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simpletrace: improve parsing of sys.argv; fix files never closed.

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The arguments extracted from `sys.argv` named and unpacked to make it
clear what the arguments are and what they're used for.

The two input files were opened, but never explicitly closed. File usage
changed to use `with` statement to take care of this. At the same time,
ownership of the file-object is moved up to `run` function. Added option
to process to support file-like objects.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Mads Ynddal <m.ynddal@samsung.com>
Message-id: 20230926103436.25700-4-mads@ynddal.dk
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Mads Ynddal 2023-09-26 12:34:25 +02:00 committed by Stefan Hajnoczi
parent 8405ec6ab6
commit f7bd4f0237
1 changed files with 33 additions and 15 deletions
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48
scripts/simpletrace.py
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@ -9,6 +9,7 @@
# #
# For help see docs/devel/tracing.rst # For help see docs/devel/tracing.rst
import sys
import struct import struct
import inspect import inspect
from tracetool import read_events, Event from tracetool import read_events, Event
@ -51,7 +52,6 @@ def get_record(edict, idtoname, rechdr, fobj):
try: try:
event = edict[name] event = edict[name]
except KeyError as e: except KeyError as e:
import sys
sys.stderr.write('%s event is logged but is not declared ' \ sys.stderr.write('%s event is logged but is not declared ' \
'in the trace events file, try using ' \ 'in the trace events file, try using ' \
'trace-events-all instead.\n' % str(e)) 'trace-events-all instead.\n' % str(e))
@ -172,11 +172,28 @@ class Analyzer(object):
pass pass
def process(events, log, analyzer, read_header=True): def process(events, log, analyzer, read_header=True):
"""Invoke an analyzer on each event in a log.""" """Invoke an analyzer on each event in a log.
Args:
events (file-object or list or str): events list or file-like object or file path as str to read event data from
log (file-object or str): file-like object or file path as str to read log data from
analyzer (Analyzer): Instance of Analyzer to interpret the event data
read_header (bool, optional): Whether to read header data from the log data. Defaults to True.
"""
if isinstance(events, str): if isinstance(events, str):
events = read_events(open(events, 'r'), events) with open(events, 'r') as f:
events_list = read_events(f, events)
elif isinstance(events, list):
# Treat as a list of events already produced by tracetool.read_events
events_list = events
else:
# Treat as an already opened file-object
events_list = read_events(events, events.name)
close_log = False
if isinstance(log, str): if isinstance(log, str):
log = open(log, 'rb') log = open(log, 'rb')
close_log = True
if read_header: if read_header:
read_trace_header(log) read_trace_header(log)
@ -187,12 +204,12 @@ def process(events, log, analyzer, read_header=True):
edict = {"dropped": dropped_event} edict = {"dropped": dropped_event}
idtoname = {dropped_event_id: "dropped"} idtoname = {dropped_event_id: "dropped"}
for event in events: for event in events_list:
edict[event.name] = event edict[event.name] = event
# If there is no header assume event ID mapping matches events list # If there is no header assume event ID mapping matches events list
if not read_header: if not read_header:
for event_id, event in enumerate(events): for event_id, event in enumerate(events_list):
idtoname[event_id] = event.name idtoname[event_id] = event.name
def build_fn(analyzer, event): def build_fn(analyzer, event):
@ -225,24 +242,25 @@ def process(events, log, analyzer, read_header=True):
fn_cache[event_num](event, rec) fn_cache[event_num](event, rec)
analyzer.end() analyzer.end()
if close_log:
log.close()
def run(analyzer): def run(analyzer):
"""Execute an analyzer on a trace file given on the command-line. """Execute an analyzer on a trace file given on the command-line.
This function is useful as a driver for simple analysis scripts. More This function is useful as a driver for simple analysis scripts. More
advanced scripts will want to call process() instead.""" advanced scripts will want to call process() instead."""
import sys
read_header = True try:
if len(sys.argv) == 4 and sys.argv[1] == '--no-header': # NOTE: See built-in `argparse` module for a more robust cli interface
read_header = False *no_header, trace_event_path, trace_file_path = sys.argv[1:]
del sys.argv[1] assert no_header == [] or no_header == ['--no-header'], 'Invalid no-header argument'
elif len(sys.argv) != 3: except (AssertionError, ValueError):
sys.stderr.write('usage: %s [--no-header] <trace-events> ' \ sys.stderr.write(f'usage: {sys.argv[0]} [--no-header] <trace-events> <trace-file>\n')
'<trace-file>\n' % sys.argv[0])
sys.exit(1) sys.exit(1)
events = read_events(open(sys.argv[1], 'r'), sys.argv[1]) with open(trace_event_path, 'r') as events_fobj, open(trace_file_path, 'rb') as log_fobj:
process(events, sys.argv[2], analyzer, read_header=read_header) process(events_fobj, log_fobj, analyzer, read_header=not no_header)
if __name__ == '__main__': if __name__ == '__main__':
class Formatter(Analyzer): class Formatter(Analyzer):