderRenderCommand):
    def validate(self, settings: dict):
        err = super().validate(settings)
        if err: return err

        cycles_num_chunks, err = self._setting(settings, 'cycles_num_chunks', True, int)
        if err: return err
        if cycles_num_chunks < 1:
            return '"cycles_num_chunks" must be a positive integer'

        cycles_chunk, err = self._setting(settings, 'cycles_chunk', True, int)
        if err: return err
        if cycles_chunk < 1:
            return '"cycles_chunk" must be a positive integer'

    def _build_blender_cmd(self, settings):
        cmd = super()._build_blender_cmd(settings)

        return cmd + [
            '--',
            '--cycles-resumable-num-chunks', str(settings['cycles_num_chunks']),
            '--cycles-resumable-current-chunk', str(settings['cycles_chunk']),
        ]


@command_executor('merge_progressive_renders')
class MergeProgressiveRendersCommand(AbstractSubprocessCommand):
    def validate(self, settings: dict):
        import shlex

        blender_cmd, err = self._setting(settings, 'blender_cmd', True)
        if err:
            return err
        cmd = shlex.split(blender_cmd)
        if not Path(cmd[0]).exists():
            return 'blender_cmd %r does not exist' % cmd[0]
        settings['blender_cmd'] = cmd

        input1, err = self._setting(settings, 'input1', True, str)
        if err: return err
        if '"' in input1:
            return 'Double quotes are not allowed in filenames: %r' % input1
        if not Path(input1).exists():
            return 'Input 1 %r does not exist' % input1
        input2, err = self._setting(settings, 'input2', True, str)
        if err: return err
        if '"' in input2:
            return 'Double quotes are not allowed in filenames: %r' % input2
        if not Path(input2).exists():
            return 'Input 2 %r does not exist' % input2

        output, err = self._setting(settings, 'output', True, str)
        if err: return err
        if '"' in output:
            return 'Double quotes are not allowed in filenames: %r' % output

        _, err = self._setting(settings, 'weight1', True, int)
        if err: return err

        _, err = self._setting(settings, 'weight2', True, int)
        if err: return err

    async def execute(self, settings: dict):
        import tempfile

        blendpath = Path(__file__).with_name('merge-exr.blend')

        cmd = settings['blender_cmd'][:]
        cmd += [
            '--factory-startup',
            '--enable-autoexec',
            '-noaudio',
            '--background',
            str(blendpath),
        ]

        # set up node properties and render settings.
        output = Path(settings['output'])
        output.parent.mkdir(parents=True, exist_ok=True)

        with tempfile.TemporaryDirectory(dir=str(output.parent)) as tmpdir:
            tmppath = Path(tmpdir)
            assert tmppath.exists()

            settings['tmpdir'] = tmpdir
            cmd += [
                '--python-expr', MERGE_EXR_PYTHON % settings
            ]

            await self.worker.register_task_update(activity='Starting Blender to merge EXR files')
            await self.subprocess(cmd)

            # move output files into the correct spot.
            await self.move(tmppath / 'merged0001.exr', output)
            await self.move(tmppath / 'preview.jpg', output.with_suffix('.jpg'))

    async def move(self, src: Path, dst: Path):
        """Moves a file to another location."""

        import shutil

        self._log.info('Moving %s to %s', src, dst)

        assert src.is_file()
        assert not dst.exists() or dst.is_file()
        assert dst.exists() or dst.parent.exists()

        await self.worker.register_log('Moving %s to %s', src, dst)
        shutil.move(str(src), str(dst))