Mercurial > personal > weather-server

annotate weather_server/logfile.py @ 36:e5a03d63b3d9 default tip

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Truncate, don’t round, temperatures displayed in HTML.
author Paul Fisher <paul@pfish.zone>
date Fri, 02 Jul 2021 20:38:11 -0400
parents 9bc3687e1e5e
children
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efe7a1eff167 Create initial logger for weather server.
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1 """The part which handles writing things out and reading things in from CSV.
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2 """
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3
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4 import attr
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5 import collections
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6 import concurrent.futures as futures
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7 import contextlib
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8 import fcntl
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9 import os
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10 import queue
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11 import threading
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12 import typing as t
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13
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14 import bson
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15
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16 from . import common
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17
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18
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19 # The number of entries to keep in memory without reading from disk.
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20 CACHED_ENTRIES = 16384
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21
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22 # How many entries to read before creating a new index entry.
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23 INDEX_GAP = 4096
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24
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25
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26 class _WriteRequest:
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27
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28 def __init__(self, entries: t.Iterable[t.Dict[str, t.Any]]):
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29 """Creates a request to write the given data to the log."""
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30 # The data to be written. We take ownership of all the dicts!
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31 self.entries = entries
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32 # Once written, a future that will resolve to None if successful.
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33 self.future = futures.Future()
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34
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35
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36 class _ReadRequest:
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37
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38 def __init__(self):
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39 # The future that will be set with the log's contnets.
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40 self.future = futures.Future()
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41 # TODO(pfish): Make it possible to read from a starting point.
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42
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43
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44 # Poison pill to tell a logger thread to stop.
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45 _POISON = object()
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46
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47
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48 class Logger:
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49 """Logger which handles reading/writing one temperature log file."""
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50
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51 _file: t.BinaryIO
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52 _index_file: t.BinaryIO
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53
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54 def __init__(
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55 self,
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56 filename: str,
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57 *,
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58 sample_field: str,
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59 cached_entries: int = CACHED_ENTRIES,
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60 index_gap: int = INDEX_GAP):
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61 """Creates a new Logger for the given file.
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62
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63 Args:
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64 filename: The filename to open, or create if not already there.
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65 sample_field: The field name to use as the strictly-increasing
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66 value to ensure that no duplicate writes occur.
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67 """
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68
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69 self._filename = filename
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70 self._cached_entries = cached_entries
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71 self._index_gap = index_gap
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72
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73 self._queue = queue.SimpleQueue()
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74 self._sample_field = sample_field
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75
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76 self._start_future = futures.Future()
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77 self._thread = threading.Thread(
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78 name=f'{filename!r} writer thread',
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79 target=self._writer_thread,
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80 daemon=True)
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81 self._thread.start()
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82
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83 self._data = collections.deque(maxlen=self._cached_entries)
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84 self._index: t.List[IndexEntry] = []
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85 self._message_count = 0
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86 self._start_future.result()
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87
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88 @property
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89 def cached_data(self) -> t.Tuple[t.Dict[str, t.Any], ...]:
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90 req = _ReadRequest()
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91 self._queue.put(req)
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92 return req.future.result()
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93
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94 def write_rows(self, entries: t.Iterable[t.Dict[str, t.Any]]):
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95 req = _WriteRequest(entries)
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96 self._queue.put(req)
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97 return req.future.result()
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98
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99 def _writer_thread(self) -> None:
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100 try:
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101 self._file = _open_or_create(self._filename)
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102 self._index_file = _open_or_create(_index_filename(self._filename))
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103 except BaseException as e:
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104 self._start_future.set_exception(e)
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105 return
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106 self._start_future.set_result(None)
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107
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108 with self._file, self._index_file:
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109 running = True
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110 while running:
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111 item = self._queue.get()
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112 if item is _POISON:
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113 # None is the poison pill that makes us stop.
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114 running = False
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115 elif isinstance(item, _ReadRequest):
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116 if not item.future.set_running_or_notify_cancel():
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117 continue
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118 with _file_lock(self._file, fcntl.LOCK_SH):
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119 try:
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120 self._catch_up()
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121 except BaseException as x:
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122 item.future.set_exception(x)
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123 else:
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124 item.future.set_result(tuple(self._data))
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125 elif isinstance(item, _WriteRequest):
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126 if not item.future.set_running_or_notify_cancel():
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127 continue
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128 try:
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129 with _file_lock(self._file, fcntl.LOCK_EX):
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130 self._catch_up()
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131 current_ptr = self._file.tell()
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132 self._file.truncate(current_ptr)
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133 if not self._data:
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134 prev_key = None
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135 else:
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136 prev_key = self._data[-1][self._sample_field]
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137 for entry in item.entries:
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138 entry_key = entry[self._sample_field]
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139 if prev_key is None or prev_key < entry_key:
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140 self._data.append(entry)
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141 self._file.write(common.bson_encode(entry))
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142 prev_key = entry_key
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143 self._file.flush()
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144 self._update_index()
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
145 except BaseException as x:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
146 item.future.set_exception(x)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
147 else:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
148 item.future.set_result(None)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
149 else:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
150 raise AssertionError(
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
151 f'Unexpected item {item!r} in the queue')
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
152
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
153 def _catch_up(self) -> None:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
154 # Preconditions:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
155 # - At least a read lock is held.
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
156 # - File pointer is at the end of the last-read entry.
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
157 self._catch_up_index()
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
158 if self._index:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
159 # Since we have an index, use it to find a starting place.
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
160 last_idx = self._index[-1]
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
161 # Figure out, based on the number of entries we want to keep
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
162 # in memory, where we should start reading from.
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
163 read_start_count = max(
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
164 0, last_idx.entry_count - self._cached_entries)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
165 if self._message_count < read_start_count:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
166 # If we've already read past that starting point, we're OK.
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
167 for idx_entry in self._index:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
168 if read_start_count <= idx_entry.entry_count:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
169 break
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
170 starting_point = idx_entry
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
171 self._data.clear()
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
172 self._file.seek(starting_point.byte, os.SEEK_SET)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
173 self._message_count = starting_point.entry_count
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
174 pointer = self._file.tell()
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
175 try:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
176 items = bson.decode_file_iter(
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
177 self._file, codec_options=common.BSON_OPTIONS)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
178 for item in items:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
179 pointer = self._file.tell()
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
180 self._data.append(item)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
181 self._message_count += 1
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
182 except bson.InvalidBSON:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
183 pass # We have reached the last valid document. Bail.
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
184 # Seek back to immediately after the end of the last valid doc.
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
185 self._file.seek(pointer, os.SEEK_SET)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
186
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
187 def _update_index(self) -> None:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
188 # Preconditions:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
189 # - File pointer is at the end of the last-written message.
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
190 # - Index pointer is at the last-read index value.
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
191 # - Exclusive lock is held.
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
192 with _dup_file(self._file) as update_fp:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
193 if self._index:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
194 last_idx = self._index[-1]
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
195 update_fp.seek(last_idx.byte)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
196 current_count = last_idx.entry_count
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
197 decoder = bson.decode_file_iter(
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
198 update_fp, codec_options=common.BSON_OPTIONS)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
199 try:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
200 # Skip the current index entry.
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
201 next(decoder)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
202 current_count += 1
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
203 current_byte = update_fp.tell()
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
204 except StopIteration:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
205 # If there are no more entries, don't update the index.
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
206 return
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
207 else:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
208 current_byte = 0
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
209 update_fp.seek(current_byte, os.SEEK_SET)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
210 current_count = 0
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
211 entries = bson.decode_file_iter(
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
212 update_fp, codec_options=common.BSON_OPTIONS)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
213 for entry in entries:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
214 if current_count % self._index_gap == 0:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
215 idx_entry = IndexEntry(
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
216 entry_count=current_count,
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
217 entry_key=entry[self._sample_field],
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
218 byte=current_byte)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
219 self._index.append(idx_entry)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
220 self._index_file.truncate()
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
221 self._index_file.write(
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
222 common.bson_encode(idx_entry.to_dict()))
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
223 current_count += 1
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
224 current_byte = update_fp.tell()
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
225 self._index_file.flush()
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
226
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
227 def _catch_up_index(self) -> None:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
228 # Preconditions:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
229 # - At least a read lock is held.
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
230 pointer = self._index_file.tell()
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
231 try:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
232 index_entries = bson.decode_file_iter(
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
233 self._index_file, codec_options=common.BSON_OPTIONS)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
234 for entry_dict in index_entries:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
235 entry = IndexEntry.from_dict(entry_dict)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
236 self._index.append(entry)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
237 pointer = self._index_file.tell()
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
238 except bson.InvalidBSON:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
239 pass # We have reached the last valid BSON document. Bail.
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
240 self._index_file.seek(pointer, os.SEEK_SET)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
241
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
242 def __del__(self) -> None:
24
20c8ec56e447 logfile: Pull logfile thread out of Logger.
Paul Fisher <paul@pfish.zone>
parents: 21
diff changeset
243 self.close()
21
beb42c835c52 Make weather server handle arbitrary data:
Paul Fisher <paul@pfish.zone>
parents: 0
diff changeset
244
31
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
245 def close(self) -> None:
24
20c8ec56e447 logfile: Pull logfile thread out of Logger.
Paul Fisher <paul@pfish.zone>
parents: 21
diff changeset
246 self._queue.put(_POISON)
31
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
247 self._thread.join()
0
efe7a1eff167 Create initial logger for weather server.
Paul Fisher <paul@pfish.zone>
parents:
diff changeset
248
24
20c8ec56e447 logfile: Pull logfile thread out of Logger.
Paul Fisher <paul@pfish.zone>
parents: 21
diff changeset
249
31
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
250 def _index_filename(filename: str) -> str:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
251 return filename + '.index.bson'
24
20c8ec56e447 logfile: Pull logfile thread out of Logger.
Paul Fisher <paul@pfish.zone>
parents: 21
diff changeset
252
20c8ec56e447 logfile: Pull logfile thread out of Logger.
Paul Fisher <paul@pfish.zone>
parents: 21
diff changeset
253
20c8ec56e447 logfile: Pull logfile thread out of Logger.
Paul Fisher <paul@pfish.zone>
parents: 21
diff changeset
254 @contextlib.contextmanager
20c8ec56e447 logfile: Pull logfile thread out of Logger.
Paul Fisher <paul@pfish.zone>
parents: 21
diff changeset
255 def _file_lock(file: t.BinaryIO, operation: int) -> t.Iterator[None]:
20c8ec56e447 logfile: Pull logfile thread out of Logger.
Paul Fisher <paul@pfish.zone>
parents: 21
diff changeset
256 assert operation in (fcntl.LOCK_SH, fcntl.LOCK_EX), 'Invalid operation.'
20c8ec56e447 logfile: Pull logfile thread out of Logger.
Paul Fisher <paul@pfish.zone>
parents: 21
diff changeset
257 fcntl.flock(file, operation)
20c8ec56e447 logfile: Pull logfile thread out of Logger.
Paul Fisher <paul@pfish.zone>
parents: 21
diff changeset
258 try:
20c8ec56e447 logfile: Pull logfile thread out of Logger.
Paul Fisher <paul@pfish.zone>
parents: 21
diff changeset
259 yield
20c8ec56e447 logfile: Pull logfile thread out of Logger.
Paul Fisher <paul@pfish.zone>
parents: 21
diff changeset
260 finally:
20c8ec56e447 logfile: Pull logfile thread out of Logger.
Paul Fisher <paul@pfish.zone>
parents: 21
diff changeset
261 fcntl.flock(file, fcntl.LOCK_UN)
20c8ec56e447 logfile: Pull logfile thread out of Logger.
Paul Fisher <paul@pfish.zone>
parents: 21
diff changeset
262
20c8ec56e447 logfile: Pull logfile thread out of Logger.
Paul Fisher <paul@pfish.zone>
parents: 21
diff changeset
263
20c8ec56e447 logfile: Pull logfile thread out of Logger.
Paul Fisher <paul@pfish.zone>
parents: 21
diff changeset
264 def _size(file: t.BinaryIO) -> int:
20c8ec56e447 logfile: Pull logfile thread out of Logger.
Paul Fisher <paul@pfish.zone>
parents: 21
diff changeset
265 return os.stat(file.fileno()).st_size
20c8ec56e447 logfile: Pull logfile thread out of Logger.
Paul Fisher <paul@pfish.zone>
parents: 21
diff changeset
266
21
beb42c835c52 Make weather server handle arbitrary data:
Paul Fisher <paul@pfish.zone>
parents: 0
diff changeset
267
31
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
268 T = t.TypeVar('T')
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
269
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
270
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
271 @attr.s(auto_attribs=True, frozen=True, slots=True)
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
272 class IndexEntry:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
273 entry_count: int
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
274 entry_key: object
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
275 byte: int
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
276
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
277 @classmethod
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
278 def from_dict(cls: t.Type[T], d: t.Dict[str, t.Any]) -> T:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
279 return cls(**{f.name: d[f.name] for f in attr.fields(cls)})
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
280
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
281 def to_dict(self) -> t.Dict[str, object]:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
282 return attr.asdict(self, recurse=False)
21
beb42c835c52 Make weather server handle arbitrary data:
Paul Fisher <paul@pfish.zone>
parents: 0
diff changeset
283
0
efe7a1eff167 Create initial logger for weather server.
Paul Fisher <paul@pfish.zone>
parents:
diff changeset
284
efe7a1eff167 Create initial logger for weather server.
Paul Fisher <paul@pfish.zone>
parents:
diff changeset
285 def _open_or_create(path: str) -> t.BinaryIO:
efe7a1eff167 Create initial logger for weather server.
Paul Fisher <paul@pfish.zone>
parents:
diff changeset
286 while True:
efe7a1eff167 Create initial logger for weather server.
Paul Fisher <paul@pfish.zone>
parents:
diff changeset
287 try:
efe7a1eff167 Create initial logger for weather server.
Paul Fisher <paul@pfish.zone>
parents:
diff changeset
288 return open(path, 'r+b')
efe7a1eff167 Create initial logger for weather server.
Paul Fisher <paul@pfish.zone>
parents:
diff changeset
289 except FileNotFoundError:
efe7a1eff167 Create initial logger for weather server.
Paul Fisher <paul@pfish.zone>
parents:
diff changeset
290 pass
efe7a1eff167 Create initial logger for weather server.
Paul Fisher <paul@pfish.zone>
parents:
diff changeset
291 try:
efe7a1eff167 Create initial logger for weather server.
Paul Fisher <paul@pfish.zone>
parents:
diff changeset
292 return open(path, 'x+b')
efe7a1eff167 Create initial logger for weather server.
Paul Fisher <paul@pfish.zone>
parents:
diff changeset
293 except FileExistsError:
efe7a1eff167 Create initial logger for weather server.
Paul Fisher <paul@pfish.zone>
parents:
diff changeset
294 pass
31
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
295
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
296
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
297 def _dup_file(file: t.BinaryIO) -> t.BinaryIO:
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
298 duplicate = os.dup(file.fileno())
9bc3687e1e5e logfile: Add an index, and don't keep everything in RAM.
Paul Fisher <paul@pfish.zone>
parents: 24
diff changeset
299 return os.fdopen(duplicate, 'r+b')