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lognestmonster / 6511286

A general-purpose single-header C logging library and parser for event-based logs. (Incomplete)

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12817 Nov 2019 17:0613604edBring updates to presentJosh Stockin144N

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1# lognestmonster Copyright (c) 2019 Joshua 'joshuas3' Stockin
2# <https://github.com/JoshuaS3/lognestmonster/>.
3
4
5# This file is part of lognestmonster.
6
7# lognestmonster is free software: you can redistribute it and/or modify
8# it under the terms of the GNU General Public License as published by
9# the Free Software Foundation, either version 3 of the License, or
10# (at your option) any later version.
11
12# lognestmonster is distributed in the hope that it will be useful,
13# but WITHOUT ANY WARRANTY; without even the implied warranty of
14# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15# GNU General Public License for more details.
16
17# You should have received a copy of the GNU General Public License
18# along with lognestmonster. If not, see <https://www.gnu.org/licenses/>.
19
20import struct
21import os
22
23STATEMENT_START = 0
24STATEMENT_END = 1
25EVENT_START = 2
26EVENT_END = 3
27
28VERBOSITY_LEVELS = {
29 0: "INIT",
30 1: "DEBUG",
31 2: "VERBOSE",
32 3: "VERYVERBOSE",
33 4: "WARNING",
34 5: "ERROR"
35}
36
37def ulonglong(bytestr):
38 return struct.unpack("@Q", bytestr)[0]
39def uchar(charv):
40 return struct.unpack("@B", charv)[0]
41def ushort(shortv):
42 return struct.unpack("@H", shortv)[0]
43
44
45class EventProto:
46 parent = None
47 pushed = [False]
48 def __init__(self):
49 self.parent = None
50 self.pushed = [False]
51
52class Reader:
53 fd = None
54
55 top_level = []
56
57 current_event = None
58
59 event_count = 0
60 statement_count = 0
61
62 total_events = 0
63 total_statements = 0
64
65 seekable = True
66 file_size = 0
67 position = 0
68
69 version = 0
70 timestamp = 0
71
72 bad_bytes = 0
73
74 filter_time_start = -1
75 filter_time_end = -1
76 filter_verbosity = -1
77 filter_tag = -1
78
79 update_callbacks = []
80
81 def __init__(self, fd, seekable=True):
82 self.fd = fd
83
84 self.top_level = []
85
86 self.current_event = None
87
88 self.event_count = 0
89 self.statement_count = 0
90
91 self.total_events = 0
92 self.total_statements = 0
93
94 self.seekable = seekable
95 self.file_size = 0
96 self.position = 0
97
98 self.version = 0
99 self.timestamp = 0
100
101 self.bad_bytes = 0
102
103 self.filters = False
104
105 self.filter_time_start = -1
106 self.filter_time_end = -1
107 self.filter_verbosity = -1
108 self.filter_tag = -1
109
110 self.update_callbacks = []
111
112 def update(self):
113 for callback in self.update_callbacks:
114 callback()
115
116 def onupdate(self, callback):
117 self.update_callbacks.append(callback)
118
119 def size(self):
120 self.fd.seek(0, os.SEEK_END) # go to end of file and get position
121 newsize = self.fd.tell()
122 self.fd.seek(self.position) # return to previous position
123
124 is_diff = self.file_size is not newsize
125 self.file_size = newsize
126 return is_diff
127
128 def pos(self):
129 p = self.fd.tell()
130 self.position = p
131 return p
132
133 def seek(self, position):
134 self.position = position
135 self.fd.seek(self.position)
136
137 def read(self, byte_count):
138 return self.fd.read(byte_count)
139
140 def fetch_item(self, position):
141 previouspos = self.pos()
142 self.seek(position)
143 timestamp = ulonglong(self.read(8))
144 verbosity = uchar(self.read(1))
145 tag_size = uchar(self.read(1))
146 tag = self.read(tag_size).decode("utf-8")
147 message_size = ushort(self.read(2))
148 message = self.read(message_size).decode("utf-8")
149 self.seek(previouspos)
150 return (timestamp, verbosity, tag, message)
151
152 def parse_block(self, in_byte):
153 seekable = self.seekable
154 if in_byte == STATEMENT_START: # the byte indicates a statement's start, begin interpreting
155 if seekable:
156 this_position = self.pos() # identify and save the seeker position of this statement
157
158 try:
159 block = self.read(10)
160 timestamp = ulonglong(block[:8]) # bytes 1-8
161 verbosity = block[8] # byte 9
162 tag = self.read(block[9]) # byte 10
163
164 append = True
165
166 if self.filters:
167 if self.filter_time_start is not -1 and append:
168 append = timestamp > self.filter_time_start
169
170 if self.filter_time_end is not -1 and append:
171 append = timestamp < self.filter_time_end
172
173 if self.filter_verbosity is not -1 and append:
174 append = verbosity in self.filter_verbosity
175
176 if self.filter_tag is not -1 and append:
177 tag = tag.decode("utf-8")
178 append = tag == self.filter_tag
179
180 message_size = ushort(self.read(2))
181 if seekable:
182 self.read(message_size)
183 while self.read(1)[0] is not STATEMENT_END and self.pos() < self.file_size:
184 self.bad_bytes += 1
185 else:
186 message = self.read(message_size).decode("utf-8")
187 while self.read(1)[0] is not STATEMENT_END:
188 self.bad_bytes += 1
189
190 if append == True:
191 self.statement_count += 1
192 if self.current_event is not None:
193 if seekable:
194 self.current_event.pushed.append(this_position)
195 else:
196 self.current_event.pushed.append((timestamp, verbosity, tag, message))
197 else:
198 if seekable:
199 self.top_level.append(this_position)
200 else:
201 self.top_level.append((timestamp, verbosity, tag, message))
202 self.total_statements += 1
203 except:
204 return -1
205
206 elif in_byte == EVENT_START: # the byte indicates an event's start, create an event
207 new_event = EventProto()
208 if self.current_event is not None: # we're already inside an event, set the new event's parent to match
209 new_event.parent = self.current_event
210 self.current_event = new_event
211
212
213 elif in_byte == EVENT_END: # end of event
214 if self.current_event is not None:
215 if len(self.current_event.pushed) > 1:
216 self.event_count += 1
217 if self.current_event.parent is not None:
218 self.current_event.parent.pushed.append(self.current_event)
219 self.current_event = self.current_event.parent
220 else:
221 self.top_level.append(self.current_event)
222 self.current_event = None
223 else: # event is empty
224 if self.current_event.parent is not None:
225 self.current_event = self.current_event.parent
226 else:
227 self.current_event = None
228 self.total_events += 1
229 else:
230 self.bad_bytes += 1 # event doesn't exist, bad byte
231 return -1
232
233 else: # unknown byte
234 self.bad_bytes += 1
235 return -1
236
237 def scan(self): # scan for events and statements from self.position to the end of file
238 if not self.seekable: raise Exception("attempting to scan non-seekable stream")
239 if self.pos() == 0: # if it's the start of the file, grab version and timestamp
240 self.version = self.read(1)[0]
241 self.timestamp = ulonglong(self.read(8))
242
243 while self.pos() < self.file_size: # while the seeker is before EOF
244 in_byte = self.read(1)[0] # read 1 byte
245 self.parse_block(in_byte) # parse block based on byte read
246 self.update() # trigger callbacks
247
248