Source code for xonsh.history.json

# -*- coding: utf-8 -*-
"""Implements JSON version of xonsh history backend."""
import os
import sys
import time
import json
import builtins
import collections
import threading
import collections.abc as cabc

from xonsh.history.base import History
import xonsh.tools as xt
import xonsh.lazyjson as xlj
import xonsh.xoreutils.uptime as uptime


def _xhj_gc_commands_to_rmfiles(hsize, files):
    """Return the history files to remove to get under the command limit."""
    rmfiles = []
    n = 0
    ncmds = 0
    for ts, fcmds, f in files[::-1]:
        if fcmds == 0:
            # we need to make sure that 'empty' history files don't hang around
            rmfiles.append((ts, fcmds, f))
        if ncmds + fcmds > hsize:
            break
        ncmds += fcmds
        n += 1
    rmfiles += files[:-n]
    return rmfiles


def _xhj_gc_files_to_rmfiles(hsize, files):
    """Return the history files to remove to get under the file limit."""
    rmfiles = files[:-hsize] if len(files) > hsize else []
    return rmfiles


def _xhj_gc_seconds_to_rmfiles(hsize, files):
    """Return the history files to remove to get under the age limit."""
    rmfiles = []
    now = time.time()
    for ts, _, f in files:
        if (now - ts) < hsize:
            break
        rmfiles.append((None, None, f))
    return rmfiles


def _xhj_gc_bytes_to_rmfiles(hsize, files):
    """Return the history files to remove to get under the byte limit."""
    rmfiles = []
    n = 0
    nbytes = 0
    for _, _, f in files[::-1]:
        fsize = os.stat(f).st_size
        if nbytes + fsize > hsize:
            break
        nbytes += fsize
        n += 1
    rmfiles = files[:-n]
    return rmfiles


def _xhj_get_history_files(sort=True, reverse=False):
    """Find and return the history files. Optionally sort files by
        modify time.
    """
    data_dir = builtins.__xonsh_env__.get('XONSH_DATA_DIR')
    data_dir = xt.expanduser_abs_path(data_dir)
    try:
        files = [os.path.join(data_dir, f) for f in os.listdir(data_dir)
                 if f.startswith('xonsh-') and f.endswith('.json')]
    except OSError:
        files = []
        if builtins.__xonsh_env__.get('XONSH_DEBUG'):
            xt.print_exception("Could not collect xonsh history files.")
    if sort:
        files.sort(key=lambda x: os.path.getmtime(x), reverse=reverse)
    return files


[docs]class JsonHistoryGC(threading.Thread): """Shell history garbage collection.""" def __init__(self, wait_for_shell=True, size=None, *args, **kwargs): """Thread responsible for garbage collecting old history. May wait for shell (and for xonshrc to have been loaded) to start work. """ super().__init__(*args, **kwargs) self.daemon = True self.size = size self.wait_for_shell = wait_for_shell self.start() self.gc_units_to_rmfiles = {'commands': _xhj_gc_commands_to_rmfiles, 'files': _xhj_gc_files_to_rmfiles, 's': _xhj_gc_seconds_to_rmfiles, 'b': _xhj_gc_bytes_to_rmfiles} def run(self): while self.wait_for_shell: time.sleep(0.01) env = builtins.__xonsh_env__ # pylint: disable=no-member if self.size is None: hsize, units = env.get('XONSH_HISTORY_SIZE') else: hsize, units = xt.to_history_tuple(self.size) files = self.files(only_unlocked=True) rmfiles_fn = self.gc_units_to_rmfiles.get(units) if rmfiles_fn is None: raise ValueError('Units type {0!r} not understood'.format(units)) for _, _, f in rmfiles_fn(hsize, files): try: os.remove(f) except OSError: pass
[docs] def files(self, only_unlocked=False): """Find and return the history files. Optionally locked files may be excluded. This is sorted by the last closed time. Returns a list of (timestamp, number of cmds, file name) tuples. """ # pylint: disable=no-member env = getattr(builtins, '__xonsh_env__', None) if env is None: return [] boot = uptime.boottime() fs = _xhj_get_history_files(sort=False) files = [] for f in fs: try: if os.path.getsize(f) == 0: # collect empty files (for gc) files.append((time.time(), 0, f)) continue lj = xlj.LazyJSON(f, reopen=False) if lj['locked'] and lj['ts'][0] < boot: # computer was rebooted between when this history was created # and now and so this history should be unlocked. hist = lj.load() lj.close() hist['locked'] = False with open(f, 'w', newline='\n') as fp: xlj.ljdump(hist, fp, sort_keys=True) lj = xlj.LazyJSON(f, reopen=False) if only_unlocked and lj['locked']: continue # info: closing timestamp, number of commands, filename files.append((lj['ts'][1] or lj['ts'][0], len(lj.sizes['cmds']) - 1, f)) lj.close() except (IOError, OSError, ValueError): continue files.sort() return files
[docs]class JsonHistoryFlusher(threading.Thread): """Flush shell history to disk periodically.""" def __init__(self, filename, buffer, queue, cond, at_exit=False, *args, **kwargs): """Thread for flushing history.""" super(JsonHistoryFlusher, self).__init__(*args, **kwargs) self.filename = filename self.buffer = buffer self.queue = queue queue.append(self) self.cond = cond self.at_exit = at_exit if at_exit: self.dump() queue.popleft() else: self.start() def run(self): with self.cond: self.cond.wait_for(self.i_am_at_the_front) self.dump() self.queue.popleft()
[docs] def i_am_at_the_front(self): """Tests if the flusher is at the front of the queue.""" return self is self.queue[0]
[docs] def dump(self): """Write the cached history to external storage.""" opts = builtins.__xonsh_env__.get('HISTCONTROL') last_inp = None cmds = [] for cmd in self.buffer: if 'ignoredups' in opts and cmd['inp'] == last_inp: # Skipping dup cmd continue if 'ignoreerr' in opts and cmd['rtn'] != 0: # Skipping failed cmd continue cmds.append(cmd) last_inp = cmd['inp'] with open(self.filename, 'r', newline='\n') as f: hist = xlj.LazyJSON(f).load() load_hist_len = len(hist['cmds']) hist['cmds'].extend(cmds) if self.at_exit: hist['ts'][1] = time.time() # apply end time hist['locked'] = False if not builtins.__xonsh_env__.get('XONSH_STORE_STDOUT', False): [cmd.pop('out') for cmd in hist['cmds'][load_hist_len:] if 'out' in cmd] with open(self.filename, 'w', newline='\n') as f: xlj.ljdump(hist, f, sort_keys=True)
[docs]class JsonCommandField(cabc.Sequence): """A field in the 'cmds' portion of history.""" def __init__(self, field, hist, default=None): """Represents a field in the 'cmds' portion of history. Will query the buffer for the relevant data, if possible. Otherwise it will lazily acquire data from the file. Parameters ---------- field : str The name of the field to query. hist : History object The history object to query. default : optional The default value to return if key is not present. """ self.field = field self.hist = hist self.default = default def __len__(self): return len(self.hist) def __getitem__(self, key): size = len(self) if isinstance(key, slice): return [self[i] for i in range(*key.indices(size))] elif not isinstance(key, int): raise IndexError( 'JsonCommandField may only be indexed by int or slice.') elif size == 0: raise IndexError('JsonCommandField is empty.') # now we know we have an int key = size + key if key < 0 else key # ensure key is non-negative bufsize = len(self.hist.buffer) if size - bufsize <= key: # key is in buffer return self.hist.buffer[key + bufsize - size].get( self.field, self.default) # now we know we have to go into the file queue = self.hist._queue queue.append(self) with self.hist._cond: self.hist._cond.wait_for(self.i_am_at_the_front) with open(self.hist.filename, 'r', newline='\n') as f: lj = xlj.LazyJSON(f, reopen=False) rtn = lj['cmds'][key].get(self.field, self.default) if isinstance(rtn, xlj.LJNode): rtn = rtn.load() queue.popleft() return rtn
[docs] def i_am_at_the_front(self): """Tests if the command field is at the front of the queue.""" return self is self.hist._queue[0]
[docs]class JsonHistory(History): """Xonsh history backend implemented with JSON files. JsonHistory implements two extra actions: ``diff``, and ``replay``. """ def __init__(self, filename=None, sessionid=None, buffersize=100, gc=True, **meta): """Represents a xonsh session's history as an in-memory buffer that is periodically flushed to disk. Parameters ---------- filename : str, optional Location of history file, defaults to ``$XONSH_DATA_DIR/xonsh-{sessionid}.json``. sessionid : int, uuid, str, optional Current session identifier, will generate a new sessionid if not set. buffersize : int, optional Maximum buffersize in memory. meta : optional Top-level metadata to store along with the history. The kwargs 'cmds' and 'sessionid' are not allowed and will be overwritten. gc : bool, optional Run garbage collector flag. """ super().__init__(sessionid=sessionid, **meta) if filename is None: # pylint: disable=no-member data_dir = builtins.__xonsh_env__.get('XONSH_DATA_DIR') data_dir = os.path.expanduser(data_dir) self.filename = os.path.join( data_dir, 'xonsh-{0}.json'.format(self.sessionid)) else: self.filename = filename self.buffer = [] self.buffersize = buffersize self._queue = collections.deque() self._cond = threading.Condition() self._len = 0 self.last_cmd_out = None self.last_cmd_rtn = None meta['cmds'] = [] meta['sessionid'] = str(self.sessionid) with open(self.filename, 'w', newline='\n') as f: xlj.ljdump(meta, f, sort_keys=True) self.gc = JsonHistoryGC() if gc else None # command fields that are known self.tss = JsonCommandField('ts', self) self.inps = JsonCommandField('inp', self) self.outs = JsonCommandField('out', self) self.rtns = JsonCommandField('rtn', self) def __len__(self): return self._len
[docs] def append(self, cmd): """Appends command to history. Will periodically flush the history to file. Parameters ---------- cmd : dict This dict contains information about the command that is to be added to the history list. It should contain the keys ``inp``, ``rtn`` and ``ts``. These key names mirror the same names defined as instance variables in the ``HistoryEntry`` class. Returns ------- hf : JsonHistoryFlusher or None The thread that was spawned to flush history """ self.buffer.append(cmd) self._len += 1 # must come before flushing if len(self.buffer) >= self.buffersize: hf = self.flush() else: hf = None return hf
[docs] def flush(self, at_exit=False): """Flushes the current command buffer to disk. Parameters ---------- at_exit : bool, optional Whether the JsonHistoryFlusher should act as a thread in the background, or execute immediately and block. Returns ------- hf : JsonHistoryFlusher or None The thread that was spawned to flush history """ if len(self.buffer) == 0: return hf = JsonHistoryFlusher(self.filename, tuple(self.buffer), self._queue, self._cond, at_exit=at_exit) self.buffer.clear() return hf
[docs] def items(self): """Display history items of current session.""" for item, tss in zip(self.inps, self.tss): yield {'inp': item.rstrip(), 'ts': tss[0]}
[docs] def all_items(self, **kwargs): """ Returns all history as found in XONSH_DATA_DIR. yield format: {'inp': cmd, 'rtn': 0, ...} """ while self.gc and self.gc.is_alive(): time.sleep(0.011) # gc sleeps for 0.01 secs, sleep a beat longer for f in _xhj_get_history_files(): try: json_file = xlj.LazyJSON(f, reopen=False) except ValueError: # Invalid json file continue try: commands = json_file.load()['cmds'] except json.decoder.JSONDecodeError: # file is corrupted somehow if builtins.__xonsh_env__.get('XONSH_DEBUG') > 0: msg = 'xonsh history file {0!r} is not valid JSON' print(msg.format(f), file=sys.stderr) continue for c in commands: yield {'inp': c['inp'].rstrip(), 'ts': c['ts'][0]} # all items should also include session items yield from self.items()
def info(self): data = collections.OrderedDict() data['backend'] = 'json' data['sessionid'] = str(self.sessionid) data['filename'] = self.filename data['length'] = len(self) data['buffersize'] = self.buffersize data['bufferlength'] = len(self.buffer) envs = builtins.__xonsh_env__ data['gc options'] = envs.get('XONSH_HISTORY_SIZE') return data def run_gc(self, size=None, blocking=True): self.gc = JsonHistoryGC(wait_for_shell=False, size=size) if blocking: while self.gc.is_alive(): continue